Motor Learning Terms of the Day

motor forgetting Skill decay, or decreased speed and accuracy for the task. Two major theories on forgetting, including motor forgetting or skill decay, are 1) trace decay (decay of the memory trace) due to lack of practice, whether this lack of practice takes place in good health or due to illness or injury, and 2) trace decay subsequent to an interference effect. A memory trace is a group of neurons, interconnected and encoded for specific memories, including motor memories.

interference theory A theory that forgetting is caused by interference from other learned information/experiences. In the 1995 paper by Neifert, Lawrence, and Seacat, “Nipple Confusion: Toward a Formal Definition”, the authors discuss interference as a factor in observable breastfeeding difficulties that often follow an infant’s learning experience with an artificial nipple.

For an intensive discussion on motor learning and motor forgetting (skill decay) within the context of the primitive survival reflexes, please join us for our dynamic webinar, More Than Reflexes: Learning, Forgetting and Relearning Infant Breastfeeding Skills. 
www.morethanreflexes.org/webinars/

Three New Studies on Duration

From Sweden:

Open Access

Title: Breastfeeding and risk for ceasing in mothers of preterm infants—Long‐term follow‐up.

In: Maternal & Child Nutrition 2018 Oct; 14(4): e12618. doi: 10.1111/mcn.12618

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175451/pdf/MCN-14-na.pdf

Authors: Jenny Ericson, Mats Eriksson, Pat Hoddinott, Lena Hellström-Westas, Renée Flacking.

From the abstract:

KEY MESSAGES:

“Exclusive breastfeeding at discharge, higher maternal educational level, and shorter length of stay in the neonatal intensive care unit were factors associated with higher breastfeeding prevalence during the preterm infants' first year of life.

The results give insights on long‐term outcomes of breastfeeding in mothers who breastfed their preterm infants at discharge from the neonatal intensive care unit, where 64% of the infants were breastfed at 6 months.

Most infants were fed breast milk directly at the breast; few infants received expressed breast milk by bottle, tube, or cup.”

From Denmark:

Open Access

Title: The role of intention and self-efficacy on the association between breastfeeding of first and second child, a Danish cohort study.

In: BMC Pregnancy and Childbirth (BioMed Central Pregnancy and Childbirth) 2018 Nov 22;18(1):454. doi: 10.1186/s12884-018-2086-5.

https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-018-2086-5

Authors: Kronborg H, Foverskov E, Væth M, Mainburg RD.

From the abstract:

“BACKGROUND: The impact of parity on breastfeeding duration may be explained by physiological as well as psychosocial factors. The aim in the present study was to investigate the mediating influence of intention and self-efficacy on the association between the breastfeeding duration of the first and the following child. CONCLUSION: Due to a reinforcing effect of intention and self-efficacy, breastfeeding support should focus on helping the first time mothers to succeed as well as to identify the second time mother with low self-efficacy and additional need for support.”

From Iran:

Open Access

Title: The Association between Household Socioeconomic Status, Breastfeeding, and Infants' Anthropometric Indices.

In: International Journal of Preventive Medicine 2018 Oct 12;9:89. doi: 10.4103/ijpvm.IJPVM_52_17. eCollection 2018.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6202780/

Authors: Ajami M, Abdollahi M, Salehi F, Oldewage-Theron W, Jamshidi-Naeini Y.

From the abstract:

“BACKGROUND: The growth, learning, and contribution to active life in the communities are better in well-nourished children, and various factors influence infants' feeding. In this study, we assessed whether household socioeconomic status (SES) affects infants' length-for-age, weight-for-age (indicators of health and nutritional status) and breastfeeding (BF) (a necessity for optimal growth and health) status. CONCLUSIONS: Nutritional status, duration of BF, and EBF might be determined by household SES and maternal education. Therefore, these findings can be used to decide how to focus on appropriate target groups in family education planning to improve children's development to its most possible.”

Three New Studies

From Germany:

Open access

Title: Intranasal breast milk for premature infants with severe intraventricular hemorrhage - an observation.

In: European Journal of Pediatrics 2018 Nov 1. doi: 10.1007/s00431-018-3279-7.

https://link.springer.com/article/10.1007%2Fs00431-018-3279-7

Authors: Keller T, Körber F, Oberthuer A, Schafmeyer L, Mehler K, Kuhr K, Kribs A.

Abstract: "For nasal application of neurotrophins and mesenchymal stem cells, successful delivery to the brain and therapeutic effects are known from experimental data in animals. Human breast milk contains neurotrophins and stem cells, but gavage tube feeding in preterm infants bypasses the naso-oropharynx. This is a first exploration on additional nasal breast milk and neuromorphological outcome after severe neonatal brain injury. We present a retrospective summary of 31 very low birth weight preterm infants with intraventricular hemorrhage °3/4 from one third-level neonatal center. All were breast milk fed. Sixteen infants additionally received nasal drops of fresh breast milk daily with informed parental consent for at least 28 days. Cerebral ultrasound courses were reviewed by a pediatric radiologist blinded to the intervention. The main outcome measure was severity of porencephalic defects before discharge. Clinical covariates were comparable in both groups. With nasal breast milk, a trend to a lower incidence for severe porencephalic defects (21% vs. 58%) was detected. Incidences were lower for progressive ventricular dilatation (71% vs. 91%) and surgery for posthemorrhagic hydrocephalus (50% vs. 67%). Conclusion: The hypothesis is generated that early intranasal application of breast milk could have a beneficial effect on neurodevelopment in preterm infants. Controlled investigation is needed. What is Known: • Successful delivery to the brain and therapeutic effects are known for nasal application of neurotrophins and mesenchymal stem cells from experimental data in animal studies. • Human breast milk contains neurotrophins and stem cells, but gavage tube feeding in preterm infants bypasses the naso-oropharynx. What is New: • This is the first report on additional nasal breast milk application in very low birth weight preterm infants with severe brain injury observing a trend for less severe porencephalic defects. • The hypothesis is generated that nasal breast milk might exert neuroprotective effects in preterm infants."

From The Netherlands:

Title: Relationship between socioeconomic status and weight gain during infancy: The BeeBOFT study.

In: PLoS One. 2018 Nov 2;13(11):e0205734. doi: 10.1371/journal.pone.0205734. eCollection 2018.

Authors: Wang L, van Grieken A, Yang-Huang J, Vlasblom E, L'Hoir MP, Boere-Boonekamp MM, Raat H.

https://mhealth.jmir.org/2018/10/e11039/

Abstract: "BACKGROUND: Increased weight gain during infancy is a risk factor for obesity and related diseases in later life. The aim of the present study was to investigate the association between socioeconomic status (SES) and weight gain during infancy, and to identify the factors mediating the association between SES and infant weight gain. METHODS: Subjects were 2513 parent-child dyads participating in a cluster randomized controlled intervention study. Family SES was indexed by maternal education level. Weight gain in different time windows (infant age 0-3, 0-6, and 6-12 months) was calculated by subtracting the weight for age z-score (WAZ) between the two time-points. Path analysis was performed to examine the mediating pathways linking SES and infant weight gain. RESULTS: On average, infants of low-educated mothers had a lower birth weight and caught-up at approximately 6 months. In the period of 0-6 months, infants with low-educated mothers had an 0.42 (95% CI 0.27-0.57) higher gain in weight for age z-score compared to children with high-educated mothers. The association between maternal education level and increased infant weight gain in the period of 0-6 months can be explained by infant birth weight, gestational age at child birth, duration of breastfeeding, and age at introduction of complementary foods. After adjusting all the mediating factors, there was no association between maternal education level and infant weight gain. CONCLUSION: Infants with lower SES had an increased weight gain during the first 6 months of infancy, and the effect can be explained by infant birth weight, gestational age at child birth, and infant feeding practices.”

From China:

Open access

Title: A Short Message Service Intervention for Improving Infant Feeding Practices in Shanghai, China: Planning, Implementation, and Process Evaluation.

In: JMIR Mhealth Uhealth 2018 Oct 29;6(10):e11039. doi: 10.2196/11039.

Authors: Jiang H, Li M, Wen L, Baur LA, He G, Ma X, Qian X.

https://mhealth.jmir.org/2018/10/e11039/

Abstract: "BACKGROUND: Although mobile health (mHealth) has been widely applied in health care services, few studies have reported the detailed process of the development and implementation of text messaging (short message service, SMS) interventions. OBJECTIVE: Our study aims to demonstrate the process and lessons learned from a community-based text messaging (SMS) intervention for improving infant feeding in Shanghai, China. METHODS: The intervention included planning and development, implementation, and process evaluation. A 3-phase process was adopted during planning and development: (1) a formative study with expectant and new mothers to explore the barriers of appropriate infant feeding practices; (2) a baseline questionnaire survey to understand potential intervention approaches; and (3) development of the text message bank. The text messaging intervention was delivered via a computer-based platform. A message bank was established before the start of the intervention containing information on the benefits of breastfeeding, preparing for breastfeeding, early initiation of breastfeeding, timely introduction of complementary foods, and establishing appropriate feeding practices, etc. An expert advisory committee oversaw the content and quality of the message bank. Process evaluation was conducted through field records and qualitative interviews with participating mothers. RESULTS: We found that the text messaging intervention was feasible and well received by mothers because of its easy and flexible access. The weekly based message frequency was thought to be appropriate, and the contents were anticipatory and trustworthy. Some mothers had high expectations for timely response to inquiries. Occasionally, the text messages were not delivered due to unstable telecommunication transmission. Mothers suggested that the messages could be more personalized. CONCLUSIONS: This study demonstrates the feasibility and value of text messaging intervention in filling gaps in delivering health care services and promoting healthy infant feeding practices in settings where personal contact is limited."

A Free CME/CE from Medscape: How Does Marijuana Use Affect Lactating Mothers?

Medscape is offering a free 0.25 CME/CE on a new lactation topic (newly released on Medscape on October 19, 2018).

Title: How Does Marijuana Use Affect Lactating Mothers?

One study cited in this short continuing ed module is the new study by Bertrand and colleagues in the journal, Pediatrics: "Marijuana use by breastfeeding mothers and cannabinoid concentrations in breast milk." Pediatrics 2018;142. http://pediatrics.aappublications.org/conte…/142/3/e20181076.

A current clinical report from the AAP on the use of cannabinoids during pregnancy and lactation is also discussed. Ryan SA, Ammerman SD, O'Connor ME; COMMITTEE ON SUBSTANCE USE AND PREVENTION; SECTION ON BREASTFEEDING. Marijuana use during pregnancy and breastfeeding: implications for neonatal and childhood outcomes. Pediatrics. 2018;142. http://pediatrics.aappublications.org/…/08/23/peds.2018-1889.

This continuing education topic and many others are available at no cost on Medscape. http://www.medscape.org

A U.S. Senator and Mother Speaks Out in Support of Family Reunification

U.S. Senator Tammy Duckworth, a nursing mother, speaking at a Washington, D.C. protest today in support of family reunification:  "I wanted to show my support for the folks here today. I could only imagine what it would be like to have my daughter — my breastfeeding child — ripped away from me the way some of these other moms’ babies have been."  http://thehill.com/blogs/blog-briefing-room/news/394723-duckworth-joins-womens-capitol-protest-with-baby

Families Belong Together: USLCA Statement on Family Reunification

I send deep gratitude to the United States Lactation Consultant Association for speaking out on the immediate need for family reunification following the forced separation of infants and children from their parents at the U.S. border.  This is the USLCA Statement on Family Reunification: 

In solidarity with thousands of individuals and many organizations across the United States of America and the world, the U.S. Lactation Consultant Association calls on lawmakers to end immediately the forced separation of children from their parents at the U.S. border. This unnecessary practice is harmful to both adults and their children, and no justification for this practice should be prioritized above the health and well-being of human beings.

As International Board-Certified Lactation Consultants (IBCLCs), we work daily alongside many more breastfeeding advocates and providers of health care to support and ensure optimal health of pregnant people, parents, infants, children, and the general public through education about and assistance with breastfeeding. The IBCLC is an expert in infant feeding and is responsible to uphold scientific, evidence-informed theory and practice that is free from conflict of interest, be it financial, academic, personal, political, or otherwise.

Separation of children from their parents creates barriers to breastfeeding and safe infant feeding, and to our knowledge, no IBCLCs have been contacted with regard to how to appropriately feed infants away from their parents, to support and protect continued lactation in lactating persons who do not have access to their children for breastfeeding, or any general information about infant and young child feeding in national emergencies, natural disasters, or humanitarian crises. It is critical to understand that globally, children breastfeed far beyond infancy and that this practice is important to the health of families and the general public. The abrupt removal of the opportunity to be breastfed or to express breast milk has serious health consequences for infants, toddlers, and their lactating parents, and USLCA firmly opposes this practice in all circumstances. In addition, all major health organizations with policies about infant feeding call for the use of pasteurized donor human milk in all situations where their own parent’s milk is not available; the use of safely prepared infant formula for all children under the age of 12 months is only recommended when neither their own parent’s milk nor pasteurized donor human milk are available.

USLCA calls for the immediate and rapid reunification of families who have been separated from each other, as well as the provision of appropriate health care and support for all persons who have been directly affected by the practice of forced separation. This includes comprehensive health consultation for all facets of physiological and mental health, as well as support for resuming breastfeeding, milk expression, and education and support to ensure safe infant and young child feeding.

Queries

In your entire professional experience in healthcare, have you ever advised a bottle-feeding family to alternate different styles of artificial nipples that differ in contour, diameter, length, and/or texture from one feeding to the next or from one day to the next, from week to week, or even on a month-to-month basis, particularly during the infant’s early skill acquisition for bottle-feeding skills?  

In your entire professional experience, have you ever observed such infant feeding advice being given to a family by a physician or nurse? 

If you are a parent who has bottle-fed your infant, have you ever received such professional advice for feeding your infant? 

Have you ever received such advice from family members or friends? 

In regard to the use of a pacifier/soother/dummy, have you ever given or received professional advice to switch pacifier styles from one use to another over the course of a day or from day to day, week to week, or from month to month?  Have you ever received such advice from family members or friends?   

I wholly support The Ten Steps to Successful Breastfeeding, although this post is primarily focused on bottle-fed infants who may be receiving all mother's milk in a bottle, human donor milk by bottle, artificial infant milk by bottle, or a mixture of any of these milks via bottle.  In my long career as a registered nurse and IBCLC, not once have I heard such switching advice given to bottle-feeding families and/or to families who are giving pacifiers/soothers/dummies to their infants. 

What I have occasionally overheard while passing through a hospital’s well-baby nursery or a neonatal intensive care unit (NICU) is an outgoing nurse giving report to an incoming nurse during shift change, stating that Baby Jones “does better” with a particular type of artificial nipple.  Although hospitals do not stock a wide variety of artificial nipples, typically there are at least two to 3 styles of artificial nipples for the nursing staff's selection.   

The departing nurse intends that both the incoming nurse and her small patient will benefit from her observations of how her infant patient fed during her shift.  We can interpret the departing nurse’s phrase, “does better,” as a reference to the infant’s motor learning for the oral grasp of a particular artificial nipple, as well as motor learning for effective suckling toward adequate transfer of milk, all while learning how to coordinate suck and swallow with breathing.  “Does better” infers that with consistent practice that is specific to the task, the infant's family, as well as the nursing staff, can expect to observe greater speed and accuracy by the infant for the oral grasp of the artificial nipple, as well as greater motor control for milk transfer from the bottle.  Motor learning is a complex process, and the healthy term infant who is bottle-fed will gradually build robust motor memory for bottle-feeding skills that are associated with a specific design of an artificial nipple, and there may be learning that is specific to the design of a bottle as well.   

Step 9 of the Ten Steps to Successful Breastfeeding reflects the basic need for the newborn to have frequent and consistent task-specific practice for learning breastfeeding skills, toward gradually building robust motor memory for these skills.       

When a six-month-old infant begins to learn drinking skills from a sippee-cup, we often intuitively give the same style of sippee cup to the baby day after day, in order to provide task-specific practice sessions in sippee-cup drinking.  If we were to offer alternating styles of sippee cups from one day to the next, we would surely observe the infant’s difficulties in task-switching from one style of sippee cup to another.    

A key aspect of our executive functions is our cognitive flexibility, the ability to adapt our thinking and/or behavior in response to changes in the environment.  In the developmental sciences, there is a well-known developmental progression for our cognitive flexibility: 

We possess the least cognitive flexibility in infancy.

We display more cognitive flexibility in childhood than in infancy. 

We display even greater cognitive flexibility in adolescence. 

We possess still greater cognitive flexibility in adulthood, although task-switching often results in decreased speed and/or accuracy for the task, regardless of age.  Consider the expected miserable experience for the serious golfer who forgets her clubs and must use a loaner set in order to participate in a scheduled game or tournament.  

Task-switching is heavily studied in the cognitive sciences, as are the switch costs of decreased speed and accuracy that often occur during task-switching.  Measurement parameters include reaction time (RT), the interval between the presentation of a stimulus and the initiation of a response; movement time (MT), the interval between the initiation of a movement and its completion or termination; response time, the interval from the presentation of a stimulus to the completion of a movement (the sum of reaction time and movement time); and inhibition of return (IOR), the delay in responding to the previously cued (or orienting) stimulus. 

Today’s PubMed search using the term “task-switching” yielded 1,384 search results.  Note that when using the search term “task switching” without a hyphen between “task” and “switching,” the yield is nearly three-fold at 3,018 search results.  

The first of the below publications is a well-known 2005 study from Adele Diamond and Natasha Kirkham on task switching and cognitive flexibility, followed by one new study and one new review paper by Kirkham and colleagues: 

1)     Title: Not Quite As Grown-Up As We Like To Think:  Parallels Between Childhood and Adulthood

Authors: Adele Diamond, Natasha Kirkham.

In:  Psychological Science 2005 Apr;16(4):291-297.  doi.10.1111/j.0956-7976.2005.01530.x

 

2)    Title:  Incidental Category Learning and Cognitive Load in a Multisensory Environment Across Childhood

Authors:  H.J. Broadbent, T. Osborne, M. Rea, A. Peng, D. Mareschal, N.Z. Kirkham.

In:  Developmental Psychology 2018; 54(6), 1020-1028.

http://dx.doi.org/10.1037/dev0000472

 

3)    Title:  Infant Statistical Learning

Authors:  Jenny R. Saffran and Natasha Z. Kirkham

In:  Annual Reviews in Psychology 2018 January 04;69:181-203. 

http://www.doi:10.1146/annurev-psych-122216-011805

 

Three Motor Learning Terms of the Day

Motor program:  Abstract representation that, when initiated, results in the production of a coordinated movement sequence. 

Gearshift analogy:  An idea about the learning of motor programs, analogous to learning to shift gears in an automobile.

Sequencing:  An invariant feature of motor programs in which the order of elements is fixed. 

Critical Aspects of Task-Specific Practice and the Home Field Advantage

Nearly all forms of early memory are fragile, with examples of learning the alphabet or a new language, learning a new telephone number or a new computer password, or building motor memory for new motor skills.  To build robust memory, the repetition of task-specific practice is critical. 

At birth, the presence of the primitive survival reflexes hastens our learning for milk-feeding skills in support of our survival.  When a breastfed infant is given a learning experience with an artificial nipple, the fragility of early motor memory is often on display for the infant's oral grasp of the nipple-areolar complex and/or effective suckling, i.e., the primitive survival reflexes are not equally weighted for all infant milk-feeding movements all the time, and a recency effect is often observed for the more recently learned milk-feeding method.  Similarly, when an exclusively bottle-fed infant is given a learning experience with a different style of artificial nipple, immediate task-switching ability by the infant for the oral grasp of the novel artificial nipple, followed by a prompt and competent return to the original artificial nipple is not at all expected.    

In the cognitive sciences, there is a well-known developmental progression of our cognitive flexibility for switching back and forth between tasks.  Cognitive flexibility is most limited in the young, and the younger we are, the more limited our cognitive flexibility.   Children display greater cognitive flexibility than infants, and adolescents display greater cognitive flexibility than children.  Adults possess greatest cognitive flexibility, yet task-switching is often complex and demanding in adulthood as well. 

Another tenet from the field of motor learning: The greater the difficulty of the task, the greater the need for practice that is specific to the task.  A timely example of the critical need for task-specific practice will be in evidence in the U.S. tonight during Game 2 of the National Basketball Association (NBA) finals between the Cleveland Cavaliers and the Golden State Warriors.  These elite athletes will never rehearse for competition with a novel basketball that differs in diameter, texture, weight, and/or bounce, followed by a sudden switch to a regulation-sized basketball for the fierce competition against their opponents.  Furthermore, such a poor and unthinkable practice strategy is never recommended by the teams' coaches.  As it is, these elite players must contend with environmental constraints in regard to changes in their visual field when they are not playing on their home court, and numerous formal studies have indeed shown a home court advantage (1).  

When infants present with a recessed chin, tethered oral tissues, or cleft lip, for example, the task of learning the oral grasp at the breast and/or effective suckling may be more challenging for the infant.  In the field of motor learning, such potential learning challenges are referred to as individual constraintsTask constraints may also be present, such as retracting nipple anatomy; and/or flat nipple anatomy that is not readily protractile; and/or inverted nipple anatomy; and/or and breast engorgement.  These anatomical variations may also present temporary and transient challenges, moderate challenges, or more prolonged challenges for the infant who is learning the oral grasp and/or effective suckling at the breast. 

The above-mentioned tenet is also applicable to newborns who are learning their first feeding skills, in that the greater the difficulty of the task, the greater the need for practice that is specific to the task, i.e., it is particularly important that artificial nipples are avoided in the presence of any possible learning constraints.  This is not at all to say that artificial nipples should be offered to breastfed infants in the absence of any possible learning constraints, nor should it be said that exclusively bottle-fed infants should receive alternating learning experiences with different styles of artificial nipples, regardless of whether possible learning constraints are present.  A reminder:  cognitive flexibility is most limited in the young, and the younger we are, the greater the limitations in our cognitive flexibility.  

The current widespread use of nipple shields in many childbearing settings in the U.S. often follows the infant's learning experience with an artificial nipple whether in non-Baby Friendly or Baby Friendly settings, even when an infant has initially learned the oral grasp at the breast, or when the infant is to become a breastfed infant but has not yet practiced feeding skills at the breast, having first learned bottle-feeding skills.  Until the baby has the opportunities to learn or relearn feeding skills at the breast, a "home field advantage" is a standard recommendation, i.e., the rich sensory milieu of the mother's chest is recommended for the infant via skin-to-skin contact.    

The frequent risks of task-switching are the well-known switch costs of decreased speed and accuracy for the task.  Measurement parameters of motor performance as well as task-switching and switch costs include reaction time (RT), movement time (MT), response time (reaction time + movement time = response time), and the inhibition of return (IOR), the delay in responding to the previously cued (or orienting) stimulus.  All of these parameters are measured in milliseconds (ms).  

Pronounced and prolonged individual constraints may include complete cleft of the lip and palate until surgical repair takes place.  In the absence of pronounced and prolonged learning constraints, many motor skills soon reach an elegant level of performance with effective practice that is specific to the task.  For the infant's acquisition of milk-feeding skills, the baby's increasing expertise is evidenced by the rapid oral grasp, as well as the baby's ability to consistently and effectively transfer adequate volumes of milk over increasingly shorter periods of time.  When the older baby is able to multi-task while nursing, such as reaching for his toes while feeding, or playing with a button on his mother's shirt while suckling, great heights in motor control have been reached.  Such an "elite" level of performance for an infant is not achieved overnight but requires months of practice, even in the absence of any possible learning constraints.   

1) Jamieson Jeremy P.  The Home Field Advantage in Athletics:  A Meta-Analysis.  Journal of Applied Social Psychology 9 July 2010.  https://doi.org/10.1111/j.1559-1816.2010.00641.x

 

New Study on the Interactive Influence of Oxytocin and Testosterone

A new open access study from Germany in the journal, Scientific Reports

Title:  Endogenous testosterone and exogenous oxytocin influence the response to baby schema in the female brain

Authors:  Sarah K. C. Holtfrerich, Roland Pfster, Alexander T. El Gammal, Eugen Bellon & Esther K. Diekhof

Abstract:  "Nurturing behavior may be critically influenced by the interplay of different hormones. The neuropeptide oxytocin is known to promote maternal behavior and its reduction has been associated with postpartum depression risk and child neglect. Contrariwise, the observed decrease in testosterone level during early parenthood may benefit caretaking behavior, whereas increased testosterone may reduce attention to infants. Here we used functional magnetic resonance imaging to investigate the interactive influence of testosterone and oxytocin on selective attention to and neural processing of the baby schema (BS). 57 nulliparous women performed a target detection task with human faces with varying degree of BS following double-blinded placebo-controlled oxytocin administration in a between-subjects design. Our results support the idea that oxytocin enhances attention to the BS. Oxytocin had a positive effect on activation of the inferior frontal junction during identification of infant targets with a high degree of BS that were presented among adult distractors. Further, activation of the putamen was positively correlated with selective attention to the BS, but only in women with high endogenous testosterone who received oxytocin. These findings provide initial evidence for the neural mechanism by which oxytocin may counteract the negative effects of testosterone in the modulation of nurturing behavior."

https://www.nature.com/articles/s41598-018-26020-4

New Study on Synthetic Oxytocin, Type of Birth, and Duration of Exclusive Breastfeeding

This new study from Spain has been published in the journal, Women and Birth.  Researchers looked at the use of synthetic oxytocin and the type of birth in regard to the duration of exclusive breastfeeding, finding that those in the group of planned cesarean birth (without oxytocin administration) had the highest risk of cessation of exclusive breastfeeding at all three intervals studied (1 month, 3 months, 6 months).  

Title:  Cessation of breastfeeding in association with oxytocin administration and type of birth

Authors:  Fernández-Cañadas Morillo A, Durán Duque M, Hernández López AB, Muriel Miguel C, Pérez Riveiro P, Salcedo Mariña A, Royuela Vicente A, Casillas Santana ML, Marín Gabriel MA

Abstract: 
"BACKGROUND: Some studies have suggested an association between synthetic oxytocin administration and type of birth with the initiation and consolidation of breastfeeding."

"AIM: This study aimed to test whether oxytocin administration and type of birth are associated with cessation of exclusive breastfeeding at different periods. A second objective was to investigate whether the administered oxytocin dose is associated with cessation of exclusive breastfeeding."

"METHODS: We conducted a prospective cohort study (n=529) in a tertiary hospital. Only full-term singleton pregnancies were included. Four groups were established based on the type of birth (vaginal or cesarean) and the intrapartum administration of oxytocin. Follow-up was performed to evaluate the consolidation of exclusive breastfeeding at 1, 3 and 6months."

"FINDINGS: During follow-up, the proportion of exclusive breastfeeding decreased in all groups. After adjusting for confounding variables, the group with cesarean birth without oxytocin (planned cesarean birth) had the highest risk of cessation of exclusive breastfeeding (odds ratio [95% confidence interval], 2.51 [1.53-4.12]). No association was found between the oxytocin dose administered during birth and puerperium period and the cessation of exclusive breastfeeding."

"CONCLUSION: Planned cesarean birth without oxytocin is associated with the cessation of exclusive breastfeeding at 1, 3 and 6months of life. It would be desirable to limit elective cesarean births to essentials as well as to give maximum support to encourage breastfeeding in this group of women. The dose of oxytocin given during birth and puerperium period is not associated with cessation of exclusive breastfeeding."

https://www.ncbi.nlm.nih.gov/pubmed/29754970

Dr. Alison Stuebe on Breastfeeding, Advocacy, and Women's Rights

Alison Stuebe MD MSc presented on this topic at the recent Breastfeeding Advocacy Collective (BAC) meeting in Toronto on May 9th.  Dr. Steube is a maternal-fetal medicine physician and president-elect of the Academy of Breastfeeding Medicine.  Dr. Stuebe's following blog post is adapted from her presentation at the recent BAC meeting.  

In June 2015, I heard a fantastic talk by Keith Hansen, Vice President for Human Development at the World BankGroup, at the Academy of Breastfeeding Medicine summit. Hansen spoke eloquently about the importance of breastfeeding for both global health and economic development; he said, “If breastfeeding did not already exist, someone who invented it today would deserve a dual Nobel Prize in medicine and economics.”

I’d brought my teenage son with me to Washington, and when we met up for lunch, I shared Hansen’s quote. He responded, “If breastfeeding were invented today, there would be an outrage, because of feminism.”

It took me a few seconds to fully process this response, as I began to consider the implications of a newly-discovered practice that would require one half of the population to engage in thousands of hours of unpaid work, at all hours of the day and night, for the greater good. There would, indeed, be an outrage. This disconnect between praise of breastfeeding and practicality of women’s lives is pervasive, and it is reflected in health promotion strategies. Posters list the ingredients of human milk vs. formula, celebrating the product of breast milk without acknowledging the process of breastfeeding.

Breastmilk is described as nature’s “most specific personalized medicine,” rather than celebrating breastfeeding as personalized nurturing. Even our public health goals aim to “increase the proportion of infants who are breastfed,” absenting the mother doing the breastfeeding from consideration. As a physician scientist, I know how easy it is to become fascinated by the science of human milk and the intricacies of oligosaccharides and the gut microbiome – but speaking of “milk as medicine” suggests a resource to be extracted from a passive mother, without regard to her bodily integrity or autonomy. As Benoit, Goldberg and Campbell-Yeo have written:

By placing breastfeeding focus on the biomedical and nutritional benefits of breastmilk, as opposed to maternal experience associated with nursing her infant, health care providers are perpetuating the patriarchal conceptualization of the ‘good mother’ as one who is defined as selflessly giving by nursing her child while asking for nothing in return.

Our excitement over the constituents of human milk reflects the reductionism of modern scientific research, in which the whole can best be understood by breaking it into its parts. And yet, doing so undermines the fundamental nurturing relationship between parent and child; as Van Esterik and O’Connor write in their critically important book, The Dance of Nurture, “Nurture is a relationship not a thing, and relationships cannot be reduced to their parts.”

Our focus on human milk constituents further fails to consider a growing body of evidence linking breastfeeding duration with maternal health. In reproductive physiology, lactation follows pregnancy, and when breastfeeding is disrupted, chronic disease burden for women increases. In observational studies that adjust for multiple confounders, shorter breastfeeding durations are associated with higher maternal risk of breast cancer, ovarian cancer, diabetes, hypertension and cardiovascular disease. Indeed, a recent cost analysis found that the health burden of suboptimal breastfeeding is far greater for mothers than for children. Policies that disrupt breastfeeding impair a woman’s lifelong health.

Given its importance in reproductive physiology and women’s health, breastfeeding is a woman’s reproductive right.  However, Judith Galtry notes that the Convention on the Elimination of Discrimination against Women (CEDAW) barely mentions breastfeeding. The absence of breastfeeding from the human rights discourse when CEDAW was written in the 1970s may reflect the influence of Western feminists who were focused on liberating women from responsibility for child-rearing. In this context, breastfeeding was a chain to be broken, rather than a right to be protected. As Galtry writes, “It did not always occur to policymakers and legislators that many women did not actually have the right to breastfeed.” This focus on “my right to not breastfeed” continues to dominate discussions among professional women in high-income countries, at the expense of recognizing that economic constraints prevent many marginalized women from breastfeeding, regardless of their personal preferences.

Framing breastfeeding as a woman’s right encourages us to address the relative costs and benefits of breastfeeding for each mother and baby. Tully and Ball note that a woman’s investment in sustained breastfeeding reflects tradeoffs, and lowering the personal cost of breastfeeding would support longer durations:

Van Esterik summarizes the need to address the costs to mothers in a 1981 essay on breastfeeding and women’s work:

Breastfeeding may be viewed by some feminists as the epitome of nurturant behavior – restrictive and unappealing, constraining an emancipated woman from employment possibilities. For these women, biologically determined functions may be devalued and, whenever possible, replaced by technological innovations such as bottlefeeding. A more radical feminist might argue instead for a restructuring of society to support women in their productive and reproductive lives.

What if we leveraged the importance of breastfeeding to restructure our society around each woman’s human right to nurture her children as she desires?

As defined by the Officer of the High Commissioner on Human Rights, “Human rights entail both rights and obligations. States assume obligations and duties under international law to respect, to protect and to fulfil human rights.” If breastfeeding is a woman’s right, then it is not sufficient to urge women to breastfeed – we must enact policies that respect, protect and fulfill that right. A human rights framework recognizes that breastfeeding is not a one-woman job – multiple social structures are essential to enable a woman to exercise her human right to nurture her child as she desires.  To that end, the Global Breastfeeding Collective has identified seven key strategies to enable mothers to achieve their infant feeding goals, including funding for breastfeeding support, implementing the WHO Code of Marketing, enacting paid family leave, implementing evidence-based maternity care, improving access to skilled support, strengthening links between health facilities and communities, and strengthening monitoring of processes and outcomes.

The collective has tracked country-level adherence to these recommendations with a Country Scorecard; to date, no country provides the minimum standard for support. Consider paid family leave: the standard for the Score Card is compliance with International Labor Organization conventions for at least 18 weeks of maternity leave and guarantees continuation of previous earnings paid out of compulsory social insurance or public funds. Slightly more than 10% of countries meet this standard; 90% of countries fail to address this fundamental barrier to a woman’s right to nurture her child.

Lack of paid leave is particularly egregious in the United States, where 23% of employed women return to paid work within 10 days of birth. Moreover, in 8 US states, single parent head-of-households with a newborn are not exempt from welfare work requirements. Women living in poverty are effectively punished for nurturing their children. As Burtle and Bezruchka have written:

The lack of policies substantially benefitting early life in the United States constitutes a grave social injustice: those who are already most disadvantaged in our society bear the greatest burden.

Given what we know about the importance of the first months of life for the health and wellbeing of mothers and infants, why haven’t we taken the necessary steps? In The Dance of Nurture, Van Esterik and O’Connor offer an explanation:

…we have not done the things that we need to do to support breastfeeding because these things conflict with deregulated capitalism and complacent consumerism.

Where to, then, from here? Do we conclude that modernity is inimical to breastfeeding, and rely on formula companies to provide “liberation in a can”? Or do we challenge societal structures that do not permit women to use their breasts and their brains at the same time? Feminist scholar Bernice Hausman writes:

Feminists …should be fighting for the right to breastfeed without social censure, loss of economic livelihood, or limitations on women’s freedom…Changing the bottle-feeding culture that we live in is a political enterprise than cannot be accomplished simply by advertising risks to replacement feeding or heralding the medicinal qualities of breast milk.

These are not new challenges, and these are not new ideas. In 1976, when I was 3 years old, Elisabet Helsing wrote:

In a world in which a female labour force is participating more and more, the peculiarities of this labour force have to be borne in mind. Until now, pregnancy and lactation have been strictly private enterprises, and society has not had to bother about how to cater to the newborn–that has always been regarded as the task of a woman… How can society adjust, so that she can remain useful to the society and simultaneously take the necessary care of her offspring?

Real liberation for women would not require us to choose between our professional and reproductive work. The current system incurs costs that reverberate across society by disrupting women’s participation in the paid work force. Indeed, a recent International Labor Organization / Gallup report found that balance between work and family is the number one challenge facing working women worldwide. Moreover, the report notes, “An ILO survey of 1,300 private-sector companies in 39 developing countries confirmed that family responsibilities borne by women was ranked as the No. 1 barrier to women’s leadership.” When societal constraints exclude women from participating in paid work, we all lose. As Gallup CEO Jim Clifton writes:

Our research also concludes that women have every bit as much game-changing talent as entrepreneurs and “builders” as do men. The problem is, millions of potential star women leaders are on the sidelines, and this isn’t good for organizations, societies or countries. Failing to maximize women’s talent to lead, manage and build stunts global economic growth and fails humankind.

It’s time for a feminist outrage that demands we restructure society to support women and men in their productive and reproductive lives. As Van Esterik wrote in 1994:

By enabling women to breastfeed we address women’s rights since the improvement of women’s social and economic status is necessary for supporting breastfeeding. Any violation of women’s right to breastfeed is a violation of women’s human rights.

Dr. Stuebe's entire blog post with graphics: https://bfmed.wordpress.com/2018/05/09/breastfeeding-advocacy-and-womens-rights/

Resources on Medications in Human Milk

Lactation consultants are often asked about the safety of various maternal medications during lactation, which is but one aspect of education and training for the International Board Certified Lactation Consultant (IBCLC).  Since the early 1990s, our profession has often referred to the invaluable text, Hale's Medications and Mothers' Milk by Thomas W. Hale RPh PhD, and on May 28th, the 19th edition of this important volume will be released.  Dr. Hale also founded the InfantRisk Center, which addresses maternal medications during lactation and more about infant health and wellbeing. 

Dr. Frank J. Nice offers the text, Nonprescription Drugs for the Breastfeeding Mother, now in its 2nd edition. 

The U.S. National Institutes of Health's Toxicology Database offers LactMed to professionals as well as the general public, and is another invaluable resource on drugs in human milk.  Most medications are compatible with breastfeeding, and in instances of a medication that is not compatible, an alternative medication is often safely prescribed.    

The website for the online version of Hale's Medications and Mothers' Milk by Dr. Thomas W. Hale RPh, PhD: https://www.medsmilk.com/

Kelly Bonyata's interview with Dr. Hale on her well-known website, KellyMom.com:   https://kellymom.com/bf/can-i-breastfeed/meds/interview-dr-hale/

Dr. Hale's website, the InfantRisk Center at Texas Tech University Health Sciences Center:   https://www.infantrisk.com/

Dr. Frank Nice's website:  https://nicebreastfeeding.com/

LactMed's website, part of the U.S. National Institutes of Health Toxicology Data Network:  https://toxnet.nlm.nih.gov/newtoxnet/lactmed.htm

 

New Study on Escitalopram (Lexapro) in Human Milk

A new study from Canada:  

Title:  Predicting Escitalopram Exposure to Breastfeeding Infants: Integrating Analytical and In Silico Techniques

Journal:  Clinical Pharmacokinetics

Authors:  Sarah R. Delaney, Paul R. V. Malik, Cristiana Stefan, Andrea N. Edginton, David A. Colantonio, Shinya Ito

Abstract: 
"Background: Escitalopram is used for post-partum depression; however, there are limited pharmacokinetic data of escitalopram in milk and plasma of infants breastfed by women taking the drug."

"Objective: The objective of this study was to apply physiologically-based pharmacokinetic (PBPK) modelling to predict infant drug exposure (plasma area under the curve from time zero to infinity [AUC∞]) based on drug monitoring data of escitalopram in breast milk."

"Methods: Using a newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, we quantified escitalopram concentrations in milk samples of 18 breastfeeding women with escitalopram therapy at steady state, collected at three to five time points. The escitalopram concentrations in breast milk were used with infant feeding parameters from the literature to simulate infant daily dose. We used PK-Sim® to develop an adult PBPK model for escitalopram and extrapolated it to a population of 1600 infants up to 12 months of age. An integration of the simulated infant daily dose and the virtual infants with variable physiological–pharmacological parameters was used to predict drug exposure (plasma AUC∞) distribution in the population of infants breastfed by women receiving escitalopram 20 mg/day." 

"Results: Escitalopram concentrations in milk were 50 ± 17 ng/mL (mean ± standard deviation). The simulated infant plasma AUC∞ following escitalopram exposure through breast milk was low, with a median of 1.7% (range 0.5–5.9%) of the corresponding maternal plasma AUC∞, indicating no substantial exposure." 

"Conclusions: Infant exposure levels to escitalopram in breast milk are low. A PBPK modeling approach can be used to translate data on drug monitoring in milk into a population distribution of infant plasma levels for drug safety assessment." 

https://link.springer.com/article/10.1007%2Fs40262-018-0657-2

 

New Study on Trajectories in Maternal Depression and Children's Behavior

Developmental cognitive neuroscientist Adele Diamond is one of the authors of this new study from the University of British Columbia.  Diamond is a leader in the field of developmental cognitive neuroscience.  

Title:  Maternal depression trajectories from pregnancy to 3 years postpartum are associated with children’s behavior and executive functions at 3 and 6 years

Journal:  Archives of Women's Health

Authors:  Mina Park, Ursula Brain, Ruth E. Grunau, Adele Diamond, Tim F. Oberlander

Abstract:  "The objective of this study was to investigate how patterns of maternal depressive symptoms from mid-pregnancy to 3 years postpartum are associated with children’s behavior at age 3 years and executive functions. Maternal depressive symptoms were measured from mid-pregnancy to 3 years postpartum. Growth mixture modeling was used on standardized maternal depression scores (n = 147) to identify trajectories. Children’s behavioral problems and mental health symptomatology (internalizing, externalizing, and attention deficit hyperactivity disorder) were obtained at 3 and 6 years. EFs were assessed by a laboratory-based computerized task and maternal-report at 6 years. Multivariable linear regressions of children’s outcomes against maternal depressive symptom trajectories were conducted (n = 103). Three distinct patterns of maternal depressive symptom trajectories were identified: low (n = 105), increasing (n = 27), and decreasing (n = 15). Children of mothers whose depressive symptoms increased reported more problem behaviors at 3 years and poorer EFs at 6 years as assessed by both instruments, but no significant differences in mental health symptomatology at 6 years, relative to those whose mothers had consistently low depressive symptoms. Children whose mothers became less depressed over time had comparable levels of behavioral problems at age 3, executive functions, and internalizing and externalizing scores at age 6; and fewer reported ADHD behaviors at age 6, than those whose mothers remained less depressed over time. If mothers’ depressive symptoms improve over the first 3 years postpartum, their children’s outlook may be comparable to those whose mothers had consistently low depressive symptoms."

http://www.devcogneuro.com/Publications/Park(2018)_maternal_depression.pdf

Dr. Diamond's developmental cognitive neuroscience website:  http://www.devcogneuro.com/

New Study on Mirror Neurons

When we provide print literature to parents as well as video teaching materials, and when we use dolls in prenatal breastfeeding classes to demonstrate various infant feeding positions, mirror neurons must be very busy.  I suspect mirror neurons are even more highly activated when observing infant feeding in real time.

This new study from the Journal of Neuroscience is on the role of mirror neurons in learning, and is yet another example of the heavily studied area of prehension (the manual reach and grasp). 

Title:  Mirror neuron populations represent sequences of behavioral epochs during both execution and observation

Authors: Kevin A. Mazurek, Adam G. Rouse and Marc H. Schieber, all with the University of Rochester in Rochester, New York

Abstract:  "Mirror neurons (MNs) have the distinguishing characteristic of modulating during both execution and observation of an action. Although most studies of MNs have focused on various features of the observed movement, mirror neurons also may monitor the behavioral circumstances in which the movement is embedded, including time periods preceding and following the observed movement. Here, we recorded multiple MNs simultaneously from implanted electrode arrays as two male monkeys executed and observed a reach, grasp, and manipulate task involving different target objects. MNs were recorded from premotor cortex (PM-MNs) and primary motor cortex (M1-MNs). During execution trials, Hidden Markov Models (HMMs) applied to the activity of either PM- or M1-MN populations most often detected sequences of 4 hidden states, which we named according to the behavioral epoch during which each state began: initial, reaction, movement, and final. The hidden states of MN populations thus reflected not only the movement, but also three behavioral epochs during which no movement occurred. HMMs trained on execution trials could decode similar sequences of hidden states in observation trials, with complete hidden state sequences decoded more frequently from PM-MN populations than from M1-MN populations. Moreover, population trajectories projected in a 2-dimensional plane defined by execution trials were preserved in observation trials more for PM- than for M1-MN populations. These results suggest that MN populations represent entire behavioral sequences, including both movement and non-movement. PM-MN populations showed greater similarity than M1-MN populations in their representation of behavioral sequences during execution versus observation."

Significance Statement:

"Mirror neurons (MNs) are thought to provide a neural mechanism for understanding the actions of others. But for an action to be understood, both the movement per se and the non-movement context before and after the movement need to be represented. We found that simultaneously recorded MN populations encoded sequential hidden neural states corresponding approximately to sequential behavioral epochs of a reach, grasp, and manipulate task. During observation trials, hidden state sequences were similar to those identified in execution trials. Hidden state similarity was stronger for MN populations in premotor cortex than for those in primary motor cortex. Execution/observation similarity of hidden state sequences may contribute to understanding the actions of others without actually performing the action oneself."
 

Motor Learning Term of the Day

Inhibition of Return (IOR): the delay in responding to the previously cued (or orienting) stimulus/stimuli.  

In the field of infant feeding, infants are often observed to inhibit the reflexive lunge toward the breast following a learning experience with an artificial nipple, regardless of whether the artificial nipple is a pacifier (soother or dummy) or a bottle nipple. 

In many infants, this inhibition is displayed as slower speed and less accuracy as the infant moves toward the nipple-areolar complex for the oral grasp/latch, and this can be studied and measured in milliseconds as a prolonged movement time [MT] for the oral grasp.  Other infants can achieve and sustain the oral grasp at the breast after a learning experience with an artificial nipple, but display an inhibition of the reflexive wide oral gape in order to learn the shallow oral grasp of an artificial nipple, and the shallow latch is a well-known risk factor for maternal nipple pain and nipple trauma.  In yet other infants who have been given a learning experience with an artificial nipple, there are observable displays of ineffective suckling which can result in inadequate transfer of milk.  An infant may display such learning difficulties (task-switching difficulties with subsequent switch costs of decreased speed and accuracy) in one of these areas, while other infants will display feeding difficulties in some or all of these areas. 

When infants are given a learning experience with an artificial nipple and are subsequently returned to the breast, some infants no longer move toward the nipple-areolar complex at all, as if waiting for other, more recently learned feeding stimuli to be offered.  

Lactation consultants are often consulted to assist the infant in returning to the breast when such difficulties occur, particularly in non-Baby Friendly childbearing facilities.  Clinicians often provide manual guidance to the mother in positioning the infant at the breast for the infant's correct trajectory toward the nipple-areolar complex, as well as manual guidance for the necessary speed in moving toward the nipple-areolar complex while the infant's mouth is reflexively open for the oral grasp, and also while the infant's tongue is reflexively extended over the lower alveolar ridge for the oral grasp.  Less tongue extension is needed for bottle-feeding skills, and during task-switching difficulties between breast and artificial nipple and back to the breast again, even the baby's reflexive tongue extension for the oral grasp can be inhibited for the oral grasp of the nipple-areolar complex.   

When a breastfeeding mother bottle-feeds her infant and subsequently returns her infant to the breast, the mother has often positioned her baby at the breast but in a bottle-feeding position, i.e., the baby is often cradled in one arm and reclining in a supine position.  With verbal and manual guidance from the clinician, the mother can quickly relearn how to position her infant at the breast, but the infant's primitive survival reflexes are often more heavily weighted toward the more recently learned feeding method, rather than equally weighted for all infant milk-feeding methods all the time.  Even the novice clinician is undertaking her own motor learning toward increasingly greater motor control.  The clinician often provides verbal and manual guidance to the mother in learning how to position her infant at the breast, and also in learning how to guide her infant in learning the oral grasp and/or effective suckling. 

Motor learning is complex, and this also applies to the mother who is also learning how to comfortably hold her infant in nursing positions, while also learning how to provide manual guidance to her infant in helping the little one to learn the oral grasp.  The mother's advantage is that she has spent a lifetime in learning her own feeding skills and other many other skills with the repetition of task-specific practice.  Nature provides remarkable assistance to the newborn mammal by endowing preadapted feeding movements that are further adapted in response to feeding stimuli.  However, these preadapted feeding movements, i.e., the primitive survival reflexes, are often more heavily weighted toward the more recently learning feeding method, an elegant and efficient approach by nature in support of the newborn's survival.  Particularly during early learning when early motor memories are most fragile, task-switching from breast to artificial nipple and back to breast is often challenging for the healthy term infant, and the challenges may be mild, moderate, or pronounced and prolonged.    

Without the presence of the infant's primitive survival reflexes, motor learning for milk-feeding skills would occur too slowly for the newborn's survival.  Consider the weeks of practice needed by the 6-month-old who is learning how to transfer liquid from a sippee-cup, and the difficulties displayed by the older baby when a different style of sippee-cup is offered.  The frequent response by many babies is a clear refusal of the novel sippee-cup, particularly during early learning.  Similarly, bottle-fed infants often display a preference for one style of artificial nipple, struggling with and often refusing a novel artificial nipple.  

When infants are exclusively bottle-fed, regardless of whether the milk is mother's milk, human donor milk, or artificial infant milk, it is also important to observe and study how infants learn to inhibit the reflexive lunge toward the bottle nipple.  In bottle-feeding, the reflexive lunge toward the bottle can be observed during earliest practice sessions in bottle-feeding, but as more practice sessions in bottle-feeding take place, newborns learn to inhibit this reflexive lunge toward the bottle very quickly, an example of the exuberant learning of infancy.   

This is a dramatic and profound display of infants learning very soon after birth to inhibit a reflexive movement when this reflexive movement is not at all needed for bottle-feeding.  The reflexive movement/lunge toward the breast is genetically designed for infant mammals to be a forward movement toward the nipple-areolar complex, but this reflexive lunge is highly adaptable in the manner of a heavier weighting toward the more recently learned milk-feeding method.  Bottles are consistently moved by the parent or other caregiver toward the baby for feeding, rather than the inefficient movement by the parent of moving the baby toward the bottle.  As the parent or other caregiver quickly learns to be efficient in their bottle-feeding movements, newborns also become quickly efficient in inhibiting the reflexive lunge that is needed for the oral grasp at the breast, but not at all needed for bottle-feeding. 

Learning is most rapid in infancy, but the cognitive demands of task-switching are greatest during infancy.  Across the lifespan, cognitive flexibility is most limited in the young.  

On Consolidating Memories During Sleep

Sleep helps us to build memory toward a robust state termed consolidation. Very soon after birth, the healthy term newborn soon enters an alert cycle that may last 1 to 5 hours (2 to 2 1/2 hours is average), and this early alert cycle is an ideal time for the youngest newborn to practice learning milk-feeding skills at the breast. Following this earliest feeding session, newborns enter a sleepy cycle of satiety and in recovery from birth. When a newborn has learned the oral grasp (or latch) in the initial alert cycle after birth, then awakens after a period of sleep, the infant's subsequent feeding movements for the oral grasp are expected to becoming increasingly more smooth and accurate (and therefore faster) at subsequent feedings when practice is specific to the task.  (An exception to the infant's display of increasing speed and accuracy for the oral grasp at the breast is during pronounced breast engorgement, which can serve as a temporary learning constraint for the infant.)  

Newborns must feed often in order to thrive, and with more task-specific feeding practice, motor memory for feeding becomes even more robust. This strengthened motor memory is reflected in the baby's increasingly greater performance of the oral grasp (the young novice soon becomes The Insta-Latch Baby), and the infant also becomes more skilled in milk transfer, so that greater volumes of milk can be transferred over increasingly shorter periods of time. Interestingly, as newborns become gradually more skilled in a milk-feeding method, gradually less sleep is required. 
                                                                                                                                          However, early memories are often fragile. Consider the fragile memory for a new computer password or a new telephone number, where the repetition of practice is necessary for building robust memory for that information.

In motor learning, such fragility can be frequently observed during the formation of early motor memories for infant feeding when a breastfed infant is given a learning experience with an artificial nipple, and particularly (but not only) if the introduction to an artificial nipple occurs during early skill acquisition at the breast, i.e., during early motor learning toward motor control.  If the infant's learning experience at the breast is followed by a learning experience with an artificial nipple, the infant's subsequent return to the nipple-areolar complex is often observed as decreased speed and accuracy (skill decay) for the oral grasp.

Following a learning experience with an artificial nipple, there are often many pronounced observations of a delayed and/or prolonged reaction time (RT) for the infant's oral grasp of the nipple-areolar complex (delayed onset of rooting and/or prolonged rooting for sensory processing, which includes but is not limited to texture and shape discrimination as well as target identification, followed by action planning); as well as a prolonged movement time (MT) for the oral grasp and/or effective suckling, resulting in a prolonged response time.  A significant inhibition of return (IOR) is also frequently observed -- the delay in responding to the previously cued (or orienting) stimulus. Although a wealth of longitudinal studies have correlated artificial infant feeding methods and artificial infant milks with both shorter duration of exclusive breastfeeding as well as early termination of the entire breastfeeding course, the universal phenomenon of infant breastfeeding difficulties that often follow the use of an artificial nipple can also be formally studied by using these real-time measurement parameters toward greater understanding of the infant’s skill acquisition for milk-feeding skills.

Among exclusively bottle-fed populations, routine task-switching between different styles of artificial nipples is never the norm in hospital settings or among families, although such task-switching of various styles of artificial nipples and subsequent switch costs of decreased speed and accuracy for the oral grasp and/or effective sucking can be studied in bottle-feeding infants as well. Skill acquisition in bottle-feeding populations can also be studied when bottle-fed infants learn their feeding skills unimpeded by task-switching to different styles of artificial nipples. The impact of sleep can also be studied among exclusively bottle-fed infants during their acquisition of bottle-feeding skills, regardless of whether the bottled milk is mother's milk, human donor milk, and/or artificial infant milk.

Motor learning is a complex process, and the presence of the primitive survival reflexes hastens the newborn's acquisition of milk-feeding skills in dramatic support of the newborn's survival. However, the newborn's reflexive movements are often more heavily weighted toward the more recently learned milk-feeding method (a recency effect), rather than equally weighted reflexive feeding movements for all infant milk-feeding methods all the time. 
                                                                                                                                        When the repetition of practice is specific to the task, the infant has the opportunity to build increasingly greater motor control during the process of motor learning for milk-feeding skills. The brain continues to process and strengthen motor memories between practice sessions, and this critical processing also takes place during sleep.

As the spring semester winds down on college campuses, parents are likely to advise their college-aged students not to stay up all night cramming for final exams, but to study as much as possible throughout the semester and to get adequate sleep, including during the week of final exams. When the repetition of frequent studying (in-session learning) is followed by regular study breaks and adequate sleep (between-session learning), this academic routine is expected to result in more robust memory for students everywhere. In studies on the impact of sleep in the aging population, adequate sleep is one of many important factors in supporting and optimizing cognitive function.

A new review article on daytime napping in infants and children from the journal, Nature and Science of Sleephttps://www.ncbi.nlm.nih.gov/pubmed/22430027

New Study on Genetic Aspects of Rapid Involution and Aggressive Breast Cancer

Infant feeding and lactation specialists often provide patient and client teaching on the many health aspects of breastfeeding and human milk.  One of these aspects is the lesser incidence of inflammatory and triple-negative breast cancers among women who breastfeed their children with greater frequency and longer duration.  This new peer-reviewed, open access study from the University of Texas looked at the genetic changes in rapid "forced" weaning and breast involution, finding an association between these genetic changes and aggressive breast cancers.   

Study title:  Gene set analysis of post-lactational mammary gland involution gene signatures in inflammatory and triple-negative breast cancer

Study authors: Arvind Bambhroliya, Renae D. Van Wyhe, Swaminathan Kumar, Bisrat G. Debeb, Jay P. Reddy, Steve Van Laere, Randa El-Zein, Arvind Rao, Wendy A. Woodward

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0192689

From the abstract:

Background: Epidemiological studies have found that triple-negative breast cancer (TNBC) and TN inflammatory breast cancer (IBC) are associated with lower frequency and duration of breast-feeding compared to non-TNBC and non-TN IBC, respectively. Limited breast-feeding could reflect abrupt or premature involution and contribute to a “primed” stroma that is permissive to the migration of cancer cells typical of IBC. We hypothesized that gene expression related to abrupt mammary gland involution after forced weaning may be enriched in the tissues of IBC patients and, if so, provide a potential correlation between limited breast-feeding and the development of aggressive breast cancer.

Results: Examining the combined data, we identified 10 involution gene clusters (Inv1-10) that share time-dependent regulation after forced weaning. Inv5 was the only cluster significantly enriched in IBC in the training and validation set (nominal p-values <0.05) and only by unadjusted p-values (FDR q-values 0.26 and 0.46 respectively). Eight genes in Inv5 are upregulated in both the training and validation sets in IBC. Combining the training and validation sets, both Inv5 and Inv6 have nominal p-values <0.05 and q-values 0.39 and 0.20, respectively. The time course for both clusters includes genes that change within 12 hours after forced weaning.