New Study on Inhibition

Following the motor learning experience with an artificial nipple, the speed and accuracy of the infant's reflexive lunge toward the breast often becomes inhibited, particularly during early learning but not only during early learning. When an infant learns to bottle-feed, the opposite movement is learned, in that the bottle is moved toward the baby, rather than the baby being moved toward the bottle.  When an infant is subsequently returned to the breast, decreased speed and accuracy are often observed for the infant's latch, and such difficulties may be mild, moderate, or profound.  In many such instances, there are also observable decreases in speed and accuracy for organized, effective suckling.  The term skill decay is defined as decreased speed and accuracy for the task.  

Following a learning experience with an artificial nipple, the infant's reflexive oral gape is often inhibited to a more shallow gape as well (a "shallow latch"), even when an infant is able to achieve and sustain the oral grasp at the breast.  

Inhibition has been heavily studied in the cognitive sciences for decades. Today's PubMed search using the term "cognitive inhibition" yielded 11,580 search results, with newest studies published this month.

How has inhibition been traditionally studied in the cognitive sciences?

Researchers often compare reaction time, movement time, response time, and inhibition of return - - parameters that are measured in milliseconds. Inhibition of return (IOR), the delay in a previously orienting response, is considered significant when the delay is at least 200 to 500 milliseconds in duration. Although the comparison of these measurement parameters is not yet an area of formal study in the field of infant feeding for lactation consultants, the clinician often observes dramatic changes in these parameters over the course of a career, particularly in non-Baby Friendly hospital settings.  IBCLCs are educated and trained in many aspects of human lactation and infant feeding, and much of the clinician's workday is spent providing skilled guidance to both members of the dyad for the infant's oral grasp and/or effective suckling.  Varying levels of manual guidance are often needed by the infant in the acquisition and re-acquisition of infant milk-feeding skills, particularly when interference takes place during a baby's learning.  Neifert, Lawrence, and Seacat (1995) cited interference in their discussion on the first formal definition of the phenomenon of nipple confusion.  

In their new study published on December 4, 2017, Johns Hopkins researchers K.Z. Xu and colleagues used fMRI (functional magnetic resonance imaging) to study response inhibition.  Prior to this study, inhibition of planned behavior was thought to be governed by a single brain system.  In their current study, Xu and colleagues concluded that inhibition of a planned behavior "depends on two distinct neural processes involving different sub-regions of the rVLPFC [right ventrolateral prefrontal cortex] and their interactions with other motor-related brain regions." 

Title: Neural Basis of Cognitive Control over Movement Inhibition: Human fMRI and Primate Electrophysiology Evidence.

In: Neuron 2017 Dec 4. pii: S0896-6273(17)31063-2. doi: 10.1016/j.neuron.2017.11.010. [Epub ahead of print]

 Authors: Xu KZ, Anderson BA, Emeric EE, Sali AW, Stuphorn V, Yantis S, Courtney SM.