Maturation of Brain Activation in Response Inhibition.

Introduction

The development of intact and proficient inhibitory function is critical to adaptive functioning. Knowledge of how response inhibition develops in typically developing individuals will inform our understanding of atypical response inhibition in psychiatric and behavioral disorders.

We therefore studied the developmental trajectory of response inhibition to determine whether there is a dissociation of function in the prefrontal cortex during the development of executive function and associated response inhibition abilities.

Method

In this study, 19 typical children and adults (8 M/11 F, 8-20 years) performed a Go-NoGo task while behavioral and fMRI data were collected.

Results

Activations from averaged group image in the coronal plane from front to back with the experimental minus control contrast for all subjects (red, NoGo–Go). A positive correlation between activation and age was seen in the left inferior frontal gyrus/insula/orbitofrontal gyrus (blue, Positive Age). A negative correlation between activation and age was seen in the left middle/superior frontal gyri (green, Negative Age). No relationship between accuracy and age emerged, but the ability to inhibit responses more quickly improved significantly with age.

Conclusions

These data provide the first evidence of dissociable processes occurring in the prefrontal cortex during development of executive functions associated with response inhibition:

1. Younger subjects activated more extensively than older subjects in discrete regions of the prefrontal cortex, presumably due to increased demands and inefficient recruitment of brain regions subserving executive functions including working memory.
   
   
2. Older subjects showed increasingly focal activation in specific regions thought to play a more critical role in response inhibition.

Leanne Tamm, Vinod Menon, and Allan L. Reiss. (2002). "Maturation of Brain Function Associated With Response Inhibition." J Am Acad Child Adolesc Psychiatry 2002 Oct;41(10):1231-8.
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