Measures of frontal functioning and the emergence of inhibitory control processes at 10 months of age.

During the first year, infants begin to exhibit initial evidence of working memory and inhibitory control in conjunction with substantial maturation of the frontal cortex and corresponding neural circuitry. Currently, relatively little is known about the neural and autonomic resources that are recruited in response to increased executive demands during the first year of development. To this end, we recorded electroencephalogram (EEG; 6-9 Hz) and electrocardiogram from 10-month-olds during a working memory and inhibitory control task (looking A-not-B). Analyses compared measures of frontal functioning (EEG power, EEG coherence, heart rate) during nonreversal (working memory) and reversal (working memory+inhibitory control) trials. The increased cognitive demand of inhibitory control processing was associated with increases in heart rate and frontal coherence (medial frontal-lateral frontal, medial frontal-temporal, medial frontal-medial parietal, and medial frontal-occipital electrode pairs). Thus, synchronized activity across distributed cortical regions appeared to be essential to inhibitory control processes during infancy. The addition of inhibitory control processes, however, was not associated with any changes in neuronal activity (EEG power). These findings are discussed in relation to other neuroscience findings and provide insight into the development of integrated frontal functioning in infancy.