Alpha activity as an index of cortical inhibition during sustained internally controlled attention in infants

Objectives: The study examined the suggestion that infant ability to mainta in attention in anticipatory task and to sustain interference is related to the active inhibitory processes in cortical neural networks. Methods: The extent of selective EEG synchronization in the alpha range has been taken as a measure of cortical inhibition. EEG was registered in 60 i nfants aged 8-11 months during: (1) attention to an object in the visual fi eld (externally controlled attention); (2) anticipation of the person in th e peek-a-boo game (internally controlled attention). Results: The infants who demonstrated longer periods of anticipatory attent ion had higher absolute spectral amplitude in the broad frequency range und er both experimental conditions. It was suggested that the effect of 'overa ll' EEG synchronization is related to some stable individual differences in psychophysiological traits. To control for the effect of overall EEG synch ronization the relation between relative alpha amplitudes in 6.4-10 Hz rang e and the duration of internally controlled attention was analyzed. The inf ants with longer compared to shorter anticipatory attention spans had relat ively higher 6.8 Hz alpha synchronization at posterior parietal sites under this experimental condition. Conclusions. It was suggested that alpha synchronization over posterior par ietal cortex reflects an active inhibition of certain parietal networks inv olved in maintaining attention to peripheral Visual field rather than merel y an 'idle' state of this cortical area. Such an inhibition appears to allo w infants to avoid interference of concurrent visual stimulation at the per iphery of the visual field. (C) 2001 Elsevier Science Ireland Ltd. All righ ts reserved.