Inhibitory control is important in everyday life. It has previously been suggested that inhibitory networks become more focal during development from childhood to adulthood (Durston & Casey 2005, Tamm et al. 2002). To test this hypothesis we made whole head electroencephalographic recordings during visual Go/NoGo task performance in healthy children (n = 10, age 8-9yrs) and adults (n = 11, age 20-36yrs).

We found that children made more errors and responded slower than adults. Both children (p < 0.01) and adults (p < 0.01) showed increases in N2 amplitude in the nogo compared to the go condition, but only adults (p < 0.01) showed significant enhancement of the P3 in the nogo compared to the go condition. In source modelling with BESA both children and adults activated six regional sources: two pairs of symmetrical sources in the posterior extrastriate and occipito-temporal areas, a precuneal/middle cingulate source and a frontal source in the anterior cingulate cortex (ACC). Both children (p < 0.05) and adults (p < 0.001) showed higher activity in the ACC during the nogo compared to the go condition. In children (p < 0.001) there was also an increased activity in the occipito-temporal sources during the nogo condition. In adults ACC activity correlated positively with the accuracy of task performance.

These results, in line with earlier work, suggest that the networks of inhibitory control develop from being more widely distributed in children to becoming more focal and efficiently activated in the adults.

REFERENCES

Durston, S. & Casey, B.J. 2005. Neuropsychologica, in press.

Tamm, L., Menon, V. & Reiss, A.L. 2002. J Am Acad Child Adolesc Psychiatry 41,1231-1238.