Neurophysiological mechanisms of the attention disturbance in children with learning difficulties.

The features of orientation reaction (OR) and the background EEG were investigated with the purpose of studying the neurophysiological mechanisms of the disturbance of voluntary attention in children aged 6.5-9 years with learning difficulties caused by delayed mental development (DMD). A decrease in the expressivity of components of the OR as compared with the norm, discovered in a situation of involuntary attention against a background of insufficiently developed cortical rhythmicity in the alpha range, was compensated for given an increase in the significance of the stimuli. These facts support the hypothesis of a deficit in regulatory corticofugal influences in children with DMD. The inadequacy of the engagement of central regions of the cortex characteristic of children with DMD in the realization of OR in a situation of directed attention can be regarded as a reflection of disturbances of the integrative activity of the brain.