Certain mechanisms of frontal cortex participation in afferent synthesis (Russian)

In dogs anesthetized with chloralose, the suppression of the frontal cortex activity (by cooling) caused an increase in the negative component of the primary response (PR) in the primary exteroceptive projection areas (somatosensory, acoustic and visual). Stimulation of the frontal cortex (by strychnization) caused an increase in amplitude of the positive component of PR. The influences applied to the frontal cortex of the cerveau isole preparation induced the same changes only in the positive component of PR. On the whole the findings suggest that the frontal cortex exerts at least 2 types of tonic influences on afferent channels. The activating type is due to changes in the specific thalamic nuclei, while the suppressing type appears after a change in the activity of the midbrain reticular structures. It is feasible that under natural conditions the frontal cortex, being activated at the stage of the prestart integration, facilitates transmission of definite afferent signals through the specific pathways and prepares favorable conditions for perception of the triggering signal. The frontal cortex influences, by suppressing the midbrain reticular structures, contribute to the same result.