Effect of GABA on a temporary connection in a neuronal population of the sensorimotor cortex in rabbits

Evoked activity of sensorimotor cortical neurones in response to stimulation of the pyramidal tract, medial lemniscus and reticular nucleus of the midbrain tegmentum; driving reaction of cortical neurones at stimulation of these brain structures of growing frequency, and conditioned reflexes elaborated by combination of direct stimulation of the sensorimotor cortex and electrocutaneous stimulation were studied in awake nonimmobilized rabbits. Application to the cortex of GABA solutions of low concentration (less than or equal to 1%) emphasizes the evoked neuronal responses, facilitates the appearance of driving reaction and contributes to the manifestation of the temporary connection. Application of GABA solutions of higher concentration (greater than 2%) leads to opposite effects. Positive correlation is found between electrical and behavioural phenomena. The described experimental approach may be used for analysis of various types of influences on temporary connection formation.