[Role of glutamate intracortical connections in conditioned reflex activity].

The effects of iontophoretic application of glutamate and its blockers on neuronal activity of the sensorimotor cortex were studied in cat during fulfillment of conditioned instrumental placing reflex. 64 neurons were investigated. Application of glutamate caused reliable facilitation of neuronal impulse reactions to the conditioned stimulus. The facilitation appeared some seconds after beginning of the application of glutamate and continued for 5-10 min after cessation of the iontophoretic application. The similar inhibitory effect in neuronal activity was observed with application of APV, kinurenate, ketamine. It is suggested that the NMDA receptors under natural conditions take part in facilitation of the synaptic transmission in glutamatergic intracortical pathways.