[Retracted: [THE CONTRIBUTION OF GABA-ERGIC INHIBITION TO THE VELOCITY TUNING OF THE SUPERIOR COLLICULUS NEURONS]].

The formation of selective sensitivity to the movement of the environment at different velocities still remains an unsolved problem. It is assumed that the basis of the creation of such sensitivity can be as processes of inhibition and facilitation at different levels of the visual system. We studied the role of GABA-ergic inhibition in shaping the velocity tuning by affecting GABA antagonist iontophoresis, bicuculine on responses that occur in 80 neurons of the superior colliculus (SC) on the movement of the light spot at 5-45 degrees/s in hamsters anesthetized by urethane.

Dopamine modulation of glutamate metabotropic receptors in conditioned reaction of sensory motor cortex neurons of the cat.

The dopamine modulation of microiontophoretic application of antagonists of glutamate metabotropic synaptic transmission was studied in the sensory motor cortex of awake cats during instrumental conditioned reflex. The substances depressed the background and intensity of evoked impulse activity of pyramidal neurons of the sensory-motor cortex and provoked significant increases in the latency of impulse reaction and corresponding conditioned movements of animals. Simultaneous application of the antagonists and dopamine (DA) eliminated their depression of the background and evoked activity of neurons and decreased the latency of the impulse reactions and movements.

The effects of activation of glutamate ionotropic connections of neurons in the sensorimotor cortex in a conditioned reflex.

Changes in conditioned reflex spike activity of neurons in the sensorimotor cortex were studied during microiontophoretic application of agonists and antagonists of glutamate and GABAergic transmission. The results of these experiments showed that the glutamate ionotropic receptors (AMPA and NMDA) of neurons in the sensorimotor cortex were intensely activated by the arrival of a conditioned signal in the cortex. This response included not only large pyramidal neurons of the deep cortical layers, but also the surrounding inhibitory interneurons.

Dopamine modulation of activity of cat sensorimotor cortex neurons during conditioned reflexes.

The effects of iontophoretic application of dopamine and selective D1 or D2 dopamine receptor agonists and antagonists on impulse activity of neurons of the deep layers of the sensorimotor cortex of cat were investigated during performance of a conditioned paw movement task. The application of dopamine, Quinpirole (selective D2 receptor agonist) or SKF 38393 (selective D1 receptor agonist) increased both background (P<0.001) and evoked impulse activity (P<0.

[Activation of glutamate ionotropic connections of sensorimotor cortex neurons during conditioning].

Changes in conditioned impulse reactions of neurons in sensorimotor cortex were studied during microiontophoretic application of glutamatergic and GABA ergic agonistic and antagonistic drugs. It was shown that ionotropic glutamate receptors (AMPA and NMDA) are activated by a conditioned stimulus. Not only large pyramidal neurons of deep cortical layers but surrounding short-axon inhibitory interneurons are involved in the reaction.