Abstract
The influence of iontophoretic application of glutamate and its blockers on the impulse activity of neurons of the sensorimotor cortex, associated with conditioned reflex activity, was investigated in chronic experiments on trained cats. It was established that in many neurons glutamate promoted an intensification of the impulse reactions to the conditioned stimulus. This intensification arose directly during the application of glutamate, several seconds after it was begun, and was maintained for 5–10 min after iontophoresis ceased. Similar inhibiting effects on neuronal reactions were demonstrated for 2-amino-5-phosphonovaleric acid, kinurenate, and ketamine. It was concluded that under natural conditions of functioning or the performance of acquired reactions, facilitation of intracortical interneuronal glutamatergic connections, providing for increased readiness of the neocortex for subsequent reactions, is systematically maintained in the cerebral cortex through the NMDA receptors. During the reactions the glutamatergic connections are intensively activated and participate negligibly in the organization of the background activity of the neurons.
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Literature cited
B. I. Kotlyar and Yu. S. Ovcharenko, "Associative properties of the micropopulation of neurons of the sensorimotor cortex," Zh. Vyssh. Nervn. Deyat,30, No. 1, 169–176 (1980).
B. I. Kotlyar, Plasticity of the Nervous System [in Russian], Moscow University Press Moscow (1986).
B. I. Kotlyar, Neurophysiological Bases of Learning [in Russian], Nauka, Moscow (1989).
V. M. Storozhuk and A. N. Tal'nov, "Reactions of neurons of the cat somatic cortex during the instrumental reflex of placing of the paw on a support," Neirofiziologiya,14, No. 4, 392–401 (1982).
V. M. Storozhuk, Neuronal Mechanisms of Learning [in Russian], Naukova Dumka, Kiev (1986).
V. M. Storozhuk and L. E. Zinyuk, "Reactions of neurons of the innominate substance of the cat brain during an instrumental conditioned reflex," Neirofiziologiya,21, No. 6, 796–804 (1989).
V. M. Storozhuk, "The system of synaptic influences on neurons of the neocortex during a conditioned reflex," Zh. Vyssh. Nervn. Deyat.,40, No. 5, 819–833 (1990).
E. U. Evarts, "Contrasts between activity of precentral and postcentral neurons of cerebral cortex during movement of the monkey," Brain Res.,40, No. 1, 25–31 (1972).
R. Metherate, N. Tremblay, and R. W. Dykes, "Acetylcholine permits long-term enhancement of neuronal responsiveness in cat primary somatosensory cortex," Neuroscience,22, No. 1, 75–81 (1987).
R. Metherate, N. Tremblay, and R. W. Dykes, "The effects of acetylcholine on response properties of cat somatosensory cortex neurons," J. Neurophysiol.,59, No. 4, 1231–1252 (1988).
M. L. Mayer, J. L. Westbrook, and L. Uyklicky, "Sites of antagonist action on N-methyl-D-aspartic acid receptors," ibid.,60, No. 2, 645–663.
U. M. Storozhuk and L. E. Zinjuk, "Influence of substantia innominata neuronal activity on neocortex neuronal reactions during conditioned reflex," Brain Res.,550, No. 1, 169–171 (1991).
B. Sutor and J. I. Hablitz, "EPSP in rat neocortical neurons in vitro. I. Electrophysiological evidence for two distinct EPSP," J. Neurophysiol.,61, No. 2, 607–620 (1989).
B. Sutor and J. I. Hablitz, "EPSP in rat neocortical neurons in vitro. II. Involvement of N-methyl-aspartate receptors in the generation of EPSP," ibid., 621–634.
H. Tamura, T. P. Hicks, I. Hata, T. Tsumoto, Iamatodani, "Release of glutamate and aspartate from the visual cortex of the cat following activatin of afferent pathways," Exp. Brain Res.,80, No. 3, 447–454 (1990).
S. B. Tieman, C. B. Cangro, and I. H. Neale, "N-Acetylaspartylglutamate immunoreactivity in neurons of the cat's visual system," Brain Res.,420, No. 1, 188–193 (1987).
N. Tremblay, R. A. Warren, and R. W. Dykes, "Electrophysiological studies of acetylcholine and the role of the basal forebrain in the somatosensory cortex of the cat. I. Cortical neurons excited by glutamate," J. Neurophysiol.,64, No. 4, 1199–1211 (1990).
N. Tremblay, R. A. Warren, and R. W. Dykes, "Electrophysiological studies of the basal forebrain in the somatosensory cortex of the cat. II. Cortical neuron excited by somatic stimuli," ibid., 1212–1221.
T. Tsumoto, K. Hagihara, H. Sato, and I. Hata, "NMDA receptors in the visual cortex of young kittens are more effective from those of adult cats," Nature,327, 513–514 (1987).
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A. A. Bogomolets Institute of Physiology, Ukrainian Academy of Sciences, Kiev. Translated from Neirofiziologiya, Vol. 24, No. 6, pp. 701–712, November–December, 1992.
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Storozhuk, V.M., Ivanova, S.F. & Sanzharovskii, A.V. Involvement of glutamatergic intracortical connections in conditioned reflex activity. Neurophysiology 24, 473–482 (1992). https://doi.org/10.1007/BF01052967
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DOI: https://doi.org/10.1007/BF01052967