Basic trends in research into the neurochemical mechanisms of learning and memory

The development of sensitization and an associative habit of rejection of a specific type of food is accompanied by short-term and long-term changes in behavior, bioelectrical activity, and the dynamics of the content of Ca(b) in the command neurons of defense behavior of the common snail. In approximately an hour from the moment of the beginning of training, behavioral and neurophysiological effects which were similar on the whole were identified during the development of these habits. During the development of sensitization, the responses to test tactile stimulations and to applications of quinine and carrot juice appeared and/or were markedly intensified from 50 through 90 min from the moment of the first sensitizing stimulation. During the development of conditioning, responses to the tactile stimulations and quinine also appeared and/or intensified from 50-60 min, while responses to the conditional stimulus appeared and intensified approximately 30 min later (from 85-95 min). Phases of an initial marked increase, with a subsequent tendency to stabilization, in the level of Ca(b) were observed in the command neurons during a brief period in the development of sensitization; during conditioning a temporary decrease was identified in the content of Ca(b) in response to each combination of stimuli with its subsequent spontaneous decrease at 40-60 min. An increase in the level of Ca(b), beginning during the development of sensitization from 50-60 min, and during conditioning from 85-90 min from the moment of the beginning of training, was observed in the long-term period.(ABSTRACT TRUNCATED AT 250 WORDS)

Section: Discussion Of Resultssupporting

confidence: 93%

Section: Discussion Of Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Molecular—Cellular mechanisms of learning of the common snail

Nikitin

1994

“…Our investigations, just as the observations of other authors [15,40], have demonstrated that responses may change significantly as early as the repeat microiontophoretic application of the very same chemical agents to neurons. We have found especially marked changes in the character of the discharge activity of individual brain neurons to neuromediators and neuropeptides in the presence of emotiogenic effects on animals.…”

Section: Specific Characteristics and Plasticity Of The Systemic Chemsupporting

confidence: 53%

Integrative activity of the neuron: The specific characteristics and plasticity of systemic mechanisms

Sudakov

1994

The notions of P. K. Anokhin regarding the integrative activity of neurons through the time course of the systemic organization of behavioral acts are developed in this article. It is shown that in the systemic organization of behavioral acts neurons in their activity not only initial motivations and reinforcement, but demonstrate anticipatory reactions on the basis of preceding reinforcements, including themselves in the formation of the apparatus of the acceptor of the result of an action. A dominant motivation substantially alters the sensitivity of brain neurons to neuromediators and neuropeptides. Change in the chemical sensitivity of neurons has been identified through the time course of the organization of the various stages of systemic organization of behavioral acts. It has been established that the sensitivity of neurons to motivational and sensory influences, as well as to biologically active substances is also determined to a substantial degree by their protein-synthesizing apparatus. Investigations have demonstrated the specific characteristics and plasticity of neurons in the systemic organization of behavioral acts.

“…It can be assumed that comparative study of such mechanisms, for which the cholinergic systems are responsible, will promote the identification of regularities and specific features of the functioning of the long-term and short-term memory formed during learning in the form of structural-functional connections in the central nervous system [1,6,7], and of their participation in various forms of behavior.…”

mentioning

confidence: 99%

Participation of cholinergic structures of the prefrontal and inferotemporal cortex in the processes of visual recognition in monkeys

Dudkin

Kruchinin

Chueva

1994

Monkeys performed a task of delayed visual differentiation of differently colored stimuli in behavioral experiments. The impulse activity of individual neurons of the prefrontal and inferotemporal cortex before and after the systemic administration of a blocker of M-cholinoreceptors, amyzil (0.8-1.0 mg/kg), was recorded simultaneously. Deterioration of the characteristics of recognition induced by amyzil was accompanied mainly by a significant increase in the activity of neurons of the prefrontal cortex which was dependant on the stage of recognition, and intensified with an increase in the delay interval. The impulse activity of the neurons of the inferotemporal cortex varied in the process without a regular pattern: at some stages of recognition it increased, at others it was inhibited. Amyzil induced a substantial decrease in the coefficients of cross correlation between the simultaneous respondent reactions of groups of neurons of the prefrontal and inferotemporal cortex. The results obtained point to the fact that the cholinergic structures of the inferotemporal and prefrontal cortex participate, at various stages of visual recognition in monkeys, in the formation of the dynamic functional systems which make their specific contribution to informational processes.