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Biomedical subjects

A A Orlov

Publications and source records attributed to A A Orlov.

At least 73 records · Page 4Linked to original sources
PubMed1979

Unit activity of the prefrontal cortex during delayed alternation performance in monkey.

Unit activity in the dorsolateral regions of the prefrontal cortex (s. principalis) of the monkey was analysed by multineuronal recording technique. The sequence during delayed-response alternation included anticipatory stimulus, non-specific expectancy, conditioned cue, delay, trigger stimulus and alternation performance. Food reward completed the sequence. Unit activity in s. principalis was found to be involved in such learning processes as integration of behavioural acts into an accomplished programme and storage of traces in short-term memory. The latter can be observed in successive involvement of neuronal populations during a 10 sec delay as well as in rearrangements of unit activity, the maximum of which shifts to the latest part of the delay period. Unit activity in s. principalis reflects the level of correct response, corresponding correlates of which depend on the level of attention. The dorsolateral prefrontal cortex has structural and functional characteristics for short-term storage of external signals in its neuronal nets according to the level of attention.

Animals↗
PubMed1976

[Changes in the activity of the cat sensomotor cortex under heterosensory stimulation].

In immobilized cats, the sensorymotor neurons were shown, in the course of habituation to the rhythmic light stimulation (1/sec), to start responding to stimuli of other modalities (somatic) when the latter were presented during the functional recovery cycle following the light stimulation. The habituation to the light stimuli did not occur when they were followed by a somatic stimulus with 100-300 msec delay. The data obtained seem to reflect the reconstruction occurring in the functional state of the sensory system.

Animals↗
PubMed1975

[The heterosensory interaction of neurons in the cat frontal association cortex].

The interaction of various sensory inputs in the cat frontal neurons was studied in the motor cortex (MI), the area of the hind-limb contralateral representation (SI), and the area of the fore-limb contralateral representation (S'I), with the aid of heteromodal stimulation. Mutual blocks between various inputs (visual, auditory, contralateral hind-limb and fore-limb projections) were observed in MI and SI within the 100-600 msec intervals. Teleceptive inputs in the contralateral fore-limb representation did not block the somatic ones, though the latter blocked the teleceptive inputs within long intervals (3000 msec and more). The somatic input interactions manifested themselves in asymmetric blocks. The cortical type of the heterosensory block seemed to prevail in the fore-limb cortical projection, while multisynaptic blocking throughout the entire neuronal chains prevailed in the MI zone and in the cortical hind-limb projection.

Animals↗
PubMedDate not supplied

Role of the frontal lobes in integrative activity of the brain in Macaca mulatta.

Unit activity in the frontal cortex (s. principalis) during the performance of a complex behavior program--nonspecific expectation after a warning stimulus, conditioned stimulus, and delay period, trigger signal, and alternative choice, followed by food award--was studied by the multineuronal recording method. Processes of combination of external stimuli into an integrated program, retention of stimulus traces in the memory, and correct and incorrect problem solving were reflected in the unit activity of s. principalis. The level of the correct responses of choice and the corresponding correlates in modifications of unit activity depended directly on the level of food motivation. The results are discussed from the standpoint of the evolutionary formation of the thalamo-frontal association system of the brain, connected with the formation of behavior programs in accordance with current biological motivation.

Animals↗