Electrophysiological analysis of corticofugal influences on preoptic neurons

Kazakov, V. N.; Kravtsov, P. Ya.; Кузнецов, И В; Терещенко, А. В.

doi:10.1007/bf01052613

Cited by 2 publications

(4 citation statements)

References 7 publications

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“…It should be mentioned that we detected a certain gradient in inhibitory drive, which we consider in the phylogenetic aspect [14,15]. The minimum proportion of inhibitory responses was observed when the neopaleocortex (the proreal gyrus) was stimulated.…”

Section: Discussionmentioning

confidence: 99%

Corticofugal influences on the neurons of different regions of the hypothalamus

1997

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Responses of the neurons of the lateral and ventromedial hypothalamic regions (HL and Hvrn, respectively), as well as of the area of the dorsal hypothalamus (arid) and the projection region of the medial forelimb bundle (MFB), evoked by stimulation of the proreal cortex (field 8), cingular cortex (field 24), pyriform Iobula (periamigdalar cortex), and hippocampus (CA3) were studied in acute experiments on cats under ketamine anesthesia. Distributions of the latent periods of the responses recorded from hypothalamic neurons at stimulation of the above cortical structures were analyzed. The responses were classified into primary excitatory and primary inhibitory. Stimulation of the proreal gyrus evoked four times more excitatory responses than inhibitory responses. With stimulation of the cingular gyrus, the ratio of excitatory/inhibitory responses was 1.5:1. Stimulation of the pyriform cortex evoked activatory and inhibitory responses with a similar probability. With hippocampal stimulation, inhibitory responses appeared two times more frequently than excitatory reactions. The hypothalamus was found to be a zone of wide convergence: one-half of all responding neurons in the HL and Hvm responded to stimulations of two or more tested cortical zones. In 26~o of the cells, only excitatOry convergence was observed, while in 10~o only inhibitory convergence was found; 21 ~/~, of the cells revealed mixed convergence.

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Section: Discussionmentioning

confidence: 99%

Corticofugal influences on the neurons of different regions of the hypothalamus

1997

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“…As was already mentioned, these were the proreal and cingular cortices, cortical regions of the pyriform lobe, and hippocampus [6,30,32,33,36].…”

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confidence: 98%

“…Series of stimuli applied to the cortical structures, in addition to changes in the mean frequency of the IA (its enhancement or inhibition), which we described earlier in detail [29,[31][32][33][34][35], can also, in many cases, evoke alterations of the temporal structure (distribution) of ISI. In the RPO neurons, responses of two types were most frequently generated after serial cortical stimulations.…”

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confidence: 99%

“…V. N. Kazakov, are directed toward examination of neuronal responses in the anterior hypothalamus, in particular in the preoptic region (RPO); these responses are evoked by electrical stimulation of a number of central structures, including cortical zones, and by different visceral stimuli. Special attention is paid to the characteristics and peculiarities of the BIA of hypothalamic neurons [6,[29][30][31][32][33][34][35][36].…”

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Modulation of neuronal impulse activity of the anterior hypothalamus as a functional basis of the mechanisms underlying hypothalamic control

Kazakov

Natrus

2005

Neurophysiology

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We examined the neuronal activity of hypothalamic neurons in acute experiments on cats under ketamine anesthesia. Using glass microelectrodes, we extracellularly recorded the impulse activity (IA) of neurons of the anterior hypothalamus in the absence of controlled influences (background IA, BIA) and after stimulation of evolutionary heterogeneous zones of the brain cortex projecting to the hypothalamus (hippocampal СА3 area, pyriform, cingular, and proreal gyri). Electrical 5-sec-long stimuli were applied with frequencies of 12, 30, or 100 sec -1 . In another experimental series, we recorded changes in the IA of hypothalamic neurons induced by visceral stimuli (heating or cooling by 7°С of the foot pad, cooling of the body of the animal, and infusions of 5% glucose, 0.2% NaCl, 3.0% NaCl, or phenylephrine in the carotid artery), modeling in such a way shifts of the constants of homeostasis within physiological limits. We also compared the parameters of neuronal BIA and stimulation-influenced IA in equal epochs of the analysis and classified the types of BIA. About 50% of the cells of the total studied sampling of hypothalamic neurons responded by a considerable modulation of their BIA with a significant change in the frequency in the course of and after stimulations of the abovementioned modalities. In some neurons after cortical or visceral stimulation, a significant transformation of the temporal structure of the IA with no changes in the mean frequency occurred. We hypothesize that stimulation-induced transformation of the IA pattern with preservation of the mean discharge frequency can be one of the modes of encoding of information necessary for triggering of one efferent reaction or another, which are controlled by the hypothalamus. Examination of the BIA parameters of subcortical neurons, as well as comparison of the parameters of such an activity with the localization of cells and with the modality of stimulation that leads to modification of the IA, should allow one to reveal reasons for the formation and modification of the IA on neurons of the anterior hypothalamus. Since functional peculiarities of the neurons correlate with their BIA pattern, such data can provide an insight into the functional bases of the neurophysiological mechanisms underlying regulatory functions of the hypothalamus.

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Electrophysiological analysis of corticofugal influences on preoptic neurons

Cited by 2 publications

References 7 publications

Corticofugal influences on the neurons of different regions of the hypothalamus

Corticofugal influences on the neurons of different regions of the hypothalamus

Modulation of neuronal impulse activity of the anterior hypothalamus as a functional basis of the mechanisms underlying hypothalamic control

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