PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 7654303

Ventral pallidum self-stimulation: a moveable electrode mapping study.

G Panagis·E Miliaressis·Y Anagnostakis·C Spyraki
View original source ↗Export metadata ↓

Abstract

The distribution of electrical self-stimulation (ESS) foci within the ventral pallidum (VP) was mapped using moveable electrodes in rats. The function relating ESS bar-pressing rate to the frequency of cathodal rectangular pulses (0.4 mA and 0.1 ms) was obtained for several positions of a moveable electrode in the VP and in the various adjacent to VP nuclei. The rate-frequency functions were fitted to a sigmoid model to obtain the asymptotic rate and threshold frequency. ESS was found in almost all (98%) VP sites tested and to a lesser degree (66%) in the surrounding areas (namely globus pallidus and caudate). Depending on the VP site, maximum rates varied from 14 to 85 bar presses/min, whereas threshold frequencies varied from 10.2 to 36.4 pulses/train; no correlation between these two aspects of ESS was found. Extra-pallidal areas contained less low-frequency threshold sites compared to VP. The lowest threshold found in the VP was slightly higher than that usually obtained for the most rewarding brain areas (VTA, dorsal raphé, LH, amygdala), which suggests that the VP represents an important structure for reward. Furthermore the threshold frequencies were found to decline along the rostrocaudal axis of the VP which supports the view that the VP is heterogeneous in regard to reward related functions.

Explore related subjects

AmygdalaAnimalsAppetitive BehaviorBrain MappingElectrodesGlobus PallidusMaleMotivationNeural PathwaysRaphe NucleiRatsRats, Sprague-DawleySelf StimulationSensory ThresholdsTegmentum MesencephaliJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G Panagis, E Miliaressis, Y Anagnostakis, C Spyraki. 1995. Ventral pallidum self-stimulation: a moveable electrode mapping study.. https://doi.org/10.1016/0166-4328(94)00169-g

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1995

Pregnenolone sulfate enhances post-training memory processes when injected in very low doses into limbic system structures: the amygdala is by far the most sensitive.

Immediate post-training, stereotactically guided, intraparenchymal administration of pregnenolone sulfate (PS) into the amygdala, septum, mammillary bodies, or caudate nucleus and of PS, dehydroepiandrosterone sulfate, and corticosterone into the hippocampus was performed in mice that had been weakly trained in a foot-shock active avoidance paradigm. Intrahippocampal injection of PS resulted in memory enhancement (ME) at a lower dose than was found with dehydroepiandrosterone sulfate and corticosterone. Intraamygdally administered PS was approximately 10(4) times more potent on a molar basis in producing ME than when PS was injected into the hippocampus and approximately 10(5) times more potent than when injected into the septum or mammillary bodies. ME did not occur on injection of PS into the caudate nucleus over the range of doses tested in the other brain structures. The finding that fewer than 150 molecules of PS significantly enhanced post-training memory processes when injected into the amygdala establishes PS as the most potent memory enhancer yet reported and the amygdala as the most sensitive brain region for ME by any substance yet tested.

Amygdala↗
PubMed1995

Organization of projections from the medial nucleus of the amygdala: a PHAL study in the rat.

The organization of axonal projections from the four recognized parts of the medial amygdalar nucleus (MEA) were characterized with the Phaesolus vulgaris leucoagglutinin (PHAL) method in male rats. The results indicate that the MEA consists of two major divisions, ventral and dorsal, and that the former may also consist of rostral and caudal regions. As a whole, the MEA generates centrifugal projections to several parts of the accessory and main olfactory sensory pathways, and projections to a) several parts of the intrahippocampal circuit (ventrally); b) the ventral striatum, ventral pallidum, and bed nuclei of the stria terminalis (BST) in the basal telencephaon; c) many parts of the hypothalamus; d) midline and medial parts of the thalamus; and e) the periaqueductal gray, ventral tegmental area, and midbrain raphé. The dorsal division of the MEA (the posterodorsal part) is characterized by projections to the principal nucleus of the BST, and to the anteroventral periventricular, medial, and central parts of the medial preoptic, and ventral premammillary hypothalamic nuclei. These hypothalamic nuclei project heavily to neuroendocrine and autonomic-related parts of the hypothalamic periventricular zone. The ventral division of the MEA (the anterodorsal, anteroventral, and posteroventral parts) is characterized by dense projections to the transverse and interfascicular nuclei of the BST, and to the lateral part of the medial preoptic, anterior hypothalamic, and ventromedial hypothalamic nuclei. However, dorsal regions of the ventral division provide rather dense inputs to the medial preoptic region and capsule of the ventromedial nucleus, whereas ventral regions of the ventral division preferentially innervate the anterior hypothalamic, dorsomedial, and ventral parts of the ventromedial nuclei. Functional evidence suggests that circuits associated with dorsal regions of the ventral division may deal with reproductive behavior, whereas circuits associated with ventral regions of the ventral division may deal preferentially with agonistic behavior.

Amygdala↗