Effects of ad libitum midbrain intracranial self-stimulation on rapid eye movement sleep in rats.
Item
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Title
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Effects of ad libitum midbrain intracranial self-stimulation on rapid eye movement sleep in rats.
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Identifier
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AAI9720148
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identifier
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9720148
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Creator
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Villegas, Francisco.
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Contributor
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Adviser: Steven J. Ellman
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Date
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1997
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Physiological | Biology, Neuroscience
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Abstract
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This study was performed to examine whether ad libitum intracranial self-stimulation (ICSS) elicited from the periaqueductal gray (PAG) significantly reduces REM sleep and prevents the occurrence of subsequent REM rebound in rats. This study evaluates the following: the placement of stimulating electrodes, the occurrence of effects either in the light or dark phase of the circadian cycle, the onset and duration of effects over the 3-day ICSS period, and amount of microcoulomb current delivered to stimulation sites. To assess the specificity of ICSS effects, in REM sleep, SWS, and AWAKE were examined over baseline, ad libitum ICSS, and recovery conditions. It was hypothesized that PAG ICSS should significantly reduce REM sleep during the stimulating condition. It was hypothesized that if PAG ICSS reduces REM sleep, it should also prevent an increase in the intensity or duration of subsequent REM time during the recovery period (REM rebound). Two independent groups (9 unilateral and 9 bilateral electrode sites) were tested for effects over a 9-day repeated measures design to assess differences between baseline, ad libitum ICSS, and recovery condition days, in independent 12-h light, 12-h dark cycles, to detect the presence or absence of cyclical effects upon REM sleep, SWS, and AWAKE. Rats were chronically implanted with bipolar stimulating electrodes aimed bilaterally at the PAG and electrodes to record EEG, EMG, and EOG. Animals were shaped to bar-press for ICSS at a variety of current intensities and were stabilized over a 5-day period at an optimal current intensity eliciting peak ICSS rates. The results show that REM and SWS were significantly decreased during the first day in the ad libitum ICSS condition in both groups of rats in the dark and light cycles. Significant decreases in REM and SWS during the first day of stimulation did not reemerge as increases in days 2 and 3 in the ad libitum condition. However, REM and SWS reductions were more pronounced during days 2 and 3 in the ad libitum condition in lights cycles than in dark cycles. Significant increases in REM sleep and SWS occurred only during the first 12 h dark cycle and were not significant in subsequent recovery cycles. Significant correlations were noted in the absolute number of microcoulombs delivered to each rat during the 3-day stimulation period and resulting REM, SWS, and AWAKE changes. Furthermore, amounts of microcoulombs delivered to unilateral and bilateral electrode sites did not differ significantly from each other for REM sleep differences scores between the baseline and ad libitum conditions.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
