Neuroscience 2002 Abstract
| Presentation Number: | 840.7 |
|---|---|
| Abstract Title: | Cellular mechanisms of sleep related modulation of somatosensory evoked potentials. |
| Authors: |
Rosanova, M.*1
; Timofeev, I.1
1Dept of Anat. & Physiol., Laval University, Quebec, Canada |
| Primary Theme and Topics |
Sensory Systems - Tactile/Somatosensory -- Cortex and thalamocortical relationships |
| Secondary Theme and Topics | Sensory Systems<br />- Tactile/Somatosensory<br />-- Pathways and processing |
| Session: |
840. Tactile/somatosensory: cortex and thalamocortical interactions II Poster |
| Presentation Time: | Thursday, November 7, 2002 10:00 AM-11:00 AM |
| Location: | Hall A2-B3 D-90 |
| Keywords: | CORTEX, THALAMUS, SLEEP, INTRACELLULAR RECORDING |
Periods of disfacilitation associated with EEG depth-positive waves and long-lasting hyperpolarization of cortical and thalamic neurons are essential features of slow wave sleep. Electrical stimulation of prethalamic pathways in cats during EEG depth-positivity fails to elicit cortical responses (Timofeev et al., 1996, J. Physiol). Recent human studies showed a modulation of somatosensory evoked potential by the slow sleep oscillation, but the responses were not abolished at any given phase of the slow sleep oscillation (Massimini et al., 2001, SFN abstr.). In the present study conducted on anesthetized cats we investigated the mechanisms of these differences. We found that electrical stimulation of contralateral forelimb elicits variable cellular and field potential responses in somatosensory cortex in all phases of the slow oscillation. The responses to electrical stimulation of medial lemniscus were significantly decreased or abolished during EEG depth-positive waves. Intracellular recordings from VPL nucleus of thalamus showed that medial lemniscus stimulation elicited single EPSPs in VPL neurons that usually reached their firing threshold outside periods of the EEG depth-positivity. Forelimb stimulation elicited barrages of 3 to 10 EPSPs that triggered spikes in VPL neurons because of temporal summation during all phases of the slow oscillation. Our data suggest that maintained responsiveness to peripheral stimuli during different components of the slow oscillation is based on ability of medulla oblongata neurons to generate high frequency firing in response to peripheral stimulation.
Supported by CIHR, FRSQ, University of Milan
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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