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Proceedings Paper

Saturation thresholds of evoked neural and hemodynamic responses in awake and asleep rats
Author(s): Jennifer L. Schei; Amy S. Van Nortwick; Peter C. Meighan; David M. Rector
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Paper Abstract

Neural activation generates a hemodynamic response to the localized region replenishing nutrients to the area. Changes in vigilance state have been shown to alter the vascular response where the vascular response is muted during wake compared to quiet sleep. We tested the saturation thresholds of the neurovascular response in the auditory cortex during wake and sleep by chronically implanting rats with an EEG electrode, a light emitting diode (LED, 600 nm), and photodiode to simultaneously measure evoked response potentials (ERPs) and evoked hemodynamic responses. We stimulated the cortex with a single speaker click delivered at random intervals 2-13 s at varied stimulus intensities ranging from 45-80 dB. To further test the potential for activity related saturation, we sleep deprived animals for 2, 4, or 6 hours and recorded evoked responses during the first hour recovery period. With increasing stimulus intensity, integrated ERPs and evoked hemodynamic responses increased; however the hemodynamic response approached saturation limits at a lower stimulus intensity than the ERP. With longer periods of sleep deprivation, the integrated ERPs did not change but evoked hemodynamic responses decreased. There may be physical limits in cortical blood delivery and vascular compliance, and with extended periods of neural activity during wake, vessels may approach these limits.

Paper Details

Date Published: 10 February 2011
PDF: 8 pages
Proc. SPIE 7898, Dynamics and Fluctuations in Biomedical Photonics VIII, 78981D (10 February 2011); doi: 10.1117/12.880184
Show Author Affiliations
Jennifer L. Schei, Washington State Univ. (United States)
Amy S. Van Nortwick, Washington State Univ. (United States)
Peter C. Meighan, Washington State Univ. (United States)
David M. Rector, Washington State Univ. (United States)

Published in SPIE Proceedings Vol. 7898:
Dynamics and Fluctuations in Biomedical Photonics VIII
Valery V. Tuchin; Donald D. Duncan; Kirill V. Larin; Martin J. Leahy; Ruikang K. Wang, Editor(s)

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