Auditory Responses and Stimulus-Specific Adaptation in Rat Auditory Cortex are Preserved Across NREM and REM Sleep

Department of Psychiatry, University of Wisconsin-Madison, Madison, WI 53719, USA.
Cerebral Cortex (Impact Factor: 8.67). 12/2013; 25(5). DOI: 10.1093/cercor/bht328
Source: PubMed


Sleep entails a disconnection from the external environment. By and large, sensory stimuli do not trigger behavioral responses
and are not consciously perceived as they usually are in wakefulness. Traditionally, sleep disconnection was ascribed to a
thalamic “gate,” which would prevent signal propagation along ascending sensory pathways to primary cortical areas. Here,
we compared single-unit and LFP responses in core auditory cortex as freely moving rats spontaneously switched between wakefulness
and sleep states. Despite robust differences in baseline neuronal activity, both the selectivity and the magnitude of auditory-evoked
responses were comparable across wakefulness, Nonrapid eye movement (NREM) and rapid eye movement (REM) sleep (pairwise differences
<8% between states). The processing of deviant tones was also compared in sleep and wakefulness using an oddball paradigm.
Robust stimulus-specific adaptation (SSA) was observed following the onset of repetitive tones, and the strength of SSA effects
(13–20%) was comparable across vigilance states. Thus, responses in core auditory cortex are preserved across sleep states,
suggesting that evoked activity in primary sensory cortices is driven by external physical stimuli with little modulation
by vigilance state. We suggest that sensory disconnection during sleep occurs at a stage later than primary sensory areas.

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Available from: Vladyslav Vyazovskiy, Dec 20, 2013

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