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Abstract:
Abstract: This study examined how the human brain allocates
its resources during sleep. In particular, it examined whether
there are unilateral brain changes in response to disrupting
environmental stimuli. Prior research suggests that some marine
mammals and birds show uni-hemispheric sleep as a means of
maintaining environmental awareness. This current study
investigated human hemispheric asymmetries in slow-wave activity
during naps. Vibration was intermittently delivered to one hand
after the subject entered stage 4 sleep. (Most studies report
asymmetries to be largest in stage 4). Delta-band activity was
compared between the left and right hemispheres before and during
stimulation. As somatosensory input is strongly lateralized to the
opposite hemisphere, it was hypothesized that during stimulation,
the hemisphere contralateral to the stimulated hand would show less
delta-band activity, since it is receiving intruding input from the
environment. Preliminary results from 6 subjects show no
significant change in asymmetry from before to during stimulation.
This finding indicates that the unilateral stimulation used in this
study does not induce hemispheric asymmetry in the EEG during
slow-wave sleep. This has interesting implications for
environmental awareness thresholds during human sleep. Future
directions may include the use of varying levels of more intrusive
stimuli.
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