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Sleep and perceptual learning| old_uid | 4152 |
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| title | Sleep and perceptual learning |
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| start_date | 2008/02/21 |
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| schedule | 14h |
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| online | no |
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| summary | Recently, a considerable number of studies have suggested that sleep
plays an important role in learning consolidation, although it is
still controversial. In the present study, we examined consolidation
related brain activity during sleep after a visual perceptual
training. We measured brain activity in sleep for 90 min
simultaneously using polysomnography and functional magnetic resonance
imaging at 3 Tesla magnetic field. First, subjects spent 2 adaptation
nights in which they slept inside the MRI scanner with electrodes
attached so that they familiarized themselves with falling asleep
inside the scanner. Then, we measured BOLD signals in the visual
cortex before and after an intensive training of a texture
discrimination task. Perceptual learning of this task has a location
specific training effect and may involve the primary visual cortex
(V1) (Karni & Sagi, 1991). The task stimulus was presented only in one
visual field quadrant. The post-training sleep session was conducted
at the same night as the training, approximately 6 hours after the
training session. Relative BOLD changes during sleep compared to that
in the wake period after sleep were calculated in both the trained and
untrained regions in V1. Sleep stages were scored according to the
standard criteria. V1 in each subject had been localized in advance in
a separate fMRI session by a standard retinotopic mapping technique.
In the post-training sleep period, the relative brain change in the
trained region in V1 was significantly higher than in the untrained
region while there was no significant difference between the untrained
and trained regions in the pre-training sleep. In the re-test
behavioral session, which was
conducted immediately after the post-training sleep, subjects'
performance was significantly higher than in the initial training. The
significant correlation was found between performance and the brain
activity in the trained region. The performance improvement is
attributed to the sleep rather than the mere time passage between the
initial training and the re-test sessions, since no performance
improvement was observed in the control condition where no sleep took
place in the same time interval as in the main experiment. These
results indicate that sleep consolidation process for the perceptual
learning occurs in a retinotopically highly localized circuit specific
to the location of a trained stimulus. |
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| responsibles | Information non disponible |
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