Reactivation of hippocampal ensemble memories during sleep.

  title={Reactivation of hippocampal ensemble memories during sleep.},
  author={M. Alice Wilson and Bruce L. McNaughton},
  volume={265 5172},
Simultaneous recordings were made from large ensembles of hippocampal "place cells" in three rats during spatial behavioral tasks and in slow-wave sleep preceding and following these behaviors. Cells that fired together when the animal occupied particular locations in the environment exhibited an increased tendency to fire together during subsequent sleep, in comparison to sleep episodes preceding the behavioral tasks. Cells that were inactive during behavior, or that were active but had non… 
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Reactivation of Hippocampal Cell Assemblies: Effects of Behavioral State, Experience, and EEG Dynamics
Pattern reinstatement was strongest during sharp wave–ripple oscillations, suggesting that these events may reflect system convergence onto attractor states corresponding to previous experiences, and do not necessarily reflect persistence of an active memory.
Firing rates of hippocampal neurons are preserved during subsequent sleep episodes and modified by novel awake experience
In a familiar environment, the discharge frequency of simultaneously recorded individual CA1 pyramidal neurons and the coactivation of cell pairs remain highly correlated across sleep–wake–sleep sequences, but both measures were affected when new sets of neurons were activated in a novel environment.
Fast-Forward Playback of Recent Memory Sequences in Prefrontal Cortex During Sleep
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The results indicate that changes in the temporal contingency between neurons are often necessary, but not sufficient, for cortical plasticity in the adult monkey: behavioral relevance is required.
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Parallel recording methods outlined here make possible the study of the dynamics of neuronal interactions during unique behavioral events, which suggests that new spatial information creates conditions in the hippocampal circuitry that are conducive to the synaptic modification presumed to be involved in learning.
Hippocampal electrical activity and voluntary movement in the rat.
  • C. H. Vanderwolf
  • Biology, Psychology
    Electroencephalography and clinical neurophysiology
  • 1969
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The results indicate that fear memory is not a single process and that the hippocampus may have a time-limited role in associative fear memories evoked by polymodal (contextual) but not unimodal (tone) sensory stimuli.
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Performance of a basic visual discrimination task improved after a normal night's sleep, indicating that a process of human memory consolidation, active during sleep, is strongly dependent on REM sleep.
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