Cellular and network mechanisms of rhythmic recurrent activity in neocortex.
The neocortex generates periods of recurrent activity, such as the slow (0.1-0.5 Hz) oscillation during slow-wave sleep. Here we demonstrate that slices of ferret neocortex maintained in vitro generate this slow (< 1 Hz) rhythm when placed in a bathing medium that mimics the extracellular ionic composition in situ. This slow oscillation seems to be initiated in layer 5 as an excitatory interaction between pyramidal neurons and propagates through the neocortex. Our results demonstrate that the cerebral cortex generates an 'up' or depolarized state through recurrent excitation that is regulated by inhibitory networks, thereby allowing local cortical circuits to enter into temporarily activated and self-maintained excitatory states. The spontaneous generation and failure of this self-excited state may account for the generation of a subset of cortical rhythms during sleep.
Sanchez-Vives
M V
MV
Section of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA. david.mccormick@yale.edu
McCormick
D A
DA
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002415:Cats; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D046508:Culture Techniques; D004594:Electrophysiology; D004827:Epilepsy / Q000503:physiopathology; D005289:Ferrets; D009415:Nerve Net / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010507:Periodicity; D012032:Refractory Period, Electrophysiological / Q000502:physiology; D012890:Sleep / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology