Spontaneously emerging cortical representations of visual attributes.
Spontaneous cortical activity--ongoing activity in the absence of intentional sensory input--has been studied extensively, using methods ranging from EEG (electroencephalography), through voltage sensitive dye imaging, down to recordings from single neurons. Ongoing cortical activity has been shown to play a critical role in development, and must also be essential for processing sensory perception, because it modulates stimulus-evoked activity, and is correlated with behaviour. Yet its role in the processing of external information and its relationship to internal representations of sensory attributes remains unknown. Using voltage sensitive dye imaging, we previously established a close link between ongoing activity in the visual cortex of anaesthetized cats and the spontaneous firing of a single neuron. Here we report that such activity encompasses a set of dynamically switching cortical states, many of which correspond closely to orientation maps. When such an orientation state emerged spontaneously, it spanned several hypercolumns and was often followed by a state corresponding to a proximal orientation. We suggest that dynamically switching cortical states could represent the brain's internal context, and therefore reflect or influence memory, perception and behaviour.
Kenet
Tal
T
Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel. (tal@phy.ucsf.edu
Bibitchkov
Dmitri
D
Tsodyks
Misha
M
Grinvald
Amiram
A
Arieli
Amos
A
D000465:Algorithms; D000758:Anesthesia; D000818:Animals; D001931:Brain Mapping; D002415:Cats; D005456:Fluorescent Dyes; D009949:Orientation / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
D005456:Fluorescent Dyes