The 5-12 Hz oscillations in the barrel cortex of awake rats--sustained attention during behavioral idling?
OBJECTIVE
5-12 Hz oscillations, observed in cortical LFP of awake rats during quiet immobility, were proposed to be either (i) epileptic events or (ii) physiological alpha-like oscillations, manifesting an idling state of the cortex. We aimed to test this controversy.


METHODS
We recorded LFP from the barrel cortex of awake Wistar rats, while applying weak tactile (whisker) and stronger arousing (electrical) stimuli.


RESULTS
We observed a mean effect of desynchronization of the 5-12 Hz rhythm by the weak tactile stimulation. Arousal reduced the incidence of the 5-12 Hz oscillations and increased the desynchronizing power of tactile stimuli.


CONCLUSIONS
Oscillations that can be disrupted by weak, purely tactile stimulation, and whose incidence is reduced by increased arousal, should be interpreted as a physiological phenomenon typical for behavioral idling while the cerebral cortex maintains sensory sensitivity.


CONCLUSIONS
Our results contradict the view that the 5-12 Hz oscillatory activity, often observed in fronto-parietal cortical regions of Wistar rats, represents epileptic discharges. Rather, this activity provides a model for studying the physiology of alpha/mu oscillations.
Sobolewski
Aleksander
A
Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland.
Swiejkowski
Daniel A
DA
Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland.
Wróbel
Andrzej
A
Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland.
Kublik
Ewa
E
Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland. Electronic address: e.kublik@nencki.gov.pl.
D000513:Alpha Rhythm; D000818:Animals; D001143:Arousal / Q000502:physiology; D016477:Artifacts; D001288:Attention / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D003344:Cortical Synchronization; D003627:Data Interpretation, Statistical; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D008297:Male; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D012146:Rest / Q000502:physiology; D013003:Somatosensory Cortex / Q000033:anatomy & histology / Q000502:physiology*; D014738:Vibrissae / Q000502:physiology; D014851:Wakefulness / Q000502:physiology*