Effects of ventrobasal lesion and cortical cooling on fast oscillations (>200 Hz) in rat somatosensory cortex.
High-frequency oscillatory activity (>200 Hz) termed "fast oscillations" (FO) have been recorded in the rodent somatosensory cortex and may reflect very rapid integration of vibrissal information in sensory cortex. Yet, while electrophysiological correlates suggest that FO is generated within intracortical networks, contributions of subcortical structures along the trigeminal pathway remain uncertain. Using surface and laminar electrode arrays, in vivo recordings of vibrissal and electrically evoked FO were made within somatosensory cortex of anesthetized rodents before and after ablation of the ventrobasal thalamus (VB) or during reversible cortical cooling. In VB-lesioned animals, vibrissal stimulation failed to evoke FO, while epicortical stimulation in lesioned animals remained effective in generating FO. In nonlesioned animals, cortical cooling eliminated vibrissal-evoked FO despite the persistence of thalamocortical input. Vibrissal-evoked FO returned with the return to physiological temperatures. Results from this study indicate that somatosensory cortex alone is able to initiate and sustain FO. Moreover, these data suggest that cortical network interactions are solely responsible for the generation of FO, while synchronized thalamocortical input serves as the afferent trigger.
Staba
Richard J
RJ
Department of Psychology, University of Colorado, Boulder 80309, USA.
Brett-Green
Barbara
B
Paulsen
Marcy
M
Barth
Daniel S
DS
D000818:Animals; D003080:Cold Temperature; D004558:Electric Stimulation; D004594:Electrophysiology; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000187:drug effects / Q000502:physiology*; D013787:Thalamic Nuclei / Q000187:drug effects / Q000502:physiology*; D014738:Vibrissae / Q000294:innervation / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine