Temporal modulation of spatial borders in rat barrel cortex.
Bhavin R. Sheth, Christopher I. Moore and Mriganka Sur.
Department of Brain and Cognitive Sciences, M.I.T., Cambridge, MA
02139.
APStracts 4:228N, 1997.
ABSTRACT
We examined the effects of varying vibrissa stimulation frequency on intrinsic
signal and neuronal responses in rat barrel cortex. Optical imaging of
intrinsic signals demonstrated that the region of cortex activated by
deflection of a single vibrissa at 1 Hz is more diffuse and more widespread
than the territory activated at 5 or 10 Hz. Using two different paradigms,
constant time of stimulation and constant number of vibrissa deflections, we
showed that optically imaged center of activity is more discrete at higher
stimulation frequencies. We combined optical imaging with multiple electrode
recording and confirmed that the neuronal response to individual vibrissa
stimulation at the optically imaged center of activity is greater than the
response away from the imaged center. Consistent with the imaging data, these
recordings also showed no response to a second vibrissa deflection at 5Hz at a
peripheral recording site, though there was a significant response to a second
vibrissa deflection at 1 Hz at the same peripheral site. These findings
demonstrate that vibrissa stimulation at higher frequencies leads to more
focused physiological responses in cortex. Thus, the spread of activation in
rat barrel cortex is modulated in a dynamic fashion by the frequency of
vibrissa stimulation.
Received 9 June 1997; accepted in final form 4 September 1997.
APS Manuscript Number J468-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 7 October 1997