JN Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


J Neurophysiol 80: 1522-1532, 1998;
0022-3077/98 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cannestra, A. F.
Right arrow Articles by Toga, A. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cannestra, A. F.
Right arrow Articles by Toga, A. W.

The Journal of Neurophysiology Vol. 80 No. 3 September 1998, pp. 1522-1532
Copyright ©1998 The American Physiological Society

Refractory Periods Observed by Intrinsic Signal and Fluorescent Dye Imaging

Andrew F. Cannestra, Nader Pouratian, Marc H. Shomer, and Arthur W. Toga

Department of Neurology, Laboratory of Neuro Imaging, Division of Brain Mapping, University of California at Los Angeles School of Medicine, Los Angeles, California 90095-1769

Cannestra, Andrew F., Nader Pouratian, Marc H. Shomer, and Arthur W. Toga. Refractory periods observed by intrinsic signal and fluorescent dye imaging. J. Neurophysiol. 80: 1522-1532, 1998. All perfusion-based imaging modalities depend on the relationship between neuronal and vascular activity. However, the relationship between stimulus and response was never fully characterized. With the use of optical imaging (intrinsic signals and intravascular fluorescent dyes) during repetitive stimulation paradigms, we observed reduced responses with temporally close stimuli. Cortical evoked potentials, however, did not produce the same reduced responsiveness. We therefore termed these intervals of reduced responsiveness "refractory periods." During these refractory periods an ability to respond was retained, but at a near 60% reduction in the initial magnitude. Although increasing the initial stimulus duration lengthened the observed refractory periods, significantly novel or temporally spaced stimuli overcame them. We observed this phenomenon in both rodent and human subjects in somatosensory and auditory cortices. These results have significant implications for understanding the capacities, mechanisms, and distributions of neurovascular coupling and thereby possess relevance to all perfusion-dependent functional imaging techniques.







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online