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- Title
Suppressed Neuronal Activity and Concurrent Arteriolar Vasoconstriction May Explain Negative Blood Oxygenation Level-Dependent Signal.
- Authors
Devor, Anna; Peifang Tian; Nishimura, Nozomi; Teng, Ivan C.; Hillman, Elizabeth M. C.; Narayanan, S. N.; Ulbert, Istvan; Boas, David A.; Kleinfeld, David; Dale, Anders M.
- Abstract
Synaptic transmission initiates a cascade of signal transduction events that couple neuronal activity to local changes in blood flow and oxygenation. Although a number of vasoactive molecules and specific cell types have been implicated, the transformation of stimulusinduced activation of neuronal circuits to hemodynamic changes is still unclear. We use somatosensory stimulation and a suite of in vivo imaging tools to study neurovascular coupling in rat primary somatosensory cortex. Our stimulus evoked a central region of net neuronal depolarization surrounded by net hyperpolarization. Hemodynamic measurements revealed that predominant depolarization corresponded to an increase in oxygenation, whereas predominant hyperpolarization corresponded to a decrease in oxygenation. On the microscopic level of single surface arterioles, the response was composed of a combination of dilatory and constrictive phases. Critically, the relative strength of vasoconstriction covaried with the relative strength of oxygenation decrease and neuronal hyperpolarization. These results suggest that a neuronal inhibition and concurrent arteriolar vasoconstriction correspond to a decrease in blood oxygenation, which would be consistent with a negative blood oxygenation level-dependent functional magnetic resonance imaging signal.
- Subjects
HEMODYNAMICS; BLOOD flow; NEURAL circuitry; MAGNETIC resonance imaging; LABORATORY rats
- Publication
Journal of Neuroscience, 2007, Vol 27, Issue 16, p4452
- ISSN
0270-6474
- Publication type
Article
- DOI
10.1523/JNEUROSCI.0134-07.2007