Functional decoupling of BOLD and gamma-band amplitudes in human primary visual cortex

Muthukumaraswamy, Suresh Daniel ORCID: https://orcid.org/0000-0001-7042-3920 and Singh, Krishna Devi ORCID: https://orcid.org/0000-0002-3094-2475 2009. Functional decoupling of BOLD and gamma-band amplitudes in human primary visual cortex. Human Brain Mapping 30 (7) , pp. 2000-2007. 10.1002/hbm.20644

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Abstract

Although functional magnetic resonance imaging is an important tool for measuring brain activity, the hemodynamic blood oxygenation level dependent (BOLD) response is only an indirect measure of neuronal activity. Converging evidence obtained from simultaneous recording of hemodynamic and electrical measures suggest that the best correlate of the BOLD response in primary visual cortex is gamma-band oscillations (∼40 Hz). Here, we examined the coupling between BOLD and gammaband amplitudes measured with magntoencephalography (MEG) in human primary visual cortex in 10 participants. In Experiment A, participants were exposed to grating stimuli at two contrast levels and two spatial frequencies and in Experiment B square and sine wave stimuli at two spatial frequencies. The amplitudes of both gamma-band oscillations and BOLD showed tuning with stimulus contrast and stimulus type; however, gamma-band oscillations showed a 300% increase across two spatial frequencies, whereas BOLD exhibited no change. This functional decoupling demonstrates that increased amplitude of gamma-band oscillations as measured with MEG is not sufficient to drive the subsequent BOLD response.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Cardiff University Brain Research Imaging Centre (CUBRIC) Neuroscience and Mental Health Research Institute (NMHRI) Psychology
Subjects:	Q Science > QM Human anatomy R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
Uncontrolled Keywords:	oscillations ; magnetoencephalography ; functional magnetic resonance imaging ; spatial frequency ; V1
Publisher:	Wiley-Blackwell
ISSN:	1065-9471
Last Modified:	18 Oct 2022 12:55
URI:	https://orca.cardiff.ac.uk/id/eprint/11598

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