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Abstract #0755

Tight Neurovascular Coupling in Human Sensorimotor Cortex: A Combined ECoG and 7T BOLD fMRI Experiment

Jeroen Cornelis Willem Siero1, 2, Dora Hermes1, 3, Hans Hoogduin2, Peter R. Luijten2, Natalia Petridou2, Nick F. Ramsey1

1Rudolf Magnus Institute, University Medical Center Utrecht, Utrecht, Netherlands; 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 3Stanford University, Stanford, CA, United States

An often reported mismatch between expected and measured BOLD responses with increasing stimulus rates has led to the notion that neurovascular coupling is non-linear. We assess the neurovascular coupling of the sensorimotor cortex with a motor task by combining presurgical 7T BOLD fMRI and high density intracranial electrocorticography (ECoG) grids post-implant in the same subjects. With increasing movement rate the amplitude of both the BOLD and the ECoG broadband high frequency gamma response declined. The latter explained almost 80% of the apparent BOLD nonlinearity, indicating that in human sensorimotor cortex the BOLD response is tightly linked to neuronal activity.