FIGURE 13.8. Comparison of negative 610 nm OIS and BOLD fMRI signals in response to 2 s somatosensory stimulus.

FIGURE 13.8

Comparison of negative 610 nm OIS and BOLD fMRI signals in response to 2 s somatosensory stimulus. (A) Sensorimotor cortex was studied using identical stimulation parameters for fMRI and OIS: 2 s 110 Hz index finger vibration in eight human subjects. The signals occurred adjacent to one another: the center of mass of the signals was separated by ~17 mm. While OIS signals were gyral, fMRI signals centered more superiorly and within sulci, consistent with a venous origin of BOLD fMRI signals. The gyral localization of the iOIS signal is consistent with optical signals emanating from capillary plexuses within the cortex. The BOLD fMRI signal is displayed as a 3D activation both at the surface of the brain and deep within the brain. The fMRI signal has been thresholded for display: all voxels with a p < .01 for the correlation of the signal with a predetermined hemodynamic function are displayed. (B) Comparison of positive 610 nm response with BOLD fMRI using a block paradigm tongue motor task (20 s blocks). Using both modalities, signals were identified near the inferior-lateral aspect of the central sulcus. The positive 610 nm response and the BOLD fMRI signal demonstrate high correlation overlapped spatially (last column). This data supports the notion that the two signals share similar etiologies, associated with the washout of deoxyhemoglobin by in functional recruitment of cerebral blood flow and excess oxyhemoglobin.

From: Chapter 13, Intraoperative Optical Imaging

Cover of In Vivo Optical Imaging of Brain Function
In Vivo Optical Imaging of Brain Function. 2nd edition.
Frostig RD, editor.
Boca Raton (FL): CRC Press/Taylor & Francis; 2009.
Copyright © 2009, Taylor & Francis Group, LLC.

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