Analysis of oxygen metabolism implies a neural origin for the negative BOLD response in human visual cortex.

ABSTRACT: The sustained negative blood oxygenation level-dependent (BOLD) response in functional MRI is observed universally, but its interpretation is controversial. The origin of the negative response is of fundamental importance because it could provide a measurement of neural deactivation. However, a substantial component of the negative response may be due to a non-neural hemodynamic artifact. To distinguish these possibilities, we have measured evoked BOLD, cerebral blood flow (CBF), and oxygen metabolism responses to a fixed visual stimulus from two different baseline conditions. One is a normal resting baseline, and the other is a lower baseline induced by a sustained negative response. For both baseline conditions, CBF and oxygen metabolism responses reach the same peak amplitude. Consequen

SUBMITTER: Pasley BN 

PROVIDER: S-EPMC2001204 | biostudies-literature | 2007 Jun

REPOSITORIES: biostudies-literature