Sustained negative BOLD, blood flow and oxygen consumption response and its coupling to the positive response in the human brain

Amir Shmuel, Essa Yacoub, Josef Pfeuffer, Pierre Francois Van de Moortele, Gregor Adriany, Xiaoping Hu, Kamil Ugurbil

Research output: Contribution to journalArticle

422 Scopus citations


Most fMRI studies are based on the detection of a positive BOLD response (PBR). Here, we demonstrate and characterize a robust sustained negative BOLD response (NBR) in the human occipital cortex, triggered by stimulating part of the visual field. The NBR was spatially adjacent to but segregated from the PBR. It depended on the stimulus and thus on the pattern of neuronal activity. The time courses of the NBR and PBR were similar, and their amplitudes covaried both with increasing stimulus duration and increasing stimulus contrast. The NBR was associated with reductions in blood flow and with decreases in oxygen consumption. Our findings support the contribution to the NBR of (1) a significant component of reduction in neuronal activity and (2) possibly a component of hemodynamic changes independent of the local changes in neuronal activity.

Original languageEnglish (US)
Pages (from-to)1195-1210
Number of pages16
Issue number6
StatePublished - Dec 19 2002


Cite this