Metabolite concentration changes associated with positive and negative BOLD responses in the human visual cortex: A functional MRS study at 7 Tesla

J Cereb Blood Flow Metab. 2020 Mar;40(3):488-500. doi: 10.1177/0271678X19831022. Epub 2019 Feb 12.


Negative blood oxygenation-level dependent (BOLD) signal observed during task execution in functional magnetic resonance imaging (fMRI) can be caused by different mechanisms, such as a blood-stealing effect or neuronal deactivation. Electrophysiological recordings showed that neuronal deactivation underlies the negative BOLD observed in the occipital lobe during visual stimulation. In this study, the metabolic demand of such a response was studied by measuring local metabolite concentration changes during a visual checkerboard stimulation using functional magnetic resonance spectroscopy (fMRS) at 7 Tesla. The results showed increases of glutamate and lactate concentrations during the positive BOLD response, consistent with previous fMRS studies. In contrast, during the negative BOLD response, decreasing concentrations of glutamate, lactate and gamma-aminobutyric acid (GABA) were found, suggesting a reduction of glycolytic and oxidative metabolic demand below the baseline. Additionally, the respective changes of the BOLD signal, glutamate and lactate concentrations of both groups suggest that a local increase of inhibitory activity might occur during the negative BOLD response.

Keywords: Functional magnetic resonance imaging; brain metabolism; functional magnetic resonance spectroscopy; inhibition; negative blood oxygenation–level dependent; neurovascular coupling; positive blood oxygenation–level dependent; visual stimulation.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Female
  • Glutamic Acid / metabolism
  • Humans
  • Lactic Acid / metabolism
  • Magnetic Resonance Imaging*
  • Male
  • Oxygen / metabolism*
  • Photic Stimulation*
  • Visual Cortex* / diagnostic imaging
  • Visual Cortex* / metabolism
  • gamma-Aminobutyric Acid / metabolism*


  • Lactic Acid
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • Oxygen