The Role of GABA and Glutamate Neuromediators in Generating the BOLD Response

Daniil P. Aksenov¹, Limin Li¹, George Iordanescu¹, Xiaomu Song¹, Alice Wyrwicz¹

Many questions remain about the relationship between the local cellular metabolic and hemodynamic changes measured by fMRI and the underlying neuronal electrical activity. In this study we examined the effect of neuromediators on BOLD and neuronal activity. Simultaneous fMRI and electrophysiological measurements of whisker stimulation were performed before and after localized injection of the GABA agonist and antagonist and glutamate antagonists into the somatosensory cortex. The cocktail of the GABA agonist and antagonist removed stimulus-dependent GABA-ergic responses without affecting the neuronal baseline level and magnitude of the BOLD signal. Glutamate antagonists decreased or abolished BOLD response.