Electrophysiological imaging suggests that task induced change in beta oscillations (13-30Hz) modulates with attention, and reflects synaptic inhibitory responses. GABA is known to mediate synaptic inhibition and hence may relate to these electrophysiological dynamics. Here, we determined GABA concentration in primary sensorimotor cortex, using MRS at 7T, and measured the electrophysiological response to a sensory attention task, using MEG, in the same region. We correlated the post-stimulus synchronisation in beta in the left sensory-motor cortex with GABA concentration detected using a STEAM sequence. Results show significant correlation (R = 0.48; p 0.010) across 28 participants.