Investigating dACC glutamate modulation during inhibitory motor control: A 1H fMRS study with a novel interleaved control condition

Motivation: Inhibitory control deficits are implicated in multiple psychiatric diseases yet the neural mechanisms supporting inhibitory control remain unclear. Goal(s): Using 1H functional Magnetic Resonance Spectroscopy (1H fMRS), we measured glutamate levels in the dorsal anterior cingulate cortex (dACC) during two cognitive paradigms: one requiring only motor control (Non-Selective) and one requiring motor and inhibitory control (Selective). Approach: We characterized shifts in dACC glutamate across Non-Selective and Selective responding using an interleaved control condition that mimicked the task conditions but without motor responses. Results: Among healthy adults, results show elevated dACC glutamate steady state levels during motor control compared to an interleaved control condition. Impact: The current study advances the application of 1H fMRS by identifying differential glutamate modulation under cognitive control processes known to be impaired in psychiatric disorders.