GABA and glutamate interplay during tactile processing: an fMRS study

Tactile adaptation, the adjustment of neural and behavioural responses to repeated stimulation, is crucial for interacting with our environment and is often affected in neurodevelopmental conditions. While GABA and glutamate, the main inhibitory and excitatory neurotransmitters, are essential for sensory encoding, their dynamic responses during tactile stimulation and their influence on perception remain unclear. Using functional magnetic resonance spectroscopy (fMRS), we investigated in vivo GABA and glutamine+glutamate (Glx) dynamics during repetitive tactile stimulation in healthy individuals. Here we found that repetitive stimulation markedly altered GABA–Glx coupling, suggesting an association with underlying adaptation processes. Moreover, during tactile stimulation, incorporating early Glx dynamics significantly improved prediction of GABA+ responses, while higher baseline Glx was associated with reduced feedforward inhibition, thereby linking excitatory tone to sensory processing. These findings highlight the critical role of GABA + /Glx interplay in shaping sensory processing. fMRS shows that repetitive touch alters GABA–Glx coupling, with early Glx changes predicting GABA+ responses. Baseline Glx shapes feedforward inhibition, linking neuronal excitatory tone to tactile adaptability