GABA-ergic inhibition in human MT predicts visuo-spatial intelligence mediated by reverberation with frontal cortex

The canonical theory emphasizes fronto-parietal network (FPN) is key in mediating general fluid intelligence (gF). Meanwhile, recent studies show that multiple sensory regions in occipito-temporal border also play a key role in gF. However, the underlying mechanism is not yet clear. To investigate this issue, this study selects human MT complex (MT+), a region locates at the occipito-temporal border representing multiple sensory flows as a target brain area. Using ultra-high field magnetic resonance spectroscopy (MRS) to measure GABA/glutamate concentrations in MT+ combining resting-state fMRI functional connectivity (FC), behavioral examinations including MT+ perception suppression test and gF subtest in visuo-spatial component, we reveal that MT+ GABA and frontal-MT+ FC significantly correlate with the performance of visuo-spatial intelligence. Further, serial mediation model demonstrates that MT+ GABA predicting visuo-spatial g F fully mediated by reverberation effect between frontal and MT+ network. Our finding highlights that sensory cortex could integrate into complex cognition system as an intellectual hub.