State-dependent associative plasticity highlights function-specific premotor-motor pathways crucial for arbitrary...

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Science

Background:

• Arbitrary visuomotor mapping (AVMM) demonstrates the brain's capacity to associate sensory stimuli with motor actions.
• The ventral premotor cortex (PMv) and primary motor cortex (M1) pathway is hypothesized to be crucial for sensorimotor transformations in AVMM.
• Direct evidence for the PMv-M1 pathway's role in AVMM has been limited.

Purpose of the Study:

• To investigate the causal role of PMv-M1 connectivity in arbitrary visuomotor mapping (AVMM).
• To explore the plasticity of the PMv-M1 pathway using cortico-cortical paired associative stimulation (ccPAS).
• To determine if state-dependent ccPAS can selectively modulate visuomotor neurons involved in AVMM.

Main Methods:

• Four experiments utilized cortico-cortical paired associative stimulation (ccPAS) to modulate PMv-to-M1 connectivity.
• State-dependent transcranial magnetic stimulation (TMS) was employed to target function-specific neural populations.
• ccPAS_PMv-M1 aimed to enhance connectivity, while ccPAS_M1-PMv aimed to inhibit it during visuomotor tasks.

Main Results:

• State-dependent ccPAS_PMv-M1 enhanced both neurophysiological and behavioral measures of AVMM.
• Conversely, ccPAS_M1-PMv demonstrated an inhibitory effect on AVMM performance.
• These modulatory effects were more significant when responding to target visual cues compared to control cues.

Conclusions:

• The PMv-M1 pathway exhibits plasticity and plays a causal role in arbitrary visuomotor mapping (AVMM).
• Spatially overlapping but functionally distinct neural populations within the PMv-M1 pathway are involved in AVMM.
• State-dependent ccPAS is a viable tool for targeted modulation of specific visuomotor pathways.