Manipulating the experienced onset of intention after action execution

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• Understanding the precise timing of conscious intention is crucial for explaining voluntary action.
• Previous research suggests intention precedes action, but the neural processes determining intention's onset remain debated.

Purpose of the Study:

• To investigate the temporal dynamics of perceived motor intention onset.
• To determine if neural activity after action execution influences the subjective experience of intention.

Main Methods:

• Utilized transcranial magnetic stimulation (TMS) over the presupplementary motor area.
• Applied TMS at different time points relative to spontaneous action execution.
• Assessed participants' perceived onset of motor intention and action execution time.

Main Results:

• TMS applied after action execution delayed the perceived onset of intention and advanced perceived action time.
• The timing of TMS (immediate vs. 200 ms post-action) did not alter the effect's magnitude.
• Control studies confirmed the effect's time-limited, modality-specific, and site-specific nature.

Conclusions:

• Perceived intention onset is influenced by neural activity occurring post-action.
• This suggests a post-hoc determination of conscious intention in spontaneous actions.
• Findings support a cue integration model and have implications for understanding conscious control.