Contralateral Hand and Foot Know the Time Better: Advantages in Temporal Order Judgment and Their Processing Stages

Area of Science:

• Neuroscience
• Human Motor Control
• Sensory Perception

Background:

• Interlimb coordination is crucial for motor tasks like walking.
• Previous research shows superior contralateral hand-foot coordination during active movements.
• The extension of this contralateral advantage to passive temporal perception was unclear.

Purpose of the Study:

• To investigate the contralateral advantage in temporal order judgment between the hand and foot.
• To explore the behavioral and neural underpinnings of this potential advantage using electroencephalography (EEG).

Main Methods:

• A temporal order judgment task involving sequential tactile stimuli on the hand and foot.
• Electroencephalography (EEG) was used to record brain activity (event-related potentials - ERPs).
• Participants judged the order of stimuli ('hand before foot' or 'foot before hand').

Main Results:

• Behaviorally, participants demonstrated a contralateral advantage, showing higher accuracy and faster reaction times (RTs) for contralateral limb stimuli.
• The RT advantage was influenced by limb crossing but persisted for right-hand responses.
• Neurophysiologically, ERPs revealed earlier centroparietal positivity latency and reduced peak amplitudes for contralateral hand-foot combinations.
• These neural findings suggest improved temporal processing in both early and late stages.

Conclusions:

• A contralateral advantage exists for temporal order judgment between the hand and foot.
• This advantage is supported by both behavioral performance and neural processing.
• Findings provide insights into the mechanisms of superior contralateral interlimb coordination and may inform treatments for movement disorders.