Viewpoint (in)dependence of action representations: an MVPA study

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Mirror neurons in macaque area F5 are hypothesized to underpin action understanding.
• Human ventral premotor cortex (PMv) is considered the homologue of macaque F5.
• Previous neuroimaging studies showed PMv's action coding primarily for first-person perspectives.

Purpose of the Study:

• To investigate action-specific cross-modal representations in human PMv.
• To compare neural coding of observed actions from first-person versus third-person perspectives.
• To identify brain regions involved in understanding actions from different viewpoints.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan participants.
• Participants viewed and executed actions from either a first-person or third-person perspective.
• Multivoxel pattern analysis (MVPA) was employed to analyze brain activity patterns.

Main Results:

• Action-specific cross-modal visual-motor representations were found in PMv for the first-person perspective only.
• No significant differences in spatial or attentional factors were observed between perspectives.
• Posterior parietal and occipitotemporal cortex showed cross-modal coding irrespective of perspective.

Conclusions:

• Human PMv exhibits action-specific coding for observed actions primarily from a first-person perspective.
• Posterior brain regions play a more significant role than PMv in understanding others' actions from a third-person viewpoint.
• These findings refine our understanding of the neural basis of action perception and understanding.