Neural Oscillations Supporting Gender Categorization of Faces and Body Silhouettes

Area of Science:

• Neuroscience
• Cognitive Science
• Social Neuroscience

Background:

• Gender categorization of faces and body shapes is crucial for social interaction.
• The neural basis for processing gender similarity in faces and body silhouettes remains incompletely understood, particularly regarding distinct processing stages.

Purpose of the Study:

• To investigate whether neural mechanisms for encoding gender similarity in faces and body silhouettes are similar or distinct across different processing stages.
• To elucidate the temporal dynamics and brain regions involved in intragender similarity processing for faces and body silhouettes.

Main Methods:

• Magnetoencephalography (MEG) was used to record brain activity in female participants.
• A repetition suppression (RS) paradigm was employed while participants viewed female faces and body silhouettes.
• Analysis focused on neural oscillatory power (alpha, beta bands) and inter-regional brain connectivity.

Main Results:

• Early neural RS effects (within 200 ms) differed: female faces engaged left inferior frontal cortex (IFC) high-beta power, while female body silhouettes involved cuneus alpha and anterior cingulate cortex (ACC) beta power.
• Later RS effects (200-300 ms) for both faces and silhouettes occurred in the left temporoparietal junction (TPJ) beta power.
• Distinct patterns of neural communication were observed: bidirectional alpha-band transfer between IFC and TPJ for faces, and unidirectional alpha/beta transfer from TPJ to ACC to cuneus for body silhouettes.

Conclusions:

• A two-stage model for neural encoding of intragender similarity during gender categorization is proposed.
• The findings highlight distinct early neural processing for faces and body silhouettes, converging in later stages.
• This research provides insights into the neural architecture underlying social perception and categorization in women.