Body inversion effect without body sense: insights from deafferentation

Area of Science:

• Cognitive Neuroscience
• Visual Perception
• Human Body Representation

Background:

• Human bodies, like faces, are recognized by the configuration of their parts, and this recognition is impaired by inversion.
• Perceptual expertise influences the processing of configural relations, suggesting humans' frequent exposure to bodies makes them experts in visual body posture processing.
• Online, multimodal body representations, reliant on proprioception, may significantly contribute to recognizing human body postures.

Purpose of the Study:

• To investigate whether static body posture recognition depends on current proprioceptive inputs.
• To determine if visual familiarity and stored body representations are sufficient for body posture recognition.
• To explore the role of the body schema in visual processing of human bodies.

Main Methods:

• Tested an individual (IW) with deafferentation (loss of cutaneous touch and proprioception) on the recognition of upright and inverted human body postures, faces, and houses.
• Utilized abstract, common, and rare human body postures for testing.
• Employed faces and houses as control stimuli to compare inversion effects across object categories.

Main Results:

• The deafferented individual (IW) exhibited an inversion effect for human body postures (abstract, common, rare) and faces.
• No significant inversion effect was observed for houses.
• These results indicate that current afferent inputs (proprioception) are not strongly required for human posture recognition.

Conclusions:

• Current proprioceptive inputs do not play a crucial role in the recognition of human body postures.
• Visual familiarity and stored body representations are sufficient for processing body configurations, supporting the concept of the body schema.
• The findings suggest that the body schema and other self-body contributions are vital for the visual processing of human bodies.