Blepharospasm as a research model for understanding the perception of facial expressions

BACKGROUND: Recognizing human emotions is a pivotal evolutionary advantage in interpersonal interactions and relies extensively on interpreting facial expressions. Sensorimotor models propose that perception of facial expressions may engage neural circuits involved in their generation. Disruption of facial motor circuits has been shown to compromise emotion perception, although the precise mechanisms remain unclear. METHODS: Twenty individuals with blepharospasm (PTS) and 20 age-, sex-, and education-matched healthy controls (CON) completed two emotion recognition tasks: an eye-based task (Baron-Cohen task; BC) and a body-based task (BEAST). RESULTS: A significant Task × Group interaction (F(1, 38) =7.38, p = .010) and a higher BEAST/BC performance ratio in patients (1.30 vs. 1.01; p = .006) indicated a selective impairment in recognizing emotions from the eyes, while recognition from body language remained intact. CONCLUSIONS: This study demonstrates a selective impairment in emotion recognition through the eyes in individuals with blepharospasm, linking motor dysfunction in a specific facial region to deficits in perceiving emotional cues conveyed by that same region in others. These findings underscore the role of facial motor circuits in emotion perception and offer new insights into the embodied neural mechanisms underlying affect recognition.