Emotional Face Expressions Influence the Delay Eye-blink Classical Conditioning

evidence raised the importance of the cerebellum in emotional processes, with specific regard to negative emotions. However, its role in the processing of face emotional expressions is still unknown. This study was aimed at assessing whether face emotional expressions influence the cerebellar learning processes, using the delay eyeblink classical conditioning (EBCC) as a model. Visual stimuli composed of faces expressing happy, sad and neutral emotions were used as conditioning stimulus in forty healthy subjects to modulate the cerebellum-brainstem pathway underlying the EBCC. The same stimuli were used to explore their effects on the blink reflex (BR) and its recovery cycle (BRRC) and on the cerebellar-brain inhibition (CBI). Data analysis revealed that the learning component of the EBCC was significantly reduced following the passive view of sad faces, while the extinction phase was modulated by both sad and happy faces. By contrast, BR, BRRC and CBI were not significantly affected by the view of emotional face expressions. The present study provides first evidence that the passive viewing of faces displaying emotional expressions, are processed by the cerebellum, with no apparent involvement of the brainstem and the cerebello-cortical connection. In particular, the view of sad faces, reduces the excitability of the cerebellar circuit underlying the learning phase of the EBCC. Differently, the extinction phase was shortened by both happy and sad faces, suggesting that different neural bases underlie learning and extinction of emotions expressed by faces. (c) 2021 IBRO. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study found that passively viewing emotional facial expressions affects cerebellar learning processes, with sad faces reducing excitability of the cerebellar circuit and both happy and sad faces shortening the extinction phase. The study provides evidence of cerebellar involvement in processing emotional facial expressions.