Lateralization of facial emotion recognition in the human cerebellum: A transcranial direct current stimulation (tDCS Study)

Abstract

The cerebellum, one of the oldest structures in the nervous system, is well-known for the important role it plays in the coordination and timing of movement. However, there has been a paradigm shift with recent clinical, neuroimaging, and experimental research suggesting that the cerebellum also plays a role in higher-order cognitive functions such as attention and emotion. The substantial increase in research regarding the cerebellum's ability for emotional processing has indicated that it may be particularly adept at recognizing and processing negative facial expressions (e.g., fear, anger, sadness). Previous research using functional brain imaging and patients with cerebellar brain injuries provide some evidence of cerebellar lateralization, with the left cerebellum being more specialized for processing emotions than the right. To examine this, we delivered transcranial direct current stimulation (tDCS) over the left cerebellum of 67 healthy participants, randomly assigned to a tDCS condition (anodal, cathodal, or sham), and had them complete a facial emotion recognition task pre-tDCS, during-tDCS, and post-tDCS. Anodal and cathodal cerebellar tDCS did not significantly alter participant reaction time and accuracy. Participants did get faster, less variable, and more accurate over time, especially for positive emotions (happy), compared to negative emotions (angry and sad). However, due to relatively limited research examining the role of the cerebellum in emotion processes, and the limitations of the current study, we cannot say for certain why there were no effects of tDCS.

Keywords: cerebellum, cerebellar lateralization, cerebellum and cognition, facial emotion recognition, transcranial direct current stimulation (tDCS)

Faculty Mentor: Dr. Christopher Striemer