The Neural Circuitry of Sweaty Palms: A Neuroimaging Meta-Analysis

Emotion and cognitive processes often cause autonomic nervous system responses. A common example is when the palms of your hands become sweaty before giving a speech or when a police officer is driving behind you. Increased sweat on the palms is a marker of sympathetic nervous system (SNS) activity. The aim of this study was to identify networks of brain activity that make our palms sweat. We compiled a list of neuroimaging studies that report brain activity associated with palm sweat. Our search resulted in sixteen studies, comprised of 251 participants. We used activation likelihood estimation analysis to determine nonrandom clustering of activation and deactivation of brain regions associated with palm sweat. Using a functional connectivity analysis performed on 1,000 human subjects, we identified the neural networks that encompass these brain regions. We found that palm sweating was associated with activation of brain regions (i.e., insula) in the salience network and deactivation of brain regions (i.e., precuneus) in the default mode network. This pattern of findings is consistent with previous research showing that detection of salient stimuli leads to activation of brain networks associated with focused attention and deactivation of brain networks associated with rest and introspection.