When defeat leaves a bad taste in the mouth: Modulation of tongue corticobulbar output during monetary loss in a gambling task

The tongue is a crucial effector involved in most everyday behaviors. Due to its complex nature (i.e., as a muscle and somatosensory/gustatory organ) the tongue is endowed with a multifunctional integration capacity that makes it an unique and important actor for survival. Neurons of the cortical representation of the tongue within the primary motor cortex (tnM1) show a specific pattern of connectivity with cortical and subcortical regions involved in reward processing, suggesting a role of tnM1 neurons in processing reward-related stimuli/outcomes and internal (physiological and mental) states. Yet, whether this role is generally relevant for experiences along the reward-punishing continuum, or rather exquisitely associated with oral dimensions, is still unclear. To address this issue, we administered TMS of the tnM1 in healthy volunteers undergoing an established gambling protocol, to investigate whether reward-related experiences associated with monetary win and loss induce consistent modulations of tnM1 corticobulbar excitability.