Abstract
One of the most important functions of the brain is to process sensory information. All the time, novel sensory inputs update our current understanding of the environment acquired through previous experiences, so that we can present adequate motor responses. At the microscopic level, the information coming from the external world joins the previous knowledge we have through electrical signals called action potentials or spikes. In order to define proper stimulus-response patterns, the brain requires spatial and temporal modulations of spike activity, often performed by neurotransmitters. Dopamine, as a neurotransmitter associated with reward, was hypothesized to regulate stimulus-evoked representations during adulthood. We found that dopamine integrates sensory and perceptual inputs within the rodent brain somatosensory cortex, specialized in tactile inputs, through significant changes in the neuronal activity via D1 and D2 receptor-mediated control of the action potential threshold. Dopamine serves as a gain-modulator and selects the information to be highlighted when the mouse prepares for action by controlling the excitability in a cell-type specific manner. Moreover, we identified a functional close-loop between the dopaminergic signaling and sensory experience. Our results suggest a critical role for dopamine in the tactile processing. Other sensory systems would profit from additional studies.
