Modulation of somatosensory signal transmission in the primate cuneate nucleus during voluntary hand movement

Successful extraction of tactile and kinematic information is crucial for appropriate motor actions in daily life. To achieve this objective, sensory signals should be effectively regulated during motor actions. This regulation is understood both empirically and conceptually, but it is not well known where and how it is implemented in the central nervous system. Here, we show that, during voluntary movement, sensory signals are already attenuated in the primate cuneate nucleus, an early processing site in the ascending lemniscus pathway. The degree of suppression was comparable with the one reported in the cortex, suggesting that psychological attenuation of somatosensation could be ascribed to the cuneate. The results also revealed that this sensory attenuation was of descending origin, suggesting that cortical sensory prediction signals could regulate cuneate sensory transmission for extracting meaningful, and attenuate unnecessary, signals for movement regulation. This recurrent sensory modulation mechanism between cortical and subcortical areas may generalize to other sensory modalities and cognitive processes.