Sensorimotor Integration Along the Neuraxis

Sensory feedback is a vital component of behavior. Oftentimes we use sensory feedback to learn new motor skills, such as riding a bike. Other times we passively consume sensory information for our own enjoyment or to support cognitive processes such as learning. We occasionally even move to acquire certain sensory experiences or achieve sensory states. When sensory feedback is impaired, movement is also impaired. However, deficiencies of sensory feedback do not necessarily prohibit movement---motor tasks can be accomplished with limited or noisy sensory feedback, even if slowly and with reduced accuracy. This suggests that there are interactions between sensory modalities as well as interactions between sensation and movement at every level of the nervous system and raises the question of how sensory feedback interacts with motor commands along the neuraxis, from the periphery to the cerebral cortex. Here we studied the neural mechanisms of interactions and integration between sensation and movement in the periphery, in spinal circuits, and finally in volitional control of a brain-computer interface using signals extracted from motor cortex. We found that contact force influences the neural encoding of tactile stimuli in primary afferents, that spinal circuits encode sterotyped motor output to sensory stimulation, and that sensory feedback interacts with movement intent in motor cortex. Together, these studies suggest that sensation and movement are intertwined at every level of the nervous system, and that sensory signals must be demultiplexed and contextualized in terms of the movements used to acquire them, and motor commands must take into account the evolving sensory state