Spinal automaticity of movement control and its role in recovering function after spinal injury

The significance of the spinal cord in controlling postural and locomotor functions largely reemerged in the mid-1970s under the leadership of Sten Grillner, demonstrating key phenomena of 'central pattern generation' and 'fictive locomotion' with an evolutionary perspective. These concepts raised the question of how much function can be recovered after paralysis, given the intrinsic automaticity of spinal networks in injured and uninjured states in adults.

This review explores biological mechanisms governing spinal control of movements such as posture and locomotion. We focus on concepts that have evolved from experiments performed over the past decade. Rather than a comprehensive review of the vast literature on the neural control of posture and locomotion, we focus on the various mechanisms underlying functional automaticity, and their clinical relevance.

We propose that multiple combinations of sensory mechanoreceptors linked to proprioception that generate an infinite number of different sensory ensembles, having species-specific meaning and extensive influence in controlling posture and locomotion. These sensory ensembles are translated as a probabilistic phenomenon into highly specific but indeterminate actions. Therefore, we opine that spinal translation of these ensembles in real-time plays a central role in the automaticity of motor control in individuals with and without severe neuromotor dysfunction.