Targeting Sensory and Motor Integration for Recovery of Movement After CNS Injury

Abstract

The central nervous system (CNS) integrates sensory and motor information to acquire skilled movements, known as sensory-motor integration (SMI). The reciprocal interaction of the sensory and motor systems is a prerequisite for learning and performing skilled movement. Injury to various nodes of the sensorimotor network causes impairment in movement execution and learning. Stimulation methods have been developed to directly recruit the sensorimotor system and modulate neural networks to restore movement after CNS injury. Part 1 reviews the main processes and anatomical interactions responsible for SMI in health. Part 2 details the effects of injury on sites critical for SMI, including the spinal cord, cerebellum, and cerebral cortex. Finally, Part 3 reviews the application of activity-dependent plasticity in ways that specifically target integration of sensory and motor systems. Understanding of each of these components is needed to advance strategies targeting SMI to improve rehabilitation in humans after injury.

Spinal cord associative plasticity improves forelimb sensorimotor function after cervical injury

“…The skull was exposed and placement holes made using a Jobber Drill (number 60, P1 Technologies, Roanoke, VA, USA) without disturbing the dura mater. Stainless steel screw electrodes (1.19mm diameter with a flat tip; Plastics One, Torrington, CT, USA) were implanted over the forelimb area of the motor cortex in one hemisphere at two locations as described in our previous work 1 . The screw electrodes were attached in advance to a head connector (Plastics One) that was secured with skull screws and dental acrylic.…”

“…A similar primary motor cortex and spinal cord stimulation paradigm were used as described by Mishra et al, 2017 1 . Briefly, a train of three biphasic square wave pulses (each pulse of 0.2ms for each polarity; interstimulus interval of 3ms; Fig.…”

“…In order to maximize the efficacy of the SCAP protocol (5-minute SCAP, Fig 3B1) 1 , we varied four parameters in order to produce the largest physiological responses: frequency, number of stimuli, number of trains, and time between trains. In two rats implanted with cortical and spinal electrodes, we first varied frequency by testing 10 stimuli delivered at 5Hz, 2Hz, 1Hz, 0.5Hz and 0.2Hz (Supplementary Fig.…”

“…Integration of sensory feedback with motor commands is required for skilled movement. Neuromodulation strategies have been developed to target sensorimotor integration 1 . The most common application, paired associative stimulation, repetitively pairs median nerve stimulation with motor cortex stimulation timed to increase cortical excitability in healthy people 2 and improve arm and hand function after injury 3, 4 .…”

Sensory Integration Disorders in Patients with Multiple Sclerosis

“…There is still little research regarding the neuroanatomical underpinnings of SID. A key role is attributed to basal ganglia, cerebellum, neocortex and neural circuitries between them [ 1 , 5 ]. A functional foundation may however be attributed to deviation in the interplay of the vestibular and somatosensory system, which in response can further disrupt proper praxis and sensory modulation.…”