Cerebellar contribution to sensorimotor adaptation deficits in humans with spinal cord injury

Abstract

Humans with spinal cord injury (SCI) show deficits in associating motor commands and sensory feedback. Do these deficits affect their ability to adapt movements to new demands? To address this question, we used a robotic exoskeleton to examine learning of a sensorimotor adaptation task during reaching movements by distorting the relationship between hand movement and visual feedback in 22 individuals with chronic incomplete cervical SCI and 22 age-matched control subjects. We found that SCI individuals showed a reduced ability to learn from movement errors compared with control subjects. Sensorimotor areas in anterior and posterior cerebellar lobules contribute to learning of movement errors in intact humans. Structural brain imaging showed that sensorimotor areas in the cerebellum, including lobules I–VI, were reduced in size in SCI compared with control subjects and cerebellar atrophy increased with increasing time post injury. Notably, the degree of spared tissue in the cerebellum was positively correlated with learning rates, indicating participants with lesser atrophy showed higher learning rates. These results suggest that the reduced ability to learn from movement errors during reaching movements in humans with SCI involves abnormalities in the spinocerebellar structures. We argue that this information might help in the rehabilitation of people with SCI.

Single cell atlas of spinal cord injury in mice reveals a pro-regenerative signature in spinocerebellar neurons

“…Spinocerebellar neurons also showed structural plasticity at their mossy fiber terminals in the cerebellum. Given the importance of these connections in locomotion and motor learning, such anatomical changes could provide a key substrate for therapeutic interventions 75 , 76 .…”

Quantifying unsupported sitting posture impairments in humans with cervical spinal cord injury using a head-mounted IMU sensor

“…Indeed, most SCIs disrupt the integrity of ascending sensory and descending motor pathways, resulting in severe proprioceptive and muscle impairments [23,24]. For example, our previous studies showed that individuals with cSCI had deficits in limb position sense [25]. Cervical SCIs cause muscle impairments in the upper limbs, lower limbs, and trunk, which decrease their ability to maintain sitting balance.…”

The secretome of macrophages has a differential impact on spinal cord injury recovery according to the polarization protocol

“…SCT neurons exhibit inherent rhythmogenic attributes and intricate circuit connectivity with spinal interneurons within the locomotor central pattern generator (55). Moreover, the indispensability of this neuronal pathway for motor function restoration in human individuals afflicted with spinal cord injuries has been well documented (56)(57)(58). Likewise, the RST plays a multifaceted role in various components of dexterous motor functions.…”