Carry-Over Effect of Deep Cerebellar Stimulation-Mediated Motor Recovery in a Rodent Model of Traumatic Brain Injury.

Abstract

We previously demonstrated that deep brain stimulation (DBS) of lateral cerebellar nucleus (LCN) can enhance motor recovery and functional reorganization of perilesional cortex in rodent models of stroke or TBI. Considering the treatment-related neuroplasticity observed at the perilesional cortex, we hypothesize that chronic LCN DBS-enhanced motor recovery observed will carry-over even after DBS has been deactivated. Here, we directly tested the enduring effects of LCN DBS in male Long Evans rats that underwent controlled cortical impact (CCI) injury targeting sensorimotor cortex opposite their dominant forepaw followed by unilateral implantation of a macroelectrode into the LCN opposite the lesion. Animals were randomized to DBS or sham treatment for 4 weeks during which the motor performance were characterize by behavioral metrics. After 4 weeks, stimulation was turned off, with assessments continuing for an additional 2 weeks. Afterward, all animals were euthanized, and tissue was harvested for further analyses. Treated animals showed significantly greater motor improvement across all behavioral metrics relative to untreated animals during the 4-week treatment, with functional gains persisting across 2-week post-treatment. This motor recovery was associated with the increase in CaMKIIα and BDNF positive cell density across perilesional cortex in treated animals. LCN DBS enhanced post-TBI motor recovery, the effect of which was persisted up to 2 weeks beyond stimulation offset. Such evidence should be considered in relation to future translational efforts as, unlike typical DBS applications, treatment may only need to be provided until such time as a new function plateau is achieved.