Neuromodulation therapies in pre-clinical models of traumatic brain injury: Systematic review and translational applications.

Traumatic brain injury (TBI) has been associated with several lasting impairments that affect the quality of life. Pre-clinical models of TBI have been studied to further our understanding of the underlying short-term and long-term symptomatology. Neuromodulation techniques have become of great interest in recent years as potential rehabilitative therapies following injury due to their capacity to alter neuronal activity and neural circuits in targeted brain regions. This systematic review aims to provide an overlook of the behavioural and neurochemical effects of transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS), deep brain stimulation (DBS), and vagus nerve stimulation (VNS) in preclinical TBI models. After screening 629 abstracts, 30 articles were pooled for review. These studies showed that tDCS, TMS, DBS or VNS delivered to rodents restored TBI-induced deficits in coordination, balance, locomotor activity and improved cognitive impairments in memory, learning and impulsivity. Potential mechanisms for these effects included neuroprotection, a decrease in apoptosis, neuroplasticity, and the restoration of neural circuits abnormalities. The translational value, potential applicability and the interpretation of these findings in light of outcome data from clinical trials in TBI patients are discussed.