High-Impact, Self-Motivated Training Within an Enriched Environment With Single Animal Tracking Dose-Dependently Promotes Motor Skill Acquisition and Functional Recovery

Abstract

Functional recovery following central nervous system injuries is strongly influenced by rehabilitative training. In the clinical setting, the intensity of training and the level of motivation for a particular task are known to play important roles. With increasing neuroscience studies investigating the effects of training and rehabilitation, it is important to understand how the amount and type of training of individuals influences outcome. However, little is known about the influence of spontaneous "self-training" during daily life as it is often uncontrolled, not recorded, and mostly disregarded. Here, we investigated the effects of the intensity of self-training on motor skill acquisition in normal, intact rats and on the recovery of functional motor behavior following spinal cord injury in adult rats. We used a custom-designed small animal tracking system, "RatTrack," to continuously record the activity of multiple rats, simultaneously in a complex Natural Habitat-enriched environment. Naïve, adult rats performed high-intensity, self-motivated motor training, which resulted in them out-performing rats that were conventionally housed and trained on skilled movement tasks, for example, skilled prehension (grasping) and ladder walking. Following spinal cord injury the amount of self-training was correlated with improved functional recovery. These data suggest that high-impact, self-motivated training leads to superior skill acquisition and functional recovery than conventional training paradigms. These findings have important implications for the design of animal studies investigating rehabilitation and for the planning of human rehabilitation programs.

Motivational state, reward value, and Pavlovian cues differentially affect skilled forelimb grasping in rats

“…Recent experiments manipulating dopamine in motor cortex have shown effects on learning rates and cortex plasticity (Molina-Luna et al 2009;Hosp et al 2011;Hosp and Luft 2013;Rioult-Pedotti et al 2015). Using enriched housing, which has been previously shown to strongly influence dopaminergic signaling in the prefrontal cortex (Zhu et al 2005;Del Arco et al 2007;Segovia et al 2008) and nucleus accumbens (Segovia et al 2010), we have previously found a highly increased learning rate in the skilled grasping compared with standard housed animals (Starkey et al 2014). Furthermore, amphetamine administration has been found to boost recovery of skilled grasping after motor cortex stroke (Feeney et al 1982;Adkins and Jones 2005;Gilmour et al 2005;Ramic et al 2006;Papadopoulos et al 2009;Wolf et al 2014).…”

Novel Activity Detection Algorithm to Characterize Spontaneous Stepping During Multimodal Spinal Neuromodulation After Mid-Thoracic Spinal Cord Injury in Rats

“…It was shown that self-motivated training within a "enriched environment" lead to superior performance in skilled movement compared to restricted task-specific training. This "RatTrack" system allows for testing self-initiated and task-specific training and doseresponses (Starkey et al, 2014). While the mentioned efforts can be extended in the direction of automation, each of these methods lack the ability to have a direct measurement of the neuromotor parameters.…”

Experimental Spinal Cord Injury Models in Rodents: Anatomical Correlations and Assessment of Motor Recovery

“…Interestingly, differences were observed between the animals' overall activity and preference for certain tasks. Healthy as well as SCI animals trained in these cages performed better in experimental tests for fine motor control of fore-and hindlimb [71]. For forelimb training, a robotic rehabilitation system was recently developed, in which the animal has to pull a bar to receive food.…”