Lack of proprioceptive feedback is one cause for the high upper-limb prosthesis abandonment rate. The lack of environmental interaction normalcy from unreliable proprioception creates dissatisfaction among prosthesis users. The purpose of this experiment is to investigate the effects of square breathing on learning to navigate without reliable proprioception. Square breathing is thought to influence the vagus nerve which is linked to increased learning rates. In this experiment, participants were instructed to reach toward targets in a semi-immersive virtual reality environment. Directional error, peak velocity, and peak acceleration of the reaching hand were investigated before and after participants underwent square breathing training. As the results of<br/>this experiment are inconclusive, further investigation needs to be done with larger sample sizes and examining unperturbed data to fully understand the effects of square breathing on learning new motor strategies in unreliable proprioceptive conditions.
Sensorimotor adaptation is a type of learning that allows sustaining accurate movements by adjusting motor output. This allows the brain to adapt to temporary changes when engaged in a certain task. Within sensorimotor adaptation, visuomotor adaptation (VMA) is one’s ability to correct a visual perturbation. In this study, we present preliminary results on the effects of VMA with the control group, compared to groups undergoing trigeminal nerve stimulation (TNS) or SHAM (placebo) effects. Twenty-two healthy subjects with no past medical history participated in this study. Subjects performed a visuomotor rotation task, which required gradually adapting to a perturbation between hand motion and corresponding visual feedback. Five total blocks were completed: two familiarization blocks, one baseline block, one rotation block with a 30◦ counterclockwise rotation, and one washout block with no rotation. The control group performed better than the 120 Hz (TNS) and SHAM groups due to less directional error (DE) on the respective learning curves. Additionally, the control group adapted faster (less DE) than the SHAM groups that either felt stimulation, or did not feel the stimulation. The results yield new information regarding VMA which can be used in the future when comparing sensorimotor adaptation and its many applications.
Neuromodulation is an emerging field of research that has a proven therapeutic benefit on a number of neurological disorders, including epilepsy and stroke. It is characterized by using exogenous stimulation to modify neural activity. Prior studies have shown the positive effect of non-invasive trigeminal nerve stimulation (TNS) on motor learning. However, few studies have explored the effect of this specific neuromodulatory method on the underlying physiological processes, including heart rate variability (HRV), facial skin temperatures, skin conductance level, and respiratory rate. Here we present preliminary results of the effects of 3kHz supraorbital TNS on HRV using non-linear (Poincaré plot descriptors) and time-domain (SDNN) measures of analysis. Twenty-one (21) healthy adult subjects were randomly assigned to 2 groups: 3kHz Active stimulation (n=11) and Sham (n=10). Participants’ physiological markers were monitored continuously across three blocks: one ten-minute baseline block, one twenty-minute treatment block, and one ten-minute recovery block. TNS targeting the ophthalmic branches of the trigeminal nerve was delivered during the treatment block for twenty minutes in 30 sec. ON/OFF cycles. The active stimulation group exhibited larger values of all Poincaré descriptors and SDNN during blocks two and three, signifying increased HRV and autonomic nervous system activity.
The second study used the same behavioral paradigm, but targeted tFUS to the right anterior insula/frontal operculum (aIns/fO). The aIns/fO is implicated in saliency, cognitive control, interoceptive awareness, autonomic function, and emotion. tFUS was found to significantly alter ERP, ERSP, conflict and error processing, and HRV responses.
The third study targeted tFUS to the right inferior frontal gyrus (rIFG), employing the Stop Signal task to study inhibition. tFUS affected ERPs and improved stopping speed. Using network modeling, causal evidence is presented for rIFG influence on subcortical nodes in stopping.
This work provides preliminarily evidence that tFUS can be used to modulate broader network function through a single node, affecting neurophysiological processing, physiologic responses, and behavioral performance. Additionally it can be used as a tool to elucidate network function. These studies suggest tFUS has the potential to affect cognitive function as a clinical tool, and perhaps even enhance wellbeing and expand conscious awareness.
Learning a novel motor pattern through imitation of the skilled performance of an expert has been shown to result in better learning outcomes relative to observational or physical practice. The aim of the present project was to examine if the advantages of imitational practice could be further augmented through a supplementary technique derived from my previous research. This research has provided converging behavioral evidence that dyads engaged in joint action in a familiar task requiring spatial and temporal synchrony end up developing an extended overlap in their body representations, termed a joint body schema (JBS). The present research examined if inducing a JBS between a trainer and a novice trainee, prior to having the dyad engage in imitation practice on a novel motor pattern would enhance both of the training process and its outcomes.
Participants either worked with their trainer on a familiar joint task to develop the JBS (Joint condition) or performed a solo equivalent of the task while being watched by their trainer (Solo condition). Participants In both groups then engaged in blocks of alternating imitation practice and free production of a novel manual motor pattern, while their motor output was recorded. Analyses indicated that the Joint participants outperformed the Solo participants in the ability to synchronize the spatial and temporal components of their imitation movements with the trainer’s pattern-modeling movements. The same group showed superior performance when attempting to freely produce the pattern. These results carry significant theoretical and translational potentials for the fields of motor learning and rehabilitation.