The influence of attentional focus on neuroplasticity following a seven-day balance training intervention

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Jed Allen Diekfuss (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Advisor
Randy Schmitz

Abstract: It is well established that focusing on the external effect of one’s movement (an external focus of attention) results in enhanced motor learning and produces superior motor performance compared to focusing inward on the body’s own physical execution of the motor movement (an internal focus). While the benefits of an external focus in motor learning, and the detriments of an inward or ‘internal’ focus have been highly replicated, there is still little mechanistic understanding pertaining to the brain-related changes that may result from these two different foci of attention during motor training. Since the brain is highly malleable and has been shown to adapt in response to motor training (i.e., neuroplasticity), it is postulated that attentional focus may change the brain’s structure and function. However, no direct examination exploring the influence of attentional focus on neuroplasticity (structural or functional) exists. The primary objective of this study was to determine the effects of balance training with different attentional foci on brain-related neuroplasticity in a young healthy population. Participants (n = 33) were randomly assigned to a control, internal focus, or external focus condition. Functional and structural brain connectivity analyses was conducted using neuroimaging data collected through functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) prior to (baseline) and following a seven-day balance training intervention (retention). Between baseline and retention data collection, participants in the internal and external focus training groups practiced a dynamic balance task for one hour per day, each day for seven consecutive days (acquisition). For the internal focus trials, participants were asked to, ‘focus on keeping their feet level;’ whereas, for the external focus trials participants were asked to, ‘focus on keeping the board level.’ The control group did not complete any balance training, but completed baseline and retention balance measurements. An inertial measurement unit was attached to the center of the balance board to assess the performance and learning of the balance task. Resting-state brain connectivity analyses were performed on the fMRI data to contrast connectivity differences for each group at retention relative to baseline, and, for the diffusion data (DTI), fractional anisotropy analyses (a metric to quantify water diffusion within a voxel of white-matter) was performed to quantify the relationship between changes in balance and water diffusivity within white-matter tracts. Classical attentional focus effects were observed for acquisition, with those in the external focus condition producing significantly less mean and standard deviation velocity compared to the internal focus group (both p < .05). Likewise, at retention, those in the external focus group produced significantly less mean and standard deviation velocity compared to the control group (both p < .05). We also observed a significant within-day effect in which both training groups adopted a more patterned and rigid movement behavior from early to late trial blocks (as measured by SampEn; p < .05). Our resting-state connectivity data revealed that those in the external focus group displayed less correlated brain activity amongst motor and sensory regions at the retention test compared to baseline (p < .05). While a few similar brain connectivity results were exhibited for the internal focus group such as in the cerebellum, this group also showed increased correlated resting-state brain activity at the retention test relative to their baseline test between motor and sensory regions (p < .05). To assess the relationship between balance and fractional anisotropy changes within white-matter we calculated percent change scores for mean velocity and fractional anisotropy within the frontal pole, precentral gyrus, and lingual gyrus. No significant relationships were revealed for these comparisons (all p > .05). These results suggest that a seven-day balance training program with attentional focus in a young healthy population influences brain function (specifically correlated activity at rest), but longer training programs or more rest may be needed to influence brain structure (as measured by fractional anisotropy). These findings have important implications for a variety of clinical populations who show altered resting-sate connectivity and deteriorations in balance control (e.g., Alzheimer’s disease, stroke survivors). Seven days of balance training with an external focus may be useful in improving balance control and may influence correlated brain activity at rest, but longer training programs or more rest may be needed to influence brain structure. We discuss these findings in the context of the constrained-action hypothesis and OPTIMAL theory.

Additional Information

Publication
Dissertation
Language: English
Date: 2017
Keywords
Attentional Focus, Balance, Motor Learning, Neuroplasticity
Subjects
Attention
Neuroplasticity
Equilibrium (Physiology)
Motor learning

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