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ATTENTIONAL FOCUS AND fMRI: BRAIN ACTIVATION DURING A LEG
MOVEMENT TASK
1Jed A. Diekfuss, 2Dustin R. Grooms, 1Randy J. Schmitz, 3Robert Kraft, 1Louisa D. Raisbeck
1The University of North Carolina at Greensboro, 2Ohio University, 3Wake Forest University
Introduction: The beneficial effects of using an external focus of attention (FOA) relative to an
internal FOA for motor performance and learning are well documented (Wulf, 2013). However,
the neural mechanisms underlying ‘why’ are mostly unknown (Wulf, 2013). Assessing brain
function using functional magnetic resonance imaging (fMRI) provides a means to fill this gap.
Objective: The purpose of this study was to investigate brain activation differences when
participants performed a gross motor movement using either an internal and external FOA.
Methods: Ten healthy subjects (5 F, 5 M; 25.2 ± 4.64 yrs.) completed a series of unilateral 45°
knee extension/flexion movements at a velocity of 1.2 Hz laying supine in an MRI scanner.
Participants were instructed to ‘squeeze their quadriceps’ during the internal FOA and to ‘focus
on a target’ positioned approximately 3 inches above their tibia during the external FOA. Trial
order was randomized with 30 sec rest, 30 sec move blocks resulting in a total time of 4m30s for
each trial block. Functional acquisition was performed with a 3T scanner (TR = 3 s, TE = 28 ms,
flip angle = 78°, voxel size = 2.5×2.5×2.5 mm). A second level fixed-effects paired samples t-
test contrasted brain activation in the external FOA with the internal FOA using a significance
level set a priori at p < .05; gaussian random field cluster corrected and z threshold set at z > 2.3.
Results: Results revealed significantly greater brain activation in the precuneous cortex (z =
5.99, p < .001), occipital pole (z = 5.49, p < .001), and frontal pole cortex (z = 4.88, p < .001)
during the external FOA compared to the internal FOA.
Conclusions: The precuneous cortex is involved in the visuospatial network for motor control,
the occipital pole is associated with vision and information processing, and the frontal pole
cortex has been linked to working memory, indicating that an external FOA activates attention,
sensory, and visual brain regions to a greater degree than an internal FOA. This neurophysiologic
data suggests a more dispersive cortical network for external FOA during motor tasks. It is
possible that this increases the salient aspects of establishing motor memories, providing a partial
explanation for the improvements in motor performance when using an external FOA.