Context-dependent motor performance is a phenomenon in which people perform better in the environ... more Context-dependent motor performance is a phenomenon in which people perform better in the environmental context where they originally practiced a task. Some animal and computer simulation studies suggested that context-dependent performance may be associated with neural activation of the dorsolateral prefrontal cortex (DLPFC). This study aimed to determine the role of the DLPFC in context-dependent motor performance by perturbing the neural processing of the DLPFC with repetitive transcranial magnetic stimulation (rTMS) in healthy adults. Thirty healthy adults were recruited into the Control, rTMS DLPFC, and rTMS Vertex groups. The participants practiced three finger sequences associated with a specific incidental context (a colored circle and a location on the computer screen). One day following practice, the rTMS groups received 1 Hz rTMS prior to the testing conditions in which the sequence-context associations remained the same as practice (SAME) or changed (SWITCH). All three groups improved significantly over practice on day one. The second day testing results showed that the DLPFC group demonstrated significantly less decrement in motor performance under the SWITCH condition than the Control and Vertex groups. This finding suggests a specific role of the DLPFC in context-dependent motor performance. This article is protected by copyright. All rights reserved.
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 8, 2014
Human pelvic floor muscles have been shown to operate synergistically with a wide variety of musc... more Human pelvic floor muscles have been shown to operate synergistically with a wide variety of muscles, which has been suggested to be an important contributor to continence and pelvic stability during functional tasks. However, the neural mechanism of pelvic floor muscle synergies remains unknown. Here, we test the hypothesis that activation in motor cortical regions associated with pelvic floor activation are part of the neural substrate for such synergies. We first use electromyographic recordings to extend previous findings and demonstrate that pelvic floor muscles activate synergistically during voluntary activation of gluteal muscles, but not during voluntary activation of finger muscles. We then show, using functional magnetic resonance imaging (fMRI), that a region of the medial wall of the precentral gyrus consistently activates during both voluntary pelvic floor muscle activation and voluntary gluteal activation, but not during voluntary finger activation. We finally confirm...
We have previously demonstrated changes in dopaminergic neurotransmission after intensive exercis... more We have previously demonstrated changes in dopaminergic neurotransmission after intensive exercise in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse model of Parkinson's disease (PD), including an increase in the dopamine D2 receptor (DA-D2R), using noninvasive PET imaging with the radioligand [18F]fallypride. The purpose of this feasibility and translational study was to examine whether intensive exercise leads to similar alterations in DA-D2R expression using PET imaging with [18F]fallypride in individuals with early-stage PD. In this pilot study, four patients with early-stage PD were randomized to receive intensive exercise (treadmill training sessions three times/week for 8 weeks) or no exercise. Two healthy age-matched individuals participated in treadmill training. Alterations in the DA-D2R binding potential (BP) as a marker for receptor expression were determined using PET imaging with [18F]fallypride. Turning performance in the patients with PD as a measure of postural control and the Unified Parkinson's Disease Rating Scale scores pre-exercise and postexercise were determined. Our data showed an exercise-induced increase in [18F]fallypride BP as well as improved postural control in patients with PD who exercised. Changes in DA-D2R BP were not observed in patients with PD who did not exercise. These results suggest that exercise can lead to neuroplasticity in dopaminergic signaling and contribute to improved function that may be task specific (postural control) in early-stage PD.
... PURPOSe: the aim of this study was to evaluate the effect of physical training on the reactiv... more ... PURPOSe: the aim of this study was to evaluate the effect of physical training on the reactivity of pulmonary artery rings from rats submitted to a pulmonary IR. MeTHOdS:Wistar male rats were divided into five groups named: control sedentary (SD); Trained (TR); sham ...
Context-dependent motor performance is a phenomenon in which people perform better in the environ... more Context-dependent motor performance is a phenomenon in which people perform better in the environmental context where they originally practiced a task. Some animal and computer simulation studies suggested that context-dependent performance may be associated with neural activation of the dorsolateral prefrontal cortex (DLPFC). This study aimed to determine the role of the DLPFC in context-dependent motor performance by perturbing the neural processing of the DLPFC with repetitive transcranial magnetic stimulation (rTMS) in healthy adults. Thirty healthy adults were recruited into the Control, rTMS DLPFC, and rTMS Vertex groups. The participants practiced three finger sequences associated with a specific incidental context (a colored circle and a location on the computer screen). One day following practice, the rTMS groups received 1 Hz rTMS prior to the testing conditions in which the sequence-context associations remained the same as practice (SAME) or changed (SWITCH). All three groups improved significantly over practice on day one. The second day testing results showed that the DLPFC group demonstrated significantly less decrement in motor performance under the SWITCH condition than the Control and Vertex groups. This finding suggests a specific role of the DLPFC in context-dependent motor performance. This article is protected by copyright. All rights reserved.
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 8, 2014
Human pelvic floor muscles have been shown to operate synergistically with a wide variety of musc... more Human pelvic floor muscles have been shown to operate synergistically with a wide variety of muscles, which has been suggested to be an important contributor to continence and pelvic stability during functional tasks. However, the neural mechanism of pelvic floor muscle synergies remains unknown. Here, we test the hypothesis that activation in motor cortical regions associated with pelvic floor activation are part of the neural substrate for such synergies. We first use electromyographic recordings to extend previous findings and demonstrate that pelvic floor muscles activate synergistically during voluntary activation of gluteal muscles, but not during voluntary activation of finger muscles. We then show, using functional magnetic resonance imaging (fMRI), that a region of the medial wall of the precentral gyrus consistently activates during both voluntary pelvic floor muscle activation and voluntary gluteal activation, but not during voluntary finger activation. We finally confirm...
We have previously demonstrated changes in dopaminergic neurotransmission after intensive exercis... more We have previously demonstrated changes in dopaminergic neurotransmission after intensive exercise in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse model of Parkinson's disease (PD), including an increase in the dopamine D2 receptor (DA-D2R), using noninvasive PET imaging with the radioligand [18F]fallypride. The purpose of this feasibility and translational study was to examine whether intensive exercise leads to similar alterations in DA-D2R expression using PET imaging with [18F]fallypride in individuals with early-stage PD. In this pilot study, four patients with early-stage PD were randomized to receive intensive exercise (treadmill training sessions three times/week for 8 weeks) or no exercise. Two healthy age-matched individuals participated in treadmill training. Alterations in the DA-D2R binding potential (BP) as a marker for receptor expression were determined using PET imaging with [18F]fallypride. Turning performance in the patients with PD as a measure of postural control and the Unified Parkinson's Disease Rating Scale scores pre-exercise and postexercise were determined. Our data showed an exercise-induced increase in [18F]fallypride BP as well as improved postural control in patients with PD who exercised. Changes in DA-D2R BP were not observed in patients with PD who did not exercise. These results suggest that exercise can lead to neuroplasticity in dopaminergic signaling and contribute to improved function that may be task specific (postural control) in early-stage PD.
... PURPOSe: the aim of this study was to evaluate the effect of physical training on the reactiv... more ... PURPOSe: the aim of this study was to evaluate the effect of physical training on the reactivity of pulmonary artery rings from rats submitted to a pulmonary IR. MeTHOdS:Wistar male rats were divided into five groups named: control sedentary (SD); Trained (TR); sham ...
Uploads
Papers by Beth Fisher