What have We Learned from “Perturbing” the Human Cortical Motor System with Transcranial Magnetic Stimulation?

The purpose of this paper is twofold. First, we will review different approaches that one can use with transcranial magnetic stimulation (TMS) to study both its effects on motor behavior and on neural connections in the human brain. Second, we will present evidence obtained in TMS-based studies showing that the dorsal premotor area (PMd), the ventral premotor area (PMv), the supplementary motor area (SMA), and the pre-supplementary motor area (pre-SMA) each have different roles to play in motor behavior. We highlight the importance of the PMd in response selection based on arbitrary cues and in the control of arm movements, the PMv in grasping and in the discrimination of bodily actions, the SMA in movement sequencing and in bimanual coordination, and the pre-SMA in cognitive control. We will also discuss ways in which TMS can be used to chart “true” cerebral reorganization in clinical populations and how TMS might be used as a therapeutic tool to facilitate motor recovery after stroke. We will end our review by discussing some of the methodological challenges and future directions for using this tool in basic and clinical neuroscience

Task specific influences of Parkinson’s disease on the striato-thalamo-cortical and cerebello-thalamo-cortical motor circuitries

The motor deficits in Parkinson’s disease (PD) have been primarily associated with internally guided (IG), but not externally guided (EG), tasks. This study investigated the functional mechanisms underlying this phenomenon using genetically-matched twins. Functional magnetic resonance images were obtained from a monozygotic twin pair discordant for clinical PD. Single-photon emission computed tomography neuroimaging using [123I](−)-2-β-carboxymethoxy-3-β-(4-iodophenyl)tropane confirmed their disease-discordant status by demonstrating a severe loss of transporter binding in the PD-twin, whereas the non-PD-twin was normal. Six runs of fMRI data were acquired from each twin performing EG and IG right-hand finger sequential tasks. The percentage of voxels activated in each of several regions of interest (ROI) was calculated. Multiple analysis of variance was used to compare each twin’s activity in ROIs constituting the striato-thalamo-cortical motor circuits [basal ganglia (BG)-cortical circuitry, but including the globus pallidus/putamen, thalamus, supplementary motor area, and primary motor cortex] and cerebello-thalamo-cortical circuits (referred to as the cerebellar–cortical circuitry, including the cerebellum, thalamus, somatosensory cortex, and lateral premotor cortex). During the EG task, there were no significant differences between the twins in bilateral BG-cortical pathways, either basally or after levodopa, whereas the PD-twin had relatively increased activity in the cerebellar-cortical pathways basally that was normalized by levodopa. During the IG task, the PD-twin had less activation than the non-PD-twin in ROIs of the bilateral BG-cortical and cerebellar-cortical pathways. Levodopa normalized the hypoactivation in the contralateral BG-cortical pathway, but “over-corrected” the activation in the ipsilateral BG-cortical and bilateral cerebellar-cortical pathways. In this first fMRI study of twins discordant for PD, the data support the hypothesis that BG-cortical and cerebellar-cortical pathways are task-specifically influenced by PD. The levodopa-induced “over-activation” of BG-cortical and cerebellar-cortical pathways, and its relevance to both compensatory changes in PD and the long-term effects of levodopa in PD, merit further exploration

Investigating reach and grasp in Parkinson's disease cognitive impairment

Reach and grasp are evolutionary conserved motor actions controlled by highly specialised neural pathways that have major nodes in the posterior parietal and premotor frontal cortices. Mild cognitive impairment is an important non-motor symptom of Parkinson’s disease (PD) and there is evidence that the risk of transition between PD mild cognitive impairment (PD-MCI) and Parkinson’s disease dementia (PDD) is dependent on which neurotransmitter systems within the brain are most dysfunctional. Studies of reach and grasp in PD subjects with normal cognition (PD-NC) suggest a greater dependence on visual feedback to guide reach and grasp compared with controls.The primary aim of this thesis is to explore how cognitive impairment influences reach and grasp in PD. Twenty two PD-NC, 23 PD-MCI, ten PDD and 19 controls reached and grasped for a target whilst wearing movement sensing equipment in four conditions: full vision, a darkened room with an illuminated target, with eyes closed at a natural speed and as quickly as possible in full vision. All PD subjects were tested whilst on. Kinematic parameters of reach and grasp were extracted from the movement data and analysed using standard statistical methods.Our results show a spectrum of change to kinematic reach parameters when reaching and grasping with eyes closed: PD-NC are disproportionately affected compared to controls and PDD are disproportionately affected compared to PD-NC. Parameters of reach and grasp were similar between PD-NC and PD-MCI in all conditions. These results have been discussed in the context of abnormal integration of sensorimotor functions and impaired spatial working memory in PD. Reaction time when reaching and grasping as quickly as possible is significantly associated with global cognition in the PD subjects after controlling for age, motor signs and disease duration. This supports a role for reaction time as a potential biomarker for cognitive impairment in PD

Does practice of multi-directional stepping with auditory stimulation improve movement performance in patients with Parkinson\u27s disease

Parkinson’s disease (PD) is a debilitating neurodegenerative disorder causing many physical limitations. Rhythmic auditory stimulation (RAS) influences motor complications not alleviated by medicine and has been used to modify straight line walking in this population. However, motor complications are exacerbated during more complex movements including those involving direction changes. Thus immediate RAS effects on direction switch duration (DSD) and other kinematic measures during a multi-directional step task were investigated in PD patients. Long term RAS application was also explored by evaluating functional gait and balance and kinematic step measures before and after 6 weeks of multi-directional stepping either with (Cue, C group) or without (No cue, NC group) RAS use. Evaluations were also administered 1, 4 and 8 weeks after training termination. Kinematic measures were collected during stepping without, then with RAS for the C group and without RAS for the NC group. Step testing/training was performed at slow, normal and fast speeds in forward, back and side directions. Participants with PD switched step direction during the stepping task faster with RAS use before training. Like straight line walking RAS application influenced the more complex task of direction switching and counteracted the well-known bradykinesia in PD. After training both groups improved their functional gait and balance measures and maintained balance improvements for at least 8 weeks. Only the C group retained gait improvements for at least 8 weeks after training termination. Adding RAS resulted in functional benefits not observed in training without it. Kinematic measures compared before and after step training clarified the underlying contributors to functional performances. Both groups reduced the variability of DSD. The C group participants maintained this alteration longer. DSD reduction also occurred after training and was retained for at least 8 weeks for this group. These outcomes further support the advantages of adding RAS to training regiments for those with PD. The current results indicate that RAS effects are not limited to simple activities like straight line walking. Moreover, RAS can be used for improving and maintaining improvements longer in activities involving various forms of transition which present most difficulties for those with PD

A Comparison of the Effectiveness of Two Handwriting Programs on Legibility in First Grade Students

Background: Handwriting is one of the most utilized forms of written communication and there is a lack of research comparing the effectiveness of two different handwriting programs in elementary aged students. Purpose: The purpose of this Doctor of Occupational Therapy (OTD) Capstone project was to compare the efficacy of two handwriting programs implemented in first grade classes at one elementary school in Kentucky. The research question that guided this Capstone Project was: Which of the following handwriting programs were more effective in achieving handwriting legibility in first grade students: Handwriting Without Tears or Write Start? Theoretical Framework: The theoretical frameworks and scientific underpinnings that guided this capstone project were the Conceptual Model for Performance in Handwriting, the Developmental Theory and Ayres Sensory Integration. Methods: A pre-experimental design comparing pretest and posttest data was utilized to analyze results using descriptive statistics and jamovi in first grade students. Students in each classroom received six sessions of handwriting interventions that lasted twenty minutes each. One classroom received Handwriting Without Tears instruction. The other classroom received Write Start instruction. Results: Statistical significance was found for improvement in handwriting legibility in students who received the Handwriting Without Tears intervention. Both programs demonstrated clinical significance and improvement in student handwriting legibility. Conclusions: The use of handwriting programs can provide a positive impact on handwriting legibility in first grade students. A hybrid model combining methods from Handwriting Without Tears and Write Start could be implemented to provide instruction to students on handwriting skills

Learning, Arts, and the Brain: The Dana Consortium Report on Arts and Cognition

Reports findings from multiple neuroscientific studies on the impact of arts training on the enhancement of other cognitive capacities, such as reading acquisition, sequence learning, geometrical reasoning, and memory

WORKING MEMORY ASSESSMENT AND TRAINING

Working memory, the ability to maintain and manipulate information, is a core cognitive function important for everyday life. The capacity of working-memory differs across individuals, with working-memory capacity a reliable predictor of general fluid intelligence, verbal and mathematical abilities, and classroom achievement. However, research has been inconclusive on whether working-memory is a unitary domain-general construct, or multi-component domain-specific construct. Most theories had until recently thought that working-memory was a fixed ability; however, recent research suggests that working-memory is malleable and can be improved through cognitive training. These training-induced improvements have also been shown on untrained cognitive tasks, such as general fluid intelligence, attention, reading, and math. My research examines the structure of working-memory, validates newly designed web-administered working-memory assessments, and investigates the malleability of domain specific working-memory training