Right Foot Movement Research Articles

Effect of Subthalamic Nucleus Stimulation during Exercise on the Mesolimbocortical Dopaminergic Region in Parkinson'S Disease: A Positron Emission Tomography Study

To elucidate the dynamic effects of deep brain stimulation (DBS) in the subthalamic nucleus (STN) during activity on the dopaminergic system, 12 PD patients who had STN-DBS operations at least 1 month prior, underwent two positron emission tomography scans during right-foot movement in DBS-off and DBS-on conditions. To quantify motor performance changes, the motion speed and mobility angle of the foot at the ankle were measured twice. Estimations of the binding potential of [(11)C]raclopride (BP(ND)) were based on the Logan plot method. Significant motor recovery was found in the DBS-on condition. The STN-DBS during exercise significantly reduced the [(11)C]raclopride BP(ND) in the caudate and the nucleus accumbens (NA), but not in the dorsal or ventral putamen. The magnitude of dopamine release in the NA correlated negatively with the magnitude of motor load, indicating that STN-DBS facilitated motor behavior more smoothly and at less expense to dopamine neurons in the region. The lack of dopamine release in the putamen and the significant dopamine release in the ventromedial striatum by STN-DBS during exercise indicated dopaminergic activation occurring in the motivational circuit during action, suggesting a compensatory functional activation of the motor loop from the nonmotor to the motor loop system.

Modeling of movement-related potentials using a fractal approach

In bio-signal applications, classification performance depends greatly on feature extraction, which is also the case for electroencephalogram (EEG) based applications. Feature extraction, and consequently classification of EEG signals is not an easy task due to their inherent low signal-to-noise ratios and artifacts. EEG signals can be treated as the output of a non-linear dynamical (chaotic) system in the human brain and therefore they can be modeled by their dimension values. In this study, the variance fractal dimension technique is suggested for the modeling of movement-related potentials (MRPs). Experimental data sets consist of EEG signals recorded during the movements of right foot up, lip pursing and a simultaneous execution of these two tasks. The experimental results and performance tests show that the proposed modeling method can efficiently be applied to MRPs especially in the binary approached brain computer interface applications aiming to assist severely disabled people such as amyotrophic lateral sclerosis patients in communication and/or controlling devices.

FMRI correlates of execution and observation of foot movements in left-handers

While several studies have assessed the brain patterns of cortical activations following executed and observed movements of the dominant and non-dominant lower limbs in right-handed (RH) subjects, the functional correlates of foot movement in left-handed (LH) subjects have not been investigated, yet. We investigated brain function lateralization during action execution and observation with the dominant and non-dominant feet in 8 left-handers (LH). Thirteen right-handers (RH) were also studied while performing the same tasks with their right-foot. Compared to left-foot movement, during right-foot movement, LH had greater activations of the left primary sensorimotor cortex (SMC) and the right cerebellum. Compared to right-foot movement, during left-foot movement, LH subjects activated areas of the sensorimotor network, the mirror-neurons system (MNS) and the visual network lateralized to the contralateral hemisphere. During right-foot movement no between-group difference was found. LH had a pattern of activations lateralized to the right hemisphere during right-foot observation and to the left hemisphere during left-foot observation. Compared to left-foot observation, during right-foot observation, LH had greater activations of frontal and parietal regions and visual areas. The opposite contrast showed higher activation of the right lateral occipito-temporal cortex in LH during left-foot observation. During right-foot observation, compared to RH, LH had greater activations of the bilateral primary SMC and of MNS and visual system regions. In LH, the performance of simple motor acts with the dominant lower limb might be achieved through a complex adaptation and interaction between different neuronal pathways and the daily-life environment.