Evaluating health risks associated with exposure to ambient surface waters during recreational activities: A systematic review and meta-analysis.

Recreational water quality guidelines protect the public from health risks associated with water recreation by helping to prevent unacceptable concentrations of pathogenic organisms in ambient water. However, illness risk is associated with both the concentration of pathogens in the water and the degree of contact with those pathogens. Different recreational activities can result in different levels of contact with ambient water containing water-borne pathogens.

External pallidal stimulation improves parkinsonian motor signs and modulates neuronal activity throughout the basal ganglia thalamic network.

Deep brain stimulation (DBS) of the internal segment of the globus pallidus (GPi) and the subthalamic nucleus (STN) are effective for the treatment of advanced Parkinson's disease (PD). We have shown previously that DBS of the external segment of the globus pallidus (GPe) is associated with improvements in parkinsonian motor signs; however, the mechanism of this effect is not known. In this study, we extend our findings on the effect of STN and GPi DBS on neuronal activity in the basal ganglia thalamic network to include GPe DBS using the 1-methyl-4-phenyl-1.

Somatotopic organization in the internal segment of the globus pallidus in Parkinson's disease.

Ablation or deep brain stimulation in the internal segment of the globus pallidus (GPi) is an effective therapy for the treatment of Parkinson's disease (PD). Yet many patients receive only partial benefit, including varying levels of improvement across different body regions, which may relate to a differential effect of GPi surgery on the different body regions. Unfortunately, our understanding of the somatotopic organization of human GPi is based on a small number of studies with limited sample sizes, including several based upon only a single recording track or plane.

Experimental and theoretical characterization of the voltage distribution generated by deep brain stimulation.

Deep brain stimulation (DBS) is an established therapy for the treatment of Parkinson's disease and shows great promise for numerous other disorders. While the fundamental purpose of DBS is to modulate neural activity with electric fields, little is known about the actual voltage distribution generated in the brain by DBS electrodes and as a result it is difficult to accurately predict which brain areas are directly affected by the stimulation. The goal of this study was to characterize the spatial and temporal characteristics of the voltage distribution generated by DBS electrodes.

Subthalamic nucleus stimulation modulates thalamic neuronal activity.

Deep brain stimulation (DBS) in the subthalamic nucleus (STN) is an effective tool for the treatment of advanced Parkinson's disease. The mechanism by which STN DBS elicits its beneficial effect, however, remains unclear. We previously reported STN stimulation increased the rate and produced a more regular and periodic pattern of neuronal activity in the internal segment of the globus pallidus (GPi).

Deep brain stimulation reduces neuronal entropy in the MPTP-primate model of Parkinson's disease.

High-frequency stimulation (HFS) of the subthalamic nucleus (STN) or internal segment of the globus pallidus is a clinically successful treatment for the motor symptoms of Parkinson's disease. However, the mechanisms by which HFS alleviates these symptoms are not understood. Whereas initial studies focused on HFS-induced changes in neuronal firing rates, recent studies suggest that changes in patterns of neuronal activity may correlate with symptom alleviation.

Pallidal burst activity during therapeutic deep brain stimulation.

Theoretical and experimental analyses of deep brain stimulation (DBS) in the subthalamic nucleus (STN) show both excitatory and inhibitory effects on the neural elements surrounding the electrode. Given these observations, the mechanism underlying the therapeutic effect of STN DBS on parkinsonian motor signs remains under debate. One hypothesis suggests that abnormal levels of bursting activity in the pallidum play a key role in the development of parkinsonian motor signs and that STN DBS may exert its beneficial effect by modifying this type of activity.

Stereotactic neurosurgical planning, recording, and visualization for deep brain stimulation in non-human primates.

Methodologies for stereotactic neurosurgery and neurophysiological microelectrode recordings (MER) in non-human primate research typically rely on brain atlases that are not customized to the individual animal, and require paper records of MER data. To address these limitations, we developed a software tool (Cicerone) that enables simultaneous interactive 3D visualization of the neuroanatomy, neurophysiology, and neurostimulation data pertinent to deep brain stimulation (DBS) research studies in non-human primates. Cicerone allows for analysis of co-registered magnetic resonance images (MRI), computed tomography (CT) scans, 3D brain atlases, MER data, and DBS electrode(s) with predictions of the volume of tissue activated (VTA) as a function of the stimulation parameters.

Computational analysis of subthalamic nucleus and lenticular fasciculus activation during therapeutic deep brain stimulation.

The subthalamic nucleus (STN) is the most common target for the treatment of Parkinson's disease (PD) with deep brain stimulation (DBS). DBS of the globus pallidus internus (GPi) is also effective in the treatment of PD. The output fibers of the GPi that form the lenticular fasciculus pass in close proximity to STN DBS electrodes.

Lesions in monkey globus pallidus externus exacerbate parkinsonian symptoms.

To further define the role of the external segment of the globus pallidus (GPe) in the development of parkinsonian motor signs, two rhesus monkeys were made parkinsonian with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Behavioral assessments of bradykinesia and akinesia as well as single neuron recordings in the internal segment of the globus pallidus (GPi) were performed in both monkeys before and after ablating the sensorimotor portion of GPe. The effects of apomorphine on behavior and neuronal activity were also assessed in the parkinsonian monkeys before and after GPe ablation.

Updating target location at the end of an orienting saccade affects the characteristics of simple point-to-point movements.

Six results are reported. (a) Reaching accuracy increases when visual capture of the target is allowed (e.g.

Neural activity in monkey dorsal and ventral cingulate motor areas: comparison with the supplementary motor area.

The cingulate motor areas are a recently discovered group of discrete cortical regions located in the cingulate sulcus with direct connections to the primary motor cortex and spinal cord. Although much is known about their anatomical relationship with other motor areas, relatively little is known about their functional neurophysiology. We investigated neural mechanisms of motor processing in the dorsal and ventral cingulate motor areas (CMAd and CMAv) during two-dimensional visually guided arm movements.