Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rhesus monkey models of Parkinson's disease were induced by injection of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Neural firings were recorded using microelectrodes placed in the internal segment of the globus pallidus. The wavelets and power spectra show gradual power reduction during the disease process along with increased firing rates in the Parkinson's disease state. Singular values of coefficients decreased considerably during tremor-related activity as well as in the Parkinson's disease state compared with normal signals, revealing that higher-frequency components weaken when Parkinson's disease occurs. We speculate that the death of neurons could be reflected by irregular frequency spike trains, and that wavelet packet decomposition can effectively detect the degradation of neurons and the loss of information transmission in the neural circuitry.
...
PMID:Reduced information transmission in the internal segment of the globus pallidus of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced rhesus monkey models of Parkinson's disease. 2562 34

We investigated simple directional hand movements based on different degrees of muscle co-activity, at behavioral and cerebral level in healthy subjects and Parkinson's disease (PD) patients. We compared "singular" movements, dominated by the activity of one agonist muscle, to "composite" movements, requiring conjoint activity of multiple muscles, in a center-out (right hand) step-tracking task. Behavioral parameters were obtained by EMG and kinematic recordings. fMRI was used to investigate differences in underlying brain activations between PD patients (N = 12) and healthy (age-matched) subjects (N = 18). In healthy subjects, composite movements recruited the striatum and cortical areas comprising bilaterally the supplementary motor area and premotor cortex, contralateral medial prefrontal cortex, primary motor cortex, primary visual cortex, and ipsilateral superior parietal cortex. Contrarily, the ipsilateral cerebellum was more involved in singular movements. This striking dichotomy between striatal and cortical recruitment vs. cerebellar involvement was considered to reflect the complementary roles of these areas in motor control, in which the basal ganglia are involved in movement selection and the cerebellum in movement optimization. Compared to healthy subjects, PD patients showed decreased activation of the striatum and cortical areas in composite movement, while performing worse at behavioral level. This implies that PD patients are especially impaired on tasks requiring highly tuned muscle co-activity. Singular movement, on the other hand, was characterized by a combination of increased activation of the ipsilateral parietal cortex and left cerebellum. As singular movement performance was only slightly compromised, we interpret this as a reflection of increased visuospatial processing, possibly as a compensational mechanism.
...
PMID:Muscle co-activity tuning in Parkinsonian hand movement: disease-specific changes at behavioral and cerebral level. 2630 Jul 61

During the early stage of the disease, idiopathic Parkinson's Disease can be very difficult to differentiate from atypical parkinsonian syndromes. Hyperechogenicity in the substantia nigra is one marker that has been shown to help make this differential diagnosis, and Transcranial Ultrasound Imaging is the preferred method for detecting SN hyperechogenicity. Hyperechogenicity is defined as an echogenic area larger than 0.2cm2. However, B-mode imaging often contains enough noise that the boundary may not be clear, thus making this diagnosis much more difficult. Harmonic imaging using a Third- Order Volterra filter is one solution that has been shown to be successful in filtering out the noise in these images. In this paper we show that regularization methods such as the Truncated Singular Value Decomposi- tion and Damped Singular Value Decomposition can be used to solve for the Volterra Filter's coefficients much more quickly than adaptive Least Mean Squared methods without sacrifice in image quality. These findings have significant implications for the viability of using the Volterra Filter in real-time applications.
 ...
PMID:Improved Real-Time Capability for Nonlinear Seperable Harmonic Filtering of Ultrasound Images Using a Damped Regularization Method With In-Vivo Results. 3044 May 34