Neurodegeneration
E Glucksman in MCQs in Neurology and Neurosurgery for Medical Students, 2022
This chapter provides that the themed presentation encourages quick, focused study and detailed answers aid comprehension and encourages familiarity with neurodegeneration with essential diagrams, colour images and sample MRIs. The motor cortex and the supplementary motor area predominantly project excitatory glutamatergic fibres to the spinal cord (lateral corticospinal tract), striatum and thalamus. The striatum consists of the caudate nucleus and the putamen, separated anatomically by the internal capsule. It comprises chiefly medium spiny neurones which are inherently inhibitory. D1 receptors are excited by dopamine and result in activation of the direct pathway and hence lead to an increase in movement, whereas D2 receptors are inhibited by dopamine and result in activation of the indirect pathway.
Pharmacology
William T. Blows in The Biological Basis of Mental Health, 2016
The subcortical degenerative diseases called the subcortical dementias, are caused by degeneration of the basal ganglia that is parts of the brain below the conscious cortex, which have a powerful influence over body movements and muscle tone. Dopamine depletion in the basal ganglia causes motor deficits, while dopamine problems in the frontal lobes generate cognitive and psychotic symptoms. Deep brain electrical stimulation (DBS) of the basal ganglia has proved to be disappointing in PD, but DBS of the pedunculopontine nucleus (PPN) has been very beneficial in helping to control two important and distressing symptoms of PD, i.e. freezing of gait and postural instability. Huntington's disease (HD) is a neurodegenerative disorder of the GABA neurons within the basal ganglia, notably the caudate nucleus first, followed by the putamen, with concurrent enlargement of the lateral ventricles. Mitochondrial DNA damage appears also to be implicated in the pathogenesis of not only Huntington's disease but also in Parkinson's disease and Alzheimer's disease.
Central nervous system
Dave Maudgil, Anthony Watkinson in The Essential Guide to the New FRCR Part 2A and Radiology Boards, 2017
Are the following statements regarding herpes simplex encephalitis true or false? Computed tomography (CT) scan is often negative for the first week. The putamen is normally spared. Haemorrhage is rarely seen. The frontal lobes are more commonly affected than the temporal lobes. Imaging changes are usually bilateral.
Efficiency of
Published in Clinical Toxicology, 2021
Katerina Kotikova, David Zogala, Vaclav Ptacnik, Jiri Trnka, Karel Kupka, Manuela Vaneckova, Zdenek Seidl, Pavel Diblik, Jarmila Heissigerova, Tomas Navratil, Martin Komarc, Ivan Zak, Kamila Polakova, Hana Brozova, Sergey Zakharov
Context Investigate whether 123I-ioflupane SPECT (DaT SPECT) has the potential as a marker of basal ganglia damage in acute methanol poisoning. Methods Prospective, single-centre, cohort study of patients with confirmed methanol poisoning was conducted. DaT SPECT was performed twice with semi-quantification using DaTQUANTTM and MRI-based volumetry was calculated. Specific binding ratios (SBR) of striatum, caudate nucleus, and putamen were correlated with laboratory parameters of outcome, volumetric data, and retinal nerve fibres layer (RNFL) thickness measurements. Results Forty-two patients (mean age 46.3 ± 4.2 years; 8 females), including 15 with MRI-detected putamen lesions (group I) and 27 patients with intact putamen (group II), underwent DaT SPECT. Volumetry was calculated in 35 of the patients assessed. SBR values for the left putamen correlated with putamen volume (r = 0.665; p < 0.001). Decreased bilateral SBR values were determined for the striatum and the putamen, but not for the nucleus caudate, in group I (p < 0.05). Significant correlation was observed between the SBR of the posterior putamen and arterial blood pH (r = 0.574; p < 0.001) and other toxicological parameters of severity of poisoning/outcome including serum lactate, glucose, and creatinine concentrations (p < 0.05). The SBR of the posterior putamen positively correlated with the global RNFL thickness (p < 0.05). ROC analysis demonstrated a significant discriminatory ability of SBR of the posterior putamen with AUC = 0.753 (95%CI 0.604–0.902; p = 0.007). The multivariate regression model demonstrated that arterial blood pH, age, and gender were the most significant factors associated with SBR of the posterior putamen. Conclusion DaT SPECT demonstrates significant potential for the diagnosis of methanol-induced basal ganglia damage.
An Atlas Based Fuzzy Method for Putamen Detection in Anatomical MR Images
Published in International Journal of Intelligent Computing in Medical Sciences & Image Processing, 2007
Tao Song, Mo Jamshidi, Roland Lee, Mingxiong Huang
Recent research discloses that the putamen in human brain has close relationship with some neurological diseases, and the most commonly used methodology in such studies is magnetic resonance (MR) imaging. In order to measure the volume of putamen in MR image, accurate detection is highly desirable. In practice, both the existence of fiber in putamen and the inhomogeneity effect in MR imaging process generates gradual changes in white-to-gray matter contrast in putamen area, which makes the segmentation task rather difficult. In this paper, a Talairach atlas based adaptive fuzzy rule base (FRB) system is proposed and applied to human brain MR images for putamen detection. Comparisons to standard region growing approach, K-means algorithm, Expectation Maximization (EM) algorithm, and FMRIB Software Library (FSL)′s Automatic Segmentation Toolbox (FAST) are performed, and the proposed atlas based FRB system demonstrated significantly better performance in putamen segmentation.
Caudate-putamen lesions in the rat may impair or potentiate maze learning depending upon availability of stimulus cues and relevance of response cues
Published in The Quarterly Journal of Experimental Psychology Section B, 1988
In Experiment 1 rats were required to learn a Y-maze in which reward was made available after a given response (e.g. a left turn) regardless of which arm was used as the start-box. Subjects with lesions of the caudate-putamen showed a deficit on this response-learning task compared with control subjects (unoperated animals and rats having lesions of the posterior cortex). In Experiment 2 rats with caudate-putamen lesions were unimpaired when the direction of the turn required to reach the correct goal-box (identified by means of a salient visual intra-maze cue) varied from trial to trial. In the absence of salient intramaze cues, but with enriched room (extra-maze) cues, the rats with caudate-putamen lesions were superior to controls on this task. It is argued that caudate-putamen lesions disrupt a mechanism responsible for processing information about responses, but that the other (spatial) mechanisms responsible for maze-learning remain intact and that caudate-putamen lesions may enhance performance on spatial tasks for which information about responses is irrelevant.
Related Knowledge Centers
- Cerebrum
- Basal Ganglia
- Substantia Nigra
- Striatum
- Caudate Nucleus
- Prosencephalon