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Left Thalamus (leave + thalamus)
Selected AbstractsThe dynamic network subserving the three phases of cognitive procedural learningHUMAN BRAIN MAPPING, Issue 12 2007Valérie Hubert Abstract Cognitive procedural learning is characterized by three phases (cognitive, associative, and autonomous), each involving distinct processes. We performed a behavioral study and a positron emission tomography (PET) activation study using the Tower of Toronto task. The aim of the behavioral study was to determine cognitive predictors for the length of each of the three learning phases, in order to preselect subjects for the PET study. The objective of the second study was to describe the cerebral substrates subtending these three phases. Contrasted with a reference (motor) task, the cognitive phase activated the prefrontal cortex, cerebellum, and parietal regions, all of which became less active as learning progressed. The associative phase was characterized by the activation of the occipital regions, right thalamus, and caudate nucleus. During the autonomous phase, new regions were involved, including the left thalamus and an anterior part of the cerebellum. These results, by employing a direct comparison between phases, provide the first evidence of the involvement and the time course of activation of different regions in each learning phase, in accordance with current models of cognitive procedural learning. The involvement of a frontoparietal network suggests the use of strategies in problem solving during the cognitive phase. The involvement of the occipital regions during the associative and autonomous phase suggests the intervention of mental imagery. Lastly, the activation of the cerebellum during the autonomous phase is consistent with the fact that performance in this phase is determined by psychomotor abilities. Hum Brain Mapp, 2007. © 2007 Wiley-Liss, Inc. [source] Value of regional cerebral blood flow in the evaluation of chronic liver disease and subclinical hepatic encephalopathyJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2003YUSUF YAZGAN Abstract Aims:, Regional changes in cerebral blood flow in patients with chronic hepatitis, cirrhosis and subclinical hepatic encephalopathy were investigated in the present study using single photon emission computed tomography (SPECT). Methods:, Twenty patients with cirrhosis, 11 patients with chronic hepatitis, and nine healthy controls were included in the study. Cerebral SPECT were obtained for all patients. The percentages of cerebral blood flow of 14 regions to the cerebellar blood flow were determined. Only the patients with cirrhosis underwent psychometric evaluation: visual evoked potentials (VEP) measurements and electroencephalogram (EEG) recordings along with blood levels of albumin, bilirubin, and ammonia were measured and prothrombin time was determined in cirrhotic patients. These patients were classified according to the Child,Pugh classification. Results:, Among cirrhotic patients, six had abnormal results in VEP studies, 11 in psychometric tests and with six in EEG evaluation. Any abnormality in psychometric tests and/or VEP studies is taken as the main criterion; subclinical hepatic encephalopathy was detected in 12 of 20 patients. According to SPECT results in patients with subclinical encephalopathy, a statistically significant decrease in cerebral blood flow in right thalamus and nearly significant decrease in left thalamus were observed. Regional blood flow was significantly higher in the frontal lobes of patients with cirrhosis when compared with healthy controls. Similarly, cerebral blood flow in frontal and cingulate regions was significantly higher in patients with chronic hepatitis than in healthy controls. There was no relationship between cerebral blood flow and blood levels of ammonia or Child,Pugh score, in cirrhotic patients. Conclusion:, Significant changes in cerebral blood flow may be present in chronic liver diseases and the authors suggest that the measurement of changes in cerebral blood flow might be useful in detecting subclinical hepatic encephalopathy. [source] Arm chorea secondary to an unruptured giant aneurysm,MOVEMENT DISORDERS, Issue 11 2003Luis M. Barreiro De Madariaga MD Abstract We describe the case of a 20-year-old male who developed right-arm choreic movements secondary to a giant unruptured aneurysm impinging upon the left thalamus, putamen, globus pallidus, cerebral peduncle, midbrain, and subthalamic nucleus. The aneurysm was treated successfully with coils and a supraclinoid balloon. Abnormal movements initially failed to ameliorate, but within a few months, it was possible to discontinue symptomatic haloperidol therapy, with only mild residual abnormal movements. © 2003 Movement Disorder Society [source] Neurofibromatosis type 1-associated unusual pleomorphic astrocytoma displaying continual malignant progressionPATHOLOGY INTERNATIONAL, Issue 7 2001Hideaki Yokoo Patients with neurofibromatosis type 1 (NF1) often have gliomas as a complication, most of which are benign pilocytic astrocytomas which have arisen in optic pathways. In the present case, a 17-year-old girl (at death) with stigmata of NF1, initially had a bulky tumor mass in the left thalamus, developing into the lateral ventricle, at 13 years of age. Partially resected tissue samples showed pleomorphic astrocytoma with abundant xanthoma cells and degenerative structures such as Rosenthal fibers (RF) and eosinophilic granular bodies. Fine eosinophilic granules identical to RF, both immunophenotypically and ultrastructurally, were also seen. The residual tumor was subtotally resected 6 months later, and the tumor histology was essentially similar as before, accompanying the regenerative structures; this was believed to be a good prognostic indicator. However, several anaplastic features such as mitosis, necrosis and vascular proliferation appeared even in areas rich in the regenerative structures. After a 2-year, disease-free interval, multiple tumor relapse occurred in June 1997. Partially resected tumor tissues were composed of monotonous small anaplastic cells with prominent proliferative activity. Surprisingly, the tumor cells had retained eosinophilic granules within the cell bodies. Postoperative chemotherapy with procarbazine, MCNU and vincristine (PCV) suppressed the residual tumor dramatically, but the regrowing tumor finally became uncontrollable, leading to the patient's death. TP53 mutation was not detected, while p27 immunopositivity was constantly high during malignant progression, suggesting acquisition of proliferative activity to overcome p53 and p27 inhibitory functions. A review of previously published reports failed to reveal any cases of this type. [source] Decreased blood flow of the left thalamus during somnolent episodes in a case of recurrent hypersomniaPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 3 2002IWAO NOSE md Abstract A 24-year-old male with recurrent hypersomnia associated with decreased blood flow in the thalamus on single photon emission computed tomography (SPECT) is reported. In the hypersomnolent period, the decrease of blood flow in the left thalamus was revealed in the SPECT and slow waves appeared sporadically or sometimes as a burst on the electroencephalogram (EEG). In a phase of insomnia in the convalescent period there were almost no slow waves in the resting EEG but many slow waves appeared on hyperventilation EEG and the power spectrum at this hyperventilation resembled the power spectrum at the resting EEG in the hypersomnolent period. In the remission period there was no abnormal data in these testings. [source] Thalamic atrophy associated with painful osteoarthritis of the hip is reversible after arthroplasty: A longitudinal voxel-based morphometric studyARTHRITIS & RHEUMATISM, Issue 10 2010Stephen E. Gwilym Objective Voxel-based morphometry (VBM) is a method of assessing brain gray matter volume that has previously been applied to various chronic pain conditions. From this previous work, it appears that chronic pain is associated with altered brain morphology. The present study was undertaken to assess these potential alterations in patients with painful hip osteoarthritis (OA). Methods We studied 16 patients with unilateral right-sided hip pain, before and 9 months after hip arthroplasty. This enabled comparison of gray matter volume in patients with chronic musculoskeletal pain versus healthy controls, as well as identification of any changes in volume following alleviation of pain (after surgery). Assessment involved self-completion questionnaires to assess pain, function, and psychosocial variables, and magnetic resonance imaging scanning of the brain for VBM analysis. Results Significant differences in brain gray matter volume between healthy controls and patients with painful hip arthritis were seen. Specifically, areas of the thalamus in patients with chronic OA pain exhibited decreased gray matter volume. Furthermore, when these preoperative changes were compared with the brain morphology of the patients 9 months after surgery, the areas of reduced thalamic gray matter volume were found to have "reversed" to levels seen in healthy controls. Conclusion Our findings confirm that gray matter volume decreases within the left thalamus in the presence of chronic pain and disability in patients with hip OA. The results also show that these thalamic volume changes reverse after hip arthroplasty and are associated with decreased pain and increased function. These findings have potential implications with regard to optimizing the timing of orthopedic interventions such as arthroplasty. [source] | ||||||||||