Patterns of Striatal Degeneration in Frontotemporal Dementia
*Departments of Neurology ∥Pathology, University of California, San Francisco, CA †Department of Neurology, National Yang-Ming University, School of Medicine ‡Taipei Veterans General Hospital, Taipei, Taiwan §Department of Pathology, University of Pennsylvania, Philadelphia, PA. Alzheimer disease and associated disorders
(Impact Factor: 2.44).
02/2012; 27(1). DOI: 10.1097/WAD.0b013e31824a7df4
Behavioral variant frontotemporal dementia and semantic dementia have been associated with striatal degeneration, but few studies have delineated striatal subregion volumes in vivo or related them to the clinical phenotype. We traced caudate, putamen, and nucleus accumbens on magnetic resonance images to quantify volumes of these structures in behavioral variant frontotemporal dementia, semantic dementia, Alzheimer disease, and healthy controls (n=12 per group). We further related these striatal volumes to clinical deficits and neuropathologic findings in a subset of patients. Behavioral variant frontotemporal dementia and semantic dementia showed significant overall striatal atrophy compared with controls. Moreover, behavioral variant frontotemporal dementia showed panstriatal degeneration, whereas semantic dementia featured a more focal pattern involving putamen and accumbens. Right-sided striatal atrophy, especially in the putamen, correlated with the overall behavioral symptom severity and with specific behavioral domains. At autopsy, patients with behavioral variant frontotemporal dementia and semantic dementia showed striking and severe tau or TAR DNA-binding protein of 43 kDa pathology, especially in ventral parts of the striatum. These results demonstrate that ventral striatum degeneration is a prominent shared feature in behavioral variant frontotemporal dementia and semantic dementia and may contribute to the social-emotional deficits common to both disorders.
Available from: Tetsuya Kimura
- "This prevents optimization of behavior or decision-making. In frontotemporal dementia patients, for example, in which the salient network – that includes the Acb has degenerated, there is a tendency not to make decisions based on contexts relating to moral and sociality , . Such decisions mismatched with context may, as a result, increase the frequency of stress for the patient. "
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ABSTRACT: In recent years, the study of resting state neural activity has received much attention. To better understand the roles of different brain regions in the regulation of behavioral activity in an arousing or a resting period, we developed a novel behavioral paradigm (8-arm food-foraging task; 8-arm FFT) using the radial 8-arm maze and examined how AcbC lesions affect behavioral execution and learning. Repetitive training on the 8-arm FFT facilitated motivation of normal rats to run quickly to the arm tips and to the center platform before the last-reward collection. Importantly, just after this point and before confirmation of no reward at the next arm traverse, locomotor activity decreased. This indicates that well-trained rats can predict the absence of the reward at the end of food seeking and then start another behavior, namely planned resting. Lesions of the AcbC after training selectively impaired this reduction of locomotor activity after the last-reward collection without changing activity levels before the last-reward collection. Analysis of arm-selection patterns in the lesioned animals suggests little influence of the lesion in the ability to predict the reward absence. AcbC lesions did not change exploratory locomotor activity in an open-field test in which there were no rewards. This suggests that the AcbC controls the activity level of planned resting behavior shaped by the 8-arm FFT. Rats receiving training after AcbC lesioning showed a reduction in motivation for reward seeking. Thus, the AcbC also plays important roles not only in controlling the activity level after the last-reward collection but also in motivational learning for setting the activity level of reward-seeking behavior.
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ABSTRACT: The pace of discovery in frontotemporal dementia (FTD) has accelerated dramatically with the discovery of new genetic causes and pathological substrates of the disease. MAPT/tau, GRN/progranulin, and C9ORF72 have emerged as common FTD genes, and TARDBP/TDP-43, VCP, FUS, and CHMP2B have been identified as less common genetic causes. TDP-43 and FUS have joined tau as common neuropathological substrates of the disease. Mouse models provide an important tool for understanding the role of these molecules in FTD pathogenesis. Here, we review recent progress with mouse models based on tau, TDP-43, progranulin, VCP, and CHMP2B. We also consider future prospects for FTD models, including developing new models to address unanswered questions. There are also opportunities for capitalizing on conservation of the salience network, which is selectively vulnerable in FTD, and the availability of FTD-related behavioral paradigms to analyze mouse models of the disease. Ann Neurol ANN NEUROL 2012;72:837-849.
Available from: Maxime Bertoux
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ABSTRACT: Behavioural disturbances in frontotemporal dementia (FTD) are thought to reflect mainly atrophy of cortical regions. Recent studies suggest that subcortical brain regions, in particular the striatum, are also significantly affected and this pathology might play a role in the generation of behavioural symptoms. Objective: To investigate prefrontal cortical and striatal atrophy contributions to behavioural symptoms in FTD. Methods: One hundred and eighty-two participants (87 FTD patients, 39 AD patients and 56 controls) were included. Behavioural profiles were established using the Cambridge Behavioural Inventory Revised (CBI-R) and Frontal System Behaviour Scale (FrSBe). Atrophy in prefrontal (VMPFC, DLPFC) and striatal (caudate, putamen) regions was established via a 5-point visual rating scale of the MRI scans. Behavioural scores were correlated with atrophy rating scores. Results: Behavioural and atrophy ratings demonstrated that patients were significantly impaired compared to controls, with bvFTD being most severely affected. Behavioural-anatomical correlations revealed that VMPFC atrophy was closely related to abnormal behaviour and motivation disturbances. Stereotypical behaviours were associated with both VMPFC and striatal atrophy. By contrast, disturbance of eating was found to be related to striatal atrophy only. Conclusion: Frontal and striatal atrophy contributed to the behavioural disturbances seen in FTD, with some behaviours related to frontal, striatal or combined fronto-striatal pathology. Consideration of striatal contributions to the generation of behavioural disturbances should be taken into account when assessing patients with potential FTD.
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