SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Looi Jeffrey C.L.) "

Sökning: WFRF:(Looi Jeffrey C.L.)

  • Resultat 1-10 av 14
  • [1]2Nästa
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Jakabek, David, et al. (författare)
  • Regional structural hypo- and hyperconnectivity of frontal–striatal and frontal–thalamic pathways in behavioral variant frontotemporal dementia
  • 2018
  • Ingår i: Human Brain Mapping. - : Wiley-Blackwell. - 1065-9471. ; 39:10, s. 4083-4093
  • Tidskriftsartikel (refereegranskat)abstract
    • Behavioral variant frontotemporal dementia (bvFTD) has been predominantly considered as a frontotemporal cortical disease, with limited direct investigation of frontal–subcortical connections. We aim to characterize the grey and white matter components of frontal–thalamic and frontal–striatal circuits in bvFTD. Twenty-four patients with bvFTD and 24 healthy controls underwent morphological and diffusion imaging. Subcortical structures were manually segmented according to published protocols. Probabilistic pathways were reconstructed separately from the dorsolateral, orbitofrontal and medial prefrontal cortex to the striatum and thalamus. Patients with bvFTD had smaller cortical and subcortical volumes, lower fractional anisotropy, and higher mean diffusivity metrics, which is consistent with disruptions in frontal–striatal–thalamic pathways. Unexpectedly, regional volumes of the striatum and thalamus connected to the medial prefrontal cortex were significantly larger in bvFTD (by 135% in the striatum, p =.032, and 217% in the thalamus, p =.004), despite smaller dorsolateral prefrontal cortex connected regional volumes (by 67% in the striatum, p =.002, and 65% in the thalamus, p =.020), and inconsistent changes in orbitofrontal cortex connected regions. These unanticipated findings may represent compensatory or maladaptive remodeling in bvFTD networks. Comparisons are made to other neuropsychiatric disorders suggesting a common mechanism of changes in frontal–subcortical networks; however, longitudinal studies are necessary to test this hypothesis.
  •  
2.
  • Lindberg, Olof, et al. (författare)
  • Hippocampal Shape Analysis in Alzheimer's Disease and Frontotemporal Lobar Degeneration Subtypes
  • 2012
  • Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 30:2, s. 355-365
  • Tidskriftsartikel (refereegranskat)abstract
    • Hippocampal pathology is central to Alzheimer's disease (AD) and other forms of dementia such as frontotemporal lobar degeneration (FTLD). Autopsy studies have shown that certain hippocampal subfields are more vulnerable than others to AD and FTLD pathology, in particular the subiculum and cornu ammonis 1 (CA1). We conducted shape analysis of hippocampi segmented from structural T1 MRI images on clinically diagnosed dementia patients and controls. The subjects included 19 AD and 35 FTLD patients [13 frontotemporal dementia (FTD), 13 semantic dementia (SD), and 9 progressive nonfluent aphasia (PNFA)] and 21 controls. Compared to controls, SD displayed severe atrophy of the whole left hippocampus. PNFA and FTD also displayed atrophy on the left side, restricted to the hippocampal head in FTD. Finally, AD displayed most atrophy in left hippocampal body with relative sparing of the hippocampal head. Consistent with neuropathological studies, most atrophic deformation was found in CA1 and subiculum areas in FTLD and AD.
  •  
3.
  • Looi, Jeffrey C. L., et al. (författare)
  • Morphometric analysis of subcortical structures in progressive supranuclear palsy: In vivo evidence of neostriatal and mesencephalic atrophy
  • 2011
  • Ingår i: Psychiatry Research: Neuroimaging. - : Elsevier. - 0925-4927. ; 194:2, s. 163-175
  • Tidskriftsartikel (refereegranskat)abstract
    • Progressive supranuclear palsy (PSP) is a neurodegenerative disease characterized by gait and postural disturbance, gaze palsy, apathy, decreased verbal fluency and dysexecutive symptoms, with some of these clinical features potentially having origins in degeneration of frontostriatal circuits and the mesencephalon. This hypothesis was investigated by manual segmentation of the caudate and putamen on MRI scans, using previously published protocols, in 15 subjects with PSP and 15 healthy age-matched controls. Midbrain atrophy was assessed by measurement of mid-sagittal area of the midbrain and pons. Shape analysis of the caudate and putamen was performed using spherical harmonics (SPHARM-PDM, University of North Carolina). The sagittal pons area/midbrain area ratio (P/M ratio) was significantly higher in the PSP group, consistent with previous findings. Significantly smaller striatal volumes were found in the PSP group - putamina were 10% smaller and caudate volumes were 17% smaller than in controls after controlling for age and intracranial volume. Shape analysis revealed significant shape deflation in PSP in the striatum, compared to controls; with regionally significant change relevant to frontostriatal and corticostriatal circuits in the caudate. Thus, in a clinically diagnosed and biomarker-confirmed cohort with early PSP, we demonstrate that neostriatal volume and shape are significantly reduced in vivo. The findings suggest a neostriatal and mesencephalic structural basis for the clinical features of PSP leading to frontostriatal and mesocortical-striatal circuit disruption. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
  •  
4.
  • Looi, Jeffrey C. L., et al. (författare)
  • The Australian, US, Scandinavian Imaging Exchange (AUSSIE): an innovative, virtually-integrated health research network embedded in health care
  • 2014
  • Ingår i: Australasian Psychiatry. - : SAGE Publications. - 1039-8562. ; 22:3, s. 260-265
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To describe the development, design and function of an innovative international clinical research network for neuroimaging research, based in Australia, within a joint state health service/medical school. This Australian, US, Scandinavian Imaging Exchange (AUSSIE) network focuses upon identifying neuroimaging biomarkers for neuropsychiatric and neurodegenerative disease. Methods: We describe a case study of the iterative development of the network, identifying characteristic features and methods which may serve as potential models for virtual clinical research networks. This network was established to analyse clinically-derived neuroimaging data relevant to neuropsychiatric and neurodegenerative disease, specifically in relation to subcortical brain structures. Results: The AUSSIE network has harnessed synergies from the individual expertise of the component groups, primarily clinical neuroscience researchers, to analyse a variety of clinical data. Conclusion: AUSSIE is an active virtual clinical research network, analogous to a connectome, which is embedded in health care and has produced significant research, advancing our understanding of neuropsychiatric and neurodegenerative disease through the lens of neuroimaging.
  •  
5.
  •  
6.
  •  
7.
  • Macfarlane, Matthew D, et al. (författare)
  • Striatal Atrophy in the Behavioural Variant of Frontotemporal Dementia: Correlation with Diagnosis, Negative Symptoms and Disease Severity.
  • 2015
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Behavioural variant frontotemporal dementia (bvFTD) is associated with changes in dorsal striatal parts of the basal ganglia (caudate nucleus and putamen), related to dysfunction in the cortico-striato-thalamic circuits which help mediate executive and motor functions. We aimed to determine whether the size and shape of striatal structures correlated with diagnosis of bvFTD, and measures of clinical severity, behaviour and cognition.
  •  
8.
  • Owens-Walton, Conor, et al. (författare)
  • Increased functional connectivity of thalamic subdivisions in patients with Parkinson’s disease
  • 2019
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Parkinson’s disease (PD) affects 2–3% of the population over the age of 65 with loss of dopaminergic neurons in the substantia nigra impacting the functioning of basal ganglia-thalamocortical circuits. The precise role played by the thalamus is unknown, despite its critical role in the functioning of the cerebral cortex, and the abnormal neuronal activity of the structure in PD. Our objective was to more clearly elucidate how functional connectivity and morphology of the thalamus are impacted in PD (n = 32) compared to Controls (n = 20). To investigate functional connectivity of the thalamus we subdivided the structure into two important regions-of-interest, the first with putative connections to the motor cortices and the second with putative connections to prefrontal cortices. We then investigated potential differences in the size and shape of the thalamus in PD, and how morphology and functional connectivity relate to clinical variables. Our data demonstrate that PD is associated with increases in functional connectivity between motor subdivisions of the thalamus and the supplementary motor area, and between prefrontal thalamic subdivisions and nuclei of the basal ganglia, anterior and dorsolateral prefrontal cortices, as well as the anterior and paracingulate gyri. These results suggest that PD is associated with increased functional connectivity of subdivisions of the thalamus which may be indicative alterations to basal ganglia-thalamocortical circuitry.
  •  
9.
  • Owens-Walton, Conor, et al. (författare)
  • Midsagittal corpus callosal thickness and cognitive impairment in Parkinson's disease
  • 2022
  • Ingår i: European Journal of Neuroscience. - : Wiley-Blackwell. - 0953-816X. ; 55:7, s. 1859-1872
  • Tidskriftsartikel (refereegranskat)abstract
    • People diagnosed with Parkinson's disease (PD) can experience significant neuropsychiatric symptoms, including cognitive impairment and dementia, the neuroanatomical substrates of which are not fully characterised. Symptoms associated with cognitive impairment and dementia in PD may relate to direct structural changes to the corpus callosum via primary white matter pathology or as a secondary outcome due to the degeneration of cortical regions. Using magnetic resonance imaging, the corpus callosum can be investigated at the midsagittal plane, where it converges to a contiguous mass and is not intertwined with other tracts. The objective of this project was thus twofold: First, we investigated possible changes in the thickness of the midsagittal callosum and cortex in patients with PD with varying levels of cognitive impairment; and secondly, we investigated the relationship between the thickness of the midsagittal corpus callosum and the thickness of the cortex. Study participants included cognitively unimpaired PD participants (n = 35), PD participants with mild cognitive impairment (n = 22), PD participants with dementia (n = 17) and healthy controls (n = 27). We found thinning of the callosum in PD-related dementia compared with PD-related mild cognitive impairment and cognitively unimpaired PD participants. Regression analyses found thickness of the left medial orbitofrontal cortex to be positively correlated with thickness of the anterior callosum in PD-related mild cognitive impairment. This study suggests that a midsagittal thickness model can uncover changes to the corpus callosum in PD-related dementia, which occur in line with changes to the cortex in this advanced disease stage.
  •  
10.
  • Owens-Walton, Conor, et al. (författare)
  • Striatal changes in Parkinson disease : An investigation of morphology, functional connectivity and their relationship to clinical symptoms
  • 2018
  • Ingår i: Psychiatry Research - Neuroimaging. - : Elsevier. - 0925-4927. ; 275, s. 5-13
  • Tidskriftsartikel (refereegranskat)abstract
    • We sought to investigate morphological and resting state functional connectivity changes to the striatal nuclei in Parkinson disease (PD) and examine whether changes were associated with measures of clinical function. Striatal nuclei were manually segmented on 3T-T1 weighted MRI scans of 74 PD participants and 27 control subjects, quantitatively analysed for volume, shape and also functional connectivity using functional MRI data. Bilateral caudate nuclei and putamen volumes were significantly reduced in the PD cohort compared to controls. When looking at left and right hemispheres, the PD cohort had significantly smaller left caudate nucleus and right putamen volumes compared to controls. A significant correlation was found between greater atrophy of the caudate nucleus and poorer cognitive function, and between greater atrophy of the putamen and more severe motor symptoms. Resting-state functional MRI analysis revealed altered functional connectivity of the striatal structures in the PD group. This research demonstrates that PD involves atrophic changes to the caudate nucleus and putamen that are linked to clinical dysfunction. Our work reveals important information about a key structure-function relationship in the brain and provides support for caudate nucleus and putamen atrophy as neuroimaging biomeasures in PD.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 14
  • [1]2Nästa

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy