Cognition and connectomes in nondementia idiopathic Parkinson’s disease

Colon-Perez, Luis M.; Tanner, Jared J.; Couret, Michelle; Goicochea, Shelby; Mareci, Thomas H.; Price, Catherine C.

doi:10.1162/netn_a_00027

Cited by 10 publications

(6 citation statements)

References 84 publications

(107 reference statements)

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“…43 Measures of global connectivity are also reduced in patients with PD and cognitive impairment compared to those without in both functional and structural imaging data. 44,45 Diffuse changes in white matter tracts in patients with PD and poor visual performance were also demonstrated in our study, consistent with reduction in global connectivity.…”

Section: Discussionsupporting

confidence: 89%

Fiber-specific white matter reductions in Parkinson hallucinations and visual dysfunction

et al. 2020

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ObjectiveTo investigate the microstructural and macrostructural white matter changes that accompany visual hallucinations and low visual performance in Parkinson disease, a risk factor for Parkinson dementia.MethodsWe performed fixel-based analysis, a novel technique that provides metrics of specific fiber-bundle populations within a voxel (or fixel). Diffusion MRI data were acquired from patients with Parkinson disease (n = 105, of whom 34 were low visual performers and 19 were hallucinators) and age-matched controls (n = 35). We used whole-brain fixel-based analysis to compare microstructural differences in fiber density (FD), macrostructural differences in fiber bundle cross section (FC), and the combined FD and FC (FDC) metric across all white matter fixels. We then performed a tract-of-interest analysis comparing the most sensitive FDC metric across 11 tracts within the visual system.ResultsPatients with Parkinson disease hallucinations exhibited macrostructural changes (reduced FC) within the splenium of the corpus callosum and the left posterior thalamic radiation compared to patients without hallucinations. While there were no significant changes in FD, we found large reductions in the combined FDC metric in Parkinson hallucinators within the splenium (>50% reduction compared to nonhallucinators). Patients with Parkinson disease and low visual performance showed widespread microstructural and macrostructural changes within the genu and splenium of the corpus callosum, bilateral posterior thalamic radiations, and left inferior fronto-occipital fasciculus.ConclusionsWe demonstrate specific white matter tract degeneration affecting posterior thalamic tracts in patients with Parkinson disease with hallucinations and low visual performance, providing direct mechanistic support for attentional models of visual hallucinations.

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Section: Discussionsupporting

confidence: 89%

Fiber-specific white matter reductions in Parkinson hallucinations and visual dysfunction

et al. 2020

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“…Neuroimaging studies have provided important insights separately into structural and functional connectivity alterations in PD [22][23][24] . Diffusion-weighted imaging revealed structural alterations in tracts including the corpus callosum and thalamo-cortical connections in PD with cognitive impairment [25][26][27][28][29] and those with visual dysfunction (higher dementia risk) 30 .…”

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confidence: 99%

Organisational and neuromodulatory underpinnings of structural-functional connectivity decoupling in patients with Parkinson’s disease

et al. 2021

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Parkinson’s dementia is characterised by changes in perception and thought, and preceded by visual dysfunction, making this a useful surrogate for dementia risk. Structural and functional connectivity changes are seen in humans with Parkinson’s disease, but the organisational principles are not known. We used resting-state fMRI and diffusion-weighted imaging to examine changes in structural-functional connectivity coupling in patients with Parkinson’s disease, and those at risk of dementia. We identified two organisational gradients to structural-functional connectivity decoupling: anterior-to-posterior and unimodal-to-transmodal, with stronger structural-functional connectivity coupling in anterior, unimodal areas and weakened towards posterior, transmodal regions. Next, we related spatial patterns of decoupling to expression of neurotransmitter receptors. We found that dopaminergic and serotonergic transmission relates to decoupling in Parkinson’s overall, but instead, serotonergic, cholinergic and noradrenergic transmission relates to decoupling in patients with visual dysfunction. Our findings provide a framework to explain the specific disorders of consciousness in Parkinson’s dementia, and the neurotransmitter systems that underlie these.

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“…This approach showed promises in almost all major neurological/psychiatric diseases. (16–19,33,34) Using resting-state fMRI, a previous study found that glioma could induce functional impairment in the distant areas from the lesion. (4,5) In this current study, we have shown glioblastomas may induce widespread structural impairment as well, which may be due to the systematic tumor invasion or Wallerian degeneration affecting normal-appearing regions.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, network analysis using the graph theory has shown its promises in characterizing various neurological and psychiatric disorders based on dMRI (16–19). Using this approach, the brain structure can be represented as a complex network, namely structural connectome, where the connectivity among cortical/subcortical brain regions is measured by the connecting tracts (20).…”

Section: Introductionmentioning

confidence: 99%

Structural connectome quantifies tumor invasion and predicts survival in glioblastoma patients

Wei

Cui

et al. 2021

Preprint

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Background: Glioblastoma is characterized by extensive invasion into brain parenchymal tissue through white matter tracts. Systematically quantifying invasion, however, is limited by the conventional imaging tools, and could potentially be achieved by a structural connectome approach. Methods: Two prospective patient cohorts of newly diagnosed glioblastoma were included for network construction. A fiber template was firstly derived by employing probabilistic tractography on healthy subjects. Through performing tract-based spatial statistics in patients and age-matched controls, the connectivity strength of each fiber was estimated in patients for network construction. Contrast-enhancing and non-enhancing tumors were segmented and overlaid to the network to identify connectome disruption in lesion and distant areas. The connectome disruption probabilities were calculated across all patients. Disruption indices and network topological features were examined using survival models. Results: Compared to healthy controls, patient networks demonstrated lower clustering coefficient, but higher characteristic path length (each P < 0.001). Higher distant area disruption (HR = 1.43, P = 0.027) and characteristic path length (HR = 1.59, P = 0.031) were associated with worse survival, while higher clustering coefficient (HR = 0.59, P = 0.016) was associated with prolonged survival. Conclusion: The occult invasion in glioblastoma could be identified and quantified using structural connectome, which may confer benefits to precise patient management.

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Cognition and connectomes in nondementia idiopathic Parkinson’s disease

Cited by 10 publications

References 84 publications

Fiber-specific white matter reductions in Parkinson hallucinations and visual dysfunction

Fiber-specific white matter reductions in Parkinson hallucinations and visual dysfunction

Organisational and neuromodulatory underpinnings of structural-functional connectivity decoupling in patients with Parkinson’s disease

Structural connectome quantifies tumor invasion and predicts survival in glioblastoma patients

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