Faculty Opinions recommendation of Altered frontal-mediated inhibition and white matter connectivity in pediatric chronic tic disorders.

AbstractTetrahydroisoquinolines (TIQs) such as salsolinol (SAL), norsalsolinol (NSAL) and their methylated derivatives N-methyl-norsalsolinol (NMNSAL) and N-methyl-salsolinol (NMSAL), modulate dopaminergic neurotransmission and metabolism in the central nervous system. Dopaminergic neurotransmission is thought to play an important role in the pathophysiology of chronic tic disorders, such as Tourette syndrome (TS). Therefore, the urinary concentrations of these TIQ derivatives were measured in patients with TS and patients with comorbid attention-deficit/hyperactivity disorder (TS + ADHD) compared with controls. Seventeen patients with TS, 12 with TS and ADHD, and 19 age-matched healthy controls with no medication took part in this study. Free levels of NSAL, NMNSAL, SAL, and NMSAL in urine were measured by a two-phase chromatographic approach. Furthermore, individual TIQ concentrations in TS patients were used in receiver-operating characteristics (ROC) curve analysis to examine the diagnostic value. NSAL concentrations were elevated significantly in TS [434.67 ± 55.4 nmol/l (standard error of mean = S.E.M.), two-way ANOVA, p < 0.0001] and TS + ADHD patients [605.18 ± 170.21 nmol/l (S.E.M.), two-way ANOVA, p < 0.0001] compared with controls [107.02 ± 33.18 nmol/l (S.E.M.), two-way ANOVA, p < 0.0001] and NSAL levels in TS + ADHD patients were elevated significantly in comparison with TS patients (two-way ANOVA, p = 0.017). NSAL demonstrated an AUC of 0.93 ± 0.046 (S.E.M) the highest diagnostic value of all metabolites for the diagnosis of TS. Our results suggest a dopaminergic hyperactivity underlying the pathophysiology of TS and ADHD. In addition, NSAL concentrations in urine may be a potential diagnostic biomarker of TS.

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White matter network damage mediates association between cerebrovascular disease and cognition

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x21990980 ◽

2021 ◽

pp. 0271678X2199098

Author(s):

Saima Hilal ◽

Siwei Liu ◽

Tien Yin Wong ◽

Henri Vrooman ◽

Ching-Yu Cheng ◽

...

Keyword(s):

White Matter ◽

Cerebrovascular Disease ◽

Verbal Memory ◽

Visual Memory ◽

Diffusion Tensor ◽

Mean Diffusivity ◽

Domain Specific ◽

Epidemiology Of Dementia ◽

Z Scores ◽

White Matter Connectivity

To determine whether white matter network disruption mediates the association between MRI markers of cerebrovascular disease (CeVD) and cognitive impairment. Participants (n = 253, aged ≥60 years) from the Epidemiology of Dementia in Singapore study underwent neuropsychological assessments and MRI. CeVD markers were defined as lacunes, white matter hyperintensities (WMH), microbleeds, cortical microinfarcts, cortical infarcts and intracranial stenosis (ICS). White matter microstructure damage was measured as fractional anisotropy and mean diffusivity by tract based spatial statistics from diffusion tensor imaging. Cognitive function was summarized as domain-specific Z-scores. Lacunar counts, WMH volume and ICS were associated with worse performance in executive function, attention, language, verbal and visual memory. These three CeVD markers were also associated with white matter microstructural damage in the projection, commissural, association, and limbic fibers. Path analyses showed that lacunar counts, higher WMH volume and ICS were associated with executive and verbal memory impairment via white matter disruption in commissural fibers whereas impairment in the attention, visual memory and language were mediated through projection fibers. Our study shows that the abnormalities in white matter connectivity may underlie the relationship between CeVD and cognition. Further longitudinal studies are needed to understand the cause-effect relationship between CeVD, white matter damage and cognition.

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White matter connectivity networks predict levodopa-induced dyskinesia in Parkinson’s disease

Journal of Neurology ◽

10.1007/s00415-021-10883-1 ◽

2021 ◽

Author(s):

Jin Ho Jung ◽

Yae Ji Kim ◽

Seok Jong Chung ◽

Han Soo Yoo ◽

Yang Hyun Lee ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

White Matter ◽

White Matter Connectivity

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Differences in white matter connectivity between treatment-resistant and treatment-responsive subtypes of schizophrenia

Psychiatry Research Neuroimaging ◽

10.1016/j.pscychresns.2018.11.002 ◽

2018 ◽

Vol 282 ◽

pp. 47-54 ◽

Cited By ~ 3

Author(s):

Carolyn Beth McNabb ◽

Rob Kydd ◽

Frederick Sundram ◽

Ian Soosay ◽

Bruce Roy Russell

Keyword(s):

White Matter ◽

Treatment Resistant ◽

White Matter Connectivity

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The convergence and divergence of episodic and semantic functions across lateral parietal cortex

10.1101/2020.12.08.416123 ◽

2020 ◽

Author(s):

Gina F. Humphreys ◽

JeYoung Jung ◽

Matthew A. Lambon Ralph

Keyword(s):

White Matter ◽

Semantic Memory ◽

Parietal Cortex ◽

Memory Retrieval ◽

Task Difficulty ◽

Structural Connectivity ◽

Angular Gyrus ◽

Episodic Retrieval ◽

Semantic Retrieval ◽

White Matter Connectivity

AbstractSeveral decades of neuropsychological and neuroimaging research have highlighted the importance of lateral parietal cortex (LPC) across a myriad of cognitive domains. Yet, despite the prominence of this region the underlying function of LPC remains unclear. Two domains that have placed particular emphasis on LPC involvement are semantic memory and episodic memory retrieval. From each domain, sophisticated models have been proposed as to the underlying function, as well as the more domain-general that LPC is engaged by any form of internally-directed cognition (episodic and semantic retrieval both being examples if this process). Here we directly address these alternatives using a combination of fMRI and DTI white-matter connectivity data. The results show that ventral LPC (angular gyrus) was positively engaged during episodic retrieval but disengaged during semantic memory retrieval. In addition, the level of activity negatively varied with task difficulty in the semantic task whereas episodic activation was independent of difficulty. In contrast, dorsal LPC (intraparietal sulcus) showed domain general activation that was positively correlated with task difficulty. In terms of structural connectivity, a dorsal-ventral and anterior-posterior gradient of connectivity was found to different processing networks (e.g., mid-angular gyrus (AG) connected with episodic retrieval). We propose a unifying model in which LPC as a whole might share a common underlying function (e.g., multimodal buffering) and variations across subregions arise due to differences in the underlying white matter connectivity.

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Exploring the laminar connectome

10.1101/2021.03.17.21253439 ◽

2021 ◽

Author(s):

Ittai Shamir ◽

Omri Tomer ◽

Ronnie Krupnik ◽

Yaniv Assaf

Keyword(s):

White Matter ◽

Grey Matter ◽

Structural Description ◽

Mri Imaging ◽

Healthy Human ◽

Cortical Grey Matter ◽

Cortical Laminar ◽

White Matter Connectivity ◽

Human Brains

The human connectome is the complete structural description of the network of connections and elements that form the wiring diagram of the brain. Because of the current scarcity of information regarding laminar end points of white matter tracts inside cortical grey matter, tractography remains focused on cortical partitioning into regions, while ignoring radial partitioning into laminar components. To overcome this biased representation of the cortex as a single homogenous unit, we use a recent data-derived model of cortical laminar connectivity, which has been further explored and corroborated in the macaque brain by comparison to published studies. The model integrates multimodal MRI imaging datasets regarding both white matter connectivity and grey matter laminar composition into a laminar-level connectome. In this study we model the laminar connectome of healthy human brains (N=20) and explore them via a set of neurobiologically meaningful complex network measures. Our analysis demonstrates a subdivision of network hubs that appear in the standard connectome into each individual component of the laminar connectome, giving a fresh look into the role of laminar components in cortical connectivity and offering new prospects in the fields of both structural and functional connectivity.

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