Increased posterior default mode network activity and structural connectivity in young adult APOE-ε4 carriers: a multi-modal imaging investigation

AbstractYoung adult APOE-ε4 carriers show increased activity in posterior regions of the default mode network (pDMN), but how this is related to structural connectivity is unknown. Thirty young adults (half APOE-ε4 carriers, the other half APOE-ε3ε3/ε2ε3; mean age 20 years) were scanned using both diffusion and functional magnetic resonance imaging. Diffusion tractography was used to quantify the microstructure (mean diffusivity, MD; fractional anisotropy, FA) of the parahippocampal cingulum bundle (PHCB), which links pDMN and the medial temporal lobe. APOE-ε4 carriers had lower MD and higher FA relative to non-carriers in PHCB. Further, PHCB microstructure was selectively associated with pDMN activity during a scene discrimination task known to be sensitive to Alzheimer’s disease (AD). These findings are consistent with a lifespan view of AD risk, where early-life structural and functional brain changes in specific, vulnerable networks leads to increased neural activity that may ultimately trigger amyloid-ß deposition.

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Increased posterior default mode network activity and structural connectivity in young adult APOE-ε4 carriers: a multimodal imaging investigation

Neurobiology of Aging ◽

10.1016/j.neurobiolaging.2018.08.026 ◽

2019 ◽

Vol 73 ◽

pp. 82-91 ◽

Cited By ~ 10

Author(s):

Carl J. Hodgetts ◽

Jonathan P. Shine ◽

Huw Williams ◽

Mark Postans ◽

Rebecca Sims ◽

...

Keyword(s):

Young Adult ◽

Default Mode Network ◽

Multimodal Imaging ◽

Structural Connectivity ◽

Network Activity ◽

Default Mode ◽

Apoe Ε4

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Dissecting the default mode network: direct structural evidence on the morphology and axonal connectivity of the fifth component of the cingulum bundle

Journal of Neurosurgery ◽

10.3171/2020.2.jns193177 ◽

2020 ◽

pp. 1-12

Author(s):

Georgios P. Skandalakis ◽

Spyridon Komaitis ◽

Aristotelis Kalyvas ◽

Evgenia Lani ◽

Chrysoula Kontrafouri ◽

...

Keyword(s):

Temporal Lobe ◽

Default Mode Network ◽

Medial Temporal Lobe ◽

Spatial Relationship ◽

Distinct Group ◽

Lateral Direction ◽

Default Mode ◽

Cingulum Bundle ◽

Face Area ◽

Close Spatial Relationship

OBJECTIVEAlthough a growing body of data support the functional connectivity between the precuneus and the medial temporal lobe during states of resting consciousness as well as during a diverse array of higher-order functions, direct structural evidence on this subcortical circuitry is scarce. Here, the authors investigate the very existence, anatomical consistency, morphology, and spatial relationships of the cingulum bundle V (CB-V), a fiber tract that has been reported to reside close to the inferior arm of the cingulum (CingI).METHODSFifteen normal, formalin-fixed cerebral hemispheres from adults were treated with Klingler’s method and subsequently investigated through the fiber microdissection technique in a medial to lateral direction.RESULTSA distinct group of fibers is invariably identified in the subcortical territory of the posteromedial cortex, connecting the precuneus and the medial temporal lobe. This tract follows the trajectory of the parietooccipital sulcus in a close spatial relationship with the CingI and the sledge runner fasciculus. It extends inferiorly to the parahippocampal place area and retrosplenial complex area, followed by a lateral curve to terminate toward the fusiform face area (Brodmann area [BA] 37) and lateral piriform area (BA35). Taking into account the aforementioned subcortical architecture, the CB-V allegedly participates as a major subcortical stream within the default mode network, possibly subserving the transfer of multimodal cues relevant to visuospatial, facial, and mnemonic information to the precuneal hub. Although robust clinical evidence on the functional role of this stream is lacking, the modern neurosurgeon should be aware of this tract when manipulating cerebral areas en route to lesions residing in or around the ventricular trigone.CONCLUSIONSThrough the fiber microdissection technique, the authors were able to provide original, direct structural evidence on the existence, morphology, axonal connectivity, and correlative anatomy of what proved to be a discrete white matter pathway, previously described as the CB-V, connecting the precuneus and medial temporal lobe.

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Abstract WP489: Disrupted Functional and Structural Connectivity Within Default Mode Network Contribute to WMH Related Cognitive Impairment

Stroke ◽

10.1161/str.51.suppl_1.wp489 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Lili Huang ◽

Qing Ye ◽

Xin Chen ◽

Dan Yang ◽

Ruomeng Qin ◽

...

Keyword(s):

Risk Factors ◽

Cognitive Impairment ◽

White Matter ◽

Default Mode Network ◽

Rating Scale ◽

Diffusion Tensor ◽

Structural Connectivity ◽

Mean Diffusivity ◽

White Matter Tracts ◽

Default Mode

Aims: The prevalence of white matter hyperintensities (WMH) rises dramatically with aging. Both the progression of WMH and default mode network (DMN) have been proven to be closely associated with cognitive function. Thus, we hypothesized that changes in functional connectivity (FC) and structural connectivity (SC) of the DMN contributed to WMH related cognitive impairment. Methods: A total of 116 subjects were enrolled from the Cerebral Small Vessel Disease Register in Drum Tower Hospital of Nanjing University, and were distributed across three categories according to Fazekas rating scale: WMH I(n=57), WMH II(n=34), and WMH III (n=25). The clinical and neuropsychological data were collected, and all participants underwent 3D T1 weighted images, T2 weighted images, 3D fluid attenuated inversion recovery (FLAIR) images, diffusion tensor images (DTI), and diffusion weighted imaging (DWI). The alterations of FC and SC within the DMN were further explored in these subjects. Results: The study found that age and hypertension were risk factors for WMH progression. Subjects with a larger WMH burden displayed higher DMN FC in the medial frontal gyrus (MFG), while lower DMN FC in the thalamus. After adjustment for age, gender, and education, the increasing FC between the MFG, posterior cingulate cortex (PCC), and ascending mean diffusivity (MD) of the white matter tracts between the hippocampus and PCC were independent indicators of worse performance in memory. Moreover, the decreasing FC between the thalamus, PCC, and ascending MD of the white matter tracts between the thalamus and PCC were independent risk factors for a slower processing speed. Conclusion: The changes in FC and SC within the DMN attributed to WMH progression were responsible for the cognitive impairment.

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Frequency domains of resting state default mode network activity in schizophrenia

Klinische Neurophysiologie ◽

10.1055/s-0034-1371243 ◽

2014 ◽

Vol 45 (01) ◽

Author(s):

G Mingoia ◽

K Langbein ◽

M Dietzek ◽

G Wagner ◽

S Smesny ◽

...

Keyword(s):

Default Mode Network ◽

Resting State ◽

Network Activity ◽

Default Mode ◽

Frequency Domains

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P.3.a.012 Altered default mode network activity in schizophrenia patients

European Neuropsychopharmacology ◽

10.1016/s0924-977x(13)70678-3 ◽

2013 ◽

Vol 23 ◽

pp. S428-S429

Author(s):

A. Pankow ◽

L. Deserno ◽

F. Bermpohl ◽

M. Walter ◽

F. Schlagenhauf ◽

...

Keyword(s):

Default Mode Network ◽

Network Activity ◽

Default Mode

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Altered default mode network activity in patient with anxiety disorders: An fMRI study

European Journal of Radiology ◽

10.1016/j.ejrad.2007.02.006 ◽

2007 ◽

Vol 63 (3) ◽

pp. 373-378 ◽

Cited By ~ 121

Author(s):

Xiao-Hu Zhao ◽

Pei-Jun Wang ◽

Chun-Bo Li ◽

Zheng-Hui Hu ◽

Qian Xi ◽

...

Keyword(s):

Anxiety Disorders ◽

Default Mode Network ◽

Network Activity ◽

Default Mode ◽

Fmri Study

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Default Mode Network Maturation and Environmental Adversities During Childhood

Chronic Stress ◽

10.1177/2470547018808295 ◽

2018 ◽

Vol 2 ◽

pp. 247054701880829 ◽

Cited By ~ 1

Author(s):

Keila Rebello ◽

Luciana M. Moura ◽

Walter H. L. Pinaya ◽

Luis A. Rohde ◽

João R. Sato

Keyword(s):

Default Mode Network ◽

Environmental Conditions ◽

Development Patterns ◽

Default Mode ◽

Functional Studies ◽

Open Questions ◽

Special Challenge ◽

Brain Changes ◽

Adverse Environmental Conditions ◽

Atypical Development

Default mode network (DMN) plays a central role in cognition and brain disorders. It has been shown that adverse environmental conditions impact neurodevelopment, but how these conditions impact in DMN maturation is still poorly understood. This article reviews representative neuroimaging functional studies addressing the interactions between DMN development and environmental factors, focusing on early life adversities, a critical period for brain changes. Studies focused on this period of life offer a special challenge: to disentangle the neurodevelopmental connectivity changes from those related to environmental conditions. We first summarized the literature on DMN maturation, providing an overview of both typical and atypical development patterns in childhood and early adolescence. Afterward, we focused on DMN changes associated with chronic exposure to environmental adversities during childhood. This summary suggests that changes in DMN development could be a potential allostatic neural feature associated with an embodiment of environmental circumstances. Finally, we discuss about some key methodological issues that should be considered in paradigms addressing environmental adversities and open questions for future investigations.

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