Altered Functional Connectivity of Hippocampal Subfields in Poststroke Dementia

2021 ◽  
Author(s):  
Zhiyong Zhao ◽  
Huaying Cai ◽  
Manli Huang ◽  
Weihao Zheng ◽  
Tingting Liu ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Hippocampal Subfields ◽  
Poststroke Dementia

scholarly journals Heritability of hippocampal functional and microstructural organisation

2021 ◽  
Author(s):  
Seyma Bayrak ◽  
Reinder Vos de Wael ◽  
H. Lina Schaare ◽  
Benoit Caldairou ◽  
Andrea Bernasconi ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Medial Temporal Lobe ◽  
Functional Organization ◽  
Hippocampal Formation ◽  
Resting State Functional Connectivity ◽  
Hippocampal Subfields ◽  
Emotional Processes ◽  
Human Connectome Project ◽  
Cornu Ammonis ◽  
Learning And Plasticity

The hippocampal formation is an uniquely infolded anatomical structure in the medial temporal lobe and it is involved in a broad range of cognitive and emotional processes. It consists of anatomically and functionally different subfields, including the subiculum (SUB), cornu ammonis areas (CA), and the dentate gyrus (DG). However, despite ample research on learning and plasticity of the hippocampal formation, heritability of its structural and functional organization is not fully known. To answer this question, we extracted microstructurally sensitive neuroimaging (i.e., T1w/T2w ratios) and resting-state functional connectivity information along hippocampal subfield surfaces from a sample of healthy twins and unrelated individuals of the Human Connectome Project Dataset. Our findings robustly demonstrate that functional connectivity and local microstructure of hippocampal subfields are highly heritable. Second, we found marked covariation and genetic correlation between the microstructure of the hippocampal subfields and the isocortex, indicating shared genetic factors influencing the microstructure of the hippocampus and isocortex. In both structural and functional measures, we observed a dissociation of cortical projections across subfields. In sum, our study shows that the functional and structural organization of the hippocampal formation is heritable and has a genetic relation to divergent macroscale functional networks within the isocortex.

scholarly journals Altered hippocampal functional connectivity patterns in patients with cognitive impairments following ischaemic stroke: a resting-state fMRI study

2020 ◽  
Author(s):  
JeYoung Jung ◽  
Rosanna Laverick ◽  
Kurdow Nader ◽  
Martin Wilson ◽  
Dorothee P. Auer ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cognitive Impairment ◽  
Functional Connectivity ◽  
Resting State ◽  
Parietal Lobe ◽  
Memory Function ◽  
Resting State Fmri ◽  
Angular Gyrus ◽  
Seed Region ◽  
Hippocampal Subfields

AbstractBackgroundIschemic stroke with cognitive impairment is a considerable risk factor for developing dementia. Identifying imaging markers of cognitive impairment following ischemic stroke will help to develop prevention strategies against post-stroke dementia.MethodsHere, we investigated the hippocampal functional connectivity (FC) pattern following ischemic stroke, using resting-state fMRI (rs-fMRI). Thirty-three cognitively impaired patients after ischemic stroke and sixteen age-matched controls with no known history of neurological disorder, were recruited for the study. Importantly, no patient had a direct ischaemic insult to hippocampus on examination of brain imaging. Seven subfields of hippocampus were used as a seed region for FC analyses.ResultsAcross all hippocampal subfields, FC with the inferior parietal lobe in patients was reduced as compared with healthy controls. This decreased FC included both supramarginal gyrus and angular gyrus. The FC of hippocampal subfields with cerebellum was increased. Importantly, the degree of the altered FC between hippocampal subfields and IPL was associated with their impaired memory function.ConclusionOur results demonstrated that decreased hippocampal-IPL connectivity was associated with cognitive impairment in patients with ischemic stroke. These findings provide novel insights into the role of hippocampus in cognitive impairment following ischemic stroke.

scholarly journals Hippocampal-striatal functional connectivity supports processing of temporal expectations from associative memory

2019 ◽  
Author(s):  
Vincent van de Ven ◽  
Chanju Lee ◽  
Julia Lifanov ◽  
Sarach Kochs ◽  
Henk Jansma ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Temporal Processing ◽  
Temporal Structure ◽  
Dorsal Striatum ◽  
Motor Preparation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Time Intervals ◽  
Hippocampal Subfields ◽  
Associative Processing

AbstractThe hippocampus and dorsal striatum are both associated with temporal processing, but they are thought to play distinct roles. The hippocampus has been reported to contribute to storing temporal structure of events in memory, whereas the striatum contributes to temporal motor preparation and reward anticipation. Here, we asked whether the striatum cooperates with the hippocampus in processing the temporal context of memorized visual associations. In our task, participants were trained to implicitly form temporal expectations for one of two possible time intervals associated to specific cue-target associations, and subsequently were scanned using 7T functional magnetic resonance imaging. During scanning, learned temporal expectations could be violated when the pairs were presented at either the learned or not-learned time intervals. When temporal expectations were not met during testing trials, activity in hippocampal subfields CA3/CA2 and CA1 decreased while right putamen activity increased, compared to when temporal expectations were met. Further, psycho-physiological interactions showed that functional connectivity between left CA1 and caudate, as well as between putamen and caudate, decreased when temporal expectations were not met. Our results indicate that the hippocampus and striatum cooperate to process implicit temporal expectation from mnemonic associations, with different but complementary contributions from caudate and putamen. Our findings provide further support for a hippocampal-striatal network in temporal associative processing.

scholarly journals Sex Differences in Re-experiencing Symptoms Between Husbands and Wives Who Lost Their Only Child in China: A Resting-State Functional Connectivity Study of Hippocampal Subfields

2021 ◽  
Vol 15 ◽  
Author(s):  
Yifeng Luo ◽  
Yu Liu ◽  
Zhao Qing ◽  
Li Zhang ◽  
Yifei Weng ◽  
...  
Keyword(s):  
Sex Differences ◽  
Functional Connectivity ◽  
Resting State ◽  
Protective Role ◽  
Post Traumatic Stress ◽  
Only Child ◽  
Resting State Functional Connectivity ◽  
Neural Basis ◽  
Hippocampal Subfields ◽  
The Right

Background: Losing one’s only child may lead to post-traumatic stress disorder (PTSD), of which re-experiencing is the core symptom. However, neuroimaging studies of sex differences in re-experiencing in the context of the trauma of losing one’s only child and PTSD are scarce; comparisons of the functional networks from the hippocampal subfields to the thalamus might clarify the neural basis.Methods: Thirty couples without any psychiatric disorder who lost their only child (non-PTSD group), 55 patients with PTSD, and 50 normal controls underwent resting-state functional magnetic resonance imaging. The functional connectivity (FC) from the hippocampal subregions to the thalamus and the correlations of FC with re-experiencing symptoms were analyzed within and between the sexes.Results: Compared with husbands without PTSD, wives without PTSD had higher re-experiencing symptoms and weaker FC between the right hippocampal cornu ammonis 3 (RCA3) and the right thalamus (RT; RCA3-RT). Moreover, only the correlation between the RCA3-RT FC and re-experiencing in wives without PTSD was significant. Among the three groups, only the RCA3-RT FC in female subjects was markedly different. Additionally, the RCA3-RT FC in wives without PTSD was remarkably lower relative to female patients with PTSD.Conclusion: Wives without PTSD who lost their only child had worse re-experiencing symptoms relative to their husbands, which was associated with the FC alteration between the hippocampal subregions and the thalamus. Importantly, the low level of the RCA3-RT FC may play a potentially protective role against the development of PTSD in wives who have lost their only child.

scholarly journals Age-related alterations in functional connectivity along the longitudinal axis of the hippocampus and its subfields

2019 ◽  
Author(s):  
Shauna M. Stark ◽  
Amy Frithsen ◽  
Craig E.L. Stark
Keyword(s):  
Older Adults ◽  
Functional Connectivity ◽  
Medial Temporal Lobe ◽  
Functional Organization ◽  
Memory Performance ◽  
Discrimination Performance ◽  
Longitudinal Axis ◽  
Memory Decline ◽  
Hippocampal Subfields ◽  
Age Related

AbstractAging causes hippocampal circuit alterations that differentially affect hippocampal subfields and are associated with age-related memory decline. Additionally, functional organization along the longitudinal axis of the hippocampus has revealed distinctions between anterior and posterior (A-P) connectivity. Here, we examined the functional connectivity (FC) differences between young and older adults at high-resolution within the medial temporal lobe network (entorhinal, perirhinal, and parahippocampal cortices), allowing us to explore how hippocampal subfield connectivity across the longitudinal axis of the hippocampus changes with age. Overall, we found reliably greater connectivity for younger adults than older adults between the hippocampus and PHC and PRC. This drop in functional connectivity was more pronounced in the anterior regions of the hippocampus than the posterior ones, consistent for each of the hippocampal subfields. Further, intra-hippocampal connectivity also reflected an age-related decrease in functional connectivity within the anterior hippocampus in older adults that was offset by an increase in posterior hippocampal functional connectivity. Interestingly, the anterior-posterior shift in older adults between hippocampus and PHC was predictive of lure discrimination performance on the MST, suggesting that this shift may reflect a compensation mechanism that preserves memory performance. While age-related dysfunction within the hippocampal subfields has been well-documented, these results suggest that the age-related A-P shift in hippocampal connectivity may also contribute significantly to memory decline in older adults.

scholarly journals Functional connectivity along the anterior–posterior axis of hippocampal subfields in the ageing human brain

Hippocampus ◽  
2019 ◽  
Vol 29 (11) ◽  
pp. 1049-1062 ◽  
Author(s):  
Marshall A. Dalton ◽  
Cornelia McCormick ◽  
Flavia De Luca ◽  
Ian A. Clark ◽  
Eleanor A. Maguire
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Hippocampal Subfields ◽  
Anterior Posterior ◽  
Anterior Posterior Axis

scholarly journals Differences in functional connectivity along the anterior-posterior axis of human hippocampal subfields

2018 ◽  
Author(s):  
Marshall A. Dalton ◽  
Cornelia McCormick ◽  
Eleanor A. Maguire
Keyword(s):  
High Resolution ◽  
Functional Connectivity ◽  
Functional Mri ◽  
Resting State ◽  
Structural Mri ◽  
List Type ◽  
Hippocampal Subfields ◽  
Anterior Posterior ◽  
Anterior Posterior Axis ◽  
Synaptic Circuit

AbstractThere is a paucity of information about how human hippocampal subfields are functionally connected to each other and to neighbouring extra-hippocampal cortices. In particular, little is known about whether patterns of functional connectivity (FC) differ down the anterior-posterior axis of each subfield. Here, using high resolution structural MRI we delineated the hippocampal subfields in healthy young adults. This included the CA fields, separating DG/CA4 from CA3, separating the pre/parasubiculum from the subiculum, and also segmenting the uncus. We then used high resolution resting state functional MRI to interrogate FC. We first analysed the FC of each hippocampal subfield in its entirety, in terms of FC with other subfields and with the neighbouring regions, namely entorhinal, perirhinal, posterior parahippocampal and retrosplenial cortices. Next, we analysed FC for different portions of each hippocampal subfield along its anterior-posterior axis, in terms of FC between different parts of a subfield, FC with other subfield portions, and FC of each subfield portion with the neighbouring cortical regions of interest. We found that intrinsic functional connectivity between the subfields aligned generally with the tri-synaptic circuit but also extended beyond it. Our findings also revealed that patterns of functional connectivity between the subfields and neighbouring cortical areas differed markedly along the anterior-posterior axis of each hippocampal subfield. Overall, these results contribute to ongoing efforts to characterise human hippocampal subfield connectivity, with implications for understanding hippocampal function.HighlightsHigh resolution resting state functional MRI scans were collectedWe investigated functional connectivity (FC) of human hippocampal subfieldsWe specifically examined FC along the anterior-posterior axis of subfieldsFC between subfields extended beyond the canonical tri-synaptic circuitDifferent portions of subfields showed different patterns of FC with neocortex

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