scholarly journals Latent patterns of task‐related functional connectivity relate to hyperactivation and associative memory impairment in SCD + and MCI

2020 ◽  
Vol 16 (S5) ◽  
Author(s):  
Nick Corriveau‐Lecavalier ◽  
Natasha Rajah ◽  
Samira Mellah ◽  
Sylvie Belleville ◽  
Keyword(s):  
Functional Connectivity ◽  
Associative Memory ◽  
Memory Impairment

The Anterior-posterior Functional Connectivity Disconnection in the Elderly with Subjective Memory Impairment and Amnestic Mild Cognitive Impairment

2020 ◽  
Vol 17 (4) ◽  
pp. 373-381
Author(s):  
Wuhai Tao ◽  
Jinping Sun ◽  
Xin Li ◽  
Wen Shao ◽  
Jing Pei ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Functional Connectivity ◽  
Memory Impairment ◽  
Amnestic Mild Cognitive Impairment ◽  
Magnetic Resonance Imaging Scan ◽  
Subjective Memory ◽  
Long Distance ◽  
Whole Brain ◽  
Subjective Memory Impairment

Background: Subjective Memory Impairment (SMI) may tremendously increase the risk of Alzheimer’s Disease (AD). The full understanding of the neuromechanism of SMI will shed light on the early intervention of AD. Methods: In the current study, 23 Healthy Controls (HC), 22 SMI subjects and 24 amnestic Mild Cognitive Impairment (aMCI) subjects underwent the comprehensive neuropsychological assessment and the resting-state functional magnetic resonance imaging scan. The difference in the connectivity of the Default Mode Network (DMN) and Functional Connectivity (FC) from the Region of Interest (ROI) to the whole brain were compared, respectively. Results: The results showed that HC and SMI subjects had significantly higher connectivity in the region of the precuneus area compared to aMCI subjects. However, from this region to the whole brain, SMI and aMCI subjects had significant FC decrease in the right anterior cingulum, left superior frontal and left medial superior frontal gyrus compared to HC. In addition, this FC change was significantly correlated with the cognitive function decline in participants. Conclusion: Our study indicated that SMI subjects had relatively intact DMN connectivity but impaired FC between the anterior and posterior brain. The findings suggest that long-distance FC is more vulnerable than the short ones in the people with SMI.

scholarly journals Early stages of tau pathology and its associations with functional connectivity, atrophy and memory

Brain ◽  
2021 ◽  
Author(s):  
David Berron ◽  
Jacob W Vogel ◽  
Philip S Insel ◽  
Joana B Pereira ◽  
Long Xie ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Entorhinal Cortex ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Memory Impairment ◽  
Memory Performance ◽  
Hippocampal Atrophy ◽  
Tau Pathology ◽  
Β Amyloid ◽  
With Memory

Abstract In Alzheimer’s disease, postmortem studies have shown that the first cortical site where neurofibrillary tangles appear is the transentorhinal region, a subregion within the medial temporal lobe that largely overlaps with area 35, and the entorhinal cortex. Here we used tau-PET imaging to investigate the sequence of tau pathology progression within the human medial temporal lobe and across regions in the posterior-medial system. Our objective was to study how medial temporal tau is related to functional connectivity, regional atrophy, and memory performance. We included 215 β-amyloid negative cognitively unimpaired, 81 β-amyloid positive cognitively unimpaired and 87 β-amyloid positive individuals with mild cognitive impairment, who each underwent [18]F-RO948 tau and [18]F-flutemetamol amyloid PET imaging, structural T1-MRI and memory assessments as part of the Swedish BioFINDER-2 study. First, event-based modelling revealed that the entorhinal cortex and area 35 show the earliest signs of tau accumulation followed by the anterior and posterior hippocampus, area 36 and the parahippocampal cortex. In later stages, tau accumulation became abnormal in neocortical temporal and finally parietal brain regions. Second, in cognitively unimpaired individuals, increased tau load was related to local atrophy in the entorhinal cortex, area 35 and the anterior hippocampus and tau load in several anterior medial temporal lobe subregions was associated with distant atrophy of the posterior hippocampus. Tau load, but not atrophy, in these regions was associated with lower memory performance. Further, tau-related reductions in functional connectivity in critical networks between the medial temporal lobe and regions in the posterior-medial system were associated with this early memory impairment. Finally, in patients with mild cognitive impairment, the association of tau load in the hippocampus with memory performance was partially mediated by posterior hippocampal atrophy. In summary, our findings highlight the progression of tau pathology across medial temporal lobe subregions and its disease-stage specific association with memory performance. While tau pathology might affect memory performance in cognitively unimpaired individuals via reduced functional connectivity in critical medial temporal lobe-cortical networks, memory impairment in mild cognitively impaired patients is associated with posterior hippocampal atrophy.

Functional Connectivity Relationships Predict Similarities in Task Activation and Pattern Information during Associative Memory Encoding

2014 ◽  
Vol 26 (5) ◽  
pp. 1085-1099 ◽  
Author(s):  
Maureen Ritchey ◽  
Andrew P. Yonelinas ◽  
Charan Ranganath
Keyword(s):  
Functional Connectivity ◽  
Functional Properties ◽  
Associative Memory ◽  
Large Scale ◽  
Memory Task ◽  
Neural Systems ◽  
General Level ◽  
Specific Information ◽  
Memory Encoding ◽  
Cortical Regions

Neural systems may be characterized by measuring functional interactions in the healthy brain, but it is unclear whether components of systems defined in this way share functional properties. For instance, within the medial temporal lobes (MTL), different subregions show different patterns of cortical connectivity. It is unknown, however, whether these intrinsic connections predict similarities in how these regions respond during memory encoding. Here, we defined brain networks using resting state functional connectivity (RSFC) then quantified the functional similarity of regions within each network during an associative memory encoding task. Results showed that anterior MTL regions affiliated with a network of anterior temporal cortical regions, whereas posterior MTL regions affiliated with a network of posterior medial cortical regions. Importantly, these connectivity relationships also predicted similarities among regions during the associative memory task. Both in terms of task-evoked activation and trial-specific information carried in multivoxel patterns, regions within each network were more similar to one another than were regions in different networks. These findings suggest that functional heterogeneity among MTL subregions may be related to their participation in distinct large-scale cortical systems involved in memory. At a more general level, the results suggest that components of neural systems defined on the basis of RSFC share similar functional properties in terms of recruitment during cognitive tasks and information carried in voxel patterns.

scholarly journals LTP and memory impairment caused by extracellular Aβ and Tau oligomers is APP-dependent

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Daniela Puzzo ◽  
Roberto Piacentini ◽  
Mauro Fá ◽  
Walter Gulisano ◽  
Domenica D Li Puma ◽  
...  
Keyword(s):  
Associative Memory ◽  
Memory Impairment ◽  
Long Term Potentiation ◽  
Neuronal Uptake ◽  
Common Mechanism ◽  
Tau Oligomers ◽  
Term Potentiation ◽  
Induced Defects ◽  
Oligomeric Forms

The concurrent application of subtoxic doses of soluble oligomeric forms of human amyloid-beta (oAβ) and Tau (oTau) proteins impairs memory and its electrophysiological surrogate long-term potentiation (LTP), effects that may be mediated by intra-neuronal oligomers uptake. Intrigued by these findings, we investigated whether oAβ and oTau share a common mechanism when they impair memory and LTP in mice. We found that as already shown for oAβ, also oTau can bind to amyloid precursor protein (APP). Moreover, efficient intra-neuronal uptake of oAβ and oTau requires expression of APP. Finally, the toxic effect of both extracellular oAβ and oTau on memory and LTP is dependent upon APP since APP-KO mice were resistant to oAβ- and oTau-induced defects in spatial/associative memory and LTP. Thus, APP might serve as a common therapeutic target against Alzheimer's Disease (AD) and a host of other neurodegenerative diseases characterized by abnormal levels of Aβ and/or Tau.

Associative memory impairment in acute stress disorder: Characteristics and time course

2013 ◽  
Vol 209 (3) ◽  
pp. 479-484 ◽  
Author(s):  
Jonathan Guez ◽  
Jonathan Cohen ◽  
Moshe Naveh-Benjamin ◽  
Asher Shiber ◽  
Yan Yankovsky ◽  
...  
Keyword(s):  
Associative Memory ◽  
Memory Impairment ◽  
Time Course ◽  
Stress Disorder ◽  
Acute Stress ◽  
Acute Stress Disorder

scholarly journals Failure of delayed nonsynaptic neuronal plasticity underlies age-associated long-term associative memory impairment

2012 ◽  
Vol 13 (1) ◽  
pp. 103 ◽  
Author(s):  
Shawn N Watson ◽  
Tara E Risling ◽  
Petra M Hermann ◽  
Willem C Wildering
Keyword(s):  
Associative Memory ◽  
Neuronal Plasticity ◽  
Memory Impairment

Memory for pairs of faces: An associative memory impairment?

2006 ◽  
Author(s):  
Matthew G. Rhodes ◽  
Alan D. Castel ◽  
Larry L. Jacoby
Keyword(s):  
Associative Memory ◽  
Memory Impairment

Abnormal dynamic functional connectivity of hippocampal subregions associated with working memory impairment in melancholic depression

2021 ◽  
pp. 1-13
Author(s):  
Lai Shunkai ◽  
Ting Su ◽  
Shuming Zhong ◽  
Guangmao Chen ◽  
Yiliang Zhang ◽  
...  
Keyword(s):  
Working Memory ◽  
Functional Connectivity ◽  
Association Analysis ◽  
Memory Impairment ◽  
Visual Learning ◽  
Verbal Learning ◽  
Anterior Lobe ◽  
Healthy Controls ◽  
Dynamic Functional Connectivity ◽  
Whole Brain

Abstract Background Previous studies have demonstrated structural and functional changes of the hippocampus in patients with major depressive disorder (MDD). However, no studies have analyzed the dynamic functional connectivity (dFC) of hippocampal subregions in melancholic MDD. We aimed to reveal the patterns for dFC variability in hippocampus subregions – including the bilateral rostral and caudal areas and its associations with cognitive impairment in melancholic MDD. Methods Forty-two treatment-naive MDD patients with melancholic features and 55 demographically matched healthy controls were included. The sliding-window analysis was used to evaluate whole-brain dFC for each hippocampal subregions seed. We assessed between-group differences in the dFC variability values of each hippocampal subregion in the whole brain and cognitive performance on the MATRICS Consensus Cognitive Battery (MCCB). Finally, association analysis was conducted to investigate their relationships. Results Patients with melancholic MDD showed decreased dFC variability between the left rostral hippocampus and left anterior lobe of cerebellum compared with healthy controls (voxel p < 0.005, cluster p < 0.0125, GRF corrected), and poorer cognitive scores in working memory, verbal learning, visual learning, and social cognition (all p < 0.05). Association analysis showed that working memory was positively correlated with the dFC variability values of the left rostral hippocampus-left anterior lobe of the cerebellum (r = 0.338, p = 0.029) in melancholic MDD. Conclusions These findings confirmed the distinct dynamic functional pathway of hippocampal subregions in patients with melancholic MDD, and suggested that the dysfunction of hippocampus-cerebellum connectivity may be underlying the neural substrate of working memory impairment in melancholic MDD.

scholarly journals Enhanced resting-state functional connectivity between core memory-task activation peaks is associated with memory impairment in MCI

2016 ◽  
Vol 45 ◽  
pp. 43-49 ◽  
Author(s):  
Yifei Zhang ◽  
Lee Simon-Vermot ◽  
Miguel Á. Araque Caballero ◽  
Benno Gesierich ◽  
Alexander N.W. Taylor ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Memory Impairment ◽  
Memory Task ◽  
Core Memory ◽  
Resting State Functional Connectivity ◽  
With Memory ◽  
Task Activation
Sign in / Sign up

Export Citation Format

Share Document