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1.
Brief Bioinform ; 22(5)2021 09 02.
Article in English | MEDLINE | ID: mdl-33401309

ABSTRACT

A-to-I RNA editing, contributing to nearly 90% of all editing events in human, has been reported to involve in the pathogenesis of Alzheimer's disease (AD) due to its roles in brain development and immune regulation, such as the deficient editing of GluA2 Q/R related to cell death and memory loss. Currently, there are urgent needs for the systematic annotations of A-to-I RNA editing events in AD. Here, we built ADeditome, the annotation database of A-to-I RNA editing in AD available at https://ccsm.uth.edu/ADeditome, aiming to provide a resource and reference for functional annotation of A-to-I RNA editing in AD to identify therapeutically targetable genes in an individual. We detected 1676 363 editing sites in 1524 samples across nine brain regions from ROSMAP, MayoRNAseq and MSBB. For these editing events, we performed multiple functional annotations including identification of specific and disease stage associated editing events and the influence of editing events on gene expression, protein recoding, alternative splicing and miRNA regulation for all the genes, especially for AD-related genes in order to explore the pathology of AD. Combing all the analysis results, we found 108 010 and 26 168 editing events which may promote or inhibit AD progression, respectively. We also found 5582 brain region-specific editing events with potentially dual roles in AD across different brain regions. ADeditome will be a unique resource for AD and drug research communities to identify therapeutically targetable editing events. Significance: ADeditome is the first comprehensive resource of the functional genomics of individual A-to-I RNA editing events in AD, which will be useful for many researchers in the fields of AD pathology, precision medicine, and therapeutic researches.


Subject(s)
Adenosine/metabolism , Alzheimer Disease/genetics , Amnesia/genetics , Inosine/metabolism , Nerve Tissue Proteins/genetics , RNA Editing , Transcriptome , Adenosine/genetics , Alternative Splicing , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amnesia/metabolism , Amnesia/pathology , Brain/metabolism , Brain/pathology , Brain Mapping , Databases, Genetic , Gene Ontology , Humans , Inosine/genetics , MicroRNAs/classification , MicroRNAs/genetics , MicroRNAs/metabolism , Molecular Sequence Annotation , Nerve Tissue Proteins/classification , Nerve Tissue Proteins/metabolism , Receptors, AMPA/genetics , Receptors, AMPA/metabolism
2.
Psychol Med ; 53(3): 805-813, 2023 02.
Article in English | MEDLINE | ID: mdl-34165068

ABSTRACT

BACKGROUND: Little is known about the neural correlates of dissociative amnesia, a transdiagnostic symptom mostly present in the dissociative disorders and core characteristic of dissociative identity disorder (DID). Given the vital role of the hippocampus in memory, a prime candidate for investigation is whether total and/or subfield hippocampal volume can serve as biological markers of dissociative amnesia. METHODS: A total of 75 women, 32 with DID and 43 matched healthy controls (HC), underwent structural magnetic resonance imaging (MRI). Using Freesurfer (version 6.0), volumes were extracted for bilateral global hippocampus, cornu ammonis (CA) 1-4, the granule cell molecular layer of the dentate gyrus (GC-ML-DG), fimbria, hippocampal-amygdaloid transition area (HATA), parasubiculum, presubiculum and subiculum. Analyses of covariance showed volumetric differences between DID and HC. Partial correlations exhibited relationships between the three factors of the dissociative experience scale scores (dissociative amnesia, absorption, depersonalisation/derealisation) and traumatisation measures with hippocampal global and subfield volumes. RESULTS: Hippocampal volumes were found to be smaller in DID as compared with HC in bilateral global hippocampus and bilateral CA1, right CA4, right GC-ML-DG, and left presubiculum. Dissociative amnesia was the only dissociative symptom that correlated uniquely and significantly with reduced bilateral hippocampal CA1 subfield volumes. Regarding traumatisation, only emotional neglect correlated negatively with bilateral global hippocampus, bilateral CA1, CA4 and GC-ML-DG, and right CA3. CONCLUSION: We propose decreased CA1 volume as a biomarker for dissociative amnesia. We also propose that traumatisation, specifically emotional neglect, is interlinked with dissociative amnesia in having a detrimental effect on hippocampal volume.


Subject(s)
Dissociative Identity Disorder , Humans , Female , Dissociative Identity Disorder/pathology , Hippocampus/diagnostic imaging , Hippocampus/pathology , Magnetic Resonance Imaging/methods , Amnesia/diagnostic imaging , Amnesia/pathology , Biomarkers
3.
J Stroke Cerebrovasc Dis ; 32(3): 106951, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36565520

ABSTRACT

BACKGROUND: Transient global amnesia is a benign syndrome characterized by a sudden onset loss of anterograde amnesia with full recovery. Magnetic resonance of the brain including diffusion-weighted imaging of patients with transient global amnesia revealed the presence of punctate hyperintense signal abnormalities in the hippocampus. OBJECTIVE: Analysis of the presence of hippocampal lesions in brain magnetic resonance imaging in patients with transient global amnesia and the possible influence of additional factors on their appearance. METHODS: In this retrospective, an observational study we assessed brain magnetic resonance imaging in 38 consecutive patients with transient global amnesia. The incidence of brain magnetic resonance imaging lesions was analyzed for the coexisting cardiovascular risk factors and precipitating events. RESULTS: Hippocampal brain magnetic resonance imaging lesions were detected in 47% of patients with transient global amnesia. Of those, 65% had unilateral lesions, 82% were left-sided, and 28% were right-sided. Most lesions were located in the CA1 subfield. The incidence of hypertension in patients with transient global amnesia was higher than in the general population. Stress and exercise preceded the onset of transient global amnesia only in 13% and 16% of patients, respectively. There was no higher incidence of migraine in transient global amnesia patients (13%). CONCLUSIONS: We found that nearly 50% of patients with transient global amnesia had hyperintense hippocampal brain magnetic resonance imaging lesions. In addition to hypertension, individuals with transient global amnesia had similar cardiovascular risk factors as the general population. We did not identify any precipitating events prior to the onset of transient global amnesia.


Subject(s)
Amnesia, Transient Global , Hypertension , Humans , Amnesia, Transient Global/diagnostic imaging , Amnesia, Transient Global/epidemiology , Amnesia, Transient Global/etiology , Retrospective Studies , Magnetic Resonance Imaging/adverse effects , Diffusion Magnetic Resonance Imaging/methods , Hippocampus/pathology , Hypertension/complications , Amnesia/complications , Amnesia/pathology
4.
Eur J Neurol ; 29(10): 2987-2995, 2022 10.
Article in English | MEDLINE | ID: mdl-35708171

ABSTRACT

BACKGROUND AND PURPOSE: Little is known about the character and underlying lesions of ischaemic amnesia. Episodic memory functions and brain lesions were therefore studied in 84 patients with acute ischaemic infarcts in the supply territory of the posterior cerebral artery. The aim was also to learn how the neural memory systems are organized. METHODS: Standard neuropsychological tests were used to assess verbal and figural memory. Patients were split into memory-impaired and memory-intact groups. Lesions were demarcated, normalized and anatomically labelled, using standard mapping procedures. RESULTS: Of the 84 patients more than 80% had an amnestic syndrome, mostly with combined memory impairment, less often with figural or verbal memory impairment. Amnesia in subjects with left hemispheric lesions was more frequent and more severe, with significantly lower scores on the verbal memory test. Normal performance or figural amnesia were prevalent after right hemispheric lesions. However, no amnesia subtype was strictly tied to left- or right-sided brain damage. Hippocampal and thalamic lesions were common, but 30% of lesions were extrahippocampal located in the ventral occipito-temporal cortex and long occipital white matter tracts. Most amnestic patients lacked awareness for their memory impairment. CONCLUSIONS: Memory impairment is a key clinical manifestation of acute posterior cerebral artery stroke. Amnesia is more frequent and more severe after left stroke, suggesting a left hemisphere dominance of the two memory systems. Domain specific memory appears not to be strictly lateralized, since deficits in verbal and figural memory were found after lesions of both sides. Extrahippocampal lesions may also cause memory impairment.


Subject(s)
Infarction, Posterior Cerebral Artery , Amnesia/etiology , Amnesia/pathology , Humans , Infarction, Posterior Cerebral Artery/complications , Magnetic Resonance Imaging , Memory , Neuropsychological Tests , Temporal Lobe/pathology
5.
J Int Neuropsychol Soc ; 28(4): 391-400, 2022 04.
Article in English | MEDLINE | ID: mdl-34130767

ABSTRACT

OBJECTIVES: Mild cognitive impairment (MCI) types may have distinct neuropathological substrates with hippocampal atrophy particularly common in amnestic MCI (aMCI). However, depending on the MCI classification criteria applied to the sample (e.g., number of abnormal test scores considered or thresholds for impairment), volumetric findings between MCI types may change. Additionally, despite increased clinical use, no prior research has examined volumetric differences in MCI types using the automated volumetric software, Neuroreader™. METHODS: The present study separately applied the Petersen/Winblad and Jak/Bondi MCI criteria to a clinical sample of older adults (N = 82) who underwent neuropsychological testing and brain MRI. Volumetric data were analyzed using Neuroreader™ and hippocampal volumes were compared between aMCI and non-amnestic MCI (naMCI). RESULTS: T-tests revealed that regardless of MCI classification criteria, hippocampal volume z-scores were significantly lower in aMCI compared to naMCI (p's < .05), and hippocampal volume z-scores significantly differed from 0 (Neuroreader™ normative mean) in the aMCI group only (p's < .05). Additionally, significant, positive correlations were found between measures of delayed recall and hippocampal z-scores in aMCI using either MCI classification criteria (p's < .05). CONCLUSIONS: We provide evidence of correlated neuroanatomical changes associated with memory performance for two commonly used neuropsychological MCI classification criteria. Future research should investigate the clinical utility of hippocampal volumes analyzed via Neuroreader™ in MCI.


Subject(s)
Amnesia , Cognitive Dysfunction , Aged , Amnesia/pathology , Cognitive Dysfunction/psychology , Hippocampus/diagnostic imaging , Hippocampus/pathology , Humans , Neuroimaging , Neuropsychological Tests
6.
Neurocase ; 28(1): 63-65, 2022 02.
Article in English | MEDLINE | ID: mdl-35037569

ABSTRACT

Acute episodes of amnestic syndrome can be a challenging diagnostic problem. Except for nonvascular etiology, thalamic strokes or infarction involving several temporal lobe structures has been reported in earlier cases. The authors report a patient who suddenly developed memory loss without any other focal neurologic deficits. Brain magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) performed 1 day after onset revealed acute infarction involving the bilateral fornix column and the genu of corpus callosum. Because simple fornix infarcts often have no obvious positive neurological signs, most of the related manifestations were provided by family members, are easy to be diagnosed falsely, and missed in clinical areas, we suggest that bilateral fornix infarction should be considered in the diagnosis of an acute onset amnestic syndrome.


Subject(s)
Amnesia , Fornix, Brain , Amnesia/diagnostic imaging , Amnesia/etiology , Amnesia/pathology , Fornix, Brain/blood supply , Fornix, Brain/diagnostic imaging , Fornix, Brain/pathology , Humans , Infarction/complications , Infarction/pathology , Magnetic Resonance Imaging , Memory Disorders
7.
Nature ; 531(7595): 508-12, 2016 Mar 24.
Article in English | MEDLINE | ID: mdl-26982728

ABSTRACT

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory decline and subsequent loss of broader cognitive functions. Memory decline in the early stages of AD is mostly limited to episodic memory, for which the hippocampus has a crucial role. However, it has been uncertain whether the observed amnesia in the early stages of AD is due to disrupted encoding and consolidation of episodic information, or an impairment in the retrieval of stored memory information. Here we show that in transgenic mouse models of early AD, direct optogenetic activation of hippocampal memory engram cells results in memory retrieval despite the fact that these mice are amnesic in long-term memory tests when natural recall cues are used, revealing a retrieval, rather than a storage impairment. Before amyloid plaque deposition, the amnesia in these mice is age-dependent, which correlates with a progressive reduction in spine density of hippocampal dentate gyrus engram cells. We show that optogenetic induction of long-term potentiation at perforant path synapses of dentate gyrus engram cells restores both spine density and long-term memory. We also demonstrate that an ablation of dentate gyrus engram cells containing restored spine density prevents the rescue of long-term memory. Thus, selective rescue of spine density in engram cells may lead to an effective strategy for treating memory loss in the early stages of AD.


Subject(s)
Alzheimer Disease/pathology , Alzheimer Disease/physiopathology , Dentate Gyrus/cytology , Dentate Gyrus/physiology , Disease Models, Animal , Memory, Long-Term/physiology , Aging , Amnesia/pathology , Amnesia/physiopathology , Amyloid beta-Protein Precursor/genetics , Animals , Dendritic Spines/pathology , Dendritic Spines/physiology , Dentate Gyrus/pathology , Dentate Gyrus/physiopathology , Early Medical Intervention , Humans , Long-Term Potentiation , Male , Memory, Episodic , Mice , Mice, Transgenic , Optogenetics , Plaque, Amyloid , Presenilin-1/genetics , Synapses/metabolism , Transgenes/genetics , tau Proteins/genetics
8.
Hum Brain Mapp ; 42(16): 5397-5408, 2021 11.
Article in English | MEDLINE | ID: mdl-34412149

ABSTRACT

White matter abnormalities represent early neuropathological events in neurodegenerative diseases such as Alzheimer's disease (AD), investigating these white matter alterations would likely provide valuable insights into pathological changes over the course of AD. Using a novel mathematical framework called "Director Field Analysis" (DFA), we investigated the geometric microstructural properties (i.e., splay, bend, twist, and total distortion) in the orientation of white matter fibers in AD, amnestic mild cognitive impairment (aMCI), and cognitively normal (CN) individuals from the Alzheimer's Disease Neuroimaging Initiative 2 database. Results revealed that AD patients had extensive orientational changes in the bilateral anterior thalamic radiation, corticospinal tract, inferior and superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and uncinate fasciculus in comparison with CN. We postulate that these orientational changes of white matter fibers may be partially caused by the expansion of lateral ventricle, white matter atrophy, and gray matter atrophy in AD. In contrast, aMCI individuals showed subtle orientational changes in the left inferior longitudinal fasciculus and right uncinate fasciculus, which showed a significant association with the cognitive performance, suggesting that these regions may be preferential vulnerable to breakdown by neurodegenerative brain disorders, thereby resulting in the patients' cognitive impairment. To our knowledge, this article is the first to examine geometric microstructural changes in the orientation of white matter fibers in AD and aMCI. Our findings demonstrate that the orientational information of white matter fibers could provide novel insight into the underlying biological and pathological changes in AD and aMCI.


Subject(s)
Alzheimer Disease/pathology , Amnesia/pathology , Cognitive Dysfunction/pathology , Diffusion Tensor Imaging , White Matter/pathology , Aged , Aged, 80 and over , Alzheimer Disease/diagnostic imaging , Amnesia/diagnostic imaging , Cognitive Dysfunction/diagnostic imaging , Female , Humans , Male , Nerve Fibers, Myelinated/pathology , White Matter/diagnostic imaging
9.
Hum Brain Mapp ; 42(1): 192-203, 2021 01.
Article in English | MEDLINE | ID: mdl-33030795

ABSTRACT

Subjective cognitive decline (SCD) is a high-risk yet less understood status before developing Alzheimer's disease (AD). This work included 76 SCD individuals with two (baseline and 7 years later) neuropsychological evaluations and a baseline T1-weighted structural MRI. A machine learning-based model was trained based on 198 baseline neuroimaging (morphometric) features and a battery of 25 clinical measurements to discriminate 24 progressive SCDs who converted to mild cognitive impairment (MCI) at follow-up from 52 stable SCDs. The SCD progression was satisfactorily predicted with the combined features. A history of stroke, a low education level, a low baseline MoCA score, a shrunk left amygdala, and enlarged white matter at the banks of the right superior temporal sulcus were found to favor the progression. This is to date the largest retrospective study of SCD-to-MCI conversion with the longest follow-up, suggesting predictable far-future cognitive decline for the risky populations with baseline measures only. These findings provide valuable knowledge to the future neuropathological studies of AD in its prodromal phase.


Subject(s)
Amnesia/diagnosis , Brain/pathology , Cognitive Dysfunction/diagnosis , Diagnostic Self Evaluation , Disease Progression , Machine Learning , Magnetic Resonance Imaging , Neuropsychological Tests , Aged , Amnesia/pathology , Amnesia/physiopathology , Amygdala/diagnostic imaging , Amygdala/pathology , Brain/diagnostic imaging , Cognitive Dysfunction/pathology , Cognitive Dysfunction/physiopathology , Educational Status , Female , Follow-Up Studies , Humans , Male , Middle Aged , Prognosis , Retrospective Studies , Self Report , White Matter/diagnostic imaging , White Matter/pathology
10.
Hum Brain Mapp ; 42(10): 3202-3215, 2021 07.
Article in English | MEDLINE | ID: mdl-33955088

ABSTRACT

A major challenge in the cognitive training field is inducing broad, far-transfer training effects. Thus far, little is known about the neural mechanisms underlying broad training effects. Here, we tested a set of competitive hypotheses regarding the role of brain integration versus segregation underlying the broad training effect. We retrospectively analyzed data from a randomized controlled trial comparing neurocognitive effects of vision-based speed of processing training (VSOP) and an active control consisting of mental leisure activities (MLA) in older adults with MCI. We classified a subset of participants in the VSOP as learners, who showed improvement in executive function and episodic memory. The other participants in the VSOP (i.e., VSOP non-learners) and a subset of participants in the MLA (i.e., MLA non-learners) served as controls. Structural brain networks were constructed from diffusion tensor imaging. Clustering coefficients (CCs) and characteristic path lengths were computed as measures of segregation and integration, respectively. Learners showed significantly greater global CCs after intervention than controls. Nodal CCs were selectively enhanced in cingulate cortex, parietal regions, striatum, and thalamus. Among VSOP learners, those with more severe baseline neurodegeneration had greater improvement in segregation after training. Our findings suggest broad training effects are related to enhanced segregation in selective brain networks, providing insight into cognitive training related neuroplasticity.


Subject(s)
Amnesia , Cerebral Cortex/pathology , Cognitive Dysfunction , Cognitive Remediation , Nerve Net/pathology , Thalamus/pathology , Aged , Aged, 80 and over , Amnesia/diagnostic imaging , Amnesia/pathology , Amnesia/physiopathology , Amnesia/therapy , Cerebral Cortex/diagnostic imaging , Cognitive Dysfunction/diagnostic imaging , Cognitive Dysfunction/pathology , Cognitive Dysfunction/physiopathology , Cognitive Dysfunction/therapy , Corpus Striatum , Diffusion Tensor Imaging , Female , Humans , Male , Middle Aged , Nerve Net/diagnostic imaging , Neuronal Plasticity/physiology , Psychomotor Performance/physiology , Retrospective Studies , Thalamus/diagnostic imaging
11.
Eur J Neurol ; 28(12): 3955-3964, 2021 12.
Article in English | MEDLINE | ID: mdl-34310802

ABSTRACT

BACKGROUND AND PURPOSE: The anterior and posterior hippocampal networks represent verbal and spatial memory, respectively, and may play different roles in the pathological mechanism of amnestic mild cognitive impairment (aMCI) and non-amnestic MCI (naMCI), which has not been explored. METHODS: A total of 990 older adults with 791 normal controls (NCs) (65 ± 6 years, 502 women), 140 aMCI (66 ± 7 years, 84 women) and 59 naMCI (66 ± 7 years, 38 women) were included. A multivariate method, partial least squares, was used to assess the structural covariance networks of the anterior hippocampus (aHC) and posterior hippocampus (pHC), and their relationships with verbal memory and spatial memory in the three groups. RESULTS: Three aHC and pHC structural covariance network patterns emerged: (1) the age pattern; (2) the specific aMCI pattern; and (3) the spatial memory pattern. Furthermore, aMCI patients had more extensive and severe damage in the three patterns, and correlated with greater decline in verbal memory, which was mainly characterized by the aHC network. CONCLUSIONS: The aMCI and naMCI showed different patterns and damage in the structural covariance networks, and functional segregation of the aHC and pHC networks still exists in the process of pathological aging. A potential neural explanation is provided for the conversion of aMCI and naMCI into different types of dementia in the future.


Subject(s)
Cognitive Dysfunction , Spatial Memory , Aged , Amnesia/pathology , Cognitive Dysfunction/psychology , Female , Hippocampus/diagnostic imaging , Hippocampus/pathology , Humans , Memory Disorders , Neuropsychological Tests
12.
Int J Mol Sci ; 22(22)2021 Nov 16.
Article in English | MEDLINE | ID: mdl-34830236

ABSTRACT

Mutations in the gene encoding amyloid precursor protein (APP) cause autosomal dominant inherited Alzheimer's disease (AD). We present a case of a 68-year-old female who presented with epileptic seizures, neuropsychiatric symptoms and progressive memory decline and was found to carry a novel APP variant, c.2062T>G pLeu688Val. A comprehensive literature review of all reported cases of AD due to APP mutations was performed in PubMed and Web of Science databases. We reviewed 98 studies with a total of 385 cases. The mean age of disease onset was 51.3 ± 8.3 (31-80 years). Mutations were most often located in exons 17 (80.8%) and 16 (12.2%). The most common symptoms were dementia, visuospatial symptoms, aphasia, epilepsy and psychiatric symptoms. Mutations in the ß-amyloid region, and specifically exon 17, were associated with high pathogenicity and a younger age of disease onset. We describe the second reported APP mutation in the Greek population. APP mutations may act variably on disease expression and their phenotype is heterogeneous.


Subject(s)
Alzheimer Disease/genetics , Amnesia/genetics , Amyloid beta-Protein Precursor/genetics , Point Mutation , Psychotic Disorders/genetics , Seizures/genetics , Adult , Aged , Aged, 80 and over , Alzheimer Disease/complications , Alzheimer Disease/diagnostic imaging , Alzheimer Disease/pathology , Amino Acid Substitution , Amnesia/complications , Amnesia/diagnostic imaging , Amnesia/pathology , Exons , Female , Gene Expression , Greece , Humans , Male , Middle Aged , Neuroimaging/methods , Psychotic Disorders/complications , Psychotic Disorders/diagnostic imaging , Psychotic Disorders/pathology , Seizures/complications , Seizures/diagnostic imaging , Seizures/pathology
13.
Molecules ; 26(23)2021 Nov 26.
Article in English | MEDLINE | ID: mdl-34885751

ABSTRACT

Cognitive decline in dementia is associated with deficiency of the cholinergic system. In this study, five mono-carbonyl curcumin analogs were synthesized, and on the basis of their promising in vitro anticholinesterase activities, they were further investigated for in vivo neuroprotective and memory enhancing effects in scopolamine-induced amnesia using elevated plus maze (EPM) and novel object recognition (NOR) behavioral mice models. The effects of the synthesized compounds on the cholinergic system involvement in the brain hippocampus and their binding mode in the active site of cholinesterases were also determined. Compound h2 (p < 0.001) and h3 (p < 0.001) significantly inhibited the cholinesterases and reversed the effects of scopolamine by significantly reducing TLT (p < 0.001) in EPM, while (p < 0.001) increased the time exploring the novel object. The % discrimination index (DI) was significantly increased (p < 0.001) in the novel object recognition test. The mechanism of cholinesterase inhibition was further validated through molecular docking study using MOE software. The results obtained from the in vitro, in vivo and ex vivo studies showed that the synthesized curcumin analogs exhibited significantly higher memory-enhancing potential, and h3 could be an effective neuroprotective agent. However, more study is suggested to explore its exact mechanism of action.


Subject(s)
Amnesia/drug therapy , Cholinesterases/drug effects , Cognitive Dysfunction/drug therapy , Curcumin/pharmacology , Dementia/drug therapy , Amnesia/chemically induced , Amnesia/diagnostic imaging , Amnesia/pathology , Animals , Catalytic Domain/drug effects , Cholinergic Agents/chemical synthesis , Cholinergic Agents/chemistry , Cholinergic Agents/pharmacology , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/pharmacology , Cognitive Dysfunction/chemically induced , Cognitive Dysfunction/diagnostic imaging , Cognitive Dysfunction/pathology , Curcumin/analogs & derivatives , Curcumin/chemical synthesis , Curcumin/chemistry , Dementia/chemically induced , Dementia/diagnostic imaging , Dementia/pathology , Hippocampus/diagnostic imaging , Hippocampus/drug effects , Hippocampus/pathology , Humans , Maze Learning/drug effects , Memory/drug effects , Mice , Molecular Docking Simulation , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , Neuroprotective Agents/pharmacology , Oxidative Stress/drug effects , Scopolamine/toxicity
14.
Bull Exp Biol Med ; 172(1): 18-21, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34796426

ABSTRACT

Proinflammatory S100A9 protein is a promoter of inflammation-linked neurodegeneration and the Tnfrsf1A gene encodes the TNF receptor 1A that binds TNFα to function as a regulator of inflammation. We studied the effects of chronic intranasal administration of in vitro prepared S100A9 fibrils alone or in combination with anti-glutamate antibodies on the expression of the Tnfrsf1A gene in the hippocampus, prefrontal cortex, and cerebellum of aging C57BL/6 mice under conditions of impaired spatial memory. A differential cerebral pattern of Tnfrsf1A gene activity and its modification by S100A9 fibrillar structures were observed: inhibition of Tnfrsf1A gene expression in the hippocampus and cerebellum and its activation in the prefrontal cortex. Anti-glutamate antibodies normalized the expression of the Tnfrsf1A gene in the prefrontal cortex by affecting the TNF signaling pathway and preventing the development of inflammation.


Subject(s)
Aging/physiology , Amnesia/pathology , Calgranulin B/metabolism , Receptors, Tumor Necrosis Factor, Type I/biosynthesis , Spatial Memory/physiology , Animals , Antibodies/immunology , Cerebellum/metabolism , Glutamic Acid/immunology , Hippocampus/metabolism , Inflammation , Male , Mice , Mice, Inbred C57BL , Prefrontal Cortex/metabolism , Spatial Navigation/physiology , Tumor Necrosis Factor-alpha/metabolism
15.
Neurocase ; 26(4): 231-240, 2020 08.
Article in English | MEDLINE | ID: mdl-32657245

ABSTRACT

Reports on social cognition in patients with developmental amnesia resulting from bilateral hippocampal lesions are rare, although the link between social cognition and temporal lobe structures is well established. We present the case of a 23-year-old male epilepsy patient, BM, with developmental amnesia due to perinatal cerebral hypoxia. The patient was examined with neuroimaging and neuropsychological methods and compared to IQ-matched patients with epilepsy to control for effects of epilepsy. In addition, we used a test battery that evaluates emotion recognition and theory of mind to study his social cognition abilities. Structural high-resolution magnetic resonance imaging showed bilateral hippocampal atrophy. The comparison to controls showed that, in addition to the well-documented memory disorders in developmental amnesia, BM showed remarkable deficits in 9 out of 17 social cognitive tasks assessing emotion recognition and theory of mind. In contrast, BM's performance on tasks of executive functions was largely preserved. The relevance of deficits in social cognition for patients with developmental amnesia is discussed.


Subject(s)
Amnesia , Cognitive Dysfunction , Epilepsy , Hippocampus/pathology , Hypoxia/complications , Infant, Newborn, Diseases , Social Cognition , Adult , Amnesia/diagnosis , Amnesia/etiology , Amnesia/pathology , Amnesia/physiopathology , Atrophy , Cognitive Dysfunction/diagnosis , Cognitive Dysfunction/etiology , Cognitive Dysfunction/pathology , Cognitive Dysfunction/physiopathology , Epilepsy/diagnosis , Epilepsy/etiology , Epilepsy/pathology , Epilepsy/physiopathology , Female , Hippocampus/diagnostic imaging , Humans , Infant, Newborn , Magnetic Resonance Imaging , Male , Pregnancy , Pregnancy, Twin , Young Adult
16.
J Cogn Neurosci ; 31(8): 1260-1269, 2019 08.
Article in English | MEDLINE | ID: mdl-31135253

ABSTRACT

To explore whether the hippocampus might be important for certain spatial operations in addition to its well-known role in memory, we administered two tasks in which participants judged whether objects embedded in scenes or whether scenes themselves could exist in 3-D space. Patients with damage limited to the hippocampus performed as well as controls in both tasks. A patient with large medial-temporal lobe lesions had a bias to judge objects in scenes and scenes themselves as possible, performing well with possible stimuli but poorly with impossible stimuli in both tasks. All patients were markedly impaired at remembering the tasks. The hippocampus appears not to be essential for judging the structural coherence of objects in scenes or the coherence of scenes. The findings conform to what is now a sizeable literature emphasizing the importance of the hippocampus for memory. We discuss our results in light of findings that other patients have sometimes been reported to be disadvantaged by spatial tasks like the ones studied here, despite less hippocampal damage and milder memory impairment.


Subject(s)
Amnesia/pathology , Amnesia/physiopathology , Hippocampus/pathology , Hippocampus/physiopathology , Mental Recall/physiology , Recognition, Psychology/physiology , Space Perception/physiology , Visual Perception/physiology , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Temporal Lobe/pathology , Temporal Lobe/physiopathology
17.
Cogn Affect Behav Neurosci ; 19(3): 523-536, 2019 06.
Article in English | MEDLINE | ID: mdl-30767129

ABSTRACT

Recent evidence suggests that the human hippocampus-known primarily for its involvement in episodic memory-plays a role in a host of motivationally relevant behaviors, including some forms of value-based decision-making. However, less is known about the role of the hippocampus in value-based learning. Such learning is typically associated with a striatal system, yet a small number of studies, both in human and nonhuman species, suggest hippocampal engagement. It is not clear, however, whether this engagement is necessary for such learning. In the present study, we used both functional MRI (fMRI) and lesion-based neuropsychological methods to clarify hippocampal contributions to value-based learning. In Experiment 1, healthy participants were scanned while learning value-based contingencies (whether players in a "game" win money) in the context of a probabilistic learning task. Here, we observed recruitment of the hippocampus, in addition to the expected ventral striatal (nucleus accumbens) activation that typically accompanies such learning. In Experiment 2, we administered this task to amnesic patients with medial temporal lobe damage and to healthy controls. Amnesic patients, including those with damage circumscribed to the hippocampus, failed to acquire value-based contingencies, thus confirming that hippocampal engagement is necessary for task performance. Control experiments established that this impairment was not due to perceptual demands or memory load. Future research is needed to clarify the mechanisms by which the hippocampus contributes to value-based learning, but these findings point to a broader role for the hippocampus in goal-directed behaviors than previously appreciated.


Subject(s)
Amnesia/pathology , Amnesia/physiopathology , Hippocampus/pathology , Hippocampus/physiology , Reward , Temporal Lobe/pathology , Adult , Aged , Amnesia/diagnostic imaging , Female , Hippocampus/diagnostic imaging , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Nucleus Accumbens/diagnostic imaging , Nucleus Accumbens/physiology , Probability Learning , Young Adult
18.
J Neurol Neurosurg Psychiatry ; 90(9): 965-974, 2019 09.
Article in English | MEDLINE | ID: mdl-31072956

ABSTRACT

OBJECTIVE: Limbic encephalitis associated with antibodies to components of the voltage-gated potassium channel complex (VGKCC-Ab-LE) often leads to hippocampal atrophy and persistent memory impairment. Its long-term impact on regions beyond the hippocampus, and the relationship between brain damage and cognitive outcome, are poorly understood. We investigated the nature of structural and functional brain abnormalities following VGKCC-Ab-LE and its role in residual memory impairment. METHOD: A cross-sectional group study was conducted. Twenty-four VGKCC-Ab-LE patients (20 male, 4 female; mean (SD) age 63.86 (11.31) years) were recruited post-acutely along with age- and sex-matched healthy controls for neuropsychological assessment, structural MRI and resting-state functional MRI (rs-fMRI). Structural abnormalities were determined using volumetry and voxel-based morphometry; rs-fMRI data were analysed to investigate hippocampal functional connectivity (FC). Associations of memory performance with neuroimaging measures were examined. RESULTS: Patients showed selective memory impairment. Structural analyses revealed focal hippocampal atrophy within the medial temporal lobes, correlative atrophy in the mediodorsal thalamus, and additional volume reduction in the posteromedial cortex. There was no association between regional volumes and memory performance. Instead, patients demonstrated reduced posteromedial cortico-hippocampal and inter-hippocampal FC, which correlated with memory scores (r = 0.553; r = 0.582, respectively). The latter declined as a function of time since the acute illness (r = -0.531). CONCLUSION: VGKCC-Ab-LE results in persistent isolated memory impairment. Patients have hippocampal atrophy with further reduced mediodorsal thalamic and posteromedial cortical volumes. Crucially, reduced FC of remaining hippocampal tissue correlates more closely with memory function than does regional atrophy.


Subject(s)
Amnesia/etiology , Autoantibodies/immunology , Autoimmune Diseases/complications , Hippocampus/pathology , Limbic Encephalitis/complications , Potassium Channels, Voltage-Gated/immunology , Adult , Aged , Amnesia/diagnostic imaging , Amnesia/pathology , Autoimmune Diseases/diagnostic imaging , Autoimmune Diseases/immunology , Autoimmune Diseases/pathology , Case-Control Studies , Cross-Sectional Studies , Female , Hippocampus/diagnostic imaging , Humans , Limbic Encephalitis/diagnostic imaging , Limbic Encephalitis/immunology , Limbic Encephalitis/pathology , Magnetic Resonance Imaging , Male , Memory Disorders/etiology , Memory Disorders/pathology , Middle Aged , Neuroimaging
19.
Neurochem Res ; 44(7): 1665-1677, 2019 Jul.
Article in English | MEDLINE | ID: mdl-30949934

ABSTRACT

Dementia is considered as the frequent cause of neurodegenerative mental disorder such as Alzheimer's disease (AD) amongst elderly people. Free radicals as well as cholinergic deficit neurons within nucleus basalis magnocellularis demonstrated to attribute with aggregation of ß amyloid which further acts as an essential hallmark in AD. Various phenolic phytoconstituents exists in Trianthema portulastrum (TP) leaves have been reported as active against various neurological disorders. The current investigation was undertaken to evaluate the antiamnesic potential of butanol fraction of TP hydroethanolic extract (BFTP) by utilizing rodent models of elevated plus maze (EPM) and Hebbs William Maze (HWM) along with in vitro and in vivo antioxidant as well as acetylcholinesterase (AChE) inhibition studies. Molecular docking studies were also performed for evaluation of molecular interaction of existed phenolic compounds in BFTP. In vitro antioxidant study revealed concentration dependant strong ability of BFTP to inhibit free radicals. In vitro AChE inhibition study showed competitive type of inhibition kinetics. BFTP significantly reversed (p < 0.005 versus scopolamine) the damaging effect of scopolamine by reducing TL (Transfer Latency) and TRC (Time taken to recognize the reward chamber) in the EPM and HWM, respectively. BFTP also contributed towards increased (p < 0.005 versus scopolamine) enzymatic antioxidant as well as hippocampal acetylcholine (ACh) levels. Histological studies also supported the results as BFTP pretreated mice significantly reversed the scopolamine induced histological changes in hippocampal region. Docking studies confirmed chlorogenic acid has the most significant binding affinity towards AChE. This research finding concludes that BFTP could be a beneficial agent for management of cognition and behavioral disorders associated with AD.


Subject(s)
Aizoaceae/chemistry , Alzheimer Disease/drug therapy , Amnesia/drug therapy , Nootropic Agents/therapeutic use , Phenols/therapeutic use , Plant Extracts/therapeutic use , Acetylcholinesterase/chemistry , Acetylcholinesterase/metabolism , Alzheimer Disease/chemically induced , Alzheimer Disease/pathology , Amnesia/pathology , Animals , Brain/metabolism , Brain/pathology , Catalase/metabolism , Catalytic Domain , Cholinesterase Inhibitors/therapeutic use , Cognitive Dysfunction/drug therapy , Cognitive Dysfunction/pathology , Glutathione Peroxidase/metabolism , Male , Maze Learning/drug effects , Mice , Molecular Docking Simulation , Plant Leaves/chemistry , Scopolamine , Superoxide Dismutase/metabolism
20.
J Int Neuropsychol Soc ; 25(10): 1001-1010, 2019 11.
Article in English | MEDLINE | ID: mdl-31543085

ABSTRACT

OBJECTIVE: Previous research in mild cognitive impairment (MCI) suggests that visual episodic memory impairment may emerge before analogous verbal episodic memory impairment. The current study examined working memory (WM) test performance in MCI to assess whether patients present with greater visual versus verbal WM impairment. WM performance was also assessed in relation to hippocampal occupancy (HO), a ratio of hippocampal volume to ventricular dilation adjusted for demographic variables and intracranial volume. METHODS: Jak et al. (2009) (The American Journal of Geriatric Psychiatry, 17, 368-375) and Edmonds, Delano-Wood, Galasko, Salmon, & Bondi (2015) (Journal of Alzheimer's Disease, 47(1), 231-242) criteria classify patients into four groups: little to no cognitive impairment (non-MCI); subtle cognitive impairment (SCI); amnestic MCI (aMCI); and a combined mixed/dysexecutive MCI (mixed/dys MCI). WM was assessed using co-normed Wechsler Adult Intelligence Scale-IV (WAIS-IV) Digit Span Backwards and Wechsler Memory Scale-IV (WMS-IV) Symbol Span Z-scores. RESULTS: Between-group analyses found worse WMS-IV Symbol Span and WAIS-IV Digit Span Backwards performance for mixed/dys MCI compared to non-MCI patients. Within-group analyses found no differences for non-MCI patients; however, all other groups scored lower on WMS-IV Symbol Span than WAIS-IV Digit Span Backwards. Regression analysis with HO as the dependent variable was statistically significant for WMS-IV Symbol Span performance. WAIS-IV Digit Span Backwards performance failed to reach statistical significance. CONCLUSIONS: Worse WMS-IV Symbol Span performance was observed in patient groups with measurable neuropsychological impairment and better WMS-IV Symbol Span performance was associated with higher HO ratios. These results suggest that visual WM may be particularly sensitive to emergent illness compared to analogous verbal WM tests.


Subject(s)
Amnesia/physiopathology , Cognitive Dysfunction/physiopathology , Data Analysis , Executive Function/physiology , Memory, Short-Term/physiology , Aged , Amnesia/pathology , Cerebral Ventricles/pathology , Cognitive Dysfunction/classification , Cognitive Dysfunction/pathology , Data Interpretation, Statistical , Female , Hippocampus/pathology , Humans , Male , Neuropsychological Tests
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