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BACKGROUND: Addiction can alter neural processes during rest and cognitive performance. Subjects with addictive disorders exhibit preoccupation and anticipation for the psychoactive substance when idle and cognitive deficits, during tasks. METHODS: 128 channel EEG was recorded in sixty subjects (30, with alcohol, opioid and internet addiction; 30 controls) during rest and while performing working memory task to ascertain underlying differences in cortical activity between the groups while at rest and during performance of the task. Artifactually clean data was then subjected to source analysis using sLORETA software in both the groups. RESULTS: EEG cortical source analysis in subjects with addictive disorders showed significant activation of areas of Default Mode Network (DMN) and reduced activation in dorsolateral prefrontal cortices (DLPFC), an area known to be involved in executive function, during performance of task. However, control subjects demonstrated significantly reduced activation in areas of DMN; and increased activation of DLPFC during task performance. CONCLUSION: Inability to suppress DMN inhibits reallocation of neural resources to areas of executive functioning leading to working memory deficits in subjects with addictive disorder.
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Electroencefalografía , Función Ejecutiva , Memoria a Corto Plazo , Humanos , Memoria a Corto Plazo/fisiología , Estudios de Casos y Controles , Función Ejecutiva/fisiología , Adulto , Masculino , Femenino , Red en Modo Predeterminado/diagnóstico por imagen , Red en Modo Predeterminado/fisiopatología , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/fisiopatología , Trastornos de la Memoria/psicología , Trastornos de la Memoria/etiología , Adulto Joven , Trastorno de Adicción a Internet/fisiopatología , Trastorno de Adicción a Internet/diagnóstico por imagen , Trastorno de Adicción a Internet/psicología , Trastornos Relacionados con Opioides/psicología , Trastornos Relacionados con Opioides/fisiopatología , Trastornos Relacionados con Opioides/diagnóstico por imagen , Alcoholismo/fisiopatología , Alcoholismo/diagnóstico por imagen , Alcoholismo/psicología , Corteza Prefontal Dorsolateral/diagnóstico por imagen , Corteza Prefontal Dorsolateral/fisiopatología , Conducta Adictiva/fisiopatología , Conducta Adictiva/psicología , Conducta Adictiva/diagnóstico por imagen , Trastornos Relacionados con Sustancias/fisiopatología , Trastornos Relacionados con Sustancias/diagnóstico por imagen , Trastornos Relacionados con Sustancias/psicologíaRESUMEN
BACKGROUND: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is characterized by distinct structural and functional brain alterations, predominantly affecting the medial temporal lobes and the hippocampus. Structural connectome analysis with graph-based investigations of network properties allows for an in-depth characterization of global and local network changes and their relationship with clinical deficits in NMDAR encephalitis. METHODS: Structural networks from 61 NMDAR encephalitis patients in the post-acute stage (median time from acute hospital discharge: 18 months) and 61 age- and sex-matched healthy controls (HC) were analyzed using diffusion-weighted imaging (DWI)-based probabilistic anatomically constrained tractography and volumetry of a selection of subcortical and white matter brain volumes was performed. We calculated global, modular, and nodal graph measures with special focus on default-mode network, medial temporal lobe, and hippocampus. Pathologically altered metrics were investigated regarding their potential association with clinical course, disease severity, and cognitive outcome. RESULTS: Patients with NMDAR encephalitis showed regular global graph metrics, but bilateral reductions of hippocampal node strength (left: p = 0.049; right: p = 0.013) and increased node strength of right precuneus (p = 0.013) compared to HC. Betweenness centrality was decreased for left-sided entorhinal cortex (p = 0.042) and left caudal middle frontal gyrus (p = 0.037). Correlation analyses showed a significant association between reduced left hippocampal node strength and verbal long-term memory impairment (p = 0.021). We found decreased left (p = 0.013) and right (p = 0.001) hippocampal volumes that were associated with hippocampal node strength (left p = 0.009; right p < 0.001). CONCLUSIONS: Focal network property changes of the medial temporal lobes indicate hippocampal hub failure that is associated with memory impairment in NMDAR encephalitis at the post-acute stage, while global structural network properties remain unaltered. Graph theory analysis provides new pathophysiological insight into structural network changes and their association with persistent cognitive deficits in NMDAR encephalitis.
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Encefalitis Antirreceptor N-Metil-D-Aspartato , Conectoma , Hipocampo , Trastornos de la Memoria , Humanos , Masculino , Femenino , Hipocampo/patología , Hipocampo/diagnóstico por imagen , Adulto , Encefalitis Antirreceptor N-Metil-D-Aspartato/diagnóstico por imagen , Encefalitis Antirreceptor N-Metil-D-Aspartato/patología , Encefalitis Antirreceptor N-Metil-D-Aspartato/complicaciones , Encefalitis Antirreceptor N-Metil-D-Aspartato/fisiopatología , Trastornos de la Memoria/etiología , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/patología , Trastornos de la Memoria/fisiopatología , Adulto Joven , Memoria a Largo Plazo/fisiología , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/patología , Red Nerviosa/fisiopatología , Persona de Mediana Edad , Imagen de Difusión Tensora , Adolescente , Red en Modo Predeterminado/diagnóstico por imagen , Red en Modo Predeterminado/patología , Red en Modo Predeterminado/fisiopatologíaRESUMEN
Background: Amyloid positron emission tomography (PET) scans provide in vivo evidence of Alzheimer's disease (AD); however, their high cost limits their use in standard clinical care. Event related potentials (ERPs) may represent an inexpensive and non-invasive additional method for detecting AD pathology. Objective: We investigated whether ERPs, along with neuropsychological data, serve as predictors of amyloid PET status in patients with memory complaints. Methods: Veterans aged 50-100 were recruited from a memory disorders clinic. Participants underwent a neuropsychological battery and an ERP auditory oddball protocol. Twenty-eight patients had a positive amyloid PET scan, and thirty-nine patients had a negative scan. Results: ERP-P200 target amplitude and P200 standard latency were predictors of amyloid PET status. When submitting to ROC analysis, P200 standard latency exhibited the highest specificity and sensitivity in predicting amyloid PET positivity, correctly classifying the amyloid PET status for 86% of patients. Conclusions: ERP-P200 measures are strong indicators of amyloid-ß presence in patients from a memory disorder clinic. Increased P200 amplitude and decreased P200 latency in patients with a positive amyloid PET scan may be attributed to hyperactivation of perceptual bottom-up processes compensating for AD-related synaptic loss in the fronto-parietal networks.
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Potenciales Evocados , Trastornos de la Memoria , Pruebas Neuropsicológicas , Tomografía de Emisión de Positrones , Humanos , Masculino , Femenino , Anciano , Persona de Mediana Edad , Potenciales Evocados/fisiología , Trastornos de la Memoria/diagnóstico por imagen , Anciano de 80 o más Años , Electroencefalografía , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Veteranos , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismoRESUMEN
In medial temporal lobe epilepsy (MTLE), the benefits of surgery must be balanced against the risk of post-operative memory decline. Prediction of postoperative outcomes based on functional magnetic resonance imaging (fMRI) tasks is increasingly common but remains uncertain. The aim of this retrospective study was to determine whether hippocampal activations elicited by fMRI language tasks could enhance or refine memory fMRI in MTLE patients candidates to surgery. Forty-six patients were included: 30 right and 16 left MTLE, mostly with hippocampal sclerosis. Preoperative assessment included neuropsychological tests and fMRI with language (syntactic verbal fluency) and memory tasks (encoding, delayed, and immediate recognition of images of objects). Thirty patients underwent surgery and had neuropsychological evaluations one year after surgery. Worsening was defined as a degradation of more than 10â¯% in postoperative forgetting scores compared to preoperative scores in verbal, non-verbal and global memory. Memory fMRI had the best sensitivity with hippocampal activations obtained in 95â¯% of patients, versus 65â¯% with language fMRI. Considering the patients who elicited an hippocampal activation, language fMRI led to 80â¯%, 65â¯% and 85â¯% of correct predictions for respectively global, verbal and non verbal memory (versus 71â¯%, 64â¯% and 68â¯% with memory fMRI). Memory and language fMRI predictions outperformed those made by neuropsychological tests. In summary, language fMRI was less sensitive than memory fMRI to elicit hippocampal activations but when it did, the proportion of correct memory predictions was better. Moreover, it proved to be an independent predictive factor regardless of the side of the epileptic focus. Given the ease of setting up a language task in fMRI, we recommend the systematic combination of memory and language tasks to predict the post-operative memory outcome of MTLE patients undergoing epilepsy surgery.
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Epilepsia del Lóbulo Temporal , Hipocampo , Lenguaje , Imagen por Resonancia Magnética , Pruebas Neuropsicológicas , Humanos , Masculino , Femenino , Hipocampo/diagnóstico por imagen , Hipocampo/fisiopatología , Adulto , Epilepsia del Lóbulo Temporal/cirugía , Epilepsia del Lóbulo Temporal/fisiopatología , Epilepsia del Lóbulo Temporal/diagnóstico por imagen , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven , Pronóstico , Trastornos de la Memoria/etiología , Trastornos de la Memoria/diagnóstico por imagen , Memoria/fisiología , Adolescente , Mapeo Encefálico/métodosRESUMEN
Schizophrenia, as a chronic and persistent disorder, exhibits working memory deficits across various stages of the disorder, yet the neural mechanisms underlying these deficits remain elusive with inconsistent neuroimaging findings. We aimed to compare the brain functional changes of working memory in patients at different stages: clinical high risk, first-episode psychosis, and long-term schizophrenia, using meta-analyses of functional magnetic resonance imaging studies. Following a systematic literature search, 56 whole-brain task-based functional magnetic resonance imaging studies (15 for clinical high risk, 16 for first-episode psychosis, and 25 for long-term schizophrenia) were included. The separate and pooled neurofunctional mechanisms among clinical high risk, first-episode psychosis, and long-term schizophrenia were generated by Seed-based d Mapping toolbox. The clinical high risk and first-episode psychosis groups exhibited overlapping hypoactivation in the right inferior parietal lobule, right middle frontal gyrus, and left superior parietal lobule, indicating key lesion sites in the early phase of schizophrenia. Individuals with first-episode psychosis showed lower activation in left inferior parietal lobule than those with long-term schizophrenia, reflecting a possible recovery process or more neural inefficiency. We concluded that SCZ represent as a continuum in the early stage of illness progression, while the neural bases are inversely changed with the development of illness course to long-term course.
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Encéfalo , Imagen por Resonancia Magnética , Memoria a Corto Plazo , Esquizofrenia , Humanos , Memoria a Corto Plazo/fisiología , Esquizofrenia/fisiopatología , Esquizofrenia/diagnóstico por imagen , Encéfalo/fisiopatología , Encéfalo/diagnóstico por imagen , Progresión de la Enfermedad , Trastornos de la Memoria/fisiopatología , Trastornos de la Memoria/etiología , Trastornos de la Memoria/diagnóstico por imagen , Psicología del Esquizofrénico , Mapeo EncefálicoRESUMEN
Importance: Studies have suggested that maternal history of late-onset Alzheimer disease, but not paternal, predisposes individuals to higher brain ß-amyloid (Aß) burden, reduced brain metabolism, and lower gray matter volumes. Objective: To characterize maternal vs paternal history of memory impairment in terms of brain Aß-positron emission tomography (Aß-PET) and baseline cognition among a large sample of cognitively unimpaired older adults. Design, Setting, and Participants: This cross-sectional study leveraged data from 4413 individuals who were screened for the Anti-Amyloid Treatment in Asymptomatic Alzheimer (A4) study, a randomized clinical trial conducted across 67 sites in the US, Australia, Canada, and Japan aimed at Alzheimer disease prevention. Data were collected between April 2014 and December 2017 and analyzed from December 2022 to June 2023. Participants were cognitively unimpaired adults (Clinical Dementia Rating = 0 and/or Mini-Mental State Examination score ≥25) between the ages of 65 and 85 years who underwent PET imaging to assess cortical Aß levels for trial eligibility. A total of 4492 participants were screened, and 79 missing data were excluded. Main Outcomes and Measures: Demographic characteristics (eg, age, sex, education), apolipoprotein E genotyping, participant-reported parental history of memory impairment and parental age at symptom onset were collected as variables. Parental history was assessed in terms of continuous neocortical 18F-florbetapir Aß-PET and the Preclinical Alzheimer Cognitive Composite. Results: Of 4413 individuals (mean [SD] age, 71.27 [4.66] years, 2617 women [59.3%]), mean Aß-PET was elevated in individuals with history of memory impairment in both parents (n = 455; mean [SD] standardized uptake value ratio [SUVR] = 1.12 [0.19]; Wilcoxon P = 1.1 × 10-5) and in those with only maternal history (n = 1772; mean [SD] SUVR = 1.10 [0.19]; Wilcoxon P = 2.70 × 10-5) compared with those with only paternal history (n = 632; mean [SD] SUVR = 1.08 [0.18]; Wilcoxon P = 1.1 × 10-5) or no family history (n = 1554; mean [SD] SUVR = 1.08 [0.19]; Wilcoxon P = 1.1 × 10-5). Paternal history of early-onset memory impairment (age <65 years) but not late-onset (age ≥65 years) was associated with elevated participant Aß-PET (mean [SD] SUVR = 1.19 [0.21]; P = 3.00 × 10-6) in comparison with no paternal history (mean [SD] SUVR = 1.09 [0.19]) whereas maternal history was associated with elevated Aß in both early-onset and late-onset groups. There was no association with cognition. Conclusions and Relevance: In this study, maternal history (at any age) and paternal history of early-onset memory impairment were associated with Aß burden among asymptomatic older individuals. Sex-specific parental history may help inform clinicians on likelihood of Aß burden in offspring and help identify high-risk individuals at the earliest stages of disease for prevention.
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Péptidos beta-Amiloides , Trastornos de la Memoria , Tomografía de Emisión de Positrones , Humanos , Femenino , Masculino , Anciano , Péptidos beta-Amiloides/metabolismo , Estudios Transversales , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/genética , Anciano de 80 o más Años , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/diagnóstico por imagen , PadresRESUMEN
BACKGROUND AND PURPOSE: Verbal memory decline is a common complaint of patients with severe asymptomatic stenosis of the internal carotid artery (aICS). Previous publications explored the associations between verbal memory decline and altered functional connectivity (FC) after aICS. Patients with severe aICS may show reduced perfusion in the ipsilateral territory and redistribution of cerebral blood flow to compensate for the deficient regions, including expansion of the posterior and contralateral ICA territories via the circle of Willis. However, aICS-related FC changes in anterior and posterior territories and the impact of the sides of stenosis were less explored. This study aims to investigate the altered FC in anterior and posterior circulation territories of patients with left or right unilateral aICS and its association with verbal memory decline. MATERIALS AND METHODS: We enrolled 15 healthy controls (HCs), 22 patients with left aICS (aICSL), and 33 patients with right aICS (aICSR) to receive fMRI, Mini-Mental State Examination (MMSE), the Digit Span Test (DST), and the 12-item Chinese version of Verbal Learning Tests. We selected brain regions associated with verbal memory within anterior and posterior circulation territories. Territory-related FC alterations and verbal memory decline were identified by comparing the aICSL and aICSR groups with HC groups (P < .05, corrected for multiple comparisons), respectively. Furthermore, the association between altered FC and verbal memory decline was tested with the Pearson correlation analysis. RESULTS: Compared with HCs, patients with aICSL or aICSR had significant impairment in delayed recall of verbal memory. Decline in delayed recall of verbal memory was significantly associated with altered FC between the right cerebellum and right middle temporal pole in the posterior circulation territory (r = 0.40, P = .03) in the aICSR group and was significantly associated with altered FC between the right superior medial frontal gyrus and left lingual gyrus in the anterior circulation territory (r = 0.56, P = .01) in the aICSL group. CONCLUSIONS: Patients with aICSL and aICSR showed different patterns of FC alterations in both anterior and posterior circulation territories, which suggests that the side of aICS influences the compensatory mechanism for decline in delayed recall of verbal memory.
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Estenosis Carotídea , Imagen por Resonancia Magnética , Trastornos de la Memoria , Humanos , Estenosis Carotídea/diagnóstico por imagen , Estenosis Carotídea/fisiopatología , Estenosis Carotídea/complicaciones , Masculino , Femenino , Trastornos de la Memoria/fisiopatología , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiología , Persona de Mediana Edad , Anciano , Arteria Carótida Interna/diagnóstico por imagen , Arteria Carótida Interna/fisiopatología , Circulación Cerebrovascular/fisiología , Aprendizaje Verbal/fisiologíaRESUMEN
Verbal memory decline is a significant concern following temporal lobe surgeries in patients with epilepsy, emphasizing the need for precision presurgical verbal memory mapping to optimize functional outcomes. However, the inter-individual variability in functional networks and brain function-structural dissociations pose challenges when relying solely on group-level atlases or anatomical landmarks for surgical guidance. Here, we aimed to develop and validate a personalized functional mapping technique for verbal memory using precision resting-state functional MRI (rs-fMRI) and neurosurgery. A total of 38 patients with refractory epilepsy scheduled for surgical interventions were enrolled and 28 patients were analyzed in the study. Baseline 30-min rs-fMRI scanning, verbal memory and language assessments were collected for each patient before surgery. Personalized verbal memory networks (PVMN) were delineated based on preoperative rs-fMRI data for each patient. The accuracy of PVMN was assessed by comparing post-operative functional impairments and the overlapping extent between PVMN and surgical lesions. A total of 14 out of 28 patients experienced clinically meaningful declines in verbal memory after surgery. The personalized network and the group-level atlas exhibited 100% and 75.0% accuracy in predicting postoperative verbal memory declines, respectively. Moreover, six patients with extra-temporal lesions that overlapped with PVMN showed selective impairments in verbal memory. Furthermore, the lesioned ratio of the personalized network rather than the group-level atlas was significantly correlated with postoperative declines in verbal memory (personalized networks: r = -0.39, p = .038; group-level atlas: r = -0.19, p = .332). In conclusion, our personalized functional mapping technique, using precision rs-fMRI, offers valuable insights into individual variability in the verbal memory network and holds promise in precision verbal memory network mapping in individuals.
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Mapeo Encefálico , Imagen por Resonancia Magnética , Humanos , Femenino , Masculino , Adulto , Adulto Joven , Mapeo Encefálico/métodos , Trastornos de la Memoria/etiología , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/fisiopatología , Persona de Mediana Edad , Epilepsia Refractaria/cirugía , Epilepsia Refractaria/diagnóstico por imagen , Epilepsia Refractaria/fisiopatología , Adolescente , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiopatología , Red Nerviosa/cirugía , Complicaciones Posoperatorias/diagnóstico por imagen , Procedimientos Neuroquirúrgicos , Aprendizaje Verbal/fisiología , Epilepsia del Lóbulo Temporal/cirugía , Epilepsia del Lóbulo Temporal/diagnóstico por imagen , Epilepsia del Lóbulo Temporal/fisiopatologíaRESUMEN
BACKGROUND: Research work has shown that hippocampal subfields are atrophic to varying extents in multiple sclerosis (MS) patients. However, studies examining the functional implications of subfield-specific hippocampal damage in early MS are limited. We aim to gain insights into the relationship between hippocampal atrophy and memory function by investigating the correlation between global and regional hippocampal atrophy and memory performance in early MS patients. METHODS: From the Italian Neuroimaging Network Initiative (INNI) dataset, we selected 3D-T1-weighted brain MRIs of 219 early relapsing remitting (RR)MS and 246 healthy controls (HC) to identify hippocampal atrophic areas. At the time of MRI, patients underwent Selective-Reminding-Test (SRT) and Spatial-Recall-Test (SPART) and were classified as mildly (MMI-MS: n.110) or severely (SMI-MS: n:109) memory impaired, according to recently proposed cognitive phenotypes. RESULTS: Early RRMS showed lower hippocampal volumes compared to HC (p < 0.001), while these did not differ between MMI-MS and SMI-MS. In MMI-MS, lower hippocampal volumes correlated with worse memory tests (r = 0.23-0.37, p ≤ 0.01). Atrophic voxels were diffuse in the hippocampus but more prevalent in cornu ammonis (CA, 79%) than in tail (21%). In MMI-MS, decreased subfield volumes correlated with decreases in memory, particularly in the right CA1 (SRT-recall: r = 0.38; SPART: r = 0.34, p < 0.01). No correlations were found in the SMI-MS group. CONCLUSION: Hippocampal atrophy spreads from CA to tail from early disease stages. Subfield hippocampal atrophy is associated with memory impairment in MMI-MS, while this correlation is lost in SMI-MS. This plays in favor of a limited capacity for an adaptive functional reorganization of the hippocampi in MS patients.
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Atrofia , Hipocampo , Imagen por Resonancia Magnética , Trastornos de la Memoria , Esclerosis Múltiple Recurrente-Remitente , Humanos , Esclerosis Múltiple Recurrente-Remitente/patología , Esclerosis Múltiple Recurrente-Remitente/diagnóstico por imagen , Esclerosis Múltiple Recurrente-Remitente/complicaciones , Esclerosis Múltiple Recurrente-Remitente/fisiopatología , Masculino , Hipocampo/patología , Hipocampo/diagnóstico por imagen , Femenino , Atrofia/patología , Adulto , Trastornos de la Memoria/etiología , Trastornos de la Memoria/patología , Trastornos de la Memoria/diagnóstico por imagen , Persona de Mediana Edad , Pruebas NeuropsicológicasRESUMEN
INTRODUCTION: In Alzheimer's disease (AD), early diagnosis facilitates treatment options and leads to beneficial outcomes for patients, their carers and the healthcare system. The neuropsychological battery of the Uniform Data Set (UDSNB3.0) assesses cognition in ageing and dementia, by measuring scores across different cognitive domains such as attention, memory, processing speed, executive function and language. However, its neuroanatomical correlates have not been investigated using 7 Tesla MRI (7T MRI). METHODS: We used 7T MRI to investigate the correlations between hippocampal subfield volumes and the UDSNB3.0 in 24 individuals with Amyloidß-status AD and 18 age-matched controls, with respective age ranges of 60 (42-76) and 62 (52-79) years. AD participants with a Medial Temporal Atrophy scale of higher than 2 on 3T MRI were excluded from the study. RESULTS: A significant difference in the entire hippocampal volume was observed in the AD group compared to healthy controls (HC), primarily influenced by CA1, the largest hippocampal subfield. Notably, no significant difference in whole brain volume between the groups implied that hippocampal volume loss was not merely reflective of overall brain atrophy. UDSNB3.0 cognitive scores showed significant differences between AD and HC, particularly in Memory, Language, and Visuospatial domains. The volume of the Dentate Gyrus (DG) showed a significant association with the Memory and Executive domain scores in AD patients as assessed by the UDSNB3.0.. The data also suggested a non-significant trend for CA1 volume associated with UDSNB3.0 Memory, Executive, and Language domain scores in AD. In a reassessment focusing on hippocampal subfields and MoCA memory subdomains in AD, associations were observed between the DG and Cued, Uncued, and Recognition Memory subscores, whereas CA1 and Tail showed associations only with Cued memory. DISCUSSION: This study reveals differences in the hippocampal volumes measured using 7T MRI, between individuals with early symptomatic AD compared with healthy controls. This highlights the potential of 7T MRI as a valuable tool for early AD diagnosis and the real-time monitoring of AD progression and treatment efficacy. CLINICALTRIALS: GOV: ID NCT04992975 (Clinicaltrial.gov 2023).
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Enfermedad de Alzheimer , Región CA1 Hipocampal , Giro Dentado , Imagen por Resonancia Magnética , Trastornos de la Memoria , Humanos , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/patología , Masculino , Imagen por Resonancia Magnética/métodos , Femenino , Anciano , Giro Dentado/diagnóstico por imagen , Giro Dentado/patología , Persona de Mediana Edad , Región CA1 Hipocampal/diagnóstico por imagen , Región CA1 Hipocampal/patología , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/patología , Adulto , Péptidos beta-Amiloides/metabolismoRESUMEN
Cerebral small vessel disease is the one of the most prevalent causes of vascular cognitive impairment. We aimed to find objective and process-based indicators related to memory function to assist in the detection of memory impairment in patients with cerebral small vessel disease. Thirty-nine cerebral small vessel disease patients and 22 healthy controls were invited to complete neurological examinations, neuropsychological assessments, and eye tracking tasks. Eye tracking indicators were recorded and analyzed in combination with imaging features. The cerebral small vessel disease patients scored lower on traditional memory task and performed worse on eye tracking memory task performance compared to the healthy controls. The cerebral small vessel disease patients exhibited longer visit duration and more visit count within areas of interest and targets and decreased percentage value of total visit duration on target images to total visit duration on areas of interest during decoding stage among all levels. Our results demonstrated the cerebral small vessel disease patients performed worse in memory scale and eye tracking memory task, potentially due to their heightened attentional allocation to nontarget images during the retrieval stage. The eye tracking memory task could provide process-based indicators to be a beneficial complement to memory assessment and new insights into mechanism of memory impairment in cerebral small vessel disease patients.
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Enfermedades de los Pequeños Vasos Cerebrales , Disfunción Cognitiva , Humanos , Tecnología de Seguimiento Ocular , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiología , Enfermedades de los Pequeños Vasos Cerebrales/complicaciones , Enfermedades de los Pequeños Vasos Cerebrales/diagnóstico por imagen , CogniciónRESUMEN
The etiology of brain fog associated with long COVID is not clear. Based on some preliminary work, disruption of the blood-brain barrier has been hypothesized, but has not been tested in patients with long COVID. In this case-control pilot study, we evaluated blood-brain barrier permeability in patients with long COVID and subjective memory loss or brain fog. We used 99 m Technetium diethylenetriaminepentaacetic acid single-photon emission computed tomography (SPECT) to measure blood-brain barrier permeability and a telephone assessment (T-cog) to measure cognitive function. The blood-brain barrier permeability was quantified via SPECT standard uptake value (SUV). We assessed the blood-brain barrier permeability in 14 long COVID patients and 10 control participants without subjective cognitive impairment or brain fog. Participants in the two groups were similar in age. The long COVID group had more comorbidities compared to the control group. There was no difference in the SUVs in the long COVID (0.22 ± 0.12) vs the control (0.17 ± 0.04) group. There was no difference in the T-cog results in the two groups either. We found no evidence of a difference in blood-brain permeability in patients with long COVID when compared to controls without a known history of COVID-19 infection. Larger studies are needed to confirm these findings.
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Barrera Hematoencefálica , COVID-19 , Tomografía Computarizada de Emisión de Fotón Único , Humanos , Barrera Hematoencefálica/diagnóstico por imagen , Proyectos Piloto , Masculino , Femenino , COVID-19/complicaciones , COVID-19/diagnóstico por imagen , Anciano , Estudios de Casos y Controles , Tomografía Computarizada de Emisión de Fotón Único/métodos , Persona de Mediana Edad , Encéfalo/diagnóstico por imagen , Síndrome Post Agudo de COVID-19 , Permeabilidad , Disfunción Cognitiva/diagnóstico por imagen , Disfunción Cognitiva/fisiopatología , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiología , Trastornos de la Memoria/fisiopatologíaRESUMEN
BACKGROUND: Cognitive impairment (CI) is a common and disabling feature of people with multiple sclerosis (pwMS), but its underlying mechanisms are heterogenous and not fully understood. A role of infiltrating immune cells in the meninges and brain parenchyma has been hypothesized. This study aimed to explore the hypothesis that intrathecal B cells might influence cognitive performance in pwMS. METHODS: A retrospective study was performed on 39 newly diagnosed pwMS who underwent cerebrospinal fluid (CSF) analysis. Kappa (κ)-index was measured as a biomarker of intrathecal B cell activation. Cognitive performance was assessed using the Brief Repeatable Battery of Neuropsychological Tests (BRBN). Brain T2 lesions number (T2LN) and volume (T2LV) together with brain, cortical grey matter, thalamic and hippocampal volumes were calculated to account for MRI-visible damage. RESULTS: κ-index was higher in pwMS with verbal memory impairment (median 99.6, range 58.5-195.2 vs. median 37.2, range 2.3-396.9, p < 0.001), and it was negatively associated with BRBN tests exploring verbal memory and information processing speed. In multivariate models, higher κ-index was confirmed to be independently associated with worse scores of BRBN tests exploring verbal memory and with a higher probability of verbal memory impairment. CONCLUSION: Intrathecal B cells might drive memory impairment in pwMS independently of brain damage visible on MRI scans.
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Linfocitos B , Trastornos de la Memoria , Esclerosis Múltiple , Humanos , Masculino , Femenino , Estudios Retrospectivos , Persona de Mediana Edad , Adulto , Linfocitos B/inmunología , Trastornos de la Memoria/etiología , Trastornos de la Memoria/diagnóstico por imagen , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/complicaciones , Esclerosis Múltiple/diagnóstico por imagen , Imagen por Resonancia Magnética , Disfunción Cognitiva/etiología , Disfunción Cognitiva/fisiopatología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Activación de Linfocitos , Pruebas NeuropsicológicasRESUMEN
Dopamine decline is suggested to underlie aging-related cognitive decline, but longitudinal examinations of this link are currently missing. We analyzed 5-year longitudinal data for a sample of healthy, older adults (baseline: n = 181, age: 64-68 years; 5-year follow-up: n = 129) who underwent positron emission tomography with 11C-raclopride to assess dopamine D2-like receptor (DRD2) availability, magnetic resonance imaging to evaluate structural brain measures, and cognitive tests. Health, lifestyle, and genetic data were also collected. A data-driven approach (k-means cluster analysis) identified groups that differed maximally in DRD2 decline rates in age-sensitive brain regions. One group (n = 47) had DRD2 decline exclusively in the caudate and no cognitive decline. A second group (n = 72) had more wide-ranged DRD2 decline in putamen and nucleus accumbens and also in extrastriatal regions. The latter group showed significant 5-year working memory decline that correlated with putamen DRD2 decline, along with higher dementia and cardiovascular risk and a faster biological pace of aging. Taken together, for individuals with more extensive DRD2 decline, dopamine decline is associated with memory decline in aging.
Asunto(s)
Envejecimiento , Dopamina , Humanos , Anciano , Encéfalo/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodos , Racloprida , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiologíaRESUMEN
BACKGROUND: The mechanisms underlying memory deficits after electroconvulsive therapy (ECT) remain unclear but altered functional interactions between hippocampus and neocortex may play a role. OBJECTIVES: To test whether ECT reduces functional connectivity between hippocampus and posterior regions of the default mode network (DMN) and to examine whether altered hippocampal-neocortical functional connectivity correlates with memory impairment. A secondary aim was to explore if these connectivity changes are present 6 months after ECT. METHODS: In-patients with severe depression (n = 35) received bitemporal ECT. Functional connectivity of the hippocampus was probed with resting-state fMRI before the first ECT-session, after the end of ECT, and at a six-month follow-up. Memory was assessed with the Verbal Learning Test - Delayed Recall. Seed-based connectivity analyses established connectivity of four hippocampal seeds, covering the anterior and posterior parts of the right and left hippocampus. RESULTS: Compared to baseline, three of four hippocampal seeds became less connected to the core nodes of the posterior DMN in the week after ECT with Cohen's d ranging from -0.9 to -1.1. At the group level, patients showed post-ECT memory impairment, but individual changes in delayed recall were not correlated with the reduction in hippocampus-DMN connectivity. At six-month follow-up, no significant hippocampus-DMN reductions in connectivity were evident relative to pre-ECT, and memory scores had returned to baseline. CONCLUSION: ECT leads to a temporary disruption of functional hippocampus-DMN connectivity in patients with severe depression, but the change in connectivity strength is not related to the individual memory impairment.
Asunto(s)
Trastorno Depresivo , Terapia Electroconvulsiva , Humanos , Red en Modo Predeterminado , Hipocampo/diagnóstico por imagen , Imagen por Resonancia Magnética , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiología , Trastornos de la Memoria/terapiaRESUMEN
BACKGROUND: We compared the ability of several plasma biomarkers versus amyloid positron emission tomography (PET) to predict rates of memory decline among cognitively unimpaired individuals. METHODS: We studied 645 Mayo Clinic Study of Aging participants. Predictor variables were age, sex, education, apolipoprotein E (APOE) ε4 genotype, amyloid PET, and plasma amyloid beta (Aß)42/40, phosphorylated tau (p-tau)181, neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and p-tau217. The outcome was a change in a memory composite measure. RESULTS: All plasma biomarkers, except NfL, were associated with mean memory decline in models with individual biomarkers. However, amyloid PET and plasma p-tau217, along with age, were key variables independently associated with mean memory decline in models combining all predictors. Confidence intervals were narrow for estimates of population mean prediction, but person-level prediction intervals were wide. DISCUSSION: Plasma p-tau217 and amyloid PET provide useful information about predicting rates of future cognitive decline in cognitively unimpaired individuals at the population mean level, but not at the individual person level.
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Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Péptidos beta-Amiloides/metabolismo , Proteínas tau/metabolismo , Tomografía de Emisión de Positrones , Disfunción Cognitiva/diagnóstico por imagen , Disfunción Cognitiva/complicaciones , Biomarcadores , Trastornos de la Memoria/diagnóstico por imagenRESUMEN
BACKGROUND: Increasing evidence is demonstrating that degeneration of specific thalamic nuclei, in addition to the hippocampus, may occur in Alzheimer's disease (AD) from the prodromal stage (mild cognitive impairment - MCI) and contribute to memory impairment. OBJECTIVE: Here, we evaluated the presence of macro and micro structural alterations at the level of the anterior thalamic nuclei (ATN) and medio-dorsal thalamic nuclei (MDTN) in AD and amnestic MCI (aMCI) and the possible relationship between such changes and the severity of memory impairment. METHODS: For this purpose, a sample of 50 patients with aMCI, 50 with AD, and 50 age- and education-matched healthy controls (HC) were submitted to a 3-T MRI protocol with whole-brain T1-weighted and diffusion tensor imaging and a comprehensive neuropsychological assessment. RESULTS: At macro-structural level, both the ATN and MDTN were found significantly smaller in patients with aMCI and AD when compared to HC subjects. At micro-structural level, instead, diffusion alterations that significantly differentiated aMCI and AD patients from HC subjects were found only in the ATN, but not in the MDTN. Moreover, diffusion values of the ATN were significantly associated with poor episodic memory in the overall patients' group. CONCLUSIONS: These findings represent the first in vivo evidence of a relevant involvement of ATN in the AD-related neurodegeneration and memory profile and strengthen the importance to look beyond the hippocampus when considering neurological conditions characterized by memory decline.
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Enfermedad de Alzheimer , Núcleos Talámicos Anteriores , Humanos , Núcleos Talámicos Anteriores/diagnóstico por imagen , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/diagnóstico por imagen , Imagen de Difusión Tensora , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiología , Núcleos TalámicosRESUMEN
OBJECTIVE: Tau pathology is recognized as a primary contributor to neurodegeneration and clinical symptoms in Alzheimer's disease (AD). This study aims to localize the early tau pathology in cognitively normal older people that is predictive of subsequent neurodegeneration and memory decline, and delineate factors underlying tau-related memory decline in individuals with and without ß-amyloid (Aß). METHODS: A total of 138 cognitively normal older individuals from the Berkeley Aging Cohort Study underwent 11 C-Pittsburgh Compound-B (PiB) positron emission tomography (PET) to determine Aß positivity and 18 F-Flortaucipir (FTP) PET to measure tau deposition, with prospective cognitive assessments and structural magnetic resonance imaging. Voxel-wise FTP analyses examined associations between baseline tau deposition and longitudinal memory decline, longitudinal hippocampal atrophy, and longitudinal cortical thinning in AD signature regions. We also examined whether hippocampal atrophy and cortical thinning mediate tau effects on future memory decline. RESULTS: We found Aß-dependent tau associations with memory decline in the entorhinal and temporoparietal regions, Aß-independent tau associations with hippocampal atrophy within the medial temporal lobe (MTL), and that widespread tau was associated with mean cortical thinning in AD signature regions. Tau-related memory decline was mediated by hippocampal atrophy in Aß- individuals and by mean cortical thinning in Aß+ individuals. INTERPRETATION: Our results suggest that tau may affect memory through different mechanisms in normal aging and AD. Early tau deposition independent of Aß predicts subsequent hippocampal atrophy that may lead to memory deficits in normal older individuals, whereas elevated cortical tau deposition is associated with cortical thinning that may lead to more severe memory decline in AD. ANN NEUROL 2024;95:249-259.
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Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Anciano , Estudios de Cohortes , Proteínas tau/metabolismo , Adelgazamiento de la Corteza Cerebral , Estudios Prospectivos , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/metabolismo , Tomografía de Emisión de Positrones , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiología , Atrofia , Disfunción Cognitiva/metabolismo , Imagen por Resonancia MagnéticaRESUMEN
AIM: The three-phase enriched environment (EE) intervention paradigm has been shown to improve learning and memory function after cerebral ischemia, but the neuronal mechanisms are still unclear. This study aimed to investigate the hippocampal-cortical connectivity and the metabolic interactions between neurons and astrocytes to elucidate the underlying mechanisms of EE-induced memory improvement after stroke. METHODS: Rats were subjected to permanent middle cerebral artery occlusion (pMCAO) or sham surgery and housed in standard environment or EE for 30 days. Memory function was examined by Morris water maze (MWM) test. Magnetic resonance imaging (MRI) was conducted to detect the structural and functional changes. [18 F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) was conducted to detect brain energy metabolism. PET-based brain connectivity and network analysis was performed to study the changes of hippocampal-cortical connectivity. Astrocyte-neuron metabolic coupling, including gap junction protein connexin 43 (Cx43), glucose transporters (GLUTs), and monocarboxylate transporters (MCTs), was detected by histological studies. RESULTS: Our results showed EE promoted memory function improvement, protected structure integrity, and benefited energy metabolism after stroke. More importantly, EE intervention significantly increased functional connectivity between the hippocampus and peri-hippocampal cortical regions, and specifically regulated the level of Cx43, GLUTs and MCTs in the hippocampus and cortex. CONCLUSIONS: Our results revealed the three-phase enriched environment paradigm enhanced hippocampal-cortical connectivity plasticity and ameliorated post-stroke memory deficits. These findings might provide some new clues for the development of EE and thus facilitate the clinical transformation of EE.