RESUMO
Alzheimer's disease (AD) is a neurodegenerative disease characterized by the progressive deterioration of cognitive functions. Due to the extended global life expectancy, the prevalence of AD is increasing among aging populations worldwide. While AD is a multifactorial disease, synaptic dysfunction is one of the major neuropathological changes that occur early in AD, before clinical symptoms appear, and is associated with the progression of cognitive deterioration. However, the underlying pathological mechanisms leading to this synaptic dysfunction remains unclear. Recent large-scale genomic analyses have identified more than 40 genetic risk factors that are associated with AD. In this review, we discuss the functional roles of these genes in synaptogenesis and synaptic functions under physiological conditions, and how their functions are dysregulated in AD. This will provide insights into the contributions of these encoded proteins to synaptic dysfunction during AD pathogenesis.
Assuntos
Doença de Alzheimer , Transtornos Cognitivos , Doenças Neurodegenerativas , Humanos , Doença de Alzheimer/metabolismo , Sinapses/genética , Sinapses/metabolismo , Doenças Neurodegenerativas/metabolismo , Transtornos Cognitivos/patologia , Fatores de RiscoRESUMO
Down syndrome (DS) is a genetic disease characterized by a supernumerary chromosome 21. Intellectual deficiency (ID) is one of the most prominent features of DS. Central nervous system defects lead to learning disabilities, motor and language delays, and memory impairments. At present, a prenatal treatment for the ID in DS is lacking. Subcutaneous administration of synthetic preimplantation factor (sPIF, a peptide with a range of biological functions) in a model of severe brain damage has shown neuroprotective and anti-inflammatory properties by directly targeting neurons and microglia. Here, we evaluated the effect of PIF administration during gestation and until weaning on Dp(16)1Yey mice (a mouse model of DS). Possible effects at the juvenile stage were assessed using behavioral tests and molecular and histological analyses of the brain. To test the influence of perinatal sPIF treatment at the adult stage, hippocampus-dependent memory was evaluated on postnatal day 90. Dp(16)1Yey pups showed significant behavioral impairment, with impaired neurogenesis, microglial cell activation and a low microglial cell count, and the deregulated expression of genes linked to neuroinflammation and cell cycle regulation. Treatment with sPIF restored early postnatal hippocampal neurogenesis, with beneficial effects on astrocytes, microglia, inflammation, and cell cycle markers. Moreover, treatment with sPIF restored the level of DYRK1A, a protein that is involved in cognitive impairments in DS. In line with the beneficial effects on neurogenesis, perinatal treatment with sPIF was associated with an improvement in working memory in adult Dp(16)1Yey mice. Perinatal treatment with sPIF might be an option for mitigating cognitive impairments in people with DS.
Assuntos
Modelos Animais de Doenças , Síndrome de Down , Neurogênese , Animais , Síndrome de Down/tratamento farmacológico , Síndrome de Down/patologia , Síndrome de Down/metabolismo , Síndrome de Down/complicações , Síndrome de Down/genética , Neurogênese/efeitos dos fármacos , Camundongos , Feminino , Gravidez , Hipocampo/metabolismo , Hipocampo/patologia , Hipocampo/efeitos dos fármacos , Microglia/metabolismo , Microglia/efeitos dos fármacos , Microglia/patologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Tirosina Quinases/genética , Quinases Dyrk , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Masculino , Transtornos Cognitivos/tratamento farmacológico , Transtornos Cognitivos/patologiaRESUMO
White matter abnormalities, related to poor cerebral perfusion, are a core feature of small vessel cerebrovascular disease, and critical determinants of vascular cognitive impairment and dementia. Despite this importance there is a lack of treatment options. Proliferation of microglia producing an expanded, reactive population and associated neuroinflammatory alterations have been implicated in the onset and progression of cerebrovascular white matter disease, in patients and in animal models, suggesting that targeting microglial proliferation may exert protection. Colony-stimulating factor-1 receptor (CSF1R) is a key regulator of microglial proliferation. We found that the expression of CSF1R/Csf1r and other markers indicative of increased microglial abundance are significantly elevated in damaged white matter in human cerebrovascular disease and in a clinically relevant mouse model of chronic cerebral hypoperfusion and vascular cognitive impairment. Using the mouse model, we investigated long-term pharmacological CSF1R inhibition, via GW2580, and demonstrated that the expansion of microglial numbers in chronic hypoperfused white matter is prevented. Transcriptomic analysis of hypoperfused white matter tissue showed enrichment of microglial and inflammatory gene sets, including phagocytic genes that were the predominant expression modules modified by CSF1R inhibition. Further, CSF1R inhibition attenuated hypoperfusion-induced white matter pathology and rescued spatial learning impairments and to a lesser extent cognitive flexibility. Overall, this work suggests that inhibition of CSF1R and microglial proliferation mediates protection against chronic cerebrovascular white matter pathology and cognitive deficits. Our study nominates CSF1R as a target for the treatment of vascular cognitive disorders with broader implications for treatment of other chronic white matter diseases.
Assuntos
Transtornos Cerebrovasculares , Transtornos Cognitivos , Disfunção Cognitiva , Leucoencefalopatias , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos , Substância Branca , Animais , Camundongos , Transtornos Cerebrovasculares/metabolismo , Transtornos Cerebrovasculares/patologia , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/patologia , Disfunção Cognitiva/metabolismo , Modelos Animais de Doenças , Leucoencefalopatias/genética , Leucoencefalopatias/metabolismo , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Receptores de Fator Estimulador de Colônias/metabolismo , Substância Branca/patologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/antagonistas & inibidores , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismoRESUMO
Orientation is a fundamental cognitive faculty and the bedrock of the neurologic examination. Orientation is defined as the alignment between an individual's internal representation and the external world in the spatial, temporal, and social domains. While spatial disorientation is a recognized hallmark of Alzheimer's disease (AD), little is known about disorientation beyond space in AD. This study aimed to explore disorientation in spatial, temporal, and social domains along the AD continuum. Fifty-one participants along the AD continuum performed an ecological orientation task in the spatial, temporal, and social domains while undergoing functional MRI. Disorientation in AD followed a three-way association between orientation domain, brain region, and disease stage. Specifically, patients with early amnestic mild cognitive impairment exhibited spatio-temporal disorientation and reduced brain activity in temporoparietal regions, while patients with AD dementia showed additional social disorientation and reduced brain activity in frontoparietal regions. Furthermore, patterns of hypoactivation overlapped different subnetworks of the default mode network, patterns of fluorodeoxyglucose hypometabolism, and cortical atrophy characteristic of AD. Our results suggest that AD may encompass a disorder of orientation, characterized by a biphasic process manifesting as early spatio-temporal and late social disorientation. As such, disorientation may offer a unique window into the clinicopathological progression of AD. SIGNIFICANCE STATEMENT: Despite extensive research into Alzheimer's disease (AD), its core cognitive deficit remains a matter of debate. In this study, we investigated whether orientation, defined as the ability to align internal representations with the external world in spatial, temporal, and social domains, constitutes a core cognitive deficit in AD. To do so, we used PET-fMRI imaging to collect behavioral, functional, and metabolic data from 51 participants along the AD continuum. Our findings suggest that AD may constitute a disorder of orientation, characterized by an early spatio-temporal disorientation and followed by late social disorientation, manifesting in task-evoked and neurodegenerative changes. We propose that a profile of disorientation across multiple domains offers a unique window into the progression of AD and as such could greatly benefit disease diagnosis, monitoring, and evaluation of treatment response.
Assuntos
Doença de Alzheimer , Transtornos Cognitivos , Disfunção Cognitiva , Humanos , Doença de Alzheimer/patologia , Encéfalo/patologia , Confusão/complicações , Confusão/patologia , Neuroimagem , Transtornos Cognitivos/patologia , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/complicações , Imageamento por Ressonância MagnéticaRESUMO
Emerging evidence now indicates that mitochondria are central regulators of neural stem cell (NSC) fate decisions and are crucial for both neurodevelopment and adult neurogenesis, which in turn contribute to cognitive processes in the mature brain. Inherited mutations and accumulated damage to mitochondria over the course of ageing serve as key factors underlying cognitive defects in neurodevelopmental disorders and neurodegenerative diseases, respectively. In this Review, we explore the recent findings that implicate mitochondria as crucial regulators of NSC function and cognition. In this respect, mitochondria may serve as targets for stem-cell-based therapies and interventions for cognitive defects.
Assuntos
Encéfalo/metabolismo , Diferenciação Celular/fisiologia , Cognição/fisiologia , Mitocôndrias/metabolismo , Células-Tronco Neurais/metabolismo , Animais , Encéfalo/citologia , Transtornos Cognitivos/metabolismo , Transtornos Cognitivos/patologia , Humanos , Células-Tronco Neurais/citologia , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neurogênese/fisiologiaRESUMO
For years, dissociation studies on neurological single-case patients with brain lesions were the dominant method to infer fundamental cognitive functions in neuropsychology. In contrast, the association between deficits was considered to be of less epistemological value. Still, associational computational methods for dimensionality reduction-such as principal component analysis or factor analysis-became popular for the identification of fundamental cognitive functions and to understand human cognitive brain architecture from post-stroke neuropsychological profiles. In the present in silico study with lesion imaging of 300 stroke patients, we investigated the dimensionality of artificial simulated neuropsychological profiles that exclusively contained independent fundamental cognitive functions without any underlying low-dimensional cognitive architecture. Still, the anatomy of stroke lesions alone was sufficient to create a dependence between variables that allowed a low-dimensional description of the data with principal component analysis. All criteria that we used to estimate the dimensionality of data, including the Kaiser criterion, were strongly affected by lesion anatomy, while the Joliffe criterion provided the least affected estimates. The dimensionality of profiles was reduced by 62-70% for the Kaiser criterion, up to the degree that is commonly found in neuropsychological studies on actual cognitive measures. The interpretability of such low-dimensional factors as deficits of fundamental cognitive functions and their provided insights into human cognitive architecture thus seem to be severely limited, and the heavy focus of current cognitive neuroscience on group studies and associations calls for improvements. We suggest that qualitative criteria and dissociation patterns could be used to refine estimates for the dimensionality of the cognitive architecture behind post-stroke deficits. Further, given the strong impact of lesion anatomy on the associational structure of data, we see the need for further optimization of interpretation strategies of computational factors in post-stroke lesion studies of cognitive deficits.
Assuntos
Transtornos Cognitivos , Acidente Vascular Cerebral , Humanos , Testes Neuropsicológicos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/patologia , Transtornos Cognitivos/patologia , Encéfalo/patologia , Cognição , Imageamento por Ressonância Magnética/métodosRESUMO
Chronic hyperglycaemia is a chief feature of diabetes mellitus and complicates with many systematic anomalies. Non-human primates (NHPs) are excellent for studying hyperglycaemia or diabetes and associated comorbidities, but lack behavioural observation. In the study, behavioural, brain imaging and histological analysis were performed in a case of spontaneously hyperglycaemic (HGM) Macaca fascicularis. The results were shown that the HGM monkey had persistent body weight loss, long-term hyperglycaemia, insulin resistance, dyslipidemia, but normal concentrations of insulin, C-peptide, insulin autoantibody, islet cell antibody and glutamic acid decarboxylase antibody. Importantly, an impaired working memory in a delayed response task and neurological dysfunctions were found in the HGM monkey. The tendency for atrophy in hippocampus was observed by magnetic resonance imaging. Lenticular opacification, lens fibres disruptions and vacuole formation also occurred to the HGM monkey. The data suggested that the spontaneous HGM monkey might present diabetes-like characteristics and associated neurobehavioral anomalies in this case. This study first reported cognitive deficits in a spontaneous hyperglycaemia NHPs, which might provide evidence to use macaque as a promising model for translational research in diabetes and neurological complications.
Assuntos
Catarata , Hiperglicemia , Macaca fascicularis , Animais , Hiperglicemia/metabolismo , Catarata/patologia , Masculino , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/patologia , Doenças do Sistema Nervoso , Hipocampo/patologia , Hipocampo/metabolismoRESUMO
Hubs are highly connected brain regions important for coordinating processing in brain networks. It is unclear, however, which measures of network "hubness" are most useful in identifying brain regions critical to human cognition. We tested how closely two measures of hubness-edge density and participation coefficient, derived from white and gray matter, respectively-were associated with general cognitive impairment after brain damage in two large cohorts of patients with focal brain lesions (N = 402 and 102, respectively) using cognitive tests spanning multiple cognitive domains. Lesions disrupting white matter regions with high edge density were associated with cognitive impairment, whereas lesions damaging gray matter regions with high participation coefficient had a weaker, less consistent association with cognitive outcomes. Similar results were observed with six other gray matter hubness measures. This suggests that damage to densely connected white matter regions is more cognitively impairing than similar damage to gray matter hubs, helping to explain interindividual differences in cognitive outcomes after brain damage.
Assuntos
Encéfalo/patologia , Encéfalo/fisiopatologia , Disfunção Cognitiva/patologia , Disfunção Cognitiva/fisiopatologia , Adulto , Encéfalo/diagnóstico por imagem , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Mapeamento Encefálico , Córtex Cerebral/patologia , Cognição , Transtornos Cognitivos/patologia , Transtornos Cognitivos/fisiopatologia , Disfunção Cognitiva/diagnóstico por imagem , Feminino , Substância Cinzenta/patologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Rede Nervosa/fisiopatologia , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Substância Branca/patologia , Adulto JovemRESUMO
Aberrant function of the RNA-binding protein TDP-43 has been causally linked to multiple neurodegenerative diseases. Due to its large number of targets, the mechanisms through which TDP-43 malfunction cause disease are unclear. Here, we report that knockdown, aggregation, or disease-associated mutation of TDP-43 all impair intracellular sorting and activity-dependent secretion of the neurotrophin brain-derived neurotrophic factor (BDNF) through altered splicing of the trafficking receptor Sortilin. Adult mice lacking TDP-43 specifically in hippocampal CA1 show memory impairment and synaptic plasticity defects that can be rescued by restoring Sortilin splicing or extracellular BDNF. Human neurons derived from patient iPSCs carrying mutated TDP-43 also show altered Sortilin splicing and reduced levels of activity-dependent BDNF secretion, which can be restored by correcting the mutation. We propose that major disease phenotypes caused by aberrant TDP-43 activity may be explained by the abnormal function of a handful of critical proteins, such as BDNF.
Assuntos
Proteínas Adaptadoras de Transporte Vesicular/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Transtornos Cognitivos/patologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/fisiologia , Plasticidade Neuronal , Splicing de RNA , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/metabolismo , Proteínas de Ligação a DNA/genética , Células-Tronco Embrionárias/metabolismo , Células-Tronco Embrionárias/patologia , Feminino , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Neurônios/metabolismo , Neurônios/patologiaRESUMO
Many patients with multiple sclerosis (MS) experience information processing speed (IPS) deficits, and the Symbol Digit Modalities Test (SDMT) has been recommended as a valid screening test. Magnetic resonance imaging (MRI) has markedly improved the understanding of the mechanisms associated with cognitive deficits in MS. However, which structural MRI markers are the most closely related to cognitive performance is still unclear. We used the multicenter 3T-MRI data set of the Italian Neuroimaging Network Initiative to extract multimodal data (i.e., demographic, clinical, neuropsychological, and structural MRIs) of 540 MS patients. We aimed to assess, through machine learning techniques, the contribution of brain MRI structural volumes in the prediction of IPS deficits when combined with demographic and clinical features. We trained and tested the eXtreme Gradient Boosting (XGBoost) model following a rigorous validation scheme to obtain reliable generalization performance. We carried out a classification and a regression task based on SDMT scores feeding each model with different combinations of features. For the classification task, the model trained with thalamus, cortical gray matter, hippocampus, and lesions volumes achieved an area under the receiver operating characteristic curve of 0.74. For the regression task, the model trained with cortical gray matter and thalamus volumes, EDSS, nucleus accumbens, lesions, and putamen volumes, and age reached a mean absolute error of 0.95. In conclusion, our results confirmed that damage to cortical gray matter and relevant deep and archaic gray matter structures, such as the thalamus and hippocampus, is among the most relevant predictors of cognitive performance in MS.
Assuntos
Transtornos Cognitivos , Esclerose Múltipla , Humanos , Esclerose Múltipla/patologia , Velocidade de Processamento , Imageamento por Ressonância Magnética/métodos , Transtornos Cognitivos/patologia , Aprendizado de Máquina , Testes NeuropsicológicosRESUMO
Cognitive impairment is increasingly recognized to be a core feature of multiple sclerosis (MS), with important implications for the everyday life of individuals with MS and for disease management. Unfortunately, the exact mechanisms that underlie this cognitive impairment are poorly understood and there are no effective therapeutic options for this aspect of the disease. During MS, focal brain inflammatory lesions, together with pathological changes of both CNS grey matter and normal-appearing white matter, can interfere with cognitive functions. Moreover, inflammation may alter the crosstalk between the immune and the nervous systems, modulating the induction of synaptic plasticity and neurotransmission. In this Review, we examine the CNS structures and cognitive domains that are affected by the disease, with a specific focus on hippocampal involvement in MS and experimental autoimmune encephalomyelitis, an experimental model of MS. We also discuss the hypothesis that, during MS, immune-mediated alterations of synapses' ability to express long-term plastic changes may contribute to the pathogenesis of cognitive impairment by interfering with the dynamics of neuronal networks.
Assuntos
Sistema Nervoso Central/patologia , Sistema Nervoso Central/fisiopatologia , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/patologia , Esclerose Múltipla/complicações , Sinapses/patologia , Animais , HumanosRESUMO
BACKGROUND: White matter hyperintensities of presumed vascular origin (WMH) are frequent in cerebral magnetic resonance imaging of older people. They are promoted by vascular risk factors, especially hypertension, and are associated with cognitive deficits at the group level. It has been suggested that not only the severity, but also the location, of lesions might critically influence cognitive deficits and represent different pathologies. METHODS: In 560 participants (65.2 ± 7.5 years, 51.4% males) of the population-based 1000BRAINS study, we analyzed the association of regional WMH using Fazekas scoring separately for cerebral lobes, with hypertension and cognition. RESULTS: WMH most often affected the frontal lobe (83.7% score >0), followed by the parietal (75.8%), temporal (32.7%), and occipital lobe (7.3%). Higher Fazekas scores in the frontal, parietal, and temporal lobe were associated with higher blood pressure and antihypertensive treatment in unadjusted ordinal regression models and in models adjusted for age, sex, and vascular risk factors (e.g., age- and sex-adjusted odds ratio = 1.14, 95% confidence interval = 1.03-1.25 for the association of frontal lobe WMH Fazekas score with systolic blood pressure [SBP] [per 10 mm Hg]; 1.13 [1.02-1.23] for the association of parietal lobe score with SBP; 1.72 [1.19-2.48] for the association of temporal lobe score with antihypertensive medications). In linear regressions, higher frontal lobe scores were associated with lower performance in executive function and non-verbal memory, and higher parietal lobe scores were associated with lower performance in executive function, verbal-, and non-verbal memory. CONCLUSIONS: Hypertension promotes WMH in the frontal, parietal, and temporal lobe. WMH in the frontal and parietal lobe are associated with reduced executive function and memory.
Assuntos
Transtornos Cognitivos , Hipertensão , Substância Branca , Masculino , Humanos , Idoso , Feminino , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Anti-Hipertensivos , Cognição/fisiologia , Transtornos Cognitivos/patologia , Hipertensão/complicações , Hipertensão/diagnóstico por imagem , Imageamento por Ressonância MagnéticaRESUMO
The logopenic variant of primary progressive aphasia is characterized by early deficits in language production and phonological short-term memory, attributed to left-lateralized temporoparietal, inferior parietal and posterior temporal neurodegeneration. Despite patients primarily complaining of language difficulties, emerging evidence points to performance deficits in non-linguistic domains. Temporoparietal cortex, and functional brain networks anchored to this region, are implicated as putative neural substrates of non-linguistic cognitive deficits in logopenic variant primary progressive aphasia, suggesting that degeneration of a shared set of brain regions may result in co-occurring linguistic and non-linguistic dysfunction early in the disease course. Here, we provide a Review aimed at broadening the understanding of logopenic variant primary progressive aphasia beyond the lens of an exclusive language disorder. By considering behavioural and neuroimaging research on non-linguistic dysfunction in logopenic variant primary progressive aphasia, we propose that a significant portion of multidimensional cognitive features can be explained by degeneration of temporal/inferior parietal cortices and connected regions. Drawing on insights from normative cognitive neuroscience, we propose that these regions underpin a combination of domain-general and domain-selective cognitive processes, whose disruption results in multifaceted cognitive deficits including aphasia. This account explains the common emergence of linguistic and non-linguistic cognitive difficulties in logopenic variant primary progressive aphasia, and predicts phenotypic diversification associated with progression of pathology in posterior neocortex.
Assuntos
Afasia Primária Progressiva , Transtornos Cognitivos , Afasia Primária Progressiva/patologia , Transtornos Cognitivos/patologia , HumanosRESUMO
Schizophrenia has long been thought to be a disconnection syndrome and several previous studies have reported widespread abnormalities in white matter tracts in individuals with schizophrenia. Furthermore, reductions in structural connectivity may also impair communication between anatomically unconnected pairs of brain regions, potentially impacting global signal traffic in the brain. Therefore, we used different communication models to examine direct and indirect structural connections (polysynaptic) communication in large-scale brain networks in schizophrenia. Diffusion-weighted magnetic resonance imaging scans were acquired from 62 patients diagnosed with schizophrenia and 35 controls. In this study, we used five network communication models including, shortest paths, navigation, diffusion, search information and communicability to examine polysynaptic communication in large-scale brain networks in schizophrenia. We showed less efficient communication between spatially widespread brain regions particulary encompassing cortico-subcortical basal ganglia network in schizophrenia group relative to controls. Then, we also examined whether reduced communication efficiency was related to clinical symptoms in schizophrenia group. Among different measures of communication efficiency, only navigation efficiency was associated with global cognitive impairment across multiple cognitive domains including verbal learning, processing speed, executive functions and working memory, in individuals with schizophrenia. We did not find any association between communication efficiency measures and positive or negative symptoms within the schizophrenia group. Our findings are important for improving our mechanistic understanding of neurobiological process underlying cognitive symptoms in schizophrenia.
Assuntos
Transtornos Cognitivos , Disfunção Cognitiva , Esquizofrenia , Humanos , Esquizofrenia/diagnóstico por imagem , Transtornos Cognitivos/complicações , Transtornos Cognitivos/patologia , Disfunção Cognitiva/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Cognição , Imageamento por Ressonância MagnéticaRESUMO
In response to the recent review by Zawar and Kapur on the overlap between mesial temporal lobe epilepsy (MTLE) and Alzheimer's disease (AD), we (1) underscore that the bidirectionality between epilepsy and dementia is of high interest, also from the epileptological perspective; (2) outline the multifactorial etiology of cognitive deficits in epilepsy; (3) emphasize that the most prevalent neuropathological findings in MTLE comprise hippocampal sclerosis, dysplastic lesions, and neurodevelopmental neoplasm; and (4) state that anti-seizure medication can also have adverse effects on cognition. We conclude that the neuropsychology and neuropathology of MTLE is actually more complex than implicated in the review by Zawar and Kapur. Their suggested model may be valid for a small specific subgroup of cases. However, more studies are needed to confirm the role of hyperphosphorylated tau in epilepsy patients with and without AD considering age and age at epilepsy onset as potential moderator variables.
Assuntos
Transtornos Cognitivos , Disfunção Cognitiva , Epilepsia do Lobo Temporal , Humanos , Epilepsia do Lobo Temporal/complicações , Epilepsia do Lobo Temporal/patologia , Hipocampo/patologia , Transtornos Cognitivos/patologia , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/patologia , Cognição , Imageamento por Ressonância MagnéticaRESUMO
Cognitive dysfunction is an important non-motor symptom in amyotrophic lateral sclerosis (ALS) that has a negative impact on survival and caregiver burden. It shows a wide spectrum ranging from subjective cognitive decline to frontotemporal dementia (FTD) and covers various cognitive domains, mainly executive/attention, language and verbal memory deficits. The frequency of cognitive impairment across the different ALS phenotypes ranges from 30% to 75%, with up to 45% fulfilling the criteria of FTD. Significant genetic, clinical, and pathological heterogeneity reflects deficits in various cognitive domains. Modern neuroimaging studies revealed frontotemporal degeneration and widespread involvement of limbic and white matter systems, with hypometabolism of the relevant areas. Morphological substrates are frontotemporal and hippocampal atrophy with synaptic loss, associated with TDP-43 and other co-pathologies, including tau deposition. Widespread functional disruptions of motor and extramotor networks, as well as of frontoparietal, frontostriatal and other connectivities, are markers for cognitive deficits in ALS. Cognitive reserve may moderate the effect of brain damage but is not protective against cognitive decline. The natural history of cognitive dysfunction in ALS and its relationship to FTD are not fully understood, although there is an overlap between the ALS variants and ALS-related frontotemporal syndromes, suggesting a differential vulnerability of motor and non-motor networks. An assessment of risks or the early detection of brain connectivity signatures before structural changes may be helpful in investigating the pathophysiological mechanisms of cognitive impairment in ALS, which might even serve as novel targets for effective disease-modifying therapies.
Assuntos
Esclerose Lateral Amiotrófica , Transtornos Cognitivos , Disfunção Cognitiva , Demência Frontotemporal , Doenças Neurodegenerativas , Doença de Pick , Humanos , Esclerose Lateral Amiotrófica/genética , Demência Frontotemporal/genética , Encéfalo/patologia , Transtornos Cognitivos/patologia , Disfunção Cognitiva/patologia , Doenças Neurodegenerativas/patologia , Doença de Pick/patologiaRESUMO
High-throughput genomic sequencing approaches have held the promise of understanding and ultimately leading to treatments for cognitive disorders such as autism spectrum disorders, schizophrenia and Alzheimer's disease. Although significant progress has been made into identifying genetic variants associated with these diseases, these studies have also uncovered that these disorders are mostly genetically complex and thus challenging to model in non-human systems. Improvements in such models might benefit from understanding the evolution of the human genome and how such modifications have affected brain development and function. The intersection of genome-wide variant information with cell-type-specific expression and epigenetic information will further assist in resolving the contribution of particular cell types in evolution or disease. For example, the role of non-neuronal cells in brain evolution and cognitive disorders has gone mostly underappreciated until the recent availability of single-cell transcriptomic approaches. In this review, we discuss recent studies that carry out cell-type-specific assessments of gene expression in brain tissue across primates and between healthy and disease populations. The emerging results from these studies are beginning to elucidate how specific cell types in the evolved human brain are contributing to cognitive disorders.
Assuntos
Transtornos Cognitivos/patologia , Evolução Molecular , Predisposição Genética para Doença , Genética Populacional , Genoma , Genômica/métodos , Animais , Transtornos Cognitivos/epidemiologia , Transtornos Cognitivos/genética , Estudo de Associação Genômica Ampla , Humanos , Primatas , TranscriptomaRESUMO
Mutations in genes that encode centrosomal/ciliary proteins cause severe cognitive deficits, while common single-nucleotide polymorphisms in these genes are associated with schizophrenia (SZ) and cognition in genome-wide association studies. The role of these genes in neuropsychiatric disorders is unknown. The ciliopathy gene SDCCAG8 is associated with SZ and educational attainment (EA). Genome editing of SDCCAG8 caused defects in primary ciliogenesis and cilium-dependent cell signalling. Transcriptomic analysis of SDCCAG8-deficient cells identified differentially expressed genes that are enriched in neurodevelopmental processes such as generation of neurons and synapse organization. These processes are enriched for genes associated with SZ, human intelligence (IQ) and EA. Phenotypic analysis of SDCCAG8-deficent neuronal cells revealed impaired migration and neuronal differentiation. These data implicate ciliary signalling in the aetiology of SZ and cognitive dysfunction. We found that centrosomal/ciliary genes are enriched for association with IQ, suggesting altered gene regulation as a general model for neurodevelopmental impacts of centrosomal/ciliary genes.
Assuntos
Autoantígenos/genética , Transtornos Cognitivos/patologia , Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Mutação , Proteínas de Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Esquizofrenia/patologia , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/genética , Humanos , Esquizofrenia/etiologia , Esquizofrenia/genéticaRESUMO
The impact of sex and menopausal status in Alzheimer's disease remains understudied despite increasing evidence of greater female risk, particularly in APOE4 carriers. Utilizing female APOE-TR mice maintained on a high-fat diet background we induced ovarian failure through repeated VCD injections, to mimic human menopause. At 12 months of age, recognition memory and spatial memory were assessed using object recognition, Y-maze spontaneous alternation, and Barnes maze. A VCD*genotype interaction reduced the recognition memory (P < .05), with APOE4 VCD-treated animals unable to distinguish between novel and familiar objects. APOE4 mice displayed an additional 37% and 12% reduction in Barnes (P < .01) and Y-maze (P < .01) performance, indicative of genotype-specific spatial memory impairment. Molecular analysis indicated both VCD and genotype-related deficits in synaptic plasticity with BDNF, Akt, mTOR, and ERK signaling compromised. Subsequent reductions in the transcription factors Creb1 and Atf4 were also evident. Furthermore, the VCD*genotype interaction specifically diminished Ephb2 expression, while Fos, and Cnr1 expression reduced as a consequence of APOE4 genotype. Brain DHA levels were 13% lower in VCD-treated animals independent of genotype. Consistent with this, we detected alterations in the expression of the DHA transporters Acsl6 and Fatp4. Our results indicate that the combination of ovarian failure and APOE4 leads to an exacerbation of cognitive and neurological deficits.
Assuntos
Apolipoproteína E4/fisiologia , Transtornos Cognitivos/patologia , Cicloexenos/toxicidade , Transtornos da Memória/patologia , Menopausa , Plasticidade Neuronal , Doenças Ovarianas/complicações , Compostos de Vinila/toxicidade , Animais , Apolipoproteína E3/fisiologia , Comportamento Animal , Carcinógenos/toxicidade , Transtornos Cognitivos/etiologia , Feminino , Transtornos da Memória/etiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Doenças Ovarianas/induzido quimicamente , Doenças Ovarianas/patologiaRESUMO
The cerebellar cognitive affective syndrome (CCAS) has been consistently described in patients with acute/subacute cerebellar injuries. However, studies with chronic patients have had controversial findings that have not been explored with new cerebellar-target tests, such as the CCAS scale (CCAS-S). The objective of this research is to prove and contrast the usefulness of the CCAS-S and the Montreal Cognitive Assessment (MoCA) test to evaluate cognitive/affective impairments in patients with chronic acquired cerebellar lesions, and to map the cerebellar areas whose lesions correlated with dysfunctions in these tests. CCAS-S and MoCA were administrated to 22 patients with isolated chronic cerebellar strokes and a matched comparison group. The neural bases underpinning both tests were explored with multivariate lesion-symptom mapping (LSM) methods. MoCA and CCAS-S had an adequate test performance with efficient discrimination between patients and healthy volunteers. However, only impairments determined by the CCAS-S resulted in significant regional localization within the cerebellum. Specifically, patients with chronic cerebellar lesions in right-lateralized posterolateral regions manifested cognitive impairments inherent to CCAS. These findings concurred with the anterior-sensorimotor/posterior-cognitive dichotomy in the human cerebellum and revealed clinically intra- and cross-lobular significant regions (portions of right lobule VI, VII, Crus I-II) for verbal tasks that overlap with the "language" functional boundaries in the cerebellum. Our findings prove the usefulness of MoCA and CCAS-S to reveal cognitive impairments in patients with chronic acquired cerebellar lesions. This study extends the understanding of long-term CCAS and introduces multivariate LSM methods to identify clinically intra- and cross-lobular significant regions underpinning chronic CCAS.