RESUMO
Hyperphosphorylation and aggregation of the protein tau play key roles in the development of Alzheimer's disease (AD). While the molecular structure of the filamentous tau aggregates has been determined to atomic resolution, there is far less information available about the smaller, soluble aggregates, which are believed to be more toxic. Traditional techniques are limited to bulk measures and struggle to identify individual aggregates in complex biological samples. To address this, we developed a novel single-molecule pull-down-based assay (MAPTau) to detect and characterize individual tau aggregates in AD and control post-mortem brain and biofluids. Using MAPTau, we report the quantity, as well as the size and circularity of tau aggregates measured using super-resolution microscopy, revealing AD-specific differences in tau aggregate morphology. By adapting MAPTau to detect multiple phosphorylation markers in individual aggregates using two-color coincidence detection, we derived compositional profiles of the individual aggregates. We find an AD-specific phosphorylation profile of tau aggregates with more than 80 % containing multiple phosphorylations, compared to 5 % in age-matched non-AD controls. Our results show that MAPTau is able to identify disease-specific subpopulations of tau aggregates phosphorylated at different sites, that are invisible to other methods and enable the study of disease mechanisms and diagnosis.
Assuntos
Doença de Alzheimer , Agregados Proteicos , Proteínas tau , Humanos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/diagnóstico , Proteínas tau/metabolismo , Proteínas tau/química , Proteínas tau/análise , Fosforilação , Imagem Individual de Molécula/métodos , Encéfalo/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/patologiaRESUMO
OBJECTIVE: High-frequency, repetitive transcranial magnetic stimulation (rTMS) targeted over the dorsolateral prefrontal cortex (DLPFC) is widely used in research to promote neuroplasticity and cognitive enhancement. RTMS is a promising intervention to tackle cognitive decline in people with age-related neurodegenerative diseases. However, there is currently no systematic evidence examining the effects of DLPFC-targeted, high-frequency rTMS on cognitive function in this population. The aim of this systematic review was to evaluate the efficacy and moderators of this treatment intervention. METHODS: A comprehensive literature search of five electronic databases was performed to identify articles published before October, 2022. Following PRISMA guidelines, the identified articles were screened, data was extracted, and the methodological quality was assessed using the Cochrane tool, Risk of Bias 2. Meta-analyses were performed using R Studio (v.4.1.2). RESULTS: Sixteen studies involving 474 participants met the inclusion criteria, of which 8 studies measured global cognitive function. The results from the random-effects meta-analysis showed rTMS significantly improved global cognitive function relative to control groups shown by a large, significant effect size (g = 1.39, 95% CI, 0.34-2.43; p = 0.017). No significant effects were found between subgroups or for individual cognitive domains. CONCLUSIONS: High-frequency rTMS, targeted over the DLPFC, appears to improve global cognitive function in people with age-related neurodegenerative diseases. However, these results should be interpreted with caution due to the small number of studies included, and high between-study heterogeneity.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Doenças Neurodegenerativas , Humanos , Estimulação Magnética Transcraniana/métodos , Doenças Neurodegenerativas/terapia , Cognição , Disfunção Cognitiva/terapia , Doença de Alzheimer/terapia , Córtex Pré-Frontal/fisiologiaRESUMO
OBJECTIVE: People with amnestic mild cognitive impairment (aMCI) are at an increased risk of developing dementia. Efficient ways of identifying this 'at risk' population are required for larger-scale research studies. This systematic review describes the diagnostic accuracy of brief cognitive tests for detecting aMCI. METHODS: Fifteen databases were searched from 1999 to July 2013 to identify papers for inclusion. Prospective studies assessing the diagnostic test accuracy of simple and brief cognitive tests for identifying people with aMCI against a reference standard (Petersen criteria) were included. Sensitivity, specificity, positive and negative predictive values and likelihood ratios were calculated. Predictive validity and test-retest reliability were also extracted, when provided. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. RESULTS: Thirty-nine studies assessing 42 index tests were included. The Montreal Cognitive Assessment was the most comprehensively assessed test with evidence of high sensitivity for aMCI and good test-retest reliability, but low specificity was reported by the only study judged to be at low risk of bias. Other brief cognitive tests that include an assessment of word recall and multi-task tests that assess several cognitive domains were also found to exhibit high sensitivities and reasonable specificities. However, the confidence of the findings was affected by overall low quality of the contributing studies. CONCLUSION: Several brief cognitive tests have shown promising diagnostic test accuracy results for identifying aMCI. However, concerns over the quality of the constituent studies and lack of evidence on the predictive validity of these tests mean that new validation studies are warranted. Copyright © 2016 John Wiley & Sons, Ltd.
Assuntos
Amnésia/diagnóstico , Escalas de Graduação Psiquiátrica Breve/normas , Disfunção Cognitiva/diagnóstico , Demência/diagnóstico , Testes Diagnósticos de Rotina , Humanos , Valor Preditivo dos Testes , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
INTRODUCTION: This study investigated the validity of two brief cognitive tests (Memory Alteration Test [M@T] and Test Your Memory [TYM] test) for identifying people with aMCI in the community. METHODS: Older people were invited to participate by their general practitioner practice. Eligible participants were assessed for aMCI using an operationalized approach to the Petersen criteria and the M@T and TYM. RESULTS: Both tests demonstrated significant ability in discriminating between people with aMCI and controls (AUC = 0.91 for M@T and 0.80 for TYM [P < .001 for both]). M@T performed with higher sensitivity than TYM (85% vs. 63%) and similar specificity (84% vs. 87%). Both tests demonstrated moderate test-retest reliability (κ = â¼0.5) and took <10 minutes to administer. DISCUSSION: M@T and TYM are quick to administer. M@T demonstrated higher diagnostic test accuracy than TYM and could provide an efficient method for identifying aMCI in clinical and research settings.
Assuntos
Disfunção Cognitiva/diagnóstico , Testes Neuropsicológicos , Fatores Etários , Idoso , Escolaridade , Feminino , Medicina Geral , Humanos , Inteligência , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores Sexuais , Fatores de TempoRESUMO
It is unclear to what extent natural differences between reading and listening result in differences in the syntactic representations formed in each modality. The present study investigated the occurrence of syntactic priming bidirectionally from reading to listening, and vice versa to examine whether reading and listening share the same syntactic representations in both first language (L1) and second language (L2). Participants performed a lexical decision task in which the experimental words were embedded in sentences with either an ambiguous or a familiar structure. These structures were alternated to produce a priming effect. The modality was manipulated whereby participants (a) first read part of the sentence list and then listened to the rest of the list (reading-listening group), or (b) listened and then read (listening-reading group). In addition, the study involved two within-modality lists in which participants either read or listened to the whole list. The L1 group showed within-modal priming in both listening and reading as well as a cross-modal priming effect. Although L2 speakers showed priming in reading, the effect was absent in listening and weak in the listening-reading condition. The absence of priming in L2 listening was attributed to difficulties in L2 listening rather than to an inability to produce abstract priming.
Assuntos
Idioma , Leitura , HumanosRESUMO
OBJECTIVES: To identify the needs of people with long COVID (LC) in the UK. DESIGN: Qualitative study using the Framework Analysis to analyse focus group discussions. PARTICIPANTS: 25 adults with LC aged 19-76 years including 17 men and 8 women. Average disease duration was 80.1 weeks. SETTING: Eight focus groups were conducted in April 2023 online and in-person at the University of Leeds (UoL), UK. Recruitment routes included advertisement via Leeds Community Healthcare services, the English National Opera Breathe Programme and within the UoL. RESULTS: Three key themes/needs were identified. (Theme 1) Support systems including community groups, disability benefits, clinical services and employment support should be accessible and tailored to the needs of people with LC. (Theme 2) Research should investigate the physiology of symptoms, new clinical tests and treatment interventions to improve clinical understanding of the condition and symptom management. (Theme 3) Societal awareness should be promoted via local and national initiatives to educate the public about the condition and reduce stigma. CONCLUSIONS: Participants experienced varied and individual challenges to daily life due to LC. There is a need for government acknowledgement of LC as a disability to ensure people with LC have access to disability support and legal protection. Policy development should be patient-driven and acknowledge the individual needs of people with LC in order to improve their quality of life.
Assuntos
COVID-19 , Grupos Focais , Pesquisa Qualitativa , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Adulto , Reino Unido , COVID-19/epidemiologia , Avaliação das Necessidades , SARS-CoV-2 , Adulto Jovem , Síndrome de COVID-19 Pós-Aguda , Necessidades e Demandas de Serviços de SaúdeRESUMO
Preventing nonspecific binding is essential for sensitive surface-based quantitative single-molecule microscopy. Here we report a much-simplified RainX-F127 (RF-127) surface with improved passivation. This surface achieves up to 100-fold less nonspecific binding from protein aggregates compared to commonly used polyethylene glycol (PEG) surfaces. The method is compatible with common single-molecule techniques including single-molecule pull-down (SiMPull), super-resolution imaging, antibody-binding screening and single exosome visualization. This method is also able to specifically detect alpha-synuclein (α-syn) and tau aggregates from a wide range of biofluids including human serum, brain extracts, cerebrospinal fluid (CSF) and saliva. The simplicity of this method further allows the functionalization of microplates for robot-assisted high-throughput single-molecule experiments. Overall, this simple but improved surface offers a versatile platform for quantitative single-molecule microscopy without the need for specialized equipment or personnel.
Assuntos
Imagem Individual de Molécula , alfa-Sinucleína , Proteínas tau , Humanos , alfa-Sinucleína/metabolismo , alfa-Sinucleína/química , Proteínas tau/metabolismo , Proteínas tau/química , Imagem Individual de Molécula/métodos , Propriedades de Superfície , Polietilenoglicóis/química , Agregados ProteicosRESUMO
The corpus callosum (CC) is the largest bundle of white matter tracts in the brain connecting the left and right cerebral hemispheres. The posterior region of the CC, known as the splenium, seems to be relatively preserved throughout the lifespan and is regularly examined for indications of various pathologies, including Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). However, the splenium has rarely been investigated in terms of its distinct inter-hemispheric tract bundles that project to bilateral occipital, parietal and temporal areas of the cortex. The aim of the present study was to determine if any of these sub-splenium tract bundles are specifically affected by individuals with AD and MCI compared to normal controls. Diffusion Tensor Imaging was used to directly examine the integrity of these distinct tract bundles and their diffusion metrics were compared between groups of MCI, AD, and control individuals. Results revealed that differences between MCI, AD, and controls were particularly evident at parietal tracts of the CC splenium and were consistent with an interpretation of compromised white matter integrity. Combined parietal tract diffusivity and density information strongly discriminated between AD patients and controls with an accuracy (AUC) of 97.19%. Combined parietal tract diffusivity parameters correctly classified MCI subjects against controls with an accuracy of 74.97%. These findings demonstrated the potential of examining the CC splenium in terms of its distinct inter-hemispheric tract bundles for the diagnosis of AD and MCI.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Substância Branca , Humanos , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/patologia , Doença de Alzheimer/patologia , Imagem de Tensor de Difusão/métodos , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/patologia , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/patologia , Substância Branca/diagnóstico por imagem , Substância Branca/patologiaRESUMO
We developed the aggregate characterization toolkit (ACT), a fully automated computational suite based on existing and widely used core algorithms to measure the number, size, and permeabilizing activity of recombinant and human-derived aggregates imaged with diffraction-limited and super-resolution microscopy methods at high throughput. We have validated ACT on simulated ground-truth images of aggregates mimicking those from diffraction-limited and super-resolution microscopies and showcased its use in characterizing protein aggregates from Alzheimer's disease. ACT is developed for high-throughput batch processing of images collected from multiple samples and is available as an open-source code. Given its accuracy, speed, and accessibility, ACT is expected to be a fundamental tool in studying human and non-human amyloid intermediates, developing early disease stage diagnostics, and screening for antibodies that bind toxic and heterogeneous human amyloid aggregates.
Assuntos
Doença de Alzheimer , Agregados Proteicos , Humanos , Doença de Alzheimer/diagnóstico , Amiloide , Proteínas Amiloidogênicas , AlgoritmosRESUMO
Tau is a soluble protein interacting with tubulin to stabilize microtubules. However, under pathological conditions, it becomes hyperphosphorylated and aggregates, a process that can be induced by treating cells with exogenously added tau fibrils. Here, we employ single-molecule localization microscopy to resolve the aggregate species formed in early stages of seeded tau aggregation. We report that entry of sufficient tau assemblies into the cytosol induces the self-replication of small tau aggregates, with a doubling time of 5 h inside HEK cells and 1 day in murine primary neurons, which then grow into fibrils. Seeding occurs in the vicinity of the microtubule cytoskeleton, is accelerated by the proteasome, and results in release of small assemblies into the media. In the absence of seeding, cells still spontaneously form small aggregates at lower levels. Overall, our work provides a quantitative picture of the early stages of templated seeded tau aggregation in cells.
Assuntos
Doença de Alzheimer , Proteínas tau , Camundongos , Animais , Proteínas tau/metabolismo , Microtúbulos/metabolismo , Tubulina (Proteína)/metabolismo , Citosol/metabolismo , Neurônios/metabolismo , Doença de Alzheimer/metabolismo , Agregados ProteicosRESUMO
A previous study has shown that actively pursuing a moving target provides a predictive motor advantage when compared with passive observation of the moving target while keeping the eyes still [Burke, M. R., & Barnes, G. R. Anticipatory eye movements evoked after active following versus passive observation of a predictable motion stimulus. Brain Research, 15, 74-81, 2008b]. By using a novel paradigm based on combining a smooth pursuit stimulus with a go/no-go task, we have been able to reveal significant differences in brain activity for the inhibition of pursuit during the presentation of a smoothly moving target. Areas that show specific inhibitory and retinocentric velocity storage activity for the passive (no-go) condition include the dorsolateral pFC, the caudate, and the posterior cingulate. The FEFs, the supramarginal gyrus, the medial occipital gyrus, and the superior parietal lobe were found to be more involved in both the acquisition and response generation during no-go trials when compared with go trials. The go trials revealed higher activity than the no-go during the acquisition phase in the uncus and posterior cingulate. Furthermore, higher motor-related activity in the go task was found in the cerebellum. In summary, the areas involved in inhibiting smooth pursuit are consistent with the findings from the saccade literature, providing further evidence in support of overlapping cortical control networks.
Assuntos
Mapeamento Encefálico , Córtex Cerebral/fisiologia , Inibição Psicológica , Percepção de Movimento/fisiologia , Acompanhamento Ocular Uniforme/fisiologia , Adulto , Análise de Variância , Atenção , Córtex Cerebral/irrigação sanguínea , Tomada de Decisões/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Oxigênio/sangue , Estimulação Luminosa/métodos , Valor Preditivo dos Testes , Tempo de Reação , Fatores de Tempo , Adulto JovemRESUMO
It is well established that the posterior region of the corpus callosum, known as the splenium, is relatively preserved during the course of normal ageing. However, the effect of age on its distinct interhemispheric tract bundles that project to bilateral occipital, parietal and temporal areas of the cortex, is largely unknown. In the present study, diffusion tensor imaging was used to directly examine the integrity of these distinct segregations and their diffusion metrics were compared between groups of young adults (n = 20, mean age = 30.75) and older adults (n = 19, mean age = 80.21). Results revealed that while occipital tracts were preserved in older adults, parietal and temporal segments were particularly impaired. These findings are the first to indicate the existence of selective alterations in the posterior region of the corpus callosum in older age.
Assuntos
Envelhecimento/patologia , Corpo Caloso/diagnóstico por imagem , Imagem de Tensor de Difusão/tendências , Substância Branca/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Corpo Caloso/patologia , Estudos Transversais , Feminino , Humanos , Masculino , Substância Branca/patologia , Adulto JovemRESUMO
Theta burst stimulation (TBS) is a form of repetitive transcranial magnetic stimulation (rTMS) that can be used to increase (intermittent TBS) or reduce (continuous TBS) cortical excitability. The current study provides a preliminary report of the effects of iTBS and cTBS in healthy young adults, to investigate the causal role of the posterior parietal cortex (PPC) during the performance of four cognitive functions: attention, inhibition, sequence learning and working memory. A 2 × 2 repeated measures design was incorporated using hemisphere (left/right) and TBS type (iTBS/cTBS) as the independent variables. 20 participants performed the cognitive tasks both before and after TBS stimulation in 4 counterbalanced experimental sessions (left cTBS, right cTBS, left iTBS and right iTBS) spaced 1 week apart. No change in performance was identified for the attentional cueing task after TBS stimulation, however TBS applied to the left PPC decreased reaction time when inhibiting a reflexive response. The sequence learning task revealed differential effects for encoding of the sequence versus the learnt items. cTBS on the right hemisphere resulted in faster responses to learnt sequences, and iTBS on the right hemisphere reduced reaction times during the initial encoding of the sequence. The reaction times in the 2-back working memory task were increased when TBS stimulation was applied to the right hemisphere. Results reveal clear differential effects for tasks explored, and more specifically where TBS stimulation on right PPC could provide a potential for further investigation into improving oculomotor learning by inducing plasticity-like mechanisms in the brain.
Assuntos
Cognição/fisiologia , Lobo Parietal/fisiologia , Adolescente , Atenção/fisiologia , Sinais (Psicologia) , Feminino , Lateralidade Funcional/fisiologia , Humanos , Inibição Psicológica , Masculino , Memória de Curto Prazo/fisiologia , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Aprendizagem Seriada/fisiologia , Ritmo Teta , Estimulação Magnética Transcraniana , Adulto JovemRESUMO
Structural learning suggests that the human nervous system learns general rules that can be applied when controlling actions involving similar structures (e.g. using a variety of bicycles when learning to ride). These general rules can then facilitate skill acquisition in novel but related situations (e.g. a new bicycle). We tested this concept by investigating whether learned asymmetries in handwriting (greater ease in moving the hand rightwards and downwards within Western-educated populations) are present in the non-preferred hand as predicted by structural learning. We found these asymmetries in both hands of a right-handed population when tracing abstract shapes. We then ruled out biomechanical explanations by finding the same results with a left-handed population. These findings provide support for structural learning and explain: (1) the rapidity with which individuals can learn to write with their non-preferred hand; (2) the presence of a higher abstract (effector independent) level within voluntary motor control organisation.
Assuntos
Lateralidade Funcional/fisiologia , Mãos/fisiologia , Escrita Manual , Aprendizagem/fisiologia , Destreza Motora/fisiologia , Volição/fisiologia , Adolescente , Adulto , Função Executiva/fisiologia , Feminino , Humanos , Masculino , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Adulto JovemRESUMO
The individual alpha peak frequency (IAPF) of the human electroencephalography (EEG) typically experiences slowing with increasing age. Despite this hallmark change, studies that investigate modulations of conventional EEG alpha power and connectivity by aging and age-related neuropathology neglect to account for intergroup differences in IAPF. To investigate the relationship of age-related IAPF slowing with EEG power and connectivity, we recorded eyes-closed resting-state EEG in 37 young adults and 32 older adults. We replicated the finding of a slowed IAPF in older adults. IAPF values were significantly correlated with the frequency of maximum global connectivity and the means of their distributions did not differ, suggesting that connectivity was highest at the IAPF. Older adults expressed reduced global EEG power and connectivity at the conventional upper alpha band (10-12 Hz) compared with young adults. By contrast, groups had equivalent power and connectivity at the IAPF. The results suggest that conventional spectral boundaries may be biased against older adults or any group with a slowed IAPF. We conclude that investigations of alpha activity in aging and age-related neuropathology should be adapted to the IAPF of the individual and that previous findings should be interpreted with caution. EEG in the dominant alpha range may be unsuitable for examining cortico-cortical connectivity due to its subcortical origins.
Assuntos
Envelhecimento , Ritmo alfa , Encéfalo/fisiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Adulto JovemRESUMO
Older adults typically experience reductions in the structural integrity of the anterior channels of the corpus callosum. Despite preserved structural integrity in central and posterior channels, many studies have reported that interhemispheric transfer, a function attributed to these regions, is detrimentally affected by aging. In this study, we use a constrained event-related potential analysis in the theta and alpha frequency bands to determine whether interhemispheric transfer is affected in older adults. The crossed-uncrossed difference and lateralized visual evoked potentials were used to assess interhemispheric transfer in young (18-27) and older adults (63-80). We observed no differences in the crossed-uncrossed difference measure between young and older groups. Older adults appeared to have elongated transfer in the theta band potentials, but this effect was driven by shortened contralateral peak latencies, rather than delayed ipsilateral latencies. In the alpha band, there was a trend toward quicker transfer in older adults. We conclude that older adults do not experience elongated interhemispheric transfer in the visuomotor or visual domains and that these functions are likely attributed to posterior sections of the corpus callosum, which are unaffected by aging.
Assuntos
Envelhecimento/fisiologia , Envelhecimento/psicologia , Corpo Caloso/fisiologia , Corpo Caloso/fisiopatologia , Transmissão Sináptica/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Potenciais Evocados/fisiologia , Potenciais Evocados Visuais/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Percepção Visual/fisiologia , Adulto JovemRESUMO
Sequence learning is common to all motor systems and is an essential aspect of human behavior necessary for the acquisition of motor skill. Many previous studies have demonstrated the ability to observe, store, and repeat sequences in a variety of modalities resulting in reduced reaction time. Recently, it has been found that subjects can make predictive smooth eye movements to a sequence of discrete horizontal target motions (C. J. Collins & Barnes, 2005). The present study extends that paradigm into two dimensions of motion in order to investigate qualitative and quantitative differences in sequences of vertical (V) and horizontal (H) eye movements. The subjects performed sequences of four discrete velocity ramps repeated either four or eight times in succession. Baseline measurements were obtained to discrete individual smooth pursuit velocity ramps to H and V predictable (PRD) and randomized (RND) targets. We found that subjects could rapidly learn and anticipate individual components of a four-ramp sequence in two dimensions. The results showed clear asymmetries in the eye movements made to horizontal and vertical targets. We found that the latencies to H targets were shorter than latencies to V targets in both the PRD and RND conditions. We also found higher initial eye velocity (50 ms after target onset) to H targets than vertical targets during the PRD condition. Because these differences in H and V eye movements are present in both RND and PRD trials, this suggests that the observed differences are not due to retention of information but are inherent asymmetries within the system.
Assuntos
Movimentos Oculares/fisiologia , Aprendizagem/fisiologia , Desempenho Psicomotor/fisiologia , Acompanhamento Ocular Uniforme/fisiologia , Adulto , Feminino , Humanos , Masculino , Tempo de Reação , Fatores de TempoRESUMO
The basis of motor learning involves decomposing complete actions into a series of predictive individual components that form the whole. The present fMRI study investigated the areas of the human brain important for oculomotor short-term learning, by using a novel sequence learning paradigm that is equivalent in visual and temporal properties for both saccades and pursuit, enabling more direct comparisons between the oculomotor subsystems. In contrast with previous studies that have implemented a series of discrete ramps to observe predictive behaviour as evidence for learning, we presented a continuous sequence of interlinked components that better represents sequences of actions. We implemented both a classic univariate fMRI analysis, followed by a further multivariate pattern analysis (MVPA) within a priori regions of interest, to investigate oculomotor sequence learning in the brain and to determine whether these mechanisms overlap in pursuit and saccades as part of a higher order learning network. This study has uniquely identified an equivalent frontal-parietal network (dorsolateral prefrontal cortex, frontal eye fields and posterior parietal cortex) in both saccades and pursuit sequence learning. In addition, this is the first study to investigate oculomotor sequence learning during fMRI brain imaging, and makes significant contributions to understanding the role of the dorsal networks in motor learning.
Assuntos
Lobo Frontal/fisiologia , Aprendizagem/fisiologia , Atividade Motora/fisiologia , Lobo Parietal/fisiologia , Acompanhamento Ocular Uniforme/fisiologia , Movimentos Sacádicos/fisiologia , Adulto , Antecipação Psicológica/fisiologia , Mapeamento Encefálico/métodos , Circulação Cerebrovascular/fisiologia , Medições dos Movimentos Oculares , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Análise Multivariada , Vias Neurais , Testes Neuropsicológicos , Oxigênio/sangue , Reconhecimento Automatizado de Padrão , Adulto JovemRESUMO
The ability to use advance information to prepare and execute a movement requires cognitive control of behaviour (e.g., anticipation and inhibition). Our aim was to explore the integrity of saccadic eye movement control in developmental coordination disorder (DCD) and typically developing (TD) children (8-12 years) and assess how these children plan and inhibit saccadic responses, the principal mechanisms within visual attention control. Eye movements and touch responses were measured (separately and concurrently) in Cued and Non-Cued conditions. We found that children with DCD had similar saccade kinematics to the TD group during saccade initiation. Advance information decreased hand movement duration in both groups during Cued trials, but decrements in accuracy were significantly worse in the DCD group. In addition, children with DCD exhibited greater inhibitory errors and inaccurate fixation during the Cued trials. Thus, children with DCD were reasonably proficient in executing saccades during reflexive (Non-Cued) conditions, but showed deficits in more complex control processes involving prediction and inhibition. These findings have implications for our understanding of motor control in children with DCD.
Assuntos
Cognição , Transtornos das Habilidades Motoras/fisiopatologia , Movimentos Sacádicos/fisiologia , Fenômenos Biomecânicos , Criança , Feminino , Fixação Ocular , Humanos , MasculinoRESUMO
BACKGROUND: Knowledge of hand anatomy and pathology is important for final year medical students as it frequently appears in examinations as a short case or in a written paper. Studies have shown that doctors in the Emergency Department have a deficient grasp of musculoskeletal anatomy secondary to a lack of dedicated teaching in medical school. METHODS: A questionnaire was handed out to 111 final year medical students. Students were asked to fill it out before and after dedicated upper limb teaching sessions during their rotation. The questionnaire consisted of an anatomical and pathological component. Students were tested on basic anatomy and pathology of several common upper limb conditions. RESULTS: There was a significant improvement in the medical students knowledge after the dedicated hand teaching. The identification of the carpal bones showed the most improvement overall. CONCLUSIONS: Basic musculoskeletal knowledge is essential to the practice of medicine. The majority of medical students gravitate towards a career in general practice or emergency medicine and good knowledge of upper limb anatomy is important. We have piloted a new interactive dedicated upper limb teaching module and have shown that there has been a significant improvement in students knowledge.