Neural Correlates of Spatial Navigation in Primate Hippocampus / 神经科学通报·英文版

The hippocampus has been extensively implicated in spatial navigation in rodents and more recently in bats. Numerous studies have revealed that various kinds of spatial information are encoded across hippocampal regions. In contrast, investigations of spatial behavioral correlates in the primate hippocampus are scarce and have been mostly limited to head-restrained subjects during virtual navigation. However, recent advances made in freely-moving primates suggest marked differences in spatial representations from rodents, albeit some similarities. Here, we review empirical studies examining the neural correlates of spatial navigation in the primate (including human) hippocampus at the levels of local field potentials and single units. The lower frequency theta oscillations are often intermittent. Single neuron responses are highly mixed and task-dependent. We also discuss neuronal selectivity in the eye and head coordinates. Finally, we propose that future studies should focus on investigating both intrinsic and extrinsic population activity and examining spatial coding properties in large-scale hippocampal-neocortical networks across tasks.

Floor Maze Test is capable of differentiating spatial navigation between frail and pre-frail institutionalized older persons / Floor Maze Test é capaz de diferenciar a navegação espacial entre idosos institucionalizados frágeis e pré-frágeis

ABSTRACT. Investigation of the association between physical frailty and cognitive performance through spatial navigation is important to enable the identification of individuals with cognitive impairment and physical comorbidity. Objective: To analyze the association between spatial navigation and frailty in frail and pre-frail institutionalized older adults. Methods: Forty older people of both sexes, aged 60 years or over, residing in four Brazilian Long-Term Care Facilities (LTCFs) participated in this study. The following tests were applied: Mini-Mental State Examination (MMSE), 2.44m Timed Up and Go, Floor Maze Test (FMT), and Fried's frailty criteria. For data analysis, the Mann-Whitney and independent t-tests were used to compare the groups (frail x pre-frail), principal component analysis was used to explore the main variables related to the data variance, and binary logistic regression to estimate associations. Results: There was a significant difference in performance in the FMT immediate maze time (IMT) (p=0.02) and in the delayed maze time (DMT) (p=0.009) between the pre-frail and frail older adults. An association between FMT DMT performance and frailty was found, showing that older people with shorter times on the DMT (better performance) had approximately four times the chance of not being frail (odds ratio - OR=4.219, 95% confidence interval - 95%CI 1.084-16.426, p=0.038). Conclusion: Frailty is associated with impaired spatial navigation ability in institutionalized older adults, regardless of gait speed performance.

RESUMO. A investigação da associação entre fragilidade física e desempenho cognitivo por meio da navegação espacial é importante para possibilitar a identificação de indivíduos com déficit cognitivo e comorbidade física. Objetivo: Analisar a associação entre navegação espacial e fragilidade em idosos institucionalizados frágeis e pré-frágeis. Métodos: Participaram deste estudo 40 idosos de ambos os sexos, com idade igual ou superior a 60 anos, residentes em quatro instituições de longa permanência (ILPI) brasileiras. Foram aplicados os seguintes testes: Miniexame do Estado Mental (MEEM), 2,44m Timed Up and Go, Floor Maze Test (FMT) e os critérios de fragilidade de Fried. Para a análise dos dados, foram utilizados os testes t independente e de Mann-Whitney para comparar os grupos (frágeis x pré-frágeis), foi feita análise de componentes principais para explorar as principais variáveis relacionadas à variância dos dados e regressão logística binária para estimar associações. Resultados: Houve diferença significativa no desempenho do FMT no tempo imediato do labirinto (TIL) (p=0,02) e no tempo posterior do labirinto (TPL) (p=0,009) entre os idosos pré-frágeis e frágeis. Encontrou-se associação entre o desempenho no FMT TPL e fragilidade, mostrando que idosos com menor tempo de TPL (melhor desempenho) tiveram aproximadamente quatro vezes mais chance de não serem frágeis (odds ratio - OR=4,219, intervalo de confiança de 95% - IC95% 1,084-16,426, p=0,038). Conclusão: A fragilidade está associada à habilidade de navegação espacial prejudicada em idosos institucionalizados, independentemente do desempenho da velocidade da marcha.

Correlation between global burden of small vessel disease on MRI and impaired spatial navigation in patients with cerebral small vessel disease / 国际脑血管病杂志

Objective:To investigate the correlation between global burden of small vessel disease(CSVD) on MRI and impaired spatial navigation in patients with CSVD.Methods:Patients with CSVD admitted to the Department of Neurology, Nanjing Jiangning Hospital from November 2020 to June 2022 were selected as the research subjects. The global burden of CSVD was scored according to the head MRI findings, and was divided into mild group (0-1 points), moderate group (2 points), and severe group (3-4 points). All patients were tested for spatial navigation function. Multivariate linear regression model was used to analyze the correlation between the global burden of CSVD and the spatial navigation function.Results:A total of 101 patients with CSVD were enrolled, including 37 patients in the mild group (36.6%), 28 in the moderate group (27.7%), and 36 in the severe group (35.6%). Age, glycosylated hemoglobin, total cholesterol, low-density lipoprotein cholesterol and creatinine, as well as the proportions of hypertension, diabetes, previous stroke or transient ischemic attack in the moderate group and the severe group were significantly higher than those in the mild group, while the high-density lipoprotein cholesterol was significantly lower than that in the mild group (all P<0.05). The spatial navigation function test showed that the environment + self-navigation, self-navigation and environment navigation functions of the moderate group and the severe group decreased significantly compared with the mild group (all P<0.05). Multivariate linear regression analysis showed that after adjusting for age, sex, hypertension, previous stroke or transient ischemic attack history and years of education, the global burden of CSVD and environment + self-navigation ( β=0.518, P<0.001), self-navigation ( β=0.481, P<0.001) and environmental navigation ( β=0.699, P<0.001) function had significant correlation. Conclusion:The global burden of CSVD is correlated with spatial navigation functions.

Spatial orientation tasks show moderate to high accuracy for the diagnosis of mild cognitive impairment: a systematic literature review / Tarefas de orientação espacial têm acurácia moderada a alta para o diagnóstico de comprometimento cognitivo leve: uma revisão sistemática

Abstract Spatial disorientation has been observed in mild cognitive impairment (MCI) and is associated with a higher risk of progression to Alzheimer's disease (AD). However, there is no gold standard assessment for spatial orientation and paper-and-pencil tests lack ecological validity. Recently, there has been an increasing number of studies demonstrating the role of spatial disorientation as a cognitive marker of pathological decline, shedding new light on its importance for MCI. This systematic review aimed to investigate the accuracy of spatial orientation tasks for the diagnosis of MCI by comparison with cognitively healthy elderly. The search was conducted in the databases Medical Literature Analysis and Retrieval System Online (MEDLINE/PubMed), Web of Science, Scopus, Excerpta Medica Database (Embase), Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs) and Scientific Electronic Library Online (SciELO). Only original studies reporting spatial orientation assessment in MCI patients compared to a healthy control group were included. Studies were excluded if the MCI classification did not follow well described criteria and/or if accuracy results of spatial orientation assessment were not provided. Seven studies met the eligibility criteria, describing a variety of spatial orientation assessments including questionnaires, paper-and-pencil, office-based route learning, and computer-based and virtual reality tasks. Spatial orientation tasks demonstrated moderate to high accuracy in detecting elderly with MCI compared to cognitively healthy elderly, with areas under the curve (AUC) ranging from 0.77 to 0.99. However, important methodological issues were found in the selected studies which should be considered when interpreting results. Although the inclusion of spatial orientation assessments in MCI evaluations seems to have significant value, further studies are needed to clarify their true capacity to distinguish pathological from non-pathological aging.

RESUMO A ocorrência de desorientação espacial foi observada no comprometimento cognitivo leve (CCL) e está associada a um maior risco de progressão para a doença de Alzheimer (DA). No entanto, não há um padrão ouro para avaliação da orientação espacial e os testes em papel e caneta não apresentam validade ecológica. Recentemente, um número cada vez maior de estudos têm apontado o papel da desorientação espacial como um marcador cognitivo do declínio patológico, lançando uma nova luz sobre sua importância para o CCL. Esta revisão sistemática teve como objetivo investigar a acurácia de tarefas de orientação espacial para se estabelecer o diagnóstico de CCL entre idosos cognitivamente saudáveis. A pesquisa foi realizada através das bases de dados Medline/PubMed, Web of Science, Scopus, Embase, Lilacs e Scielo. Apenas artigos originais que reportassem avaliação da orientação espacial em idosos CCL comparados a um grupo controle saudável foram incluídos. Foram excluídos os estudos que não utilizassem a classificação de CCL segundo critérios bem descritos e/ou que não reportassem resultados de acurácia da avaliação da orientação espacial. Sete estudos atenderam aos critérios de elegibilidade, descrevendo uma variedade de formas de avaliação da orientação espacial, incluindo questionários, tarefas em papel e lápis, tarefas de aprendizado de rotas no escritório, tarefas baseadas em computador e com realidade virtual. As tarefas de orientação espacial demonstraram acurácia moderada a alta na detecção de CCL em comparação com idosos cognitivamente saudáveis, com áreas sob a curva (area under the curve — AUC) variando de 0,77 a 0,99. No entanto, um viés metodológico importante foi identificado nos estudos selecionados, o que deve ser levado em consideração na interpretação dos resultados. Apesar da inclusão da orientação espacial na avaliação cognitiva em CCL parecer ter um valor significativo, mais estudos são necessários para esclarecer sua verdadeira capacidade de distinguir o envelhecimento patológico do não patológico.

The parietal association cortex of the rat

Spatial cognition is a complex higher function in mammals and is involved in a variety of tasks that can be explored in the laboratory. In this review we will discuss the role of the posterior parietal/anteromedial cortex of rodents, also known as the parietal association cortex, and the hippocampal formation in spatial navigation. We will also discuss other higher associational functions of the posterior parietal/anteromedial cortex as they relate to Dr. Pinto-Hamuy's contribution to understanding behavioral functions.