RESUMO

In this systematic review and meta-analysis, we compared the spatial navigation performance of older adults with mild cognitive impairment (MCI), Alzheimer's Disease (AD), and other dementias, using healthy older adults as controls. In addition, we evaluated the possible influence of the environment type (virtual and real), protocol (object- or environment-based), and the navigation mode (active and passive navigation) on spatial navigation task performance. In total, 1372 articles were identified and 24 studies were included in the meta-analysis. We found a large effect size on the spatial navigation performance of patients with cognitive decline (standardized mean difference (SMD) = 0.87, confidence interval (CI95%) = 0.62-1.09, p < 0.001), especially amnestic MCI (SMD = 1.10, CI95% = 0.71-1.49, p < 0.001) and patients with AD (SMD = 1.60, CI95% = 1.25-1.95, p < 0.001). However, the tasks did not identify mixed and vascular dementia (SMD = 0.92, CI95% = -0.33-2.18, p = 0.15 and SMD = 0.65, CI95% = -0.67-1.97, p = 0.33, respectively). Spatial navigation ability assessed using the Floor Maze Test showed the largest effect size in differentiating healthy older adults and patients with cognitive decline (SMD = 1.98,CI95% = 1.00-2.97, p < 0.001). In addition, tasks that require walking showed the greatest differences between the two groups. These results suggest that spatial navigation impairment is important, but disease-specific behavioral biomarker of the dementia pathology process that can be identified even in the early stages.

Assuntos

RESUMO

How do animals adopt a given behavioral strategy to solve a recurrent problem when several effective strategies are available to reach the goal? Here we provide evidence that striatal cholinergic interneurons (SCINs) modulate their activity when mice must select between different strategies with similar goal-reaching effectiveness. Using a cell type-specific transgenic murine system, we show that adult SCIN ablation impairs strategy selection in navigational tasks where a goal can be independently achieved by adopting an allocentric or egocentric strategy. SCIN-depleted mice learn to achieve the goal in these tasks, regardless of their appetitive or aversive nature, in a similar way as controls. However, they cannot shift away from their initially adopted strategies, as control mice do, as training progresses. Our results indicate that SCINs are required for shaping the probability function used for strategy selection as experience accumulates throughout training. Thus, SCINs may be critical for the resolution of cognitive conflicts emerging when several strategies compete for behavioral control while adapting to environmental demands. Our findings may increase our understanding about the emergence of perseverative/compulsive traits in neuropsychiatric disorders with a reported SCIN reduction, such as Tourette and Williams syndromes.SIGNIFICANCE STATEMENT Selecting the best suited strategy to solve a problem is vital. Accordingly, available strategies must be compared across multiple dimensions, such as goal attainment effectiveness, cost-benefit trade-off, and cognitive load. The striatum is involved in strategy selection when strategies clearly diverge in their goal attainment capacity; however, its role whenever several strategies can be used for goal reaching-therefore making selection dependent on additional strategy dimensions-remains poorly understood. Here, we show that striatal cholinergic interneurons can signal strategy competition. Furthermore, they are required to adopt a given strategy whenever strategies with similar goal attainment capacity compete for behavioral control. Our study suggests that striatal cholinergic dysfunction may result in anomalous resolution of problems whenever complex cognitive valuations are required.

Assuntos

RESUMO

Although normal aging has been related to several cognitive difficulties, other processes have been studied less, such as spatial memory. Our aim was to compare egocentric and allocentric memory in an elderly population using ecological tasks. Twenty-eight cognitively unimpaired participants performed Egocentric and Allocentric Spatial Memory Tasks, as well as Spatial Span from CANTAB, Benton's Judge of Line Orientation test (JoLO), and Montreal Cognitive Assessment test (MoCA). The results revealed that younger participants showed better performance than older participants on both the Egocentric and Allocentric Spatial Memory Tasks, although only the Egocentric test was able to discriminate between younger, middle, and older elderly participants. Learning effect was found in Allocentric Spatial Memory Task in younger and older groups, but not in the middle group. Allocentric and egocentric performance was not related to other visuospatial neuropsychological scores and gender did not influence performance in any task. Egocentric and Allocentric Spatial Memory Tasks may be useful tools in early screening for cognitive decline, as they are able to detect age differences in the cognitive unimpaired elderly population.

Assuntos

RESUMO

Spatial orientation is emerging as an early and reliable cognitive biomarker of Alzheimer's disease (AD) pathophysiology. However, no evidence exists as to whether spatial orientation is also affected in vascular dementia (VaD). OBJECTIVE: To examine allocentric (map-based) and egocentric (viewpoint-based) spatial orientation in an early stage VaD case. METHODS: A spatial test battery was administered following clinical and neuropsychological cognitive evaluation. RESULTS: Despite the patient's complaints, little evidence of episodic memory deficits were detected when cueing was provided to overcome executive dysfunction. Similarly, medial temporal lobe-mediated allocentric orientation was intact. By contrast, medial parietal-mediated egocentric orientation was impaired, despite normal performance on standard visuospatial tasks. CONCLUSION: To our knowledge, this is the first in-depth investigation of spatial orientation deficits in VaD. Isolated egocentric deficits were observed. This differs from AD orientation deficits which encompass both allocentric and egocentric orientation deficits. A combination of egocentric orientation and executive function tests could serve as a promising cognitive marker for VaD pathophysiology.

A orientação espacial está emergindo como um biomarcador cognitivo precoce e confiável da fisiopatologia da doença de Alzheimer (DA). No entanto, não existe evidência de que a orientação espacial também seja afetada na demência vascular (DVa). OBJETIVO: Examinar a orientação espacial alocêntrica (baseada em mapas) e egocêntrica (baseada no ponto de vista) em um caso de DVa em fase incial. MÉTODOS: Uma bateria de testes espaciais foi administrada após avaliação clínica e neuropsicológica cognitiva. RESULTADOS: Apesar das queixas do paciente, poucas evidências de déficits de memória episódica foram detectadas quando foram fornecidas pistas para superar a disfunção executiva. Da mesma forma, a orientação alocêntrica mediada pelo lobo temporal medial estava intacta. Em contrapartida, a orientação egocêntrica mediada pela região parietal medial estava comprometida, apesar do desempenho normal em tarefas visuoespaciais padrão. CONCLUSÃO: Pelo nosso conhecimento, esta é a primeira investigação aprofundada dos déficits de orientação espacial na DVa. Foram observados déficits egocêntricos isolados. Isso difere dos déficits de orientação da DA que abrangem déficits de orientação alocêntricos e egocêntricos. Uma combinação de orientação egocêntrica e testes de função executiva poderia servir como um marcador cognitivo promissor para a fisiopatologia de DVa.

RESUMO

ABSTRACT Spatial orientation is emerging as an early and reliable cognitive biomarker of Alzheimer's disease (AD) pathophysiology. However, no evidence exists as to whether spatial orientation is also affected in vascular dementia (VaD). Objective: To examine allocentric (map-based) and egocentric (viewpoint-based) spatial orientation in an early stage VaD case. Methods: A spatial test battery was administered following clinical and neuropsychological cognitive evaluation. Results: Despite the patient's complaints, little evidence of episodic memory deficits were detected when cueing was provided to overcome executive dysfunction. Similarly, medial temporal lobe-mediated allocentric orientation was intact. By contrast, medial parietal-mediated egocentric orientation was impaired, despite normal performance on standard visuospatial tasks. Conclusion: To our knowledge, this is the first in-depth investigation of spatial orientation deficits in VaD. Isolated egocentric deficits were observed. This differs from AD orientation deficits which encompass both allocentric and egocentric orientation deficits. A combination of egocentric orientation and executive function tests could serve as a promising cognitive marker for VaD pathophysiology.

RESUMO A orientação espacial está emergindo como um biomarcador cognitivo precoce e confiável da fisiopatologia da doença de Alzheimer (DA). No entanto, não existe evidência de que a orientação espacial também seja afetada na demência vascular (DVa). Objetivo: Examinar a orientação espacial alocêntrica (baseada em mapas) e egocêntrica (baseada no ponto de vista) em um caso de DVa em fase incial. Métodos: Uma bateria de testes espaciais foi administrada após avaliação clínica e neuropsicológica cognitiva. Resultados: Apesar das queixas do paciente, poucas evidências de déficits de memória episódica foram detectadas quando foram fornecidas pistas para superar a disfunção executiva. Da mesma forma, a orientação alocêntrica mediada pelo lobo temporal medial estava intacta. Em contrapartida, a orientação egocêntrica mediada pela região parietal medial estava comprometida, apesar do desempenho normal em tarefas visuoespaciais padrão. Conclusão: Pelo nosso conhecimento, esta é a primeira investigação aprofundada dos déficits de orientação espacial na DVa. Foram observados déficits egocêntricos isolados. Isso difere dos déficits de orientação da DA que abrangem déficits de orientação alocêntricos e egocêntricos. Uma combinação de orientação egocêntrica e testes de função executiva poderia servir como um marcador cognitivo promissor para a fisiopatologia de DVa.

Assuntos

RESUMO

Este manuscrito estudia el sentido de orientación de las personas en situaciones en que existe información de tipo contextual, que permite a las personas a ver locaciones muy distantes. Para ello se preguntó a 133 individuos indicar la ubicación de cinco hitos próximos y lejanos de la ciudad de Valparaíso, en 2 situaciones distintas: miradores urbanos y lugares en el medio de la trama urbana en el que la visión de información contextual no es posible. Los resultados mostraron que no existía una asociación entre la Precisión Promedio por Persona y el sexo, edad, o el grado familiaridad, pero que sí con el lugar donde se habían hecho estas estimaciones.

This manuscript examines how people gain a sense of orientation in scenarios where large-scale, contextual information is available. Two locations of the city of Valparaiso where one can see the entire city from the heights were selected for an experiment, as well as two areas in the middle of the urban grid where no large-scale information was available. A total of 133 people were asked to point to five non-visible landmarks in these scenarios and their estimations were compared with the real position of each target. Results showed no association between this value and people's gender, age or familiarity with the neighborhood. However, a positive relationship was found between this value and the places in which estimates were made.

Assuntos

RESUMO

Este manuscrito estudia el sentido de orientación de las personas en situaciones en que existe información de tipo contextual, que permite a las personas a ver locaciones muy distantes. Para ello se preguntó a 133 individuos indicar la ubicación de cinco hitos próximos y lejanos de la ciudad de Valparaíso, en 2 situaciones distintas: miradores urbanos y lugares en el medio de la trama urbana en el que la visión de información contextual no es posible. Los resultados mostraron que no existía una asociación entre la Precisión Promedio por Persona y el sexo, edad, o el grado familiaridad, pero que sí con el lugar donde se habían hecho estas estimaciones.(AU)

This manuscript examines how people gain a sense of orientation in scenarios where large-scale, contextual information is available. Two locations of the city of Valparaiso where one can see the entire city from the heights were selected for an experiment, as well as two areas in the middle of the urban grid where no large-scale information was available. A total of 133 people were asked to point to five non-visible landmarks in these scenarios and their estimations were compared with the real position of each target. Results showed no association between this value and people's gender, age or familiarity with the neighborhood. However, a positive relationship was found between this value and the places in which estimates were made.(AU)

Assuntos