ABSTRACT
Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive impairment, with the predominant clinical diagnosis of spatial working memory (SWM) deficiency, which seriously affects the physical and mental health of patients. However, the current pharmacological therapies have unsatisfactory cure rates and other problems, so non-pharmacological physical therapies have gradually received widespread attention. Recently, a novel treatment using 40 Hz light flicker stimulation (40 Hz-LFS) to rescue the cognitive function of model animals with AD has made initial progress, but the neurophysiological mechanism remains unclear. Therefore, this paper will explore the potential neural mechanisms underlying the modulation of SWM by 40 Hz-LFS based on cross-frequency coupling (CFC). Ten adult Wistar rats were first subjected to acute LFS at frequencies of 20, 40, and 60 Hz. The entrainment effect of LFS with different frequency on neural oscillations in the hippocampus (HPC) and medial prefrontal cortex (mPFC) was analyzed. The results showed that acute 40 Hz-LFS was able to develop strong entrainment and significantly modulate the oscillation power of the low-frequency gamma (lγ) rhythms. The rats were then randomly divided into experimental and control groups of 5 rats each for a long-term 40 Hz-LFS (7 d). Their SWM function was assessed by a T-maze task, and the CFC changes in the HPC-mPFC circuit were analyzed by phase-amplitude coupling (PAC). The results showed that the behavioral performance of the experimental group was improved and the PAC of θ-lγ rhythm was enhanced, and the difference was statistically significant. The results of this paper suggested that the long-term 40 Hz-LFS effectively improved SWM function in rats, which may be attributed to its enhanced communication of different rhythmic oscillations in the relevant neural circuits. It is expected that the study in this paper will build a foundation for further research on the mechanism of 40 Hz-LFS to improve cognitive function and promote its clinical application in the future.
Subject(s)
Humans , Adult , Rats , Animals , Memory, Short-Term/physiology , Rats, Wistar , Neurodegenerative Diseases , Hippocampus , Prefrontal CortexABSTRACT
OBJECTIVES: The aim of this study was to develop auditory-verbal and visual-spatial memory tasks using smart devices for children aged 8 to 10 years and examine their validity. METHODS: One-hundred and fourteen school-aged children were recruited through internet advertising. We developed memory tasks assessing auditory-verbal memory, visual-spatial memory, and working memory, and then examined their construct validity by examining the developmental trend of the children's mean scores with age. In order to examine the concurrent validity of the tasks, we conducted correlation analyses between the children's scores on the newly developed auditory-verbal, visual-spatial memory and working memory tasks and their scores on well-known standardized tests of memory and working memory, including the auditory-verbal memory subtests of the Korean Luria-Nebraska Neuropsychological Battery for Children, Korean Rey-Osterrieth Complex Figure Test, digit span and arithmetic subtest of Korean Educational Development Institute Wechsler Intelligence Scale for Children Revised, and Corsi block test. RESULTS: The memory and working memory scores measured by the newly developed tasks tended to increase with age. Further, there were significant correlations between the scores of the four cognitive tasks and the corresponding scores of the standardized assessment tools. CONCLUSION: This study revealed promising evidence for the validity of the memory tasks using smart devices, suggesting their utility for school-aged children in research and clinical settings.
Subject(s)
Child , Humans , Intelligence , Internet , Luria-Nebraska Neuropsychological Battery , Memory , Memory, Short-TermABSTRACT
Objective To explore the changes of different brain regions of the human beings during completion of spatial working memory tasks under hyperthermia condition with functional magnetic yesonance.Methods Twenty-eight right-handed healthy young male volunteers were divided into control group and hyperthermia group randomly,and working memory task using block design was performed during behavioral test and fMRI scanning on both conditions.Activation intensity and location of different brain areas were compared in control and hyperthermia group.Results The activations of frontal,parietal,occipital and insular lobe were seen in both of the control group and the hyperthermia group.Right lateralization was shown in control group during spatial working memory (Li=0.05 1).While,in hyperthermia group the effect of the right lateralization significantly was enhanced (Li=0.103). Moreover,activation of bilateral middle frontal gyrus and right parietal lobe were significantly enhanced.Conclusion It is found for the first time that the hyperthermia could affect bilateral middle frontal gyrus and right parietal lobe,and enhance the effect of right lateralization in the spatial working memory task.
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Objective To investigate the difference of spatial working memory among first-episode patients with deficit and nondeficit schizophrenia. Methods The study recruited 116 first-episode treatment-naive patients with schizo-phrenia, and 60 normal controls. Positive and Negative Syndrome Scale (PANSS) was used to assess symptoms of patients and Schedule for the Deficit Syndrome (SDS) was used to divide schizophrenia patients into deficit group (28 patients) and nondeficit group (88 patients). Spatial Working Memory (SWM) test from the Cambridge Neuropsychological Test Automat-ed Battery (CANTAB) was used to test the spatial working memory function. Results Adjusted for age, gender and years of education, there were significant differences in the performance of between errors of 4 boxes (P=0.03), between errors of 6 boxes (P=0.01), between errors of 8 boxes (P=0.03), total errors (P=0.01) and strategy (P0.05). Conclusion The impairment of SWM was more severe in deficit schizophrenia patients than in nondeficit patients at early stage of the disease, suggesting they are different subtypes of schizophrenia.
ABSTRACT
La memoria de trabajo es un sistema neuro-conductual en el que participan la memoria a corto y a largo plazo, la orientación espacial, la planeación y la ejecución de tareas espaciales y lingüísticas, la adaptación social, las operaciones cognitivas complejas y los logros académicos, y que se ha utilizado para estudiar los cambios cognitivos asociados al envejecimiento. Objetivo. Explorar en ratas Wistar si existe deterioro progresivo de la memoria de trabajo, dependiente de la edad. Materiales y métodos. Se utilizaron 11 ratas Wistar, hembras, divididas en tres grupos: 3 jóvenes de 7 a 14 meses de edad, 4 adultas de 16 a 20 meses de edad, y 4 viejas de 25 a 30 meses de edad. Se estructuró un diseño bifactorial de medidas repetidas y se utilizó una caja de agujeros, en la que los sujetos debían obtener comida, seleccionando 4 de 16 comederos durante 99 ensayos. Resultados. Los animales viejos mostraron gran variabilidad interindividual en los resultados. No se encontró curva de deterioro dependiente de la edad. Algunos animales viejos obtuvieron mejor puntaje en el aprendizaje y en el desarrollo de la memoria de trabajo. Las ratas jóvenes alcanzaron el criterio de memoria entre la tercera y la cuarta sesión, las adultas, a partir de la decimoquinta, y las ratas viejas, entre la séptima y la novena; las diferencias debidas a la edad fueron estadísticamente significativas, con a £ 0.001, con un tamaño del efecto h2 de 0,403 y una potencia estadística de 1,0 Conclusión. No se encontró evidencia de deterioro progresivo de la memoria de trabajo, dependiente del envejecimiento en la rata Wistar.
Working memory is a neuro-behavioral system in which short- and long-term memory, spatial orientation, some executive functions, social adaptation, complex cognitive tasks, and academic achievements participate. All of these have been utilized in aging cognitive changes studies. Objective: To explore progressive working memory deterioration, depending on aging, in Wistar rats. Materials and methods: There were 11 female Wistar rats divided in 3 groups: 3 young, 4 adults and 4 elder. A bifactorial repeated-measures design was structured. It was used a hole-board, where subjects had to obtain food, selecting always 4 between 16 feeders. throughout 99 trials. Results: There was not any aging dependent progressive working memory deterioration. Youngest subjects reached learning and working memory criteria between the third and the fourth session; the adult subjects reached them at the fifteenth session. Elderly subjects reached working memory between the seventh and the ninth session. Differences due to age were statistically significant with £ = 0.001, an effect strength h2 = 0.403 and a statistical power of 1.0. Conclusion: There is no evidence of spatial working memory progressive deterioration, depending on aging.
Subject(s)
Aging/psychology , Memory/physiology , Rats, WistarABSTRACT
Objective To explore visual-spatial working memory deficits of patients with basal ganglia damage, based on which tried to provide the new method for detecting the injuries in basal ganglia. Methods Twenty-five patients with lesions in the basal ganglia and twenty-five healthy controls performed visual-spatial working memory tasks, including a face-recognition and a spatial delayed-response. Results For the basal ganglia damage group ,the correct rate of both visual- face ( 54.5 ± 9.6 ) % and visual-spatial ( 80.0 ± 11.7 ) % working memory tasks was significantly lower than that of the control group ( ( 64.3 ± 9.5 ) %, ( 93.6 ± 4.9) %, respectively) ,and the difference was statistically significant ( u= - 147.5,80.5, P＜0. 01 ). For the patients injured in the left basal ganglia, the correct rate of visual- face working memory (48.5 ± 5.4 )% was obviously lower than that of patients injured in the right basal ganglia ( 59.2 ± 9.8 ) %, and the difference was statistically significant ( u =25.5, P＜0. 01 ) ;but the difference of correct rate for the visual-space working memory was not statistically significant( u = 52.5, P＞ 0.05 ). In contrast to the controls, both the visual-face and visual-space working memory of the group with injuries in basal ganglia,had appeared to be disable. Conclusions The results confirmed that patients with lesions in basal ganglia had deficits of visual-spatial working memory,and that injuries either in the left or the right basal ganglia can probably cause the shiftiness of cognitive function. Therefore, the injuries in basal ganglia can be detected by the visual-spatial working memory tests.
ABSTRACT
Topographical disorientation (TD) has not been as extensively studied as other frequent manifestations of Alzheimer's disease (AD). OBJECTIVE: To verify the occurrence of TD and to identify the neuropsychological dysfunctions associated with TD in AD. METHOD: Thirty patients with probable AD, their caregivers and 30 subjects without dementia (controls) were interviewed with a questionnaire and evaluated with tests related to topographical orientation. RESULTS: AD patients, even those with mild dementia, differ from controls in the questionnaire on topographical orientation and in most neuropsychological tests except for tests of spatial working memory, point localization, three dimension and nonsense figure copy. When the performances in the neuropsychological tests of patients with mild or moderate dementia were compared, only landmark recognition and route description were more impaired in moderate dementia. CONCLUSION: TD occurs even in mild dementia of AD, a finding apparently not explained by the impairments of more elementary spatial functions.
Desorientação topográfica (DT) não tem sido tão exaustivamente estudada quanto outros sintomas frequentes da doença de Alzheimer (DA). OBJETIVO: Verificar a ocorrência de DT e identificar as disfunções neuropsicológicas associadas com a DT na DA. Método: Trinta pacientes com DA provável, seus cuidadores e trinta sujeitos sem demência (controles) foram entrevistados com um questionário e testes relacionados à orientação topográfica. RESULTADOS: Pacientes com DA, mesmo aqueles com demência leve, diferiram dos controles no questionário de orientação topográfica e na maioria dos testes neuropsicológicos, exceto nos testes memória operacional espacial, localização de pontos, cópia de figuras sem sentido e de figura em três dimensões. Quando os desempenhos de pacientes com demência leve ou moderada foram comparados, apenas os testes de reconhecimento de marcos e descrição de rotas foram mais comprometidos na demência moderada. CONCLUSÃO: DT ocorre mesmo na demência leve da DA, um achado aparentemente não explicado pelo comprometimento das funções espaciais mais elementares.
Subject(s)
Aged , Female , Humans , Male , Alzheimer Disease/complications , Confusion/etiology , Orientation/physiology , Spatial Behavior/physiology , Alzheimer Disease/physiopathology , Case-Control Studies , Educational Status , Neuropsychological Tests , Surveys and QuestionnairesABSTRACT
BACKGROUND: Graphesthesia is the ability to recognize letters or symbols via somatic sensation. We employed functional MRI to determine neurological substrates underlying this ability. We also designed a behavioral experiment to examine the relationship between graphesthesia and working memory. METHODS: Images were acquired in a 1.5T scanner from ten right-handed normal subjects while tactile stimulation was applied for either graphesthesia or simple sensation. Additional eight right-handed normal observers participated in the behavioral experiment where they performed a visuo-spatial or a verbal working memory task, simultaneously with graphesthesia. Overall performance times were measured to detect interference in the dual-task situations. RESULTS: Comparison between graphesthesia and simple sensory stimulation revealed activations at bilateral prefrontal, parietal and superior temporal cortices, regardless of the hand stimulated. The right parietal operculum was activated for both hand conditions, while the corresponding area in the left hemisphere was activated by right-hand stimulation only, suggesting a right-hemisphere dominance for graphesthesia. From the behavioral experiments, we observed that the visuo-spatial task, but not the verbal task, interfered with graphaesthesia. CONCLUSIONS: Taken together, these results suggest that the brain areas underlying the visuo-spatial sub-system of working memory are involved in graphesthesia and that some cognitive processes underlying graphesthesia are right-lateralized.