Bases anatomiques de la mémoire

Résumé Les données cliniques et anatomo-pathologiques ont permis de suggérer le rôle du circuit hippocampo-mamillo-thalamique dans certains processus mnésiques. Récemment des critiques ont été apportées mettant en cause le rôle même de ce circuit et impliquant d'autres formations: hile du lobe temporal; noyau médio-dorsal du thalamus, amygdale. L'étude des relations anatomiques précises du circuit hippocampo-mamillo-thalamique permet de montrer l'importance dans le circuit lui-même de certaines formations comme le subiculum et l'aire entorhinale. Par ailleurs, ce circuit s'intègre totalement au sein du système limbique au sens large, tel que l'a défini Nauta (1961) et par là à des structures comme l'amygdale, le noyau médio-dorsal du thalamus, le cortex orbito-frontal, le septum et la réticulée mésencéphalique.Mais au sein même de ce système limbique, il semble exister une spécificité de relation des éléments en rapport avec le circuit hippocampo-mamillo-thalamique.Enfin, le circuit HMT ne peut pas se concevoir comme restreint au système limbique. Il est en relation étroite avec l'ensemble du cortex et particulièrement avec le cortex frontal, ce que rappellent les désordres mnésiques entraînés par les lésions de cette région.Le circuit HMT n'est donc pas la mémoire mais reste un modèle et un point de départ utile sinon indispensable dans son étude.     

人体背部云纹的测量方法、正常值及临床意义

本文对人体背部云纹提出了新的计算方法。根据161例正常人背部云纹图表现,把后视图分为中线型及偏离型;侧视图分为重合型、分离型、重合分离无交叉型及重合分离交叉型。并经统计学处理求得了其偏离及分离间距的平均值和正常值范围。从而对背部云纹变形程度提供了观察指标,对影像云纹在临床上的应用进行了初步的探讨。     

基于云纹干涉与钻孔法的等离子热障涂层残余应力实验研究

应用云纹干涉法与钻孔法结合的光测力学实验方法,研究了等离子热障涂层基体材料镍基高温合金DZ125的残余应力。通过实验和计算获得了等离子喷涂工艺下基体DZ125的残余变形场、残余应变场和残余应力,并描述了其主要特征。结果表明,采用云纹干涉法与钻孔法结合测定热障涂层残余应力具有全场测量和高灵敏度等优点,这对于采用光学手段研究热障涂层残余应力有着积极的意义。     

Standardization of the 5-word test in a group of 191 normal subjects aged 50 to 90 years

INTRODUCTION: The 5-word test (5WT) is a serial verbal memory test with semantic cuing. It allows to estimate cued learning, free recall, and cued recall of 5 words during immediate and delayed recalls (5 min later). The 5WT is proposed to rapidly evaluate memory of aging people. It has shown its sensitivity and its specificity in identifying patients with Alzheimer's disease (AD). OBSERVATIONS: We report the constitution of a sample of 191 French speaking normal subjects, aged from 50 to 90 years, in four age classes (50 years, 60 years, 70 years, 80 years) and three education levels. Total Score, Total Weighted Score, Free Delayed Recall, Delayed Recalls Total (memory score), and Free Recalls Total appear to be the best scores to appreciate the memory performance of the normal subjects. A Total Score of 10 was obtained in 74.9 p.cent of the subjects. No immediate nor delayed intrusions were recorded. In spite of the absence of an explicit consign, the recalled words were often ordered as they were in the list. CONCLUSION: The 5WT is a simple and reliable test for investigating memory in elderly people above 50 years old.     

An odd manifestation of the Capgras syndrome: Loss of familiarity even with the sexual partner

We report the case of a patient who presented visual hallucinations and identification disorders associated with a Capgras syndrome. During the Capgras periods, there was not only a misidentification of his wife's face, but also a more global perceptive and emotional sexual identification disorder. Thus, he had sexual intercourse with his wife's "double" without having the slightest recollection feeling of familiarity towards his "wife" and even changed his sexual habits. To the best of our knowledge, he is the only neurological patient who made his wife a mistress. Starting from this global familiarity loss, we discuss the mechanism of Capgras delusion with reference to the role of the implicit system of face recognition. Such behavior of familiarity loss not only with face but also with all intimacy aspects argues for a specific disconnection between the ventral visual pathway of face identification and the limbic system involved in emotional and episodic memory contents.     

Assessment of neuropsychological impairments in regular cannabis users

BackgroundCannabis is the most widely used illicit drug in the world. It is responsible for cognitive dysfunction of memory, speed of information processing, attention, and executive functions. Cognitive performance depends on the level of study, tolerance, and duration of abstinence from cannabis use. This study analyses cognitive function in a large population of regular cannabis consumers taking into account level of education.MethodsA battery of neuropsychological tests using the Cambridge Neuropsychological Test Automated Battery was performed on a population of 58 cannabis users categorized into two groups according to their level of education with a threshold of 12 years of study, and 25 non-users.ResultsIn Attention Switching Task percent correct trials, significant differences were found between the group of cannabis smokers with less than 12 years of study and the non-smoker group (P = 0.022), and between the cannabis users with more than 12 years of study and the non-smoker group (P = 0.008). A significantly lower performance in the Rapid Visual Information Processing (Mean latency, Probability of hit, Total hits, Total misses, Correct rejections) was found in the cannabis users with less than 12 years of study compared with the non-user group.ConclusionIn our population, chronic cannabis users presented divided and sustained attention and working memory disorders. Rapid Visual Information Processing performance may be influenced by education level in cannabis smokers.     

Le dilemme du réfugié

The experiences of trauma, displacement, and forced migration faced by refugees raise profound questions about the relationship of self and community. This article explores some ways in which the intrapsychic dynamics of refugees' suffering and remembering interact with the larger social dynamics of refugee communities and host societies. The narrative construction of the self constitutes the pivot between the realms of the social and the psychological and rests on cultural meta-narratives. In Euro-American folk psychology two of the meta-narratives or concepts of the self can be compared in terms of their root metaphors: the adamantine self, characterized by its integrity, coherence, autonomy, self-definition, self-determination and self-control; and the transactional self, characterized by its fluidity, sensitivity to context, deference to authority, multivocality, deference and yielding to or accommodating others. These two accounts of the self shape how we view people who have suffered wrenching transformations of their worlds through violence, dislocation and loss. The changes produced through the therapeutic process can be understood as the development of a form of dialogue that is at once, within and without, personal and transcendental, rooted in communal tradition and in the open confrontation of the face of the other. The ethics of storytelling has its necessary counterpart in the ethics of listening, of witnessing and taking part in the creation of community through copresence.     

Nature and amplitude of the effects of acetoxycycloheximide on the retention of an instrumental task in mice (author's transl)

Mice injected subcutaneously with AXM (7 mg/kg) 60 minutes or less after acquisition of a nondiscriminative instrumental task, show low levels of lever press responding, when tested 6 days after the treatment. AXM injected 180 min after acquisition has no effect whatsoever on the performance. The analysis of various parameters such as, (1) the number of nonreinforced responses (A) preceding the first reinforced response (AR), and (2) the latency of the first reinforced response, shows that only the animals treated with AXM during the first 3 min following acquisition differ significantly from the control animals: they seem to have forgotten the significance of the lever. On the contrary, the low levels of responding observed in the animals treated 30–60 min after acquisition does not seem to be due to a nonretention of the significance of the liver. The mechanisms by which the AXM affects the level of responding remain obscure.     

Métamémoire, remémoration et familiarité dans la maladie d’Alzheimer

Introduction

The main objective of this review is to present a new approach to the memory deficit in Alzheimer's disease. Recent memory models suggest that information is recovered either on the basis of recollection or on the basis on familiarity. Recollection, unlike familiarity, requires the retrieval of contextual details related to the encoded information.

State of the art

This review suggests that recollection is particularly affected in Alzheimer's disease. In contrast, familiarity seems to be relatively preserved. A related deficit in metamemory is observed when recollection is required; a decrease in recollection in Alzheimer's disease could explain the pattern of metamemory problems. The deficit in recollection could be explained by a disconnection between medial temporal areas and frontal areas.

Perspectives

This novel approach to memory gives research perspectives concerning both early diagnosis and rehabilitation strategies of Alzheimer disease.

Conclusion

This overview showed deficits in conscious memory processes conceived of as recollection. These novel insights should provide new explanations for the deficits observed in Alzheimer's disease, particularly metamemory.