Aging, eye movements, and object-location memory

This study investigated whether "intentional" instructions could improve older adults' object memory and object-location memory about a scene by promoting object-oriented viewing. Eye movements of younger and older adults were recorded while they viewed a photograph depicting 12 household objects in a cubicle with or without the knowledge that memory about these objects and their locations would be tested (intentional vs. incidental encoding). After viewing, participants completed recognition and relocation tasks. Both instructions and age affected viewing behaviors and memory. Relative to incidental instructions, intentional instructions resulted in more accurate memory about object identity and object-location binding, but did not affect memory accuracy about overall positional configuration. More importantly, older adults exhibited more object-oriented viewing in the intentional than incidental condition, supporting the environmental support hypothesis.     

Incidental learning and memory for three basic tastes in food

Forty three subjects were invited under the pretence that they would take part in an experiment on hunger feelings. They came without having eaten anything that morning and received a standard breakfast containing orange juice, cream cheese on crackers and yoghurt. These products were later (when subjects returned after scoring hunger feelings during the day) used as targets amidst a set of distractors varied by adding or subtracting different amounts of two basic tastes. Orange juice was varied in sweetness and bitterness, cream cheese in sourness and bitterness and yoghurt in sweetness and sourness. The changes were made comparable by using just noticeable differences, determined in preliminary experiments with other subjects, as units of change. Two measurements of memory were compared, an absolute (indicating which were the targets) and a relative one (indicating whether the targets and distractors were more, less or equally pleasant, sweet, sour, bitter or salty as the item eaten at breakfast). Both methods showed incidental learning, but relative memory was superior. Memory differed between tastes and was partly product dependent. These experiments suggest that taste memory is tuned to detect novel and potentially dangerous stimuli rather than to remember features of earlier experienced stimuli with great precision.     

The effect of altered selenium and vitamin E nutritional status on learning and memory of third-generation rats

It has been proposed that selenium (Se) and Vitamin E (Vit E) are involved synergistically in protection of cell membrane lipids from peroxidation. However, little is known about the effect of both deficiencies of Se and Vit E and toxic status of those antioxidants on the peroxidation potentiality of the brain. We aimed to study the effects of both Se and Vit E inadequate diet and Se rich diet on the learning and memory processes of third-generation young rats. Their ancestors were also fed by the same diets starting from their births. To test the learning and memory, the rats aged 60 days were trained by using automated two ways active avoidance shuttle box. The acquisition tests were terminated with training the rat from each group to be 25 trials per day during three days. Ten days after the last acquisition test, the retention test was performed and the acquisition of the conditioned avoidance responses (CAR) of the rats were evaluated. It is demonstrated that the CAR of all rats from three groups showed a significant increase in three consecutive days while the differences observed in CAR of same sessions was not significantly different among three groups. The memory process of these young rats also was not affected significantly by two types of diets. Under the light of our results one can suggest that, in the case of alterations in antioxidant defense status, the learning and the memory mechanisms seems to be not affected. Further researches are needed to be able to explain the possible role of oxidative stress on the mechanisms of learning and memory.     

Incidental Findings on Brain MR Imaging in Older Community-Dwelling Subjects Are Common but Serious Medical Consequences Are Rare: A Cohort Study

Objectives

Incidental findings in neuroimaging occur in 3% of volunteers. Most data come from young subjects. Data on their occurrence in older subjects and their medical, lifestyle and financial consequences are lacking. We determined the prevalence and medical consequences of incidental findings found in community-dwelling older subjects on brain magnetic resonance imaging.

Design

Prospective cohort observational study.

Setting

Single centre study with input from secondary care.

Participants

Lothian Birth Cohort 1936, a study of cognitive ageing.

Main Outcome Measures

Incidental findings identified by two consultant neuroradiologists on structural brain magnetic resonance imaging at age 73 years; resulting medical referrals and interventions.

Primary and Secondary Outcome Measures

Prevalence of incidental findings by individual categories: neoplasms, cysts, vascular lesions, developmental, ear, nose or throat anomalies, by intra- and extracranial location; visual rating of white matter hyperintensities and brain atrophy.

Results

There were 281 incidental findings in 223 (32%) of 700 subjects, including 14 intra- or extracranial neoplasms (2%), 15 intracranial vascular anomalies (2%), and 137 infarcts or haemorrhages (20%). Additionally, 153 had moderate/severe deep white matter hyperintensities (22%) and 176 had cerebral atrophy at, or above, the upper limit of normal (25%) compared with a normative population template. The incidental findings were unrelated to white matter hyperintensities or atrophy; about a third of subjects had both incidental findings and moderate or severe WMH and a quarter had incidental findings and atrophy. The incidental findings resulted in one urgent and nine non-urgent referrals for further medical assessment, but ultimately in no new treatments.

Conclusions

In community-dwelling older subjects, incidental findings, including white matter hyperintensities and atrophy, were common. However, many findings were not of medical importance and, in this age group, most did not result in further assessment and none in change of treatment.     

Dietary restriction affects lifespan but not cognitive aging in Drosophila melanogaster

Dietary restriction extends lifespan in a wide variety of animals, including Drosophila, but its relationship to functional and cognitive aging is unclear. Here, we study the effects of dietary yeast content on fly performance in an aversive learning task (association between odor and mechanical shock). Learning performance declined at old age, but 50‐day‐old dietary‐restricted flies learned as poorly as equal‐aged flies maintained on yeast‐rich diet, even though the former lived on average 9 days (14%) longer. Furthermore, at the middle age of 21 days, flies on low‐yeast diets showed poorer short‐term (5 min) memory than flies on rich diet. In contrast, dietary restriction enhanced 60‐min memory of young (5 days old) flies. Thus, while dietary restriction had complex effects on learning performance in young to middle‐aged flies, it did not attenuate aging‐related decline of aversive learning performance. These results are consistent with the hypothesis that, in Drosophila, dietary restriction reduces mortality and thus leads to lifespan extension, but does not affect the rate with which somatic damage relevant for cognitive performance accumulates with age.     

Memory retention capacity using two different training methods,appetitive and aversive learning,in juvenile red sea bream Chrysophrys major

Memory retention based on appetitive and aversive learning was studied in juvenile red sea bream Chrysophrys major. The fish were individually trained via appetitive and aversive learning. In general, they retained appetitive memories for 30 days, but not for 60 days. Conversely, aversive memory endured for 1 day, but not for 3 days or longer. Analyses at the individual level revealed that some fish retained appetitive memories for 60 days, whereas others lost it within 3 days; this suggests considerable variability in memory retention capacity among individual fish. The memory duration for aversive learning was remarkably short, which should be considered when releasing trained fish into the wild for stock enhancement. Furthermore, the high inter-individual variability suggests that evaluating memory retention capacity through group experiments might lead to overestimation of fishes’ ability.     

Food perception with age and its relationship to pleasantness

Differences between elderly subjects (n = 46, 61-86 years) and young subjects (n = 36, 18-25 years) in food perception and food liking were investigated. Intensity and liking ratings were assessed for custard dessert, in which flavor enrichment, textural change, and irritant addition were incorporated as strategies to compensate for sensory losses with increasing age. The sensory acuity (taste, olfaction, irritation, chewing efficiency) of both young and elderly subjects was measured with the help of different sensitivity tests. The elderly perceived the custards differently from the young, mainly as less intense in flavor (cherry/vanilla) and less intense in creaminess/swallowing effort. Several of the observed interaction effects were different for the elderly and the young. The majority of these differences manifested as lower intensity slopes for the elderly. Losses in sensitivity to taste and to olfactory and trigeminal stimuli as well as a reduced chewing efficiency were observed on average for the elderly compared with the young. Furthermore, subgroups of the elderly were observed in which the compensatory strategies flavor enrichment, textural change, and irritant addition led to an increase in food liking. However, these subgroups did not differ in their sensory acuity. The present study does not support the assumption that age-associated changes in food perception-caused by losses in sensory acuity-inevitably reduce the food liking of the elderly.     

Song recognition memory in juvenile zebra finches: effects of varying the number of presentations of heterospecific and conspecific songs

Seven male and three female zebra finches were exposed to 14 zebra finch (CON) and 14 starling (HET) songs during their sensitive period for song learning and then tested for their recognition memory of both the CON and HET songs in two separate memory tests. Amount of song exposure was varied by presenting individual songs either 3, 9, 27, or 81 times per day for nine consecutive days. After song exposure the birds were trained to discriminate two of the exposed, familiar songs (FAM) from two novel songs (NOV) in a go/no-go operant discrimination procedure, with FAM songs as "go" stimuli. Following discrimination training, untrained FAM and NOV songs were presented as probe songs without reinforcement. Birds responded more to FAM than NOV songs at all levels of song exposure, indicating that the songs were recognized. There were no differences in recognition memory for CON and HET song at any level of song exposure. The results suggest that selective song learning does not result from selective memorization of conspecific song.     

Measurement of sensitivity to olfactory flavor: application in a study of aging and dentures

Olfaction involves a dual sensory process for perceiving odors orthonasally (through the nostrils) and retronasally (through the mouth). This investigation entailed developing a measure of sensitivity to an odor delivered in an orally sampled food (orange flavoring in a sucrose-sweetened gelatin) and examining sensitivity in the elderly. In experiment 1, olfactory flavor sensitivity was 49 times lower in elderly (n = 21) than in young (n = 28) subjects. In experiment 2, with 73 elderly women, higher olfactory flavor sensitivity correlated significantly with higher orthonasal perception (Connecticut Chemosensory Clinical Research Center test). Some women, however, exhibited low olfactory flavor sensitivity despite high orthonasal perception; none had high olfactory flavor sensitivity and low orthonasal perception. Those who wore complete or palatal covering dentures had lower olfactory flavor sensitivity than those who were dentate or wore dentures that did not cover the palate. Through multiple regression analysis, orthonasal perception and denture status were found to be independent contributors to predicting olfactory flavor sensitivity. In summary, elderly subjects showed depressed olfactory flavor sensitivity (i.e. retronasal sensitivity) that related to poor orthonasal olfactory perception and denture characteristic. Thus, while good orthonasal olfaction may be necessary for good olfactory flavor sensitivity, it is not sufficient. Other factors, some associated with oral conditions, may impede release and retronasal transport of odors from the mouth to the olfactory receptors.     

慢性束缚应激对SD和Wistar大鼠学习记忆能力的影响

目的探讨慢性束缚应激对Wistar、SD两种品系大鼠学习记忆能力的影响,为应激模型中实验动物的选择提供依据。方法对两种品系大鼠(Wistar、SD)采用每天束缚10 h,束缚28 d建立慢性应激模型。采用物体认知新物体识别实验和Morris水迷宫空间学习、工作记忆行为学检测方法,观察束缚应激对两种品系实验动物学习记忆能力的影响。结果束缚28 d后,物体识别实验中,Wistar、SD模型组的辨别指数(discrimination index,DI)均低于对照组,但只有SD两组间差异存在显著性(P0.05);水迷宫空间学习阶段,SD模型组潜伏期高于对照组,第5天差异有显著性(P0.05),而Wistar模型组与对照组间的潜伏期没有差异;水迷宫工作记忆阶段,SD大鼠模型组与正常组比较,潜伏期显著增加(P0.05),Wistar模型大鼠的潜伏期与对照组比较没有显著差异。结论新物体识别实验和水迷宫实验,这两种反应动物不同学习记忆能力的行为学实验结果都表明,慢性束缚应激(10 h,28 d)对SD大鼠学习记忆能力的损伤较Wistar大鼠明显。SD大鼠可能更适合作为慢性应激所致学习记忆损伤动物模型。     

Incidental and Intentional Learning of Verbal Episodic Material Differentially Modifies Functional Brain Networks

Learning- and memory-related processes are thought to result from dynamic interactions in large-scale brain networks that include lateral and mesial structures of the temporal lobes. We investigate the impact of incidental and intentional learning of verbal episodic material on functional brain networks that we derive from scalp-EEG recorded continuously from 33 subjects during a neuropsychological test schedule. Analyzing the networks'' global statistical properties we observe that intentional but not incidental learning leads to a significantly increased clustering coefficient, and the average shortest path length remains unaffected. Moreover, network modifications correlate with subsequent recall performance: the more pronounced the modifications of the clustering coefficient, the higher the recall performance. Our findings provide novel insights into the relationship between topological aspects of functional brain networks and higher cognitive functions.     

A Potential Role of Central Insulin in Learning and Memory Related to Feeding

1. Hypothalamic insulin (HI) is well known for its role in feeding regulation. In addition, its concentration is modified in response to meals. Recent studies suggest that brain insulin participates in memory processes, possibly through stimulation by glucose.2. The present microdialysis study focused on local in vivo regulation of HI by glucose and on the effects of aging on HI, since aging is characterized by deterioration of memory, body weight regulation, and central glucose utilization. Glucose (8 mM) infused for 5 min increased extracellular HI levels rapidly, by 4.6-fold, and cerebellar insulin levels by 0.4-fold only, suggesting a specific area-dependent regulation of HI by glucose. Neither insulinemia nor glycemia were affected, suggesting a central mechanism. The same dose of glucose induced a modest (0.4-fold), delayed (45 min) increase in hypothalamic serotonin, suggesting that the effect of glucose on HI is independent of a previously defined local serotonin-induced insulin release. HI levels in old normal weight rats were half the levels of young rats. In genetically old obese (fa/fa) Zucker rats, HI concentration was 30% of that in young normal rats, suggesting a deterioration of HI availability when aging and obesity are combined.3. The above results, in line with recent considerations on a potential role of central insulin in learning and memory, suggest particular effects of HI on feeding and memory and probably on a specific memory for food.     

轻度认知损伤患者的联系记忆损伤特征

遗忘型轻度认知损伤患者(aMCI)在项目记忆和联系记忆上都有损伤．本文通过临床记忆量表中的项目记忆和联系记忆测验,研究aMCI的联系记忆是否比项目记忆有更显著的损伤．另外,通过分析配对联想学习测验,进一步研究aMCI联系记忆损伤的特点．25名aMCI和28名健康老人参与了两个联系记忆测验(配对联想学习测验和联想回忆测验)和两个项目记忆测验(图像自由回忆和无意义图形再认),aMCI患者在联系记忆测验上表现出了更显著的损伤,即使控制了项目记忆的损伤,aMCI的联系记忆仍然比健康老人显著降低．另外,ROC分析表明联系记忆测验比项目记忆测验对aMCI病人有更高的区分度．对配对联想学习测验的分析表明,相对于健康老人,aMCI患者在记忆有语言联系的词对要比记忆无语义联系的词对更为困难．本研究进一步表明aMCI患者的联系记忆比项目记忆有更大的损伤．相对于健康老人,aMCI患者不仅难以在两个无关项目间创建记忆连接,而且在有效利用项目间本身的语义联系方面存在更大的损伤．联系记忆测验比项目记忆测验对aMCI患者有更高的区分度．在神经心理评估中增加联系记忆测验,能更加有效地识别aMCI患者．     

Experimental evolution of olfactory memory in Drosophila melanogaster

In order to address the nature of genetic variation in learning performance, we investigated the response to classical olfactory conditioning in "high-learning" Drosophila melanogaster lines previously subject to selection for the ability to learn an association between the flavor of an oviposition medium and bitter taste. In a T-maze choice test, the seven high-learning lines were better at avoiding an odor previously associated with aversive mechanical shock than were five unselected "low-learning" lines originating from the same natural population. Thus, the evolved improvement in learning ability of high-learning lines generalized to another aversion learning task involving a different aversive stimulus (shock instead of bitter taste) and a different behavioral context than that used to impose selection. In this olfactory shock task, the high-learning lines showed improvements in the learning rate as well as in two forms of consolidated memory: anesthesia-resistant memory and long-term memory. Thus, genetic variation underlying the experimental evolution of learning performance in the high-learning lines affected several phases of memory formation in the course of olfactory aversive learning. However, the two forms of consolidated memory were negatively correlated among replicate high-learning lines, which is consistent with a recent hypothesis that these two forms of consolidated memory are antagonistic.     

误捕及其对海兽种群的影响

几乎在全世界都有误捕海兽的记录．有误捕记录的海兽有鲸目１４科６２种,鳍脚目３科１２种,海牛目２科２种及食肉目１科１种．误捕海兽的渔具包括刺网、拖网、围网、张网、插网和陷阱等．误捕可导致种群数量的下降及生活史特征的改变．我国需要开展这方面的研究工作．     

磁场作用对小鼠学习记忆的影响

目的 :探讨磁场作用对小鼠学习记忆能力的影响。方法 :应用水迷宫学习模型测定并对比 30分钟磁场处理组、1 5分钟磁场处理组和非磁场处理的正常对照组动物的空间学习记忆能力。结果 :水迷宫学习训练的实验表明 30分钟磁场处理组与正常对照组比较 ,动物到达水下平台的时间延长 ;游程增加 ;平均游速减慢 ,且均具有显著性差异 (p <0 .0 5)。 1 5分钟磁场处理组与正常对照组比较 ,动物到达水下平台的时间延长 ,且具有显著性差异 (p <0 .0 5) ;游程和平均速度与正常对照组相比无显著性差异 (p >0 .0 5)。结论 :磁场处理 30分钟或 1 5分钟损伤小鼠的空间学习记忆能力 ,且以 30分钟的磁场处理作用较强     

老年学习记忆减退的神经行为学基础

用改良Ｍｏｒｒｉｓ水迷宫将老年大鼠分为老年学习记忆减退组和老年学习记忆正常组,并与青年组对照,检测其空间参考记忆和空间工作记忆,并对海马结构内胶质纤维酸性蛋白（ＧＦＡＰ）阳性胶质细胞和ＧＡＢＡ能中间神经元在光镜和电镜水平进行定量分析。结果显示老年学习记忆减退大鼠的空间参考记忆能力明显下降,并且其行为模式发生了改变,空间工作记忆改变不明显;齿状回分子层的病理改变非常明显,表现为ＧＡＢＡ能神经元丢失和     

The association between flavor labeling and flavor recall ability in children

This study sought to determine if the ability to label a flavor is associated with an improved ability to recall having tasted the flavor in preschool-aged children. A total of 120 3- to 6-year-old English-speaking children tasted and labeled 20 different flavors, blinded to color. Children's labels for the flavors were scored for consistency and accuracy. Recall for having tasted the flavor was tested. Both labeling ability and recall ability improved rapidly between the ages of 3 and 6 years in this cohort. Regression analysis indicated that independent of the child's age, consistent accurate labeling was positively associated with recall ability. Higher maternal education was an independent and marginal contributor to greater recall ability. The combination of consistent and accurate labeling, age, and maternal education accounted for 28% of the variance in flavor recall ability. Consistent but inaccurate labeling alone contributed little to the variance in flavor recall ability. We conclude from these findings that children's ability to recall having tasted a flavor develops rapidly during the preschool age range and that improved recall ability is associated with the ability to consistently and accurately label the flavor. We conclude that language mediates memory for flavors in young children.     

水迷宫实验中三种品系小鼠学习记忆能力的比较

目的探讨三种品系小鼠在Morris水迷宫实验中的学习记忆能力差异,为与改善学习记忆能力相关新药研究的实验动物选择提供参考。方法选用C57BL/6小鼠、昆明种小鼠和ICR小鼠,进行定位航行实验(5d)、空间搜索实验(1d)和工作记忆实验(4d),考察其学习记忆能力。结果定位航行实验从第3天起C57BL/6小鼠的潜伏期明显小于昆明种小鼠和ICR小鼠(P0.01);空间搜索实验C57BL/6小鼠穿过原平台位置的次数、在原平台象限游程比率和时间比率均明显多于昆明种小鼠和ICR小鼠(P0.05);动物每天工作记忆实验的潜伏期随测试次数增加而缩短,C57BL/6小鼠缩短的较昆明种小鼠和ICR小鼠稍多。结论C57BL/6小鼠的空间参考记忆能力与工作记忆能力均优于昆明种小鼠和ICR小鼠,且非空间因素对其学习记忆能力的评价干扰较小,可作为优先选择的水迷宫实验动物。