Visuospatial working memory in very preterm and term born children--impact of age and performance.

Working memory is crucial for meeting the challenges of daily life and performing academic tasks, such as reading or arithmetic. Very preterm born children are at risk of low working memory capacity. The aim of this study was to examine the visuospatial working memory network of school-aged preterm children and to determine the effect of age and performance on the neural working memory network. Working memory was assessed in 41 very preterm born children and 36 term born controls (aged 7-12 years) using functional magnetic resonance imaging (fMRI) and neuropsychological assessment. While preterm children and controls showed equal working memory performance, preterm children showed less involvement of the right middle frontal gyrus, but higher fMRI activation in superior frontal regions than controls. The younger and low-performing preterm children presented an atypical working memory network whereas the older high-performing preterm children recruited a working memory network similar to the controls. Results suggest that younger and low-performing preterm children show signs of less neural efficiency in frontal brain areas. With increasing age and performance, compensational mechanisms seem to occur, so that in preterm children, the typical visuospatial working memory network is established by the age of 12 years.

Probabilistic contingency learning with limbic or prefrontal damage.

A fundamental capacity of the human brain is to learn relations (contingencies) between environmental stimuli and the consequences of their occurrence. Some contingencies are probabilistic; that is, they predict an event in some situations but not in all. Animal studies suggest that damage to limbic structures or the prefrontal cortex may disturb probabilistic learning. The authors studied the learning of probabilistic contingencies in amnesic patients with limbic lesions, patients with prefrontal cortex damage, and healthy controls. Across 120 trials, participants learned contingent relations between spatial sequences and a button press. Amnesic patients had learning comparable to that of control subjects but failed to indicate what they had learned. Across the last 60 trials, amnesic patients and control subjects learned to avoid a noncontingent choice better than frontal patients. These results indicate that probabilistic learning does not depend on the brain structures supporting declarative memory.

Low reliability of perceptual priming: consequences for the interpretation of functional dissociations between explicit and implicit memory.

In this study, three experiments are presented that investigate the reliability of memory measures. In Experiment 1, the well-known dissociation between explicit (recall, recognition) and implicit memory (picture clarification) as a function of age in a sample of 335 persons aged between 65 and 95 was replicated. Test-retest reliability was significantly lower in implicit than in explicit measures. In Experiment 2, parallel-test reliabilities in a student sample confirmed the finding of Experiment 1. In Experiment 3, the reliability of cued recall and word stem completion was investigated. There were significant priming effects and a dissociation between explicit and implicit memory as a function of levels of processing. However, the reliability of implicit memory measures was again substantially lower than in explicit tests in all test conditions. As a consequence, differential reliabilities of direct and indirect memory tests should be considered as a possible determinant of dissociations between explicit and implicit memory as a function of experimental or quasi-experimental manipulations.

Apolipoprotein E genotypes and cognitive functions in healthy elderly persons.

OBJECTIVES: We investigated whether apoE genotypes correlate with cognitive functions in clinically healthy persons. METHODS: In 1993 and 1995, we measured information processing speed, delayed free recall and semantic aspects of long-term memory in 227 men and 105 women aged 65 and over, a randomly selected subsample of the prospective Basel Study. Cardiovascular risk factors and education were assessed. RESULTS: E2 were more prevalent in old-old (>75 years, 23.5% vs. 15%) compared to E4 than in young-old (<75 years, 19.3% vs. 23.5%). Taking into account age and education, subjects with epsilon3/epsilon4 or epsilon4/epsilon4 alleles (E4) performed lowest in all 3 tests compared to those homozygous for epsilon3 (E3) or carriers of one or two epsilon2 alleles (E2) (reaction time P = 0.009, free recall P = 0.05, WAIS-R vocabulary P<0.05). In old-old there was a significant difference between E2 and E4 for reaction time (P = 0.02) and free recall (P<0.02) but not for vocabulary (P = 0.086). In all 3 groups there were no significant changes after 2 years. The subgroup with the genotype epsilon2/epsilon4 performed consistently best in the cognitive tests. Cholesterol was significantly increased in the E4 and E3 group compared to the E2 group. CONCLUSION: ApoE genotype correlates with cognitive performance. The increased prevalence of E2 in the old-old and the significantly lower plasma cholesterol levels suggest differential morbidity and mortality as important factors influencing the prevalence of cognitive disorders in late life.

The effects of resistance training on well-being and memory in elderly volunteers.

OBJECTIVE: To determine the short- and long-term effects of resistance training on muscle strength, psychological well-being, control-beliefs, cognitive speed and memory in normally active elderly people. METHODS: 46 elderly people (mean age 73.2 years; 18 women and 28 men), were randomly assigned to training and control groups (n=23 each). Pre- and post-tests were administered 1 week before and 1 week after the 8-week training intervention. The training sessions, performed once a week, consisted of a 10 min warm-up phase and eight resistance exercises on machines. RESULTS: There was a significant increase in maximum dynamic strength in the training group. This training effect was associated with a significant decrease in self-attentiveness, which is known to enhance psychological well-being. No significant changes could be observed in control-beliefs. Modest effects on cognitive functioning occurred with the training procedure: although there were no changes in cognitive speed, significant pre/post-changes could be shown in free recall and recognition in the experimental group. A post-test comparison between the experimental group and control group showed a weak effect for recognition but no significant differences in free recall. Significant long-term effects were found in the training group for muscular strength and memory performance (free recall) 1 year later. CONCLUSION: An 8-week programme of resistance training lessens anxiety and self-attentiveness and improves muscle strength.

The relation between antioxidants and memory performance in the old and very old.

OBJECTIVES: Aging processes, and among them brain aging, are thought to be associated with free radical action. It is hypothesized that plasma antioxidant vitamin levels correlate with cognitive performance in healthy older subjects. DESIGN: Longitudinal and cross-sectional comparisons. SETTING: The city of Basle, considered representative of the older urban population in Switzerland. PARTICIPANTS: A total of 442 subjects aged 65 to 94 years (mean: 75 years; 312 male, 132 female) was selected from a random sample. MEASUREMENTS: In 1993, participants were tested for memory, and plasma vitamin levels were measured for the three antioxidants alpha-tocopherol, ascorbic acid, and beta-carotene. These vitamin parameters, measured previously in 1971 in the same sample, were integrated in our analyses. In addition, plasma cholesterol, ferritin, and systolic blood pressure were taken into account. Memory variables were priming, working-memory, free recall, recognition and the WAIS-R vocabulary test (semantic memory). RESULTS: Correlations showed significant stability of the plasma antioxidants over the time lag of 22 years (alpha-tocopherol: r = .47, P < or = .001; beta-carotene: r = .43, P < .001; ascorbic acid: r = .22, P < .001). Free recall, recognition, and vocabulary (but not priming and working-memory) correlated significantly with ascorbic acid and beta-carotene in the cross-sectional 1993 data as well as in the longitudinal 1971-1993 analysis. These two antioxidants remained significant predictors, especially of semantic memory, after controlling for possible confounding variables like age, education, and gender using multiple regression analyses and ANOVAs. CONCLUSION: Among people aged 65 and older, higher ascorbic acid and beta-carotene plasma level are associated with better memory performance. These results indicate the important role played by antioxidants in brain aging and may have implications for prevention of progressive cognitive impairments.

[Lipoprotein(a) and plasma lipids in 429 elderly and very old subjects: significance as risk factor, effect of nutrition and life style]. / Lipoprotein(a) und Plasma-Lipide bei 429 Betagten und Hochbetagten: Bedeutung als Risikofaktor, Einfluss von Ernährung und Lebensstil.

Lipoprotein(a) [Lp(a)] was discovered in 1962. Lp(a) consists of an LDL particle linked to apolipoprotein(a). The latter shows large genetically determined interindividual variation in size. The close relationship of apo(a) to plasminogen suggests interactions with coagulation. Epidemiological studies established Lp(a) as an independent cardiovascular risk factor. In a follow-up to the Basel Study, we measured Lp(a) in 429 healthy men and women aged 65-95. The influence of nutrition and lifestyle and correlation with plasma lipids and other cardiovascular risk factors was analyzed. The mean concentration was 416 +/- 266 mg/l (median 320 mg/l). Lp(a) concentration did not differ between men and women. In contrast to the simultaneously determined lipid fractions, Lp(a) concentration is lower with increasing age. The correlation with plasma cholesterol is low but statistically significant (p < 0.01). Higher Lp(a) values were associated with a history of myocardial infarction and anticoagulant medication (p < 0.01). Other risk factors did not correlate with Lp(a). There was a low but statistically significant correlation between low Lp(a) and regular intake of vitamin pills. Our results confirm the association of longer life expectancy with low Lp(a) concentration, which are to a large extent independent of external factors. Thus, Lp(a) could be a true longevity gene.

[Wellbeing, health and autonomy in old age: the Basal IDA Study (Interdisciplinary Aging Study)]. / Wohlbefinden, Gesundheit und Autonomie im Alter: Die Basler IDA-Studie (Interdisziplinäre Altersstudie).

Current research on successful aging reflects a multicriteria approach, although a consensus on the interrelationship between different factors has not yet been achieved. The longitudinal-sequential study presented here aims at identifying psychological, biological and sociobiographical predictors of well-being, health and autonomy in old age and their interdependency. The concern of this study is thus a multidisciplinary approach including psychology, psychiatry, geriatrics and sports sciences. The ongoing study is described and first findings are reported. Four hundred and forty-two people, aged 65 to 94, were tested twice (1993 and 1995). Since this project is a pursuit of a medical longitudinal study (Basler-Studie), bio-medical parameters from former status measurements (1960, 1965, 1971, 1985, 1990) are available and taken into account for comparison with the newly collected data from 1993 and 1995. The tests included both a medical examination and cognitive and personality measurements. The medical test battery included: clinical and anthropometrical data, bio-chemical data as well as the medical history, health behaviour, complaints and subjective health. The psychological assessment included psychological well-being, health-related control beliefs, causal attribution, religiosity, etc. For memory assessment a computerized test was used which allows to test 1) perceptual error-scanning, 2) naming speed, and memory resources in terms of 3) capacity, 4) explicit and 5) implicit components. It therefore integrates direct (free recall, recognition) and indirect memory tests (perceptual identification: clarification), that were used previously in different experimental and quasi-experimental studies to investigate memory performance over the life-span. Furthermore, the following three experimental interventions are performed: memory and reattribution training, physical training and psychoanalytical group therapy. First descriptive results are presented concerning age-correlated changes in biological and medical parameters, health behavior, cognitive performances and psychological well-being and functional autonomy. The results show the strongest age effects in the cognitive variables (with the exception of priming). Beside age effects in speed variables and episodic memory we also find an age-correlated decline in semantic memory. Psychological well-being however, is not affected by age.

[Subconscious image recognition]. / Unbewusstes Bilderkennen.

Two experiments demonstrate the influence of an unconscious form of information storage on behavior. In the learning phase, subjects see pictures in which other pictures or figures are embedded. The experimental procedure makes sure that these embedded figures cannot be seen (or consciously identified) by the subjects. Nevertheless, the results of a perceptual identification task in the test phase prove that information of these unidentified figures has been stored by the subjects: In a clarification task, subjects were shown the cut out, previously embedded figures and other pictures which they had to name as quickly as possible. The experimental group, which had seen the pictures with the embedded figures in the learning phase, was much quicker in responding to the naming task than the control group, which had not seen these pictures before. These results are discussed in terms of a distinction between sensori-perceptual and conceptual information storage in humans. Conceptual information is characterized as meaningful, symbolic, and accessible to conscious reasoning and remembering, while sensori-perceptual information is seen as nonsymbolic, modality-bound, and restricted to unconscious reactivations in data-driven process repetitions.