Sleep-dependent hippocampal slow activity correlates with waking memory performance in humans

The positive effect of postlearning sleep on memory consolidation as well as the relationship between sleep-related memory processes and the hippocampal formation are increasingly clarified topics in neurobiology. However, the possibility of a stable relationship between waking mnemonic performance and sleep-dependent hippocampal electric activity is unexplored. Here we report a correlative analysis between sleep-dependent parahippocampal-hippocampal (pHip-Hip) electric activity recorded by foramen ovale (FO) electrodes and different types of memory performances in epileptic patients. Psychological testing was performed days or weeks before electrophysiological recordings. The relative spectral power of the slow activity (below 1.25 Hz) during deep non-REM (NREM) sleep at the right pHip-Hip region correlated positively with the visual memory performance according to Rey-Osterrieth Complex Figure Test (ROCFT). Along the posterior-anterior direction of the hippocampal formation a linear increasing of correlations was observed. The relative power of the activity below 1.25 Hz at the left pHip-Hip during phasic REM sleep correlated positively with verbal learning performance and mnemonic retention values according to ROCFT. It is concluded that the pHip-Hip structures' capacity of producing high amplitude and synchronized slow (< 1 Hz) oscillation during deep NREM sleep is related to the functional power of these structures. We hypothesize that the asymmetric (side-specific) propagation of ponto-geniculo-occipital (PGO) activity to the pHip-Hip region is related to the memory correlates of phasic REM sleep.     

Stress and memory: opposing effects of glucocorticoids on memory consolidation and memory retrieval

It is well established that glucocorticoid hormones, secreted by the adrenal cortex after a stressful event, influence cognitive performance. Some studies have found glucocorticoid-induced memory enhancement. However, many studies have reported impairing effects of glucocorticoids on memory function. This paper reviews recent findings from this laboratory on the acute effects of glucocorticoids in rats on specific memory phases, i.e., memory consolidation and memory retrieval. The evidence suggests that the consequences of glucocorticoid activation on cognition depend largely on the different memory phases investigated. Posttraining activation of glucocorticoid-sensitive pathways involving glucocorticoid receptors enhances memory consolidation in a pattern highly similar to that previously described for adrenal catecholamines. Also, similar to catecholamine effects on memory consolidation, glucocorticoid influences on memory consolidation depend on noradrenergic activation of the basolateral complex of the amygdala and interactions with other brain regions. By contrast, memory retrieval processes are usually impaired with high circulating levels of glucocorticoids or following infusions of glucocorticoid receptor agonists into the hippocampus. The hypothesis is proposed that these apparently dual effects of glucocorticoids on memory consolidation and memory retrieval might be related and that the basolateral complex of the amygdala is a key structure in a memory-modulatory system that regulates, in concert with other brain regions, stress and glucocorticoid effects on both memory consolidation and memory retrieval.     

Clinical manifestations and stages of Rett syndrome

The presentation and clinical diagnosis of Rett syndrome at various ages and stages are reviewed. In addition to the classical form, variability in phenotype between different atypical Rett forms is given. Obligatory, supportive, and differential diagnostic criteria are summarized. Long-term follow-up findings in ageing Rett women are addressed.     

The myth of technology in health care

Technology is believed to have liberated health care from dogmas, myths and speculations of earlier times. However, we are accused of using technology in an excessive, futile and even detrimental way, as if technology is compelling our actions. It appears to be like the monster threatening Dr. Frankenstein or like the socerer’s broom in the hand of the apprentice. That is, the same technology that should liberate us from myths, appears to be mythical. The objective of this article is to investigate the background for the re-entrance of the myth: How we encounter it and how we can explain it. The main point is that a myth of technology is normative: it relates ‘is’ and ‘ought’ and directs our actions. This becomes particularly clear in health care. Hence, if there is a myth of technology, it is an ethical issue, and should be taken seriously.     

Effects of normal aging and Alzheimer's disease on emotional memory

Recall is typically better for emotional than for neutral stimuli. This enhancement is believed to rely on limbic regions. Memory is also better for neutral stimuli embedded in an emotional context. The neural substrate supporting this effect has not been thoroughly investigated but may include frontal lobe, as well as limbic circuits. Alzheimer's disease (AD) results in atrophy of limbic structures, whereas normal aging relatively spares limbic regions but affects prefrontal areas. The authors hypothesized that AD would reduce all enhancement effects, whereas aging would disproportionately affect enhancement based on emotional context. The results confirmed the authors' hypotheses: Young and older adults, but not AD patients, showed better memory for emotional versus neutral pictures and words. Older adults and AD patients showed no benefit from emotional context, whereas young adults remembered more items embedded in an emotional versus neutral context.     

What does the implicit association test measure? A test of the convergent and discriminant validity of prejudice-related IATs

Drawing on recent criticism of the Implicit Association Test (IAT), the present study tested the convergent and discriminant validity of two prejudice-related IATs to corresponding explicit prejudice measures in a German student sample (N = 61). Confirming convergent validity, (a) an IAT designed to assess negative associations related to Turkish people was significantly related to the explicit endorsement of prejudiced beliefs about Turkish people, and (b) an IAT designed to assess negative associations related to East Asians was significantly related to explicit prejudice against East Asians. Moreover, confirming discriminant validity, (c) the Asian IAT was unrelated to the explicit endorsement of prejudiced beliefs about Turkish people, and (d) the Turkish IAT was unrelated to explicit prejudice against Asian people. These results further corroborate the assumption that the IAT is a valid method to assess the strength of evaluative associations in the domain of prejudice and stereotypes.     

Framing interethnic ideology: effects of multicultural and color-blind perspectives on judgments of groups and individuals

In 3 experiments, White American college students received a message advocating either a color-blind or a multicultural ideological approach to improving interethnic relations and then made judgments about various ethnic groups and individuals. Relative to a color-blind perspective, the multicultural perspective led to stronger stereotypes, greater accuracy in these stereotypes, and greater use of category information in judgments of individuals. This increase in between-category differentiation occurred both for attributes that favored the in-group and for attributes that favored the out-group and was also paired in some cases with greater overall positivity toward the out-group. The findings lead us to question the implicit assumption driving the majority of social psychological efforts at prejudice reduction: that the categorization process leads to prejudice, and that the relevance of social categories must therefore be de-emphasized.     

Additional study of the Youth-Depression Adjective Check List

Replicated and extended aspects of determinations of reliability and validity for the State version of the Youth-Depression Adjective Check List. Students from Grades 9 through 12 (64 girls and 41 boys) completed the State version and the Adolescent Activities Checklist on each of 12 consecutive days and completed the Trait version, the Reynolds Adolescent Depression Scale, the Multiple Affect Adjective Check List--Revised Grade 6, and the Adolescent Activities Checklist at the beginning and the end of the study. Good reliability and validity of the State version were confirmed and extended, and preliminary information on characteristics of the Trait version of the Youth-Depression Adjective Check List also was presented. The State version seems suitable for use in research with adolescents and preadolescents. More study of the Trait version is recommended.