Memory processes and experimental continuity

What are the memory processes that produce coherent representations of temporally discontinuous experiences? In this article, we describe the memory process of resonance, a process that provides renewed access to long-term memory information that is relevant to cues in working memory. Our experiments demonstrate c parallel waxing and waning of information as a function of relevance to a current episode, a pattern of accessibility of information that contributes to the achievement of continuity across experiences.     

Representation of visuotactile space in the split brain

Recent neurophysiological research in the monkey has revealed bimodal neuronal cells with both tactile receptive fields on the hand and visual receptive fields that follow the hands as they move, suggesting the existence of a bimodal map of visuotactile space. Using a cross-modal congruency task, we examined the representation of visuotactile space in normal people and in a split-brain patient (J.W.) as the right arm assumed different postures. The results showed that the congruency effects from distracting lights followed the hand around in space in normal people, but failed to do so in the split-brain patient when the hand crossed the midline. This suggests that cross-cortical connections are required to remap visual space to the current hand position when the hand crosses the midline.     

Flashbulb memories in social groups: a comparative test-retest study of the memory of French President Mitterrand's death in a French and a Belgian group

Flashbulb memories are vivid and long-lasting memories for the reception context of an important public event (Brown & Kulik, 1977). They are assumed to be triggered by emotional factors (i.e., intensity of emotional feeling, appraisal of the original event) and by social factors (i.e., social sharing of the news, following media debate about the event). The present study investigated the memory for the death of the former President of France F. Mitterrand in two social groups, i.e., French and Belgian people. This study tests whether the flashbulb memory attributes, the memory for the original event, and the impact of the emotional and social determinants of flashbulb memory differed across groups. The results indicated that the flashbulb memory for Mitterrand's death is affected by group provenance, as French people showed higher levels of recall for the flashbulb memory attributes and their determinants than Belgian people. Time impaired recollections in both groups, so that flashbulb memories appear prone to decay and share the same destiny as ordinary memories. The theoretical construct of concern--as the most basic antecedent of emotional experiences and its related appraisal (Frijda, 1994)--is discussed in order to explain the differences in memory of the two social groups.     

Prevalence,and intellectual outcome of unilateral focal cortical brain damage as a function of age,sex and aetiology

Neurologists and neuropsychologists are aware that aging men are more at risk than women for brain damage, principally because of the well known male-predominant risk for cardiovascular disease and related cerebrovascular accidents. However, a disproportion in prevalence of brain damage between the sexes in childhood may be less suspected. Furthermore, sex-specific risk for other aetiologies of brain damage may be little known, whether in the pediatric or adult populations. Proposals of a sex difference in cognitive recovery from brain damage have also been controversial. Six hundred and thirty five "consecutive" cases with cortical focal lesions including cases of all ages and both sexes were reviewed. Aetiology of the lesion was determined for each case as was postlesion IQ. Risk was highly male prevalent in all age groups, with a predominance of cardiovascular aetiology explaining much of the adult male prevalence. However, several other aetiological categories were significantly male prevalent in juveniles (mitotic, traumatic, dysplasic) and adults (mitotic, traumatic). There was no sex difference in outcome (i.e., postlesion IQ) of these cortical brain lesions for the cohort as a whole, after statistical removal of the influence of lesion extent, aetiology and presence of epilepsy. Mechanisms potentially responsible for sex differences in prevalence, aetiology of brain damage, and recovery, are reviewed and discussed.     

Implicit memory is vulnerable to proactive interference

We investigated the possibility that implicit memory, like explicit memory, can be disrupted by proactive interference. Participants first viewed a list of words, with nontargets in the first half of the list and targets in the second. Nontargets were either similar in structure (e.g., "ANALOGY") or unrelated (e.g., "URGENCY") to the targets (e.g., "ALLERGY"). After several filler tasks, participants completed an implicit fragment-completion test (e.g., "A_L__ GY") for the target items. Participants who viewed similar nontargets completed fewer fragments with target items and made more intrusions than did participants who viewed unrelated nontargets. Together with previous findings, these results suggest that similar nontargets can compete with target items to produce interference in implicit memory.     

Emotion knowledge as a predictor of social behavior and academic competence in children at risk

Following leads from differential emotions theory and empirical research, we evaluated an index of emotion knowledge as a long-term predictor of positive and negative social behavior and academic competence in a sample of children from economically disadvantaged families ( N = 72). The index of emotion knowledge represents the child's ability to recognize and label emotion expressions. We administered control and predictor measures when the children were 5 years old and obtained criterion data at age 9. After controlling for verbal ability and temperament, our index of emotion knowledge predicted aggregate indices of positive and negative social behavior and academic competence. Path analysis showed that emotion knowledge mediated the effect of verbal ability on academic competence. We argue that the ability to detect and label emotion cues facilitates positive social interactions and that a deficit in this ability contributes to behavioral and learning problems. Our findings have implications for primary prevention.     

Word length and phonological similarity effects in simple, complex, and delayed serial recall tasks: implications for working memory

Some current models of working memory argue that a passive short-term store is not involved in more dynamic working memory tasks. Other models argue that standard short-term memory and working memory tasks rely on common storage facilities. We examine these issues by exploring two signature effects of passive short-term storage in simple span, complex span, and Brown-Peterson tasks. The finding that all three tasks show word length and phonological similarity effects suggests that common processes or storage mechanisms are involved in all tasks. The implications for models of working memory are discussed.     

What have we learned about burnout and health?

Abstract It has been a decade since an international group of scholars came together to discuss and debate the construct of job burnout. That conference, which took place in Krakow, Poland in 1990, was a major turning point in the development of this field. Not only did it bring together a wide range of theoretical perspectives and empirical data, it generated new directions for the work that needed to be done in the future (Schaufeli et al., 1993). Now that we are 10 years into that future, it would be worthwhile to assemble a new group of international scholars and discover what progress has been made. In essence, that is what the editors of this Special Issue have done. They have invited several of the leading burnout researchers from several continents to contribute their newest studies on this important social phenomenon. Thus this Special Issue affords us the opportunity to assess the strides that have been made since that first meeting in Krakow. So what have we now learned about burnout and its relation to health?     

Cognitive performances and locomotor activity following dentate granule cell damage in rats: role of lesion extent and type of memory tested

Intradentate injection of colchicine is one of the techniques used to destroy granule cells. This study compared the behavioral effects of various amounts of colchicine (1.0, 3.0, and 6.0 microg; Col 1, Col 3, and Col 6, respectively) injected into the dentate gyrus of adult Long-Evans male rats. Starting 10 days after lesion surgery, behavioral testing assessed home-cage and open-field locomotion, alternation in a T-maze, water-maze, and radial-maze learning according to protocols placing emphasis on reference, and working memory. All of these tasks are sensitive to hippocampal disruption. Histological verifications showed that the extent of the lesions depends on the dose of colchicine (index of dentate gyrus shrinkage: -33% in Col 1, -54% in Col 3, and -67% in Col 6 rats). Colchicine dose-dependently increased nocturnal home cage activity (an effect found 10 days but not 5 months after surgery), but had no significant effect on open-field locomotion or T-maze alternation. A dose-dependent reference memory impairment was found during the acquisition of spatial navigation in the water maze; Col 3 and Col 6 rats were more impaired than Col 1 rats. During the probe trial (platform removed), control rats spent a longer distance swimming over the platform area than all rats with colchicine lesions. In the working memory version of the test, all rats with colchicine lesions showed significant deficits. The deficits were larger in Col 3 and Col 6 rats compared to Col 1 rats. The lesions had no effect on swimming speed. In the radial-maze test, there was also a dose-dependent working memory impairment. However, reference memory was disrupted in a manner that did not differ among the three groups of lesioned rats. Our data are in line with the view that the dentate gyrus plays an important role in the acquisition of new information and is an integral neural substrate for spatial reference and spatial working memory. They also suggest that damage to granule cells might have more pronounced effects on reference than on working memory in the radial maze. Finally, they demonstrate that part of the variability in the conclusions from previous experiments concerning the role of granule cells in cognitive processes, particularly in spatial learning and memory, may be due to the type of tests used and/or the extent of the damage produced.     

Self-injurious behavior: gene-brain-behavior relationships

This paper summarizes a conference held at the National Institute of Child Health and Human Development on December 6-7, 1999, on self-injurious behavior [SIB] in developmental disabilities. Twenty-six of the top researchers in the U.S. from this field representing 13 different disciplines discussed environmental mechanisms, epidemiology, behavioral and pharmacological intervention strategies, neurochemical substrates, genetic syndromes in which SIB is a prominent behavioral phenotype, neurobiological and neurodevelopmental factors affecting SIB in humans as well as a variety of animal models of SIB. Findings over the last decade, especially new discoveries since 1995, were emphasized. SIB is a rapidly growing area of scientific interest to both basic and applied researchers. In many respects it is a model for the study of gene-brain-behavior relationships in developmental disabilities.