Judi A. Ellis

Blueberry-induced changes in spatial working memory correlate with changes in hippocampal CREB phosphorylation and brain-derived neurotrophic factor (BDNF) levels.

Phytochemical-rich foods have been shown to be effective at reversing age-related deficits in memory in both animals and humans. We show that a supplementation with a blueberry diet (2% w/w) for 12 weeks improves the performance of aged animals in spatial working memory tasks. This improvement emerged within 3 weeks and persisted for the remainder of the testing period. Memory performance correlated well with the activation of cAMP-response element-binding protein (CREB) and increases in both pro- and mature levels of brain-derived neurotrophic factor (BDNF) in the hippocampus. Changes in CREB and BDNF in aged and blueberry-supplemented animals were accompanied by increases in the phosphorylation state of extracellular signal-related kinase (ERK1/2), rather than that of calcium calmodulin kinase (CaMKII and CaMKIV) or protein kinase A. Furthermore, age and blueberry supplementation were linked to changes in the activation state of Akt, mTOR, and the levels of Arc/Arg3.1 in the hippocampus, suggesting that pathways involved in de novo protein synthesis may be involved. Although causal relationships cannot be made among supplementation, behavior, and biochemical parameters, the measurement of anthocyanins and flavanols in the brain following blueberry supplementation may indicate that changes in spatial working memory in aged animals are linked to the effects of flavonoids on the ERK-CREB-BDNF pathway.

Distributed cognition: an alternative framework for analysing and explaining collaborative working

This paper examines the theoretical and practical problems that arise from attempts to develop formal characterizations and explanations of many work activities, in particular, collaborative activities. We argue that even seemingly discrete individual activities occur in, and frequently draw upon a complex network of factors: individual, social and organizational. Similarly, organizational and social constraints and practices impact upon individual cognitive processes and the realization of these in specific tasks. Any adequate characterization of work activities therefore requires the analysis and synthesis of information from these traditionally separate sources. We argue that existing frameworks, emanating separately from the respective disciplines (cognitive, social and organizational) do not present an adequate means of studying the dynamics of collaborative activity in situ. An alternative framework, advocated in this paper, is distributed cognition. Its theoretical basis is outlined together with examples of applied studies of computer-mediated work activities in different organizational settings.

The coordination of work activities: cooperation and conflict in a hospital context

An understanding of the ways in which work coordination is achieved in practice is essential to the development of effective CSCW technologies. However, previous studies are limited in their focus on small, self-contained work groups. In this analysis of work coordination in a hospital context, a broader perspective was adopted, allowing examination of activities across time, group and location. The use of a relevant structured methodology and a focus on deviations from formal procedures enabled the consideration of a range of contextual factors in interaction: Important aspects of work coordination to emerge included: status influences on the effectiveness of working practices; the social and political uses of information; conflicts between work goals and between motivations for coordinating activities; the role of informal practices; and the use of formal procedures to regulate inter-group relations. The implications of these issues for CSCW design in the hospital context are illustrated.

Flavonoids and cognitive function: a review of human randomized controlled trial studies and recommendations for future studies.

Evidence in support of the neuroprotective effects of flavonoids has increased significantly in recent years, although to date much of this evidence has emerged from animal rather than human studies. Nonetheless, with a view to making recommendations for future good practice, we review 15 existing human dietary intervention studies that have examined the effects of particular types of flavonoid on cognitive performance. The studies employed a total of 55 different cognitive tests covering a broad range of cognitive domains. Most studies incorporated at least one measure of executive function/working memory, with nine reporting significant improvements in performance as a function of flavonoid supplementation compared to a control group. However, some domains were overlooked completely (e.g. implicit memory, prospective memory), and for the most part there was little consistency in terms of the particular cognitive tests used making across study comparisons difficult. Furthermore, there was some confusion concerning what aspects of cognitive function particular tests were actually measuring. Overall, while initial results are encouraging, future studies need to pay careful attention when selecting cognitive measures, especially in terms of ensuring that tasks are actually sensitive enough to detect treatment effects.

Retrieval Cue Specificity and the Realization of Delayed Intentions

Successful performance of a delayed intention relies, in part, on recognition that a cue provides a signal for the retrieval and realization of that intention. The relative ease with which cues are recognized should influence the likelihood of successfully acting upon a delayed intention (cf. Einstein & McDaniel, 1990). We report three studies in which we manipulated ease of recognition by providing, at encoding, either the particular cues (category exemplars) that subsequently appeared during the test phase or the name of the category from which these cues were drawn—specific or general encoding instructions, respectively. Recognition of cues at test, and thus delayed intention performance, should be enhanced by the provision of specific rather than general instructions at encoding—the “specificity effect” identified by Einstein, McDaniel, Richardson, Guynn, and Cunfer (1995). This contrast, however, is likely to be influenced by both category-exemplar and exemplar-exemplar relations. The experiments reported here explored the influence of these relations on delayed intention performance. The results indicate the importance of the semantic relations (a) among cues and (b) between cues and the category from which they are drawn in determining the superiority of specific over general cue instructions.

The representation of delayed intentions: a prospective subject-performed task?

To-be-enacted material is more accessible in tests of recognition and lexical decision than material not intended for action (T. Goschke & J. Kuhl, 1993; R. L. Marsh, J. L. Hicks, & M. L. Bink, 1998). This finding has been attributed to the superior status of intention-related information. The current article explores an alternative (action-superiority) account that draws parallels between the intended enactment effect (IEE) and the subject performed task effect. Using 2 paradigms, the authors observed faster recognition latencies for both enacted and to-be-enacted material. It is crucial to note that there was no evidence of an IEE for items that had already been executed during encoding. The IEE was also eliminated when motor processing was prevented after verbal encoding. These findings suggest an overlap between overt and intended enactment and indicate that motor information may be activated for verbal material in preparation for subsequent execution.

Experimental tests of prospective remembering : The influence of cue-event frequency on performance

During recent years there has been an upsurge of interest in the processes underlying success or failure of intentions to perform an action in the future e.g. carry out an errand for a friend. Much of this research focuses on simulating these delayed-intention or prospective-memory tasks in the laboratory. A currently popular variant of these tasks is a repeated-instance event-based one in which the same action should be performed whenever a particular (repeated) event-cue occurs during an ongoing activity (e.g. a word in a running memory test of word recall). We report two experiments that investigated important dimensions of this task design, along which recent experimental tasks differ considerably, and explored their influence on prospective remembering. The results revealed that the variations in the event-cue frequencies explored here did not influence overall performance: relatively high event-cue frequency did not improve prospective remembering. However, performance was lower when event-cues were embedded in a general knowledge test than when a prose-reading task was used. Moreover, when remembering was compared for the first and final set of event-cues there was evidence for improvement over presentations during the general knowledge task and a contrasting decline using the prose task, under high event-cue frequency conditions only. The results have important repercussions for current experimental design and the development of tests of prospective remembering skills in particular population subgroups.

The impact of flavonoids on spatial memory in rodents: from behaviour to underlying hippocampal mechanisms

Emerging evidence suggests that a group of dietary-derived phytochemicals known as flavonoids are able to induce improvements in memory, learning and cognition. Flavonoids have been shown to modulate critical neuronal signalling pathways involved in processes of memory, and therefore are likely to affect synaptic plasticity and long-term potentiation mechanisms, widely considered to provide a basis for memory. Animal dietary supplementation studies have further shown that flavonoid-rich foods are able to reverse age-related spatial memory and spatial learning impairments. A more accurate understanding of how a particular spatial memory task works and of which aspects of memory and learning can be assessed in each case, are necessary for a correct interpretation of data relating to diet-cognition experiments. Further understanding of how specific behavioural tasks relate to the functioning of hippocampal circuitry during learning processes might be also elucidative of the specific observed memory improvements. The overall goal of this review is to give an overview of how the hippocampal circuitry operates as a memory system during behavioural tasks, which we believe will provide a new insight into the underlying mechanisms of the action of flavonoids on cognition.

Chronic consumption of flavanone-rich orange juice is associated with cognitive benefits: an 8-wk, randomized, double-blind, placebo-controlled trial in healthy older adults

BACKGROUND Research indicates that the chronic consumption of flavonoids is associated with cognitive benefits in adults with mild cognitive impairment and neurodegenerative disease, although to our knowledge, there have been no such studies in healthy older adults. Furthermore, the effects of commonly consumed orange juice flavanones on cognitive function remain unexplored. OBJECTIVE We investigated whether 8 wk of daily flavanone-rich orange juice consumption was beneficial for cognitive function in healthy older adults. DESIGN High-flavanone (305 mg) 100% orange juice and an equicaloric low-flavanone (37 mg) orange-flavored cordial (500 mL) were consumed daily for 8 wk by 37 healthy older adults (mean age: 67 y) according to a crossover, double-blind, randomized design separated by a 4-wk washout. Cognitive function, mood, and blood pressure were assessed at baseline and follow-up by using standardized validated tests. RESULTS Global cognitive function was significantly better after 8-wk consumption of flavanone-rich juice than after 8-wk consumption of the low-flavanone control. No significant effects on mood or blood pressure were observed. CONCLUSIONS Chronic daily consumption of flavanone-rich 100% orange juice over 8 wk is beneficial for cognitive function in healthy older adults. The potential for flavanone-rich foods and drinks to attenuate cognitive decline in aging and the mechanisms that underlie these effects should be investigated.

The intention‐superiority effect for naturally occurring activities: The role of intention accessibility in everyday prospective remembering in young and older adults

This study examined age differences in the accessibility of a single pool of naturally occurring intentions both before and after completion. Following Maylor, Darby, and Della Sala (2000), accessibility was measured in terms of the number of activities generated in a 4‐minute activity fluency task. Each participant undertook two such tasks. A prospective task in which they generated activities intended for completion during the following week and a retrospective task, 1 week later, in which they generated activities carried out over the previous week. In a partial replication of Maylor et al.s findings, young, but not healthy older, adults generated more to‐be‐completed intentions than completed ones, demonstrating an intention‐superiority effect (ISE) for everyday activities. The absence of an ISE for older adults appeared to reflect the reduced accessibility of intentions prior to completion, rather than the impaired inhibition of fulfilled intentions. Moreover, both groups showed greater inaccessibil...