Spatial memory in a food storing corvid I. Near tall landmarks are primarily used

This work suggests how food storing corvids use spatial memory to relocate caches, and how they can do this after some landmarks surrounding caches have become hidden due to leaf fall, snow fall or plant growth. Experiments involved training European jays (Garrulus glandarius) to find buried food, the location of which was specified by an array of 12 landmarks. Tests were then performed with the array rotated, or with certain landmarks removed from the array. The.main findings were: (1) birds primarily remembered the position of the goal using the near tall landmarks (15-30 cm from the goal and 20 cm high); (2) birds obtained a sense of direction both from the landmark array and something external to the array; (3) birds did not use smell or marks in the surface of the ground to find the goal. Memory of near tall landmarks is likely to be functional for these birds since (a) nearer landmarks provide a more accurate fix, and (b) taller landmarks are less likely to be completely obscured by snow fall, leaf fall or intervening vegetation. The work also demonstrates the use of G.I.S. software for the analysis and representation of animal search patterns.

Do animals have cognitive maps?

Drawing on studies of humans, rodents, birds and arthropods, I show that 'cognitive maps' have been used to describe a wide variety of spatial concepts. There are, however, two main definitions. One, sensu Tolman, O'Keefe and Nadel, is that a cognitive map is a powerful memory of landmarks which allows novel short-cutting to occur. The other, sensu Gallistel, is that a cognitive map is any representation of space held by an animal. Other definitions with quite different meanings are also summarised. I argue that no animal has been conclusively shown to have a cognitive map, sensu Tolman, O'Keefe and Nadel, because simpler explanations of the crucial novel short-cutting results are invariably possible. Owing to the repeated inability of experimenters to eliminate these simpler explanations over at least 15 years, and the confusion caused by the numerous contradictory definitions of a cognitive map. I argue that the cognitive map is no longer a useful hypothesis for elucidating the spatial behaviour of animals and that use of the term should be avoided.

The effects of ethinylestradiol and progestins ("the pill") on cognitive function in pre-menopausal women

Oral contraceptives (OCs), often referred to as "the pill", are the most commonly employed form of reversible contraception. OCs are comprised of combined synthetic estrogen and progestin, which work to suppress ovulation and subsequently protect against pregnancy. To date, almost 200 million women have taken various formulations of OC, making it one of the most widely consumed classes of medication in the world. While a substantial body of literature has been dedicated to understanding the physical effects of OCs, much less is known about the long term consequences of OC use on brain anatomy and the associated cognitive effects. Accumulating evidence suggests that sex hormones may significantly affect human cognition. This phenomenon has been commonly studied in older populations, such as in post-menopausal women, while research in healthy, pre-menopausal women remains limited. The current review focused on the effects of OCs on human cognition, with the majority of studies comparing pre-menopausal OC users to naturally cycling women. Human neuroimaging data and animal studies are also described herein. Taken together, the published findings on OC use and human cognition are varied. Of those that do report positive results, OC users appear to have improved verbal memory, associative learning and spatial attention. We recommend future research to employ blinding procedures and randomised designs. Further, more detailed information pertaining to the specific generation and phasic type of OCs, as well as menstrual cycle phase of the OC non-users should be considered to help unmask the potential impact of OC use on human cognition.

Improved processing speed: online computer-based cognitive training in older adults

In an increasingly aging population, a number of adults are concerned about declines in their cognitive abilities. Online computer-based cognitive training programs have been proposed as an accessible means by which the elderly may improve their cognitive abilities; yet, more research is needed in order to assess the efficacy of these programs. In the current study, a commercially available 21-day online computer-based cognitive training intervention was administered to 34 individuals aged between 53 and 75 years. The intervention consisted of computerized training in reaction time, inspection time, short-term memory for words, executive function, visual spatial acuity, arithmetic, visual spatial memory, visual scanning/discrimination, and n-back working memory. An active solitaire control group was also included. Participants were tested at baseline, posttraining and at three-weeks follow-up using a battery of neuropsychological outcome measures. These consisted of simple reaction time, complex reaction time, digit forwards and backwards, spatial working memory, digit symbol substitution, RAVLT, and trail making. Significant improvement in simple reaction time and choice reaction time task was found in the cognitive training group both posttraining and at three-weeks follow-up. However, no significant improvements on the other cognitive tasks were found. The training program was found to be successful in achieving transfer of trained cognitive abilities in speed of processing to similar untrained tasks. © 2012 Copyright Taylor and Francis Group, LLC.

Clozapine reverses schizophrenia-related behaviours in the metabotropic glutamate receptor 5 knockout mouse: association with N-methyl-d-aspartic acid receptor up-regulation

Abnormalities in glutamatergic signalling are proposed in schizophrenia in light of the schizophreniform psychosis elicited by NMDA antagonists. The metabotropic glutamate receptor 5 (mGluR5) interacts closely with the NMDA receptor and is implicated in several behavioural endophenotypes of schizophrenia. We have demonstrated that mice lacking mGluR5 have increased sensitivity to the hyperlocomotive effects of the NMDA antagonist MK-801. Mice lacking mGluR5 also show abnormal locomotor patterns, reduced prepulse inhibition (PPI), and deficits on performance of a short-term spatial memory task on the Y-maze. Chronic administration of the antipsychotic drug clozapine ameliorated the locomotor disruption and reversed the PPI deficit, but did not improve Y-maze performance. Chronic clozapine increased NMDA receptor binding ([3H]MK-801) but did not alter dopamine D2 ([3H]YM-09151), 5-HT2A ([3H]ketanserin), or muscarinic M1/M4 receptor ([3H]pirenzepine), binding in these mice. These results demonstrate behavioural abnormalities that are relevant to schizophrenia in the mGluR5 knockout mouse and a reversal of behaviours with clozapine treatment. These results highlight both the interactions between mGluR5 and NMDA receptors in the determination of schizophreniform behaviours and the potential for the effects of clozapine to be mediated by NMDA receptor regulation.
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Spatial ability is impaired and mineralcorticoid receptor mRNA expression in zebra finches (Taeniopygia guttata) selected for acute high corticosterone response to stress

In mammals, stress hormones have profound influences on spatial learning and memory. Here, we investigated whether glucocorticoids influence cognitive abilities in birds by testing a line of zebra finches selectively bred to respond to an acute stressor with high plasma corticosterone (CORT) levels. Cognitive performance was assessed by spatial and visual one-trial associative memory tasks. Task performance in the high CORT birds was compared with that of the random-bred birds from a control breeding line. The birds selected for high CORT in response to an acute stressor performed less well than the controls in the spatial task, but there were no significant differences between the lines in performance during the visual task. The birds from the two lines did not differ in their plasma CORT levels immediately after the performance of the memory tasks; nevertheless, there were significant differences in peak plasma CORT between the lines. The high CORT birds also had significantly lower mineralocorticoid receptor mRNA expression in the hippocampus than the control birds. There was no measurable difference between the lines in glucocorticoid receptor mRNA density in either the hippocampus or the paraventricular nucleus. Together, these findings provide evidence to suggest that stress hormones have important regulatory roles in avian spatial cognition.

Recognising and monitoring high-level behaviours in complex spatial environments

The recognition of activities from sensory data is important in advanced surveillance systems to enable prediction of high-level goals and intentions of the target under surveillance. The problem is complicated by sensory noise and complex activity spanning large spatial and temporal extents. This paper presents a system for recognising high-level human activities from multi-camera video data in complex spatial environments. The Abstract Hidden Markov mEmory Model (AHMEM) is used to deal with noise and scalability The AHMEM is an extension of the Abstract Hidden Markov Model (AHMM) that allows us to represent a richer class of both state-dependent and context-free behaviours. The model also supports integration with low-level sensory models and efficient probabilistic inference. We present experimental results showing the ability of the system to perform real-time monitoring and recognition of complex behaviours of people from observing their trajectories within a real, complex indoor environment.

Malondialdehyde plasma concentration correlates with declarative and working memory in patients with recurrent depressive disorder

Oxidative stress has been implicated in the cognitive decline, especially in memory impairment. The purpose of this study was to determine the concentration of malondialdehyde (MDA) in patients with recurrent depressive disorders (rDD) and to define relationship between plasma levels of MDA and the cognitive performance. The study comprised 46 patients meeting criteria for rDD. Cognitive function assessment was based on: The Trail Making Test , The Stroop Test, Verbal Fluency Test and Auditory-Verbal Learning Test. The severity of depression symptoms was assessed using the Hamilton Depression Rating Scale (HDRS). Statistically significant differences were found in the intensity of depression symptoms, measured by the HDRS on therapy onset versus the examination results after 8 weeks of treatment (P < 0.001). Considering the 8-week pharmacotherapy period, rDD patients presented better outcomes in cognitive function tests. There was no statistically significant correlation between plasma MDA levels, and the age, disease duration, number of previous depressive episodes and the results in HDRS applied on admission and on discharge. Elevated levels of MDA adversely affected the efficiency of visual-spatial and auditory-verbal working memory, short-term declarative memory and the delayed recall declarative memory. 1. Higher concentration of plasma MDA in rDD patients is associated with the severity of depressive symptoms, both at the beginning of antidepressants pharmacotherapy, and after 8 weeks of its duration. 2. Elevated levels of plasma MDA are related to the impairment of visual-spatial and auditory-verbal working memory and short-term and delayed declarative memory.

The impact of working memory load on task execution and online plan adjustment during multitasking in a virtual environment

Three experiments investigated the impact of working memory load on online plan adjustment during a test of multitasking in young, nonexpert, adult participants. Multitasking was assessed using the Edinburgh Virtual Errands Test (EVET). Participants were asked to memorize either good or poor plans for performing multiple errands and were assessed both on task completion and on the extent to which they modified their plans during EVET performance. EVET was performed twice, with and without a secondary task loading a component of working memory. In Experiment 1, articulatory suppression was used to load the phonological loop. In Experiment 2, oral random generation was used to load executive functions. In Experiment 3, spatial working memory was loaded with an auditory spatial localization task. EVET performance for both good- and poor-planning groups was disrupted by random generation and sound localization, but not by articulatory suppression. Additionally, people given a poor plan were able to overcome this initial disadvantage by modifying their plans online. It was concluded that, in addition to executive functions, multiple errands performance draws heavily on spatial, but not verbal, working memory resources but can be successfully completed on the basis of modifying plans online, despite a secondary task load.

Multitasking, working memory and remembering intentions

Multitasking refers to the performance of a range of tasks that have to be completed within a limited time period. it differs from dual task paradigms in that tasks are performed not in parallel, but by interleaving, switching from one to the other. it differs also from task switching paradigms in that the time scale is very much longer, multiple different tasks are involved, and most tasks have a clear end point. Multitasking has been studied extensively with particular sets of experts such as in aviation and in the military, and impairments of multitasking performance have been studied in patients with frontal lobe lesions. Much less is known as to how multitasking is achieved in healthy adults who have not had specific training in the necessary skills. This paper will provide a brief review of research on everyday multitasking, and summarise the results of some recent experiments on simulated everyday tasks chosen to require advance and on-line planning, retrospective memory, prospective memory, and visual, spatial and verbal short-term memory.

Age-related changes to the neural correlates of working memory which emerge after midlife

Previous research has indicated that the neural processes which underlie working memory change with age. Both age-related increases and decreases to cortical activity have been reported. This study investigated which stages of working memory are most vulnerable to age-related changes after midlife. To do this we examined age-differences in the 13 Hz steady state visually evoked potential (SSVEP) associated with a spatial working memory delayed response task. Participants were 130 healthy adults separated into a midlife (40-60 years) and an older group (61-82 years). Relative to the midlife group, older adults demonstrated greater bilateral frontal activity during encoding and this pattern of activity was related to better working memory performance. In contrast, evidence of age-related under activation was identified over left frontal regions during retrieval. Findings from this study suggest that after midlife, under-activation of frontal regions during retrieval contributes to age-related decline in working memory performance. © 2014 Macpherson, White, Ellis, Stough, Camfield, Silberstein and Pipingas.

Memory improvements in elderly women following 16 weeks treatment with a combined multivitamin, mineral and herbal supplement: a randomized controlled trial.

RATIONALE: There is potential for multivitamin supplementation to improve cognition in the elderly. This randomized, double-blind, placebo-controlled trial was conducted to investigate the effects of 16 weeks multivitamin supplementation (Swisse Women's 50+ Ultivite ®) on cognition in elderly women. METHODS: Participants in this study were 56 community dwelling, elderly women, with subjective complaints of memory loss. Cognition was assessed using a computerized battery of memory and attention tasks designed to be sensitive to age-related declines to fluid intelligence, and a measure of verbal recall. Biochemical measures of selected nutrients, homocysteine, markers of inflammation, oxidative stress, and blood safety parameters were also collected. All cognitive and haematological parameters were assessed at baseline and 16 weeks post-treatment. RESULTS: The multivitamin improved speed of response on a measure of spatial working memory, however benefits to other cognitive processes were not observed. Multivitamin supplementation decreased levels of homocysteine and increased levels of vitamin B(6) and B(12), with a trend for vitamin E to increase. There were no hepatotoxic effects of the multivitamin formula indicating this supplement was safe for everyday usage in the elderly. CONCLUSION: Sixteen weeks ssupplementation with a combined multivitamin, mineral and herbal formula may benefit working memory in elderly women at risk of cognitive decline.