Glucose administration and cognitive function: differential effects of age and effort during a dual task paradigm in younger and older adults

RATIONALE: Current research suggests that glucose facilitates performance on cognitive tasks which possess an episodic memory component and a relatively high level of cognitive demand. However, the extent to which this glucose facilitation effect is uniform across the lifespan is uncertain. METHODS: This study was a repeated measures, randomised, placebo-controlled, cross-over trial designed to assess the cognitive effects of glucose in younger and older adults under single and dual task conditions. Participants were 24 healthy younger (average age 20.6 years) and 24 healthy older adults (average age 72.5 years). They completed a recognition memory task after consuming drinks containing 25 g glucose and a placebo drink, both in the presence and absence of a secondary tracking task. RESULTS AND CONCLUSIONS: Glucose enhanced recognition memory response time and tracking precision during the secondary task, in older adults only. These findings do not support preferential targeting of hippocampal function by glucose, rather they suggest that glucose administration differentially increases the availability of attentional resources in older individuals.

Analysis of spherical indentation of superelastic shape memory alloys

Dimensional analysis and the finite element method are applied in this paper to study spherical indentation of superelastic shape memory alloys. The scaling relationships derived from dimensional analysis bridge the indentation response and the mechanical properties of a superelastic shape memory alloy. Several key variables of a superelastic indentation curve are revealed and examined. We prove that the bifurcation force in a superelastic indentation curve only relies on the forward transformation stress and the elastic properties of the initial austenite; and the return force in a superelastic indentation curve only relies on the reverse transformation stress and the elastic properties of the initial austenite. Furthermore, the dimensionless functions to determine the bifurcation force and the return force are proved to be identical. These results not only enhance our understanding of spherical indentation of superelastic shape memory alloys, but also provide the theoretical basis for developing a practicable method to calibrate the mechanical properties of a superelastic material from the spherical indentation test.

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.

Beyond mimesis : place, interpretation and response

My study examines the subjective nature of artistic interpretation through the notion of mimesis as process or transformation of material. Influential factors that mediate in the artistic process, such as memory, reflection and an awareness of cultural analogy and metaphor, are examined and related to a specific project in the studio, where the mediation process is further influenced by the materials used to produce the images. My studies of the concept of mimesis have revealed an intermediary realm that exists in the space between empirical reality and its interpretation. Throughout history the process of mimesis has been integral to all forms of the arts. In Plato's time the production of an image that simulated things as they appeared to the eye was considered a desired ideal. Aristotle later introduced developments which extended this concept to include a refiguring or reforming of material derived from the original source, making new connections between existing factors and in this transformation bringing new meanings to a symbolically constituted world. This discussion of the representation of reality, the influence of a dialogue between notions of imitation and the recreation of material continues throughout the exegesis. My study emphasises the interpretive stage of the mimetic process where a consideration of these themes is most relevant and some of the factors that can influence its outcome. It is my opinion that the production of images in response to the particularities of place can be defined in three stages. Firstly, the experience of the place; secondly, the beginning and maturation of the idea or concept; where mimesis takes place, and thirdly, the production of the art work in response. This process is illustrated in Part 2 of the exegesis, where the development of the studio work is documented and linked with the themes discussed in Part 1. The geographic site or place I selected to study is adjacent to Mt. Noorat, a volcanic site in the Western district of Victoria; the surrounding plains are littered with scoria that has been thrown out of the volcano thousands of years ago. Early British, Scottish and Irish settlers to this region used the stone to construct fences reminiscent of their homeland, through this activity they cleared the land and confined and protected their stock. My interests are in factors that include - the material of the stone, notions of enclosure and safety, of boundaries and circumscribed space, and of the cultural reflection that has taken place in this reconstruction of Eurocentric vision. These walls also represent the means by which land was enclosed and property defined, moving from a situation of public access to notions of ownership and the annexation of land for individual gain. Around each point of eruption, the craggy volcanic scoria has been used to create a constructed landscape which both symbolises and mirrors the Anglo - Celtic origins of the people. I have used the legend of Narcissus to illustrate the self-reflective and introspective processes that the settlers invoked in their attempts to come to terms with a strange land. I consider that the story of Narcissus, who fell in love with his own reflection, finds a parellel in the creation of the walls. The re-creation of artifacts from their own cultural environment provided the settlers with a familiar 'face' in an alien world; a reassurance of the familiar in an unfamiliar terrain. Part of this study is an investigation of this notion of landscape as cultural reflection. Geographers have long known that landscape is a cultural construct, an historically evolving ideal manifested in painting, prints and drawings as well as poetry, gardens and parks. One can view these constructions as illustrations or images of meaning which constitute representations of cultural ideals. The neo-classical influence reflected in the paintings of artists who accompanied the early expeditions to Australia demonstrates these themes. The medium of the mirror provides the opportunity to suggest aspects of a cultural reflection and an awareness of identity that has relevance to contemporary Australian culture, therefore, I have allowed it to play a major role throughout this study. Its role in mimesis, firstly, as a reflection in an imitative sense is established, then in its refigurative role, in which the similarities between the original and the reformed rely more on correlative factors than representation. I have used examples from the history of art to illustrate this potential. The formation and development of a narrative involving reflection threads throughout the thesis, both in the visual presentation and in the exegesis. The production of a body of paintings, drawings and sculpture reflect my interpretation and response to the particular site. The correspondences between these works and my theoretical concerns is articulated in the exegesis. The metaphor implied by the use of the walls as agents of enclosure also refers to the capacity of the individual to be confined by notional boundaries and restrictive practices where totalising systems of thought dominate theoretical debate and restrict its freedom. I have used images where gaps in the walls represent the potential implicit to the concept of liminal space, where the spectator moves from one physical space to another and from one stage of development to another. The threshold of this opening in the walls becomes the site where transformation can take place, a metaphor for the mimetic process where the initial experience is translated and transformed into the final product. The paintings, drawings and other works in this series fulfil the role of marks on the surface of the mirror, separating the initial experience from the processes of memory, reflection and speculation. The works draw attention to the materiality that they represent and yet provide the opportunity for new insights and experiences, allowing the subjective nature of artistic activity to combine symbolic elements relating to the site, resulting in the production of meaning.

Location rather than CD62L phenotype is critical in the early establishment of influenza-specific T cell memory

The rapid recall of influenza virus-specific CD8+ T cell effector function is protective, although our understanding of T cell memory remains incomplete. Recent debate has focused particularly on the CD62L lymph node homing receptor. The present analysis shows that although functional memory can be established from both CD62Lhi and CD62Llo CD8+ T cell subsets soon after initial encounter between naive precursors and antigen, the optimal precursors are CD8+CD44hiCD25lo immune lymphocytes isolated from draining lymph nodes on day 3.5 after influenza virus infection. Analysis of primed T cells at different times after challenge indicates that the capacity to transfer memory is diminished at the peak of the primary cytotoxic T lymphocyte response, challenging speculations that the transition to memory first requires full differentiation to effector status. It seems that location rather than CD62Lhi/lo phenotype may be the more profitable focus for further dissection of the early establishment of T cell memory.

Protection and compensation in the influenza virus-specific CD8+ T cell response.

Influenza virus-specific CD8+ T cells generally recognize peptides derived from conserved, internal proteins that are not subject to antibody-mediated selection pressure. Prior exposure to any one influenza A virus (H1N1) can prime for a secondary CD8+ T cell response to a serologically different influenza A virus (H3N2). The protection afforded by this recall of established CD8+ T cell memory, although limited, is not negligible. Key characteristics of primary and secondary influenza-specific host responses are probed here with recombinant viruses expressing modified nucleoprotein (NP) and acid polymerase (PA) genes. Point mutations were introduced into the epitopes derived from the NP and PA such that they no longer bound the presenting H2Db MHC class I glycoprotein, and reassortant H1N1 and H3N2 viruses were made by reverse genetics. Conventional (C57BL/6J, H2b, and Ig+/+) and Ig-/- (muMT) mice were more susceptible to challenge with the single NP [HKx31 influenza A virus (HK)-NP] and PA (HK-PA) mutants, but unlike the Ig-/- mice, Ig+/+ mice were surprisingly resistant to the HK-NP/-PA double mutant. This virus was found to promote an enhanced IgG response resulting, perhaps, from the delayed elimination of antigen-presenting cells. Antigen persistence also could explain the increase in size of the minor KbPB1703 CD8+ T cell population in mice infected with the mutant viruses. The extent of such compensation was always partial, giving the impression that any virus-specific CD8+ T cell response operates within constrained limits. It seems that the relationship between protective humoral and cellular immunity is neither simple nor readily predicted.

Recognition and response to human movement contained in motion capture data using the Self Organising Map

Neural Networks have been used successfully for recognition of human gestures in many applications including analysis of motion capture data. This paper investigates the potential for using the same methods for both recognition and synthesising responses in relation to movement contained in motion capture sequences.

Determination of crystal structure and crystallographic characteristics in Ni-Mn-Ga ferromagnetic shape memory alloys

Ni-Mn-Ga ferromagnetic shape memory alloys (FSMAs) have received great attention during the past decade due to their giant magnetic shape memory effect and fast dynamic response. The crystal structure and crystallographic features of two Ni-Mn-Ga alloys were precisely determined in this study. Neutron diffraction measurements show that Ni48Mn30Ga22 has a Heusler austenitic structure at room temperature; its crystal structure changes into a seven-layered martensitic structure when cooled to 243K. Ni53Mn25Ga22 has an I4/mmm martensitic structure at room temperature. Electron backscattered diffraction (EBSD) analyses reveal that there are only two martensitic variants with a misorientation of ~82° around <110> axis in each initial austenite grain in Ni53Mn25Ga22. The investigation on crystal structure and crystallographic features will shed light on the development of high-performance FSMAs with optimal properties.

Prospective memory in a virtual environment: beneficial effects of cue saliency

Prospective Memory (PM) research focuses on how the cognitive system successfully encodes and retains an intention, before retrieving it at a particular future time or in response to a particular future event. Previous work using 2D text stimuli has shown that increasing the saliency of the retrieval cue can improve performance. In this work, we investigated the effect of increased cue saliency in a more ecologically valid 3D virtual environment. The findings indicate that increased perceptual saliency of the cue does benefit PM in a dynamic and visually rich environment but that the impact of cue saliency does not interact with attentional load.

Nicotine improves memory for delayed intentions

Rationale
The present paper asked first whether the cholinergic agonist nicotine improves memory for delayed intentions (prospective memory, ProM) and second whether pharmacological dissociation would support the psychological distinction that is made between strategic (effortful) and automatic (non-effortful) intention activation in prospective 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.

Cameras and body memory create new blends of performance with visual art practice

I propose that a learnt somatic experience of dance can translate into another discipline such as visual art. In my visual art practice I combine both photography, which is traditionally seen as a still medium, and performance in order to create a new form of embodiment. I have developed two series of art works of prints and video made in response to the Australian landscape. By analyzing my method of movement and photography I will describe how an embodied dance language can result in a material outcome – a series of drawings of light and movement, a body signature made possible through old and new technology. I have activated a performative state while capturing images discovering new ways of using technology reliant upon my knowledge of dance, performance and photography. Making a human size camera to make analogue prints I gained an intuitive knowledge of light – a skill that has become foundational in performance and photography. In response to space and light in the Australian landscape I then built a custom made camera that allows for the longest possible time to capture an image. I move while taking the image and use the camera as if an eye at the end of my arm. In this way I activate dance skills and embodied knowledge of space, timing and light, opening up a radical space for new thinking, making and performing.Furthermore this process engages memory and sentiment embodied through age. Many artists have responded to the unique qualities of the Australian landscape and by using a performative/photographic approach I have engaged with my own body memory. Being brought up in the landscape and training in ballet my body has acquired memories at a cellular level. My method has given memory a voice. In doing these works I have become conscious of how unconscious memories of the space and light in the landscape is a movement vocabulary activated in a way that ‘feels’ like dancing. As an ageing person this experience is profound and the resultant materialisation of the photographs and videos leave a material record of the event. The sentiments evoked through my process bridge the past with the present, the body with the mind, memory with body and space connecting disciplines in a new way.The materialisation of artworks itself continues cross-disciplinary processes using a technique that is a continuum of the performative. Through using technology I release memory of the landscape and pixel by pixel build imagery that relies on and is a part of the performative process. It is a photographic performance dance manifesting as pigment on paper exhibited a gallery context. The exhibition allows a space for the viewer to respond - re-membering the universal the act of moving. The works titled ‘body signatures’ and ‘Fly Rhythm’ become a communicative device in the gallery context.My paper through an analysis of process and methods used in making the two series will talk to several of the subjects listed and reveal a new way of connecting performance and visual art and old and new technologies.