The cognitive neuroscience of visual working memory

Visual working memory allows us to temporarily maintain and manipulate visual information in order to solve a task. The study of the brain mechanisms underlying this function began more than half a century ago, with Scoville and Milner’s (1957) seminal discoveries with amnesic patients. This timely collection of papers brings together diverse perspectives on the cognitive neuroscience of visual working memory from multiple fields that have traditionally been fairly disjointed: human neuroimaging, electrophysiological, behavioural and animal lesion studies, investigating both the developing and the adult brain

Brain Function and Health, Sports, and Exercise

This reprint represents the articles published in the Special Issue “Brain Function and Health, Sports, and Exercise”. Fifteen articles were published, with topics covering the relationship between acute effects of exercise on cognitive function, as well as the influence of exercise on positive medium-term adaptations in populations as children, youth, adults and older. We think that the different approaches used in the different articles will help the readers to have a greater overview of the current research in brain and exercise

Auditory cues for attention management

An exhaustible supply of mental resources necessitate that we are selective for what we attend to. Attention prioritizes what ought to be processed and what ignored, allocating valuable resources to selected information at the cost of unattended information elsewhere. For this purpose it is necessary to know the conditions that help the brain decide when attention should be paid, where to and to what information. The question that is central to this dissertation is how auditory cues can support the management of limited attentional resources based on auditory characteristics. Auditory cues can (1) increase the overall alertness, (2) orient attention to unattended information, or (3) manage attentional resources by informing of an upcoming task-switch and, therefore, indicate when to pay attention to which task. The first study of this dissertation investigated whether different population groups might process auditory cues differently, thus resulting in different levels of alertness (1). Study two examined more specifically whether the type of auditory cue (verbal command or auditory icon) used as in-vehicle notifications can influence the level of alertness (1). Studies three and four investigated the use of a special auditory cue characteristic, the looming intensity profile, for directing attention to regions of interest (2). Here, attention orienting to peripheral events was tested within a dual-task paradigm which required attention shifts between the two tasks (3). Throughout the studies, I show that electroencephalography (EEG) is an indispensable tool for evaluating auditory cues and their influence on crossmodal attention. By using EEG measurements, I was able to demonstrate that auditory cues evoked the same level of alertness across different populations and that differences in behavioral responses are not due to subjective differences of cue processing (Chapter 2). More importantly, I was able to show that verbal commands and auditory cues can be functionally discriminated by the brain. While both sounds are alerting they ought to be used complementary, depending on the intended goal (Chapter 3). The studies that employed the looming sound to redirect spatial attention to an unattended visual target showed a robust benefit in response times at longer cue-target intervals (Chapter 4 and 5). The looming benefit in processing visual targets is also apparent as enhanced neural activity in the right posterior hemisphere 280ms after target onset. Source-estimation results suggest that a preferential activation of frontal and parietal areas, which are involved in attention orienting, give rise to this looming benefit (Chapter 5). Finally, auditory cues improved performance for unattended targets but might also benefit the central visuo-motor task by only directing attention to the periphery without moving the eyes away from the visuo-motor task. This demonstrates that auditory cues also help in managing attention by preparing for task switches such that covert attention is allocated to the respective task when this task has to be performed. Overall this dissertation demonstrates that the careful selection of auditory cues can go a long way in supporting attention management

NMDA and dopamine interactions in the nucleus accumbens modulate cortical acetylcholine release

The nucleus accumbens (NAC) plays a key role in directing appropriate motor output following the presentation of behaviorally relevant stimuli. As such, we postulate that accumbens efferents also participate in the modulation of neuronal circuits regulating attentional processes directed toward the identification and selection of these stimuli. In this study, N -methyl-d-aspartate (NMDA) and D1 ligands were perfused into the shell region of the NAC of awake rats. Cortical cholinergic transmission, a mediator of attentional processes, was measured via microdialysis probes inserted into the prefrontal cortex (PFC). NMDA perfusions (150 or 250 µm) into NAC resulted in significant increases in acetylcholine (ACh) efflux in PFC (150–200% above baseline levels). Co-administration of the D1 antagonist SCH-23390 (150 µm) markedly attenuated (by approx. 70%) ACh efflux following perfusions of 150 µm NMDA but not following 250 µm NMDA, suggesting that D1 receptor activity contributes to the ability of the lower but not the higher concentration of NMDA to increase cortical ACh release. Collectively, these data reveal a positive modulation of NMDA receptors by D1 receptors in NAC that is expressed trans -synaptically at the level of cortical transmission. This modulation may underlie the coordinated linking of attentional processes and motor output following exposure to salient and behaviorally relevant stimuli.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72309/1/j.1460-9568.2005.04333.x.pd

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 375)

This bibliography lists 212 reports, articles, and other documents recently introduced into the NASA Scientific and Technical Information System database. Subject coverage includes the following: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Brain imaging studies in severe somatization

Somatization was described 4000 years ago but the pathophysiology of the, phenomenon is unknown. The aim of this investigation was to explore whether central nervous system (CNS) pathology is associated with severe somatization which was operationalized as somatization disorder (SD) and undifferentiated somatoform disorder. The study sample consisted of severely somatizing people who were included into the study after a multi-phase screening procedure in order to exclude psychiatric comorbidities and physical illnesses. Diagnosis of somatization disorder or undifferentiated sofatoform disorder were set according to Diagnostic and Statistical Manual of Mental Disorders 4th ed. (DSM-IV). The first study explored the regional cerebral metabolic rate of glucose (rCMRGlc) in severely somatizing females and found it to be reduced in several regions of the brain compared to healthy controls. The second study observed brain morphology with magnetic resonance imaging (MRI) based on the findings from the first study and showed enlarged caudate nuclei in somatizing women compared to healthy volunteers. The third study investigated temperament factors and brain metabolism, and their association with severe somatization. Low caudate and putamen metabolism, low novelty seeking as well as high harm avoidance were found to be associated with severe somatization in women, reduced caudate metabolism having the strongest association. The last study is a report of man with left-side gradient of multiple symptoms of unknown origin in the body. The examination revealed a hypermetabolic nucleus putamen on the contralateral side. All the main results reported in these four articles are original findings. The results suggest that CNS pathology is involved in the pathophysiology of severe somatization.Siirretty Doriast

Oral sodium butyrate supplementation ameliorates paclitaxel-induced behavioral and intestinal dysfunction

Paclitaxel (PTX) is one of the most broadly used chemotherapeutic agents for the treatment of several tumor types including ovarian, breast, and non-small cell lung cancer. However, its use is limited by debilitating side effects, involving both gastrointestinal and behavioral dysfunctions. Due to growing evidence showing a link between impaired gut function and chemotherapy-associated behavioral changes, the aim of this study was to identify a novel therapeutic approach to manage PTX-induced gut and brain comorbidities. Mice were pre-treated with sodium butyrate (BuNa) for 30 days before receiving PTX. After 14 days, mice underwent to behavioral analysis and biochemical investigations of gut barrier integrity and microbiota composition. Paired evaluations of gut functions revealed that the treatment with BuNa restored PTX-induced altered gut barrier integrity, microbiota composition and food intake suggesting a gut-to-brain communication. The treatment with BuNa also ameliorated depressive- and anxiety-like behaviors induced by PTX in mice, and these effects were associated with neuroprotective and anti-inflammatory outcomes. These results propose that diet supplementation with this safe postbiotic might be considered when managing PTX-induced central side effects during cancer therapy