1.
The effects of breakfast on short-term cognitive function among Chinese white-collar workers: protocol for a three-phase crossover study.
Tang, Z, Zhang, N, Liu, A, Luan, D, Zhao, Y, Song, C, Ma, G
BMC public health. 2017;(1):92
Abstract
BACKGROUND As the first meal of the day, breakfast plays an important role in supplying energy and nutrients, which are critical to working and learning activities. A three-phase crossover study was designed to investigate the effects of breakfast on cognitive function among Chinese white-collar workers. The planned study protocol is presented. METHODS A total of 264 participants aged 25-45 years will be recruited from Shenyang and Chongqing. Self-administered questionnaires will be used to collect information on age, gender, marital status, education level, occupation, smoking habits, drinking habits, and breakfast behaviours. The participants will be randomly assigned to 3 equal-sized groups (Groups A, B, and C) and will be provided with a nutrition-adequate breakfast, a nutrition-inadequate breakfast, or no breakfast, respectively. Each participant will receive the breakfast treatment on the basis of assignment to one of three sequences (ABC/BCA/CAB). Each participant will complete a battery of cognitive tests assessing short-term memory, attention, and working memory 120 minutes after breakfast. Mood will be measured through a self-administered questionnaire assessing the dimensions of positive and negative frames of mind. Additionally, fasting blood glucose and postprandial 2-hour blood glucose levels will be tested with a blood-glucose meter (Roche ACCU-CHEK®-Performa). All the participants will take all the tests in three successive weeks, and the order of presentation will be counter-balanced across groups. DISCUSSION The present study will be the first investigation of the effect of breakfast food type and quality on cognitive function amongst white-collar workers in China. We predict that a nutrition-adequate breakfast, compared with a nutrition-inadequate breakfast and no breakfast, will significantly improve short-term cognitive function. The results of this study should provide scientific evidence of the effect of breakfast quality on cognitive function and provide scientific data to inform nutrition education strategies and promote a healthy lifestyle. TRIAL REGISTRATION Chinese clinical trial registry (Primary registry in the WHO registry network) Registration number: ChiCTR-IPR-15007114 . Date of registration: August 25, 2015.
2.
Attention induced neural response trade-off in retinotopic cortex under load.
Torralbo, A, Kelley, TA, Rees, G, Lavie, N
Scientific reports. 2016;:33041
Abstract
The effects of perceptual load on visual cortex response to distractors are well established and various phenomena of 'inattentional blindness' associated with elimination of visual cortex response to unattended distractors, have been documented in tasks of high load. Here we tested an account for these effects in terms of a load-induced trade-off between target and distractor processing in retinotopic visual cortex. Participants were scanned using fMRI while performing a visual-search task and ignoring distractor checkerboards in the periphery. Retinotopic responses to target and distractors were assessed as a function of search load (comparing search set-sizes two, three and five). We found that increased load not only increased activity in frontoparietal network, but also had opposite effects on retinotopic responses to target and distractors. Target-related signals in areas V2-V3 linearly increased, while distractor response linearly decreased, with increased load. Critically, the slopes were equivalent for both load functions, thus demonstrating resource trade-off. Load effects were also found in displays with the same item number in the distractor hemisphere across different set sizes, thus ruling out local intrahemispheric interactions as the cause. Our findings provide new evidence for load theory proposals of attention resource sharing between target and distractor leading to inattentional blindness.
3.
Catechol-O-methyltransferase val158met genotype modulates sustained attention in both the drug-free state and in response to amphetamine.
Hamidovic, A, Dlugos, A, Palmer, AA, de Wit, H
Psychiatric genetics. 2010;(3):85-92
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Abstract
OBJECTIVE Variation in the catechol-O-methyltransferase (COMT) val(158)met polymorphism has been associated with executive cognition and working memory, presumably mediated by the prefrontal cortex. Here, we extend these observations by examining two measures of cognitive function, lapses in attention and visuo-spatial-motor speed of processing, in both the drug-free state and after administration of d-amphetamine. METHODS Healthy Caucasian male and female participants (n=161) participated in a double-blind, crossover design study where they received placebo or d-amphetamine (10 and 20 mg). The outcome measures included self-reported mood states, a simple reaction time task, and a task measuring visuo-spatial-motor speed of processing. We first evaluated whether the genotypic groups differed on any of the measures in the absence of drug administration, including a measure of personality. We then determined whether the genotypic groups differed in their responses to acute doses of d-amphetamine (10 or 20 mg). RESULTS We found that without drug, val/val and val/met carriers showed greater lapses in attention on the reaction time task than met/met carriers, but the genotypic groups did not differ on the visuo-spatial-motor speed of processing task. Val/val carriers scored higher on a personality measure of extraversion than val/met and met/met carriers. Compared with placebo, the lower dose of d-amphetamine (10 mg) improved lapses in attention and visuo-spatial-motor speed of processing in val/val carriers, and decreased lapses in attention in val/met carriers. The highest dose of d-amphetamine (20 mg) improved performance on lapses in attention and visuo-spatial-motor speed of processing tasks in both val/val and val/met carriers, but not in met/met carriers. None of the genotypic groups differed on mood states, either with or without drug administration. CONCLUSION The results of this study extend earlier findings with the COMT genotypes to additional measures of cognition, and suggest that the presence of the val allele is associated with poorer performance and greater improvement with a stimulant drug. The results further suggest that this polymorphism does not affect the mood-altering effects of d-amphetamine, consistent with the preferential influence of COMT in cortical regions.
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A physiological correlate of the "Zoom Lens" of visual attention.
Müller, NG, Bartelt, OA, Donner, TH, Villringer, A, Brandt, SA
The Journal of neuroscience : the official journal of the Society for Neuroscience. 2003;(9):3561-5
Abstract
Attending a certain region in space enhances activity in visual areas retinotopically mapped to this region; stimuli presented in this region are preferentially processed. The zoom lens model of visual attention proposes that the attended region can be adjusted in size and predicts a tradeoff between its size and processing efficiency because of limited processing capacities. By means of event-related functional magnetic resonance imaging, we analyzed neural activity in multiple visual areas as a function of the size of an attended visual field region, which was defined by a spatial cue stimulus. After cueing, a target object, defined by a specific feature conjunction, had to be identified among objects within the cued region. Neural activity preceding the objects in multiple retinotopic visual areas correlated with the size of the attended region, as did subjects' performance. While the extent of activated retinotopic visual cortex increased with the size of the attended region, the level of neural activity in a given subregion decreased. These findings are consistent with the physiological predictions of the zoom lens model. Size-related modulations of neural activity were pronounced in early visual areas. We relate this finding to the small receptive field of these areas, whereby only neuronal units with receptive fields covering the attended region received a top-down bias. This preactivation of neuronal units may then have gated selective processing of the features of the object that appeared at the attended location, thus enabling feature integration and object identification.