| 1. |
- Craig, Michael, et al.
(författare)
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How does intentionality of encoding affect memory for episodic information?
- 2016
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Ingår i: Learning & memory (Cold Spring Harbor, N.Y.). - : Cold Spring Harbor Laboratory. - 1072-0502 .- 1549-5485. ; 23:11, s. 648-659
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Tidskriftsartikel (refereegranskat)abstract
- Episodic memory enables the detailed and vivid recall of past events, including target and wider contextual information. In this paper, we investigated whether/how encoding intentionality affects the retention of target and contextual episodic information from a novel experience. Healthy adults performed (1) a What-Where-When (WWW) episodic memory task involving the hiding and delayed recall of a number of items (what) in different locations (where) in temporally distinct sessions (when) and (2) unexpected tests probing memory for wider contextual information from the WWW task. Critically, some participants were informed that memory for WWW information would be subsequently probed (intentional group), while this came as a surprise for others (incidental group). The probing of contextual information came as a surprise for all participants. Participants also performed several measures of episodic and nonepisodic cognition from which common episodic and nonepisodic factors were extracted. Memory for target (WWW) and contextual information was superior in the intentional group compared with the incidental group. Memory for target and contextual information was unrelated to factors of nonepisodic cognition, irrespective of encoding intentionality. In addition, memory for target information was unrelated to factors of episodic cognition. However, memory for wider contextual information was related to some factors of episodic cognition, and these relationships differed between the intentional and incidental groups. Our results lead us to propose the hypothesis that intentional encoding of episodic information increases the coherence of the representation of the context in which the episode took place. This hypothesis remains to be tested.
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| 2. |
- Finkelmeyer, A., et al.
(författare)
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Altered hippocampal function in major depression despite intact structure and resting perfusion
- 2016
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 46:10, s. 2157-2168
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Tidskriftsartikel (refereegranskat)abstract
- Background. Hippocampal volume reductions in major depression have been frequently reported. However, evidence for functional abnormalities in the same region in depression has been less clear. We investigated hippocampal function in depression using functional magnetic resonance imaging (fMRI) and neuropsychological tasks tapping spatial memory function, with complementing measures of hippocampal volume and resting blood flow to aid interpretation. Method. A total of 20 patients with major depressive disorder (MDD) and a matched group of 20 healthy individuals participated. Participants underwent multimodal magnetic resonance imaging (MRI): fMRI during a spatial memory task, and structural MRI and resting blood flow measurements of the hippocampal region using arterial spin labelling. An offline battery of neuropsychological tests, including several measures of spatial memory, was also completed. Results. The fMRI analysis showed significant group differences in bilateral anterior regions of the hippocampus. While control participants showed task-dependent differences in blood oxygen level-dependent (BOLD) signal, depressed patients did not. No group differences were detected with regard to hippocampal volume or resting blood flow. Patients showed reduced performance in several offline neuropsychological measures. All group differences were independent of differences in hippocampal volume and hippocampal blood flow. Conclusions. Functional abnormalities of the hippocampus can be observed in patients with MDD even when the volume and resting perfusion in the same region appear normal. This suggests that changes in hippocampal function can be observed independently of structural abnormalities of the hippocampus in depression.
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| 3. |
- Regan, Callum, et al.
(författare)
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Acute effects of nitrate and breakfast on working memory, cerebral blood flow, arterial stiffness, and psychological factors in adolescents : Study protocol for a randomised crossover trial.
- 2023
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 18:5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Inorganic nitrate has been shown to acutely improve working memory in adults, potentially by altering cerebral and peripheral vasculature. However, this remains unknown in adolescents. Furthermore, breakfast is important for overall health and psychological well-being. Therefore, this study will investigate the acute effects of nitrate and breakfast on working memory performance, task-related cerebral blood flow (CBF), arterial stiffness, and psychological outcomes in Swedish adolescents.METHODS: This randomised crossover trial will recruit at least 43 adolescents (13-15 years old). There will be three experimental breakfast conditions: (1) none, (2) low-nitrate (normal breakfast), and (3) high-nitrate (concentrated beetroot juice with normal breakfast). Working memory (n-back tests), CBF (task-related changes in oxygenated and deoxygenated haemoglobin in the prefrontal cortex), and arterial stiffness (pulse wave velocity and augmentation index) will be measured twice, immediately after breakfast and 130 min later. Measures of psychological factors and salivary nitrate/nitrite will be assessed once before the conditions and at two-time points after the conditions.DISCUSSION: This study will provide insight into the acute effects of nitrate and breakfast on working memory in adolescents and to what extent any such effects can be explained by changes in CBF. This study will also shed light upon whether oral intake of nitrate may acutely improve arterial stiffness and psychological well-being, in adolescents. Consequently, results will indicate if nitrate intake from beetroot juice or if breakfast itself could acutely improve cognitive, vascular, and psychological health in adolescents, which can affect academic performance and have implications for policies regarding school meals.TRIAL REGISTRATION: The trial has been prospectively registered on 21/02/2022 at https://doi.org/10.1186/ISRCTN16596056. Trial number: ISRCTN16596056.
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| 4. |
- Mattsson, C. Mikael
(författare)
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Konditionsträning för lagbollsidrottare
- 2012
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Ingår i: Idrott & kunskap. - 1652-6961. ; :1, s. 46-49
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Vilka konditionstestvärden har elitspelare i fotboll, ishockey och basket? Och hur tränar man effektivast sinkondition om man är bollidrottare? Mikael Mattson, doktor i fysiologi vid GIH, reder ut begreppen.
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| 5. |
- Mattsson, C. Mikael
(författare)
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Requirements for Soldiers’ Endurance Capacity in Prolonged Continuous Work
- 2014
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Konferensbidrag (refereegranskat)abstract
- Physiological factors that influence soldier’s ability to sustain performance level in prolonged continuous work are such as A) initial physical level; B) ability to carry; and C) ability to sustain performance level over prolonged periods of time.A) General fitness level is obviously crucial, such as strength and aerobic capacity, but so is also being completely healthy when the effort initiates. We have presented an immunological profile that might be useful to determine which soldiers that will underperform. Before a 6-day military training course expression of CD3 on CD8+ lymphocytes and percent CD8+CD3 lymphocytes was lower, whereas CD4/CD8 ratio was higher among soldiers who failed compared to those who completed the training (Ekblom et al. 2011).B) It is well know that energy expenditure increases with increased carried weight, but at heavier loads (>30 kg) we found a disproportionate increase. Our hypothesis is that this is due to inaccurate technique, caused by insufficient strength relative to the carried weight, which may lead to unusual tiredness. In our preliminary results all soldiers had a point, carried weight, above which the work economy decreased. Therefore, it would be relevant to determine each soldier’s maximum optimal weight to carry.C) Fatigue and performance in ultra-endurance exercise, such as military efforts, is determined by (in part) other factors compared to traditional endurance sports. One of the most important aspects is energy balance. The total energy expenditure for a 24-h Adventure Race can be as high as 18-20 000 kcal (Enqvist et al. 2010). One reason for fatigue is the substantial energy deficit. Partly because that the profile of amino acids in blood and muscle change (Borgenvik et al. 2012), muscle damage (Wichardt et al. 2011), hormonal changes (Berg et al 2008), and immunological responses (Wallberg et al. 2011, Marklund et al. 2013). This combined indicates that specific supplementations may be needed. We have recently examined the energy balance in military situations. Two situations were 100 h, 78 km by foot in summer alpine terrain (6200 kcal/24h), and 187 h of mixed military tasks (5600 kcal/24h). Even though the allotment of rations was sufficient to cover the energy expenditure the actual intake was substantially lower, energy deficit being approximately 50 % and 33 %, respectively. However, we see large individual differences. If possible, energy availability should be individualized so that heavier soldiers and those with heavier tasks have opportunities to get higher energy supply compared to soldiers with lighter tasks and lower weight.
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| 6. |
- Mattsson, C. Mikael, et al.
(författare)
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NSAID inom multisport
- 2011
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Ingår i: Svensk IdrottsMedicin. - 1103-7652. ; 30:4, s. 18-21
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Användning av NSAID är mycket vanligt bland deltagare i längre multisporttävlingar. Ofta i tron att NSAID påskyndar återhämtningen, trots att kunskapen om dess påverkan vid idrott är begränsad. Det är till och med möjligt att NSAID har motsatt effekt och istället påverkar muskelåterhämtning och -uppbyggnad negativt.
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| 7. |
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| 8. |
- Mattsson, C. Mikael, et al.
(författare)
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Sports genetics moving forward - lessons learned from medical research
- 2016
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 48:3, s. 175-182
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Tidskriftsartikel (refereegranskat)abstract
- Sports genetics can take advantage of lessons learned from human disease genetics. By righting past mistakes and increasing scientific rigor, the breadth and depth of knowledge in the field can be magnified. We present an outline of challenges facing sports genetics in the light of experiences from medical research.Sports performance is complex, resulting from a combination of a wide variety of different traits and attributes. Improving sports genetics will foremost require analyses based on detailed phenotyping. In order to find widely valid, reproducible common variants associated with athletic phenotypes, study sample sizes must be dramatically increased. One paradox is that in order to confirm relevance, replications in specific populations must be undertaken. Family studies of athletes may facilitate the discovery of rare variants with large effects on athletic phenotypes. The complexity of the human genome, combined with the complexity of athletic phenotypes, will require additional metadata and biological validation to identify a comprehensive set of genes involved.Analysis of personal genetic and multiomic profiles contribute to our conceptualization of precision medicine; the same will be the case in precision sports science. In the refinement of sports genetics it is essential to evaluate similarities and differences between genders and among ethnicities. Sports genetics to date have been hampered by small sample sizes and biased methodology which can lead to erroneous associations and overestimation of effect sizes. Consequently, currently available genetic tests based on these inherently limited data cannot predict athletic performance with any accuracy.
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| 9. |
- Mattsson, C. Mikael, et al.
(författare)
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The ELITE project (Exercise at the Limit - Inherited Traits of Endurance) - the genetic profiles of the best endurance athletes in the world.
- 2017
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Konferensbidrag (refereegranskat)abstract
- Cardiovascular health exists as a spectrum of wellness and disease states. Moreover, a significant portion of what defines these states is due to genetics. We hypothesize that there exist genes and pathways that dually contribute to both disease and extreme health states. Interrogating the ‘adaptive’ tail of the distribution for individuals with extreme phenotypes, such as high maximum oxygen uptake (VO2max) in endurance athletes, will inform prevention, cause and treatment of pathogenic (‘maladaptive’) conditions. 1 To date, most genetic studies in the athlete population have examined a subset of genes (out of more than 21,000 in the genome), using small sample sizes and qualitative measures of performance. To the best of our knowledge, there has not been a comprehensive genetic study of endurance athletes with strict quantitative eligibility criteria.2-4The ELITE project (Exercise at the Limit – Inherited Traits of Endurance) intends to investigate the world’s best endurance athletes, i.e. individuals with extremely high VO2max. A primary goal is to determine what role genetic variation plays in athletic ability. One of the ancillary goals of the project is to understand the unique genetic differences contributing to extreme fitness in women versus men. We will sequence and analyze the genomes of elite level competitive athletes from various countries (including USA, Scandinavia, UK, Japan, and Brazil) who are highly successful in one of several endurance sports (such as running, cross country skiing, triathlon, cycling, rowing). We have recruited 750 elite athletes (142 women and 608 men) who have been consented and undergone enhanced whole exome sequencing and/or MEGA chip GWAS analysis. Inclusion criteria for the study restricts to the highest tail end (>99.98th percentile or 1/5000), i.e. VO2max >63 ml/kg for women and >75 ml/kg for men. Even with differential eligibility, skewed recruitment (1:4) is a challenge.Our preliminary results show tantalizing evidence for potentially beneficial genetic variants in several highly plausible genes. Additionally, pilot burden testing on a subset of the athletes also showed promising results. While already promising, rigorous analysis, increased sample size and orthogonal replication is required as our next step. Mattsson CM, Wheeler M, Waggott D, Caleshu C, Ashley EA. Sports genetics moving forward - lessons learned from medical research. Physiol Genomics. 2016; 48(3):175-182.Bouchard C, Sarzynski MA, Rice TK, Kraus WE, Church TS, Sung YJ, Rao DC, Rankinen T. Genomic predictors of the maximal O₂ uptake response to standardized exercise training programs. J Appl Physiol (1985). 2011; 110(5):1160-70.Eynon N, Morán M, Birk R, Lucia A. The champions' mitochondria: is it genetically determined? A review on mitochondrial DNA and elite athletic performance. Physiol Genomics. 2011;43(13):789-98.Pitsiladis YP, Tanaka M, Eynon N, Bouchard C, North KN, Williams AG, Collins M, Moran CN, Britton SL, Fuku N, Ashley EA, Klissouras V, Lucia A, Ahmetov II, de Geus E, Alsayrafi M; Athlome Project Consortium. Athlome Project Consortium: a concerted effort to discover genomic and other "omic" markers of athletic performance. Physiol Genomics. 2016;48(3):183-90.
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| 10. |
- Nilsson, Avlant, 1985, et al.
(författare)
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Complex I is bypassed during high intensity exercise
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Human muscles are tailored towards ATP synthesis. When exercising at high work rates muscles convert glucose to lactate, which is less nutrient efficient than respiration. There is hence a trade-off between endurance and power. Metabolic models have been developed to study how limited catalytic capacity of enzymes affects ATP synthesis. Here we integrate an enzyme-constrained metabolic model with proteomics data from muscle fibers. We find that ATP synthesis is constrained by several enzymes. A metabolic bypass of mitochondrial complex I is found to increase the ATP synthesis rate per gram of protein compared to full respiration. To test if this metabolic mode occurs in vivo, we conduct a high resolved incremental exercise tests for five subjects. Their gas exchange at different work rates is accurately reproduced by a whole-body metabolic model incorporating complex I bypass. The study therefore shows how proteome allocation influences metabolism during high intensity exercise.
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