| 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. |
- Nilsson, Jonna, et al.
(författare)
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Associations of cardiorespiratory fitness and moderate-to-vigorous physical activity with latent cognitive abilities in older adults
- 2022
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Ingår i: Psychology of Sport And Exercise. - : Elsevier. - 1469-0292 .- 1878-5476. ; 60, s. 102171-102171
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Tidskriftsartikel (refereegranskat)abstract
- It has been demonstrated that physical activity has a small but positive effect on cognition in old age, which suggests that it may be possible to alter the trajectory of age-related cognitive decline. However, our understanding of which aspects of physical activity that are important for modifying cognition remains incomplete. Adopting an exploratory approach in a sample of 115 healthy older adults (65–75 years), the present cross-sectional study used structural equation modelling to investigate the dissociable associations of physical activity (moderate-to-vigorous activity, derived from 7-day accelerometry) and cardiorespiratory fitness (VO2 max, derived from maximal treadmill ergometer test) with multiple latent cognitive abilities (working memory, episodic memory, spatial and verbal reasoning). The results showed a significant positive association between fitness and working memory, when physical activity was statistically controlled for, and a positive association of similar point magnitude between physical activity and episodic memory, when fitness was statistically controlled for, although the latter association did not reach statistical significance. The results add to the foundation for a more careful investigation of the dissociable associations of moderate-to-vigorous physical activity and fitness with cognition in old age, and encourages future research to test the hypothesis that cardiorespiratory fitness benefits working memory via general cerebrovascular effects on grey matter volume, whilst moderate-to-vigorous physical activity benefits episodic memory via effects on neuroplastic processes.
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| 5. |
- Nilsson, Jonna, et al.
(författare)
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No Significant Effect of Prefrontal tDCS on Working Memory Performance in Older Adults
- 2015
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Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Transcranial direct current stimulation (tDCS) has been put forward as a non pharmacological alternative for alleviating cognitive decline in old age. Although results have shown some promise, little is known about the optimal stimulation parameters for modulation in the cognitive domain. In this study, the effects of tDCS over the dorsolateral prefrontal cortex (dIPFC) on working memory performance were investigated in thirty older adults. An N-back task assessed working memory before, during and after anodal tDCS at a current strength of 1 mA and 2 mA, in addition to sham stimulation. The study used a single-blind, cross-over design. The results revealed no significant effect of tDCS on accuracy or response times during or after stimulation, for any of the current strengths. These results suggest that a single session of tDCS over the dIPFC is unlikely to improve working memory, as assessed by an N-back task, in old age.
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| 6. |
- Wang, Rui, et al.
(författare)
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MRI load of cerebral microvascular lesions and neurodegeneration, cognitive decline, and dementia
- 2018
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Ingår i: Neurology. - 0028-3878 .- 1526-632X. ; 91:16, s. 1487-1497
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Tidskriftsartikel (refereegranskat)abstract
- Objective To explore the differential associations of neurodegeneration and microvascular lesion load with cognitive decline and dementia in older people and the modifying effect of the APOE genotype on these associations. Methods A sample of 436 participants (age >= 60 years) was derived from the population-based Swedish National study on Aging and Care in Kungsholmen, Stockholm, and clinically examined at baseline (2001-2003) and 3 occasions during the 9-year follow-up. At baseline, we assessed microvascular lesion load using a summary score for MRI markers of lacunes, white matter hyperintensities (WMHs), and perivascular spaces and neurodegeneration load for markers of enlarged ventricles, smaller hippocampus, and smaller gray matter. We assessed cognitive function using the Mini-Mental State Examination (MMSE) test and diagnosed dementia following the Diagnostic and Statistical Manual of Mental Disorders, 4th edition criteria. We analyzed data using linear mixed-effects, mediation, and random-effects Cox models. Results During the follow-up, 46 participants were diagnosed with dementia. Per 1-point increase in microvascular lesion and neurodegeneration score (range 0-3) was associated with multiple adjusted beta-coefficients of -0.35 (95% confidence interval, -0.51 to -0.20) and -0.44 (-0.56 to -0.32), respectively, for the MMSE score and multiple adjusted hazard ratios of 1.68 (1.12-2.51) and 2.35 (1.58-3.52), respectively, for dementia; carrying APOE epsilon 4 reinforced the associations with MMSE decline. WMH volume changes during the follow-up mediated 66.9% and 12.7% of the total association of MMSE decline with the baseline microvascular score and neurodegeneration score, respectively. Conclusions Both cerebral microvascular lesion and neurodegeneration loads are strongly associated with cognitive decline and dementia. The cognitive decline due to microvascular lesions is exacerbated by APOE epsilon 4 and is largely attributed to progression and development of microvascular lesions.
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| 7. |
- Berggren, Rasmus, et al.
(författare)
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Education Does Not Affect Cognitive Decline in Aging : A Bayesian Assessment of the Association Between Education and Change in Cognitive Performance.
- 2018
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Ingår i: Frontiers in psychology. - : Frontiers Media SA. - 1664-1078. ; 9, s. 1138-
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Tidskriftsartikel (refereegranskat)abstract
- Education is positively associated with level of cognitive function but the association between education and rate of cognitive decline remains unresolved, partly for methodological reasons. In this article, we address this issue using linear mixed models and Bayesian hypothesis testing, using data from the Betula cohort-sequential longitudinal study. Our results support the null hypothesis that education does not alter the rate of cognitive decline for visuospatial ability, semantic knowledge, and episodic memory. We propose that education is only a relevant variable for understanding cognitive performance in older age because of the association between performance and education that is formed in early development.
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| 8. |
- Berggren, Rasmus, et al.
(författare)
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Foreign language learning in older age does not improve memory or intelligence : Evidence from a randomized controlled study.
- 2020
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Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 35:2, s. 212-219
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Tidskriftsartikel (refereegranskat)abstract
- Foreign language learning in older age has been proposed as a promising avenue for combatting age-related cognitive decline. We tested this hypothesis in a randomized controlled study in a sample of 160 healthy older participants (aged 65-75 years) who were randomized to 11 weeks of either language learning or relaxation training. Participants in the language learning condition obtained some basic knowledge in the new language (Italian), but between-groups differences in improvements on latent factors of verbal intelligence, spatial intelligence, working memory, item memory, or associative memory were negligible. We argue that this is not due to either poor measurement, low course intensity, or low statistical power, but that basic studies in foreign languages in older age are likely to have no or trivially small effects on cognitive abilities. We place this in the context of the cognitive training and engagement literature and conclude that while foreign language learning may expand the behavioral repertoire, it does little to improve cognitive processing abilities. (PsycINFO Database Record (c) 2020 APA, all rights reserved).
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| 9. |
- Bojsen-Møller, Emil, et al.
(författare)
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The effect of breaking up prolonged sitting on paired associative stimulation-induced plasticity.
- 2020
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Ingår i: Experimental Brain Research. - : Springer. - 0014-4819 .- 1432-1106. ; 238, s. 2497-2506
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Tidskriftsartikel (refereegranskat)abstract
- Paired associative stimulation (PAS) can induce plasticity in the motor cortex, as measured by changes in corticospinal excitability (CSE). This effect is attenuated in older and less active individuals. Although a single bout of exercise enhances PAS-induced plasticity in young, physically inactive adults, it is not yet known if physical activity interventions affect PAS-induced neuroplasticity in middle-aged inactive individuals. Sixteen inactive middle-aged office workers participated in a randomized cross-over design investigating how CSE and short-interval intracortical inhibition (SICI) were affected by PAS preceded by 3 h of sitting (SIT), 3 h of sitting interrupted every 30 min by 3 min of frequent short bouts of physical activity (FPA) and 2.5 h of sitting followed by 25 min of moderate-intensity exercise (EXE). Transcranial magnetic stimulation was applied over the primary motor cortex (M1) of the dominant abductor pollicis brevis to induce recruitment curves before and 5 min and 30 min post-PAS. Linear mixed models were used to compare changes in CSE using time and condition as fixed effects and subjects as random effects. There was a main effect of time on CSE and planned within-condition comparisons showed that CSE was significantly increased from baseline to 5 min and 30 min post-PAS, in the FPA condition, with no significant changes in the SIT or EXE conditions. SICI decreased from baseline to 5 min post-PAS, but this was not related to changes in CSE. Our findings suggest that in middle-aged inactive adults, FPAs may promote corticospinal neuroplasticity. Possible mechanisms are discussed.
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| 10. |
- Brehmer, Yvonne, et al.
(författare)
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The importance of the ventromedial prefrontal cortex for associative memory in older adults : A latent structural equation analysis
- 2020
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 209
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Tidskriftsartikel (refereegranskat)abstract
- Older adults show relatively minor age-related decline in memory for single items, while their memory for associations is markedly reduced. Inter-individual differences in memory function in older adults are substantial but the neurobiological underpinnings of such differences are not well understood. In particular, the relative importance of inter-individual differences in the medio-temporal lobe (MTL) and the lateral prefrontal cortex (PFC) for associative and item recognition in older adults is still ambiguous. We therefore aimed to first establish the distinction between inter-individual differences in associative memory (recollection-based) performance and item memory (familiarity-based) performance in older adults and subsequently link these two constructs to differences in cortical thickness in the MTL and lateral PFC regions, in a latent structural equation modelling framework. To this end, a sample of 160 older adults (65-75 years old) performed three intentional itemassociative memory tasks, of which a subsample (n = 72) additionally had cortical thickness measures in MTL and PFC regions of interest available. The results provided support for a distinction between familiarity-based item memory and recollection-based associative memory performance in older adults. Cortical thickness in the ventro-medial prefrontal cortex was positively correlated with associative recognition performance, above and beyond any relationship between item recognition performance and cortical thickness in the same region and between associative recognition performance and brain structure in the MTL (parahippocampus). The findings highlight the relative importance of the ventromedial prefrontal cortex in allowing for intentional recollection-based associative memory functioning in older adults.
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