| 1. |
- Johansson, Roger, et al.
(författare)
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Gaze position regulates memory accessibility during competitive memory retrieval
- 2020
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Ingår i: Cognition. - : Elsevier BV. - 0010-0277. ; 197
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Tidskriftsartikel (refereegranskat)abstract
- While previous research has demonstrated that gaze position can increase the accessibility of previous memories when reconstructing the past (Johansson & Johansson, 2014), the present study tested whether such gaze behavior can assist in selecting target memories in the face of competing memories. An adapted retrieval practice paradigm was used, where participants were engaged in selective retrieval while looking at locations that overlapped with the encoding location of either the target item or the competing item. Replicating previous findings, we show that encoding-retrieval compatibility in gaze positions increases the likelihood of successful remembering. We furthermore provide novel evidence that looking at locations where competing items were encoded during retrieval practice induces forgetting of the competitors during subsequent tests of memory. Corroborating evidence from changes in pupil size suggests that such gaze induced forgetting is modulated by the increased demands to successfully resolve interference from competing memories. This study represents the first demonstration that gaze position can both up- and downregulate memory accessibility during competitive memory retrieval and offers novel insights into the underlying dynamics.
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| 2. |
- Johansson, Roger, et al.
(författare)
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How encoding-retrieval overlap in gaze positions influences episodic memory accessibility in the “real world”
- 2020
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Konferensbidrag (refereegranskat)abstract
- An extensive body of research has shown that episodic remembering involves spontaneous eye movements that largely reproduce the gaze patterns that were present during encoding (e.g. Brandt & Stark, 1997; Johansson, et al., 2006; 2012; Johansson & Johansson, 2014; Richardson & Spivey, 2000). We have further demonstrated that gaze positions showing compatibility between encoding and retrieval increase the likelihood of successful remembering (Johansson & Johansson, 2014, 2020). However, to date, there is virtually no research on how gaze direction influences episodic remembering outside the laboratory. The aim of the present project was, therefore, to systematically investigate this effect in a “real-world” scenario. In a first experiment, participants (N=40, equipped with a mobile eye tracker) entered a room where they were faced with six framed stimuli at six different locations. Each stimulus comprised a letter in the center and an associated item to the left or right side of this letter. Participants were given 60 s to freely inspect and encode how each letter was associated with the items’ three features (shape, color and location). Participants then exited the room and engaged in a two-minute distracter task before they re-entered the room. They were now faced with the six frames again, but this time only the letter cue was present. They were then given 90 s to orally recall the associated items’ features in a free-recall procedure. For each participant, the same encoding-retrieval procedure was repeated over four rounds. During retrieval, the framed letters were either located in the same location as they were encoded in (congruent) or shuffled around to different locations (incongruent). Results overall replicated our previous lab-finding, with superior retrieval performance in the congruent condition. However, the effect was virtually absent for the participants who faced an incongruent condition in their first round of retrieval. In four follow-up experiments, we manipulated the number of congruent and incongruent frames within trials over the four rounds (0, 2, 4 or 6 congruent frames) and also introduced different degrees of interference between associated items. Interference was created by using two exemplars of each shape and each color instead of using unique shapes and unique colors across stimuli frames. In effect, this creates a situation where there are overlapping and competing features between items across frames. Collectively, the results from those follow-up experiments revealed that the congruency benefit is dependent on both contextual expectation and the need to handle interference from competing memories. Specifically, we show that the expectation of how relevant the spatial context is for the retrieval task can be both up- and down-regulated depending on previous rounds and that the congruency effect increases in accordance with the need to handle interference from competing memories. Those findings are further qualified by data from participants’ gaze patterns. In sum, we extend previous work by demonstrating that facilitatory effects of gaze direction on episodic remembering generalize to “real-world” scenarios, and we present novel findings that shed light on the underlying mechanisms.
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| 3. |
- Nikolaev, Andrey, et al.
(författare)
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Neural correlates of episodic memory buildup in naturalistic viewing behavior
- 2021
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Konferensbidrag (refereegranskat)abstract
- In everyday life, we bind visual samples of the world into a coherent episodic memory via eye movements. Previous eye tracking research revealed that visual scrutiny, gaze transitions between event elements, and refixations during encoding predict successful memory formation. However, little is known about the neural mechanisms of these processes. Here, we combine EEG and eye tracking to investigate the buildup of episodic memory representations in naturalistic viewing behavior.Twenty-eight participants encoded a series of events. Each event consisted of elements from three categories (faces, places, objects) and was presented for 10 s. After a distractor task, memory was tested for all event-specific element combinations. To succeed in the test, participants had to separate the different events by making strong associations between within-event elements. The simultaneously recorded EEG and eye movements were analyzed at the encoding stage of the task.A major problem of EEG-eye movement coregistration in free viewing concerns the overlapping effects of sequential saccades on EEG. We overcame this by using the regression-based deconvolution method, which allows correction of such overlap as well as removal of the confounding effects from eye movement characteristics and ordering factors, such as fixation rank. After deconvolution, we extracted EEG theta and alpha activity in epochs from -200 to +400 ms relative to the fixation onset.As expected, subsequent memory performance for the whole event increased with the cumulative number of fixations within single elements and inter-category gaze transitions between elements. We found that these two gaze memory effects are associated with two distinct memory effects of the fixation-related EEG activity: theta synchronization over the frontal and centro-parietal areas, respectively. The frontal theta effect may indicate the sampling of individual elements, whereas the centro-parietal theta effect may reflect the binding of elements into a coherent episodic event. Furthermore, memory performance was predicted by gaze returns to already visited categories. This refixation effect was associated with a fixation-related alpha desynchronization over the occipital areas. This may indicate the pivotal role of refixations in temporal accumulation of visual information that is needed for building a coherent representation of the whole event.We conclude that the combination of theta synchronization and alpha desynchronization at the fixation level supports the buildup of a coherent episodic memory across sequential eye movements.
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| 4. |
- Zahed, Hana, et al.
(författare)
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Epidemiology of 40 blood biomarkers of one-carbon metabolism, vitamin status, inflammation, and renal and endothelial function among cancer-free older adults
- 2021
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Imbalances of blood biomarkers are associated with disease, and biomarkers may also vary non-pathologically across population groups. We described variation in concentrations of biomarkers of one-carbon metabolism, vitamin status, inflammation including tryptophan metabolism, and endothelial and renal function among cancer-free older adults. We analyzed 5167 cancer-free controls aged 40–80 years from 20 cohorts in the Lung Cancer Cohort Consortium (LC3). Centralized biochemical analyses of 40 biomarkers in plasma or serum were performed. We fit multivariable linear mixed effects models to quantify variation in standardized biomarker log-concentrations across four factors: age, sex, smoking status, and body mass index (BMI). Differences in most biomarkers across most factors were small, with 93% (186/200) of analyses showing an estimated difference lower than 0.25 standard-deviations, although most were statistically significant due to large sample size. The largest difference was for creatinine by sex, which was − 0.91 standard-deviations lower in women than men (95%CI − 0.98; − 0.84). The largest difference by age was for total cysteine (0.40 standard-deviation increase per 10-year increase, 95%CI 0.36; 0.43), and by BMI was for C-reactive protein (0.38 standard-deviation increase per 5-kg/m2 increase, 95%CI 0.34; 0.41). For 31 of 40 markers, the mean difference between current and never smokers was larger than between former and never smokers. A statistically significant (p < 0.05) association with time since smoking cessation was observed for 8 markers, including C-reactive protein, kynurenine, choline, and total homocysteine. We conclude that most blood biomarkers show small variations across demographic characteristics. Patterns by smoking status point to normalization of multiple physiological processes after smoking cessation.
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| 5. |
- Bergvall, Niklas, et al.
(författare)
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Continuous Slurry Hydrocracking of Biobased Fast Pyrolysis Oil
- 2021
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Ingår i: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 35:3, s. 2303-2312
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Tidskriftsartikel (refereegranskat)abstract
- Co-refining of fast pyrolysis bio-oil together with fossil oil in existing refinery infrastructure is an attractive and cost-efficient route to conversion of lignocellulosic biomass to transportation fuel. However, due to large differences in properties between the two oils, special notice is needed to reduce process-related issues. Here, fast pyrolysis bio-oil produced from lignocellulosic biomass was co-refined with vacuum gas oil at a 20:80 weight ratio in continuous operation in a pilot-scale slurry hydrocracker in order to investigate the impact of process parameters on product quality and process performance. Mass balances together with product characterization were used to investigate product yields, product composition, and hydrodeoxygenation. Best conversion and hydrodeoxygenation of the fast pyrolysis bio-oil was achieved using an unsupported catalyst loading of 900 ppm Mo with either a low temperature (410 °C) and long residence time (2 h) or higher temperature (435 °C) and shorter residence time (1 h). These settings resulted in about 94% hydrodeoxygenation but also led to highest yield of biogenic carbon to gas phase (40-43 wt %) and lowest yield of biogenic carbon to oil fractions (53-56 wt %) as well as the water fraction (3-5 wt %). Successfully, coke yield remained low at around 0.07-0.10 wt % for all performed runs, which was comparable to the insoluble particle content in the feed due to the presence of particles in the untreated fast pyrolysis bio-oil. Co-processing pyrolysis oil with fossil oil in a slurry hydrocracker seems to be a robust process with regard to coke formation, which should lead to reduced plugging issues compared to fixed bed hydrotreaters. Although this study gives a brief understanding of the effect of process parameters on the processing of fast pyrolysis bio-oil, further research is required to find optimal process parameters and to fully comprehend the possibilities and limitations for production of transportation fuels from fast pyrolysis bio-oil using this technology.
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| 6. |
- Berndtsson, Emilia, et al.
(författare)
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Side Streams of Broccoli Leaves: A Climate Smart and Healthy Food Ingredient
- 2020
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Ingår i: International journal of environmental research and public health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Human consumption of fruits and vegetables are generally below recommended levels. Waste from the production, e.g., of un-used parts such as broccoli leaves and stem when producing broccoli florets for food, is a sustainability issue. In this study, broccoli leaves were analyzed for the content of various dietary fibre and phenolics, applying the Uppsala method and HPLC analyses, respectively. The results showed that broccoli leaves had comparable levels of dietary fibre (26%-32% of dry weight (DW)) and phenolic compounds (6.3-15.2 mg/g DW) to many other food and vegetables considered valuable in the human diet from a health perspective. A significant positive correlation was found among soluble dietary fibre and phenolic acids indicating possible bindings between these components. Seasonal variations affected mainly the content of conjugated phenolics, and the content of insoluble dietary fibre. This study verified the importance of the use of broccoli production side streams (leaves) as they may contribute with health promoting components to the human diet and also socio-economic and environmental benefits to the bioeconomic development in the society.
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| 7. |
- Brännström, Jonas, et al.
(författare)
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Listening effort and fatigue in native and non-native primary school children
- 2021
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Ingår i: Journal of Experimental Child Psychology. - : Elsevier BV. - 0022-0965 .- 1096-0457. ; 210
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Tidskriftsartikel (refereegranskat)abstract
- Background noise makes listening effortful and may lead to fatigue. This may compromise classroom learning, especially for children with a non-native background. In the current study, we used pupillometry to investigate listening effort and fatigue during listening comprehension under typical (0 dB signal-to-noise ratio [SNR]) and favorable (+10 dB SNR) listening conditions in 63 Swedish primary school children (7–9 years of age) performing a narrative speech–picture verification task. Our sample comprised both native (n = 25) and non-native (n = 38) speakers of Swedish. Results revealed greater pupil dilation, indicating more listening effort, in the typical listening condition compared with the favorable listening condition, and it was primarily the non-native speakers who contributed to this effect (and who also had lower performance accuracy than the native speakers). Furthermore, the native speakers had greater pupil dilation during successful trials, whereas the non-native speakers showed greatest pupil dilation during unsuccessful trials, especially in the typical listening condition. This set of results indicates that whereas native speakers can apply listening effort to good effect, non-native speakers may have reached their effort ceiling, resulting in poorer listening comprehension. Finally, we found that baseline pupil size decreased over trials, which potentially indicates more listening-related fatigue, and this effect was greater in the typical listening condition compared with the favorable listening condition. Collectively, these results provide novel insight into the underlying dynamics of listening effort, fatigue, and listening comprehension in typical classroom conditions compared with favorable classroom conditions, and they demonstrate for the first time how sensitive this interplay is to language experience.
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| 8. |
- Carlie, Johanna, et al.
(författare)
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Development of an Auditory Passage Comprehension Task for Swedish Primary School Children of Cultural and Linguistic Diversity
- 2021
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Ingår i: Journal of Speech, Language, and Hearing Research. - : American Speech-Language-Hearing Association. - 1558-9102 .- 1092-4388. ; 64:10
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study reports on the development of an auditory passage comprehension task for Swedish primary school children of cultural and linguistic diversity. It also reports on their performance on the task in quiet and in noise. Method Eighty-eight children aged 7-9 years and showing normal hearing participated. The children were divided into three groups based on presumed language exposure: 13 children were categorized as Swedish-speaking monolinguals, 19 children were categorized as simultaneous bilinguals, and 56 children were categorized as sequential bilinguals. No significant difference in working memory capacity was seen between the three language groups. Two passages and associated multiple-choice questions were developed. During development of the passage comprehension task, steps were taken to reduce the impact of culture-specific prior experience and knowledge on performance. This was achieved by using the story grammar principles, universal topics and plots, and simple language that avoided complex or unusual grammatical structures and words. Results The findings indicate no significant difference between the two passages and similar response distributions. Passage comprehension performance was significantly better in quiet than in noise, regardless of language exposure group. The monolinguals outperformed both simultaneous and sequential bilinguals in both listening conditions. Conclusions Because the task was designed to minimize the effect of cultural knowledge on auditory passage comprehension, this suggests that compared with monolinguals, both simultaneous and sequential bilinguals have a disadvantage in auditory passage comprehension. As expected, the findings demonstrate that noise has a negative effect on auditory passage comprehension. The magnitude of this effect does not relate to language exposure. The developed auditory passage comprehension task seems suitable for assessing auditory passage comprehension in primary school children of linguistic and cultural diversity.
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| 9. |
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| 10. |
- Crescitelli, Rossella, 1985, et al.
(författare)
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Subpopulations of extracellular vesicles from human metastatic melanoma tissue identified by quantitative proteomics after optimized isolation
- 2020
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Ingår i: Journal of Extracellular Vesicles. - : Wiley. - 2001-3078. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The majority of extracellular vesicle (EV) studies conducted to date have been performed on cell lines with little knowledge on how well these represent the characteristics of EVs in vivo. The aim of this study was to establish a method to isolate and categorize subpopulations of EVs isolated directly from tumour tissue. First we established an isolation protocol for subpopulations of EVs from metastatic melanoma tissue, which included enzymatic treatment (collagenase D and DNase). Small and large EVs were isolated with differential ultracentrifugation, and these were further separated into high and low-density (HD and LD) fractions. All EV subpopulations were then analysed in depth using electron microscopy, Bioanalyzer (R), nanoparticle tracking analysis, and quantitative mass spectrometry analysis. Subpopulations of EVs with distinct size, morphology, and RNA and protein cargo could be isolated from the metastatic melanoma tissue. LD EVs showed an RNA profile with the presence of 18S and 28S ribosomal subunits. In contrast, HD EVs had RNA profiles with small or no peaks for ribosomal RNA subunits. Quantitative proteomics showed that several proteins such as flotillin-1 were enriched in both large and small LD EVs, while ADAM10 were exclusively enriched in small LD EVs. In contrast, mitofilin was enriched only in the large EVs. We conclude that enzymatic treatments improve EV isolation from dense fibrotic tissue without any apparent effect on molecular or morphological characteristics. By providing a detailed categorization of several subpopulations of EVs isolated directly from tumour tissues, we might better understand the function of EVs in tumour biology and their possible use in biomarker discovery.
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