| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Cortes, Diana S., et al.
(författare)
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Age-Related Differences in Evaluation of Social Attributes From Computer-Generated Faces of Varying Intensity
- 2019
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Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 34:5, s. 686-697
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Tidskriftsartikel (refereegranskat)abstract
- In everyday life throughout the life span, people frequently evaluate faces to obtain information crucial for social interactions. We investigated age-related differences in judgments of a wide range of social attributes based on facial appearance. Seventy-one younger and 60 older participants rated 196 computer-generated faces that systematically varied in facial features such as shape and reflectance to convey different intensity levels of seven social attributes (i.e., attractiveness, competence, dominance, extraversion, likeability, threat, and trustworthiness). Older compared to younger participants consistently gave higher attractiveness ratings to faces representing both high and low levels of attractiveness. Older participants were also less sensitive to the likeability of faces and tended to evaluate faces representing low likeability as more likable. The age groups did, however, not differ substantially in their evaluations of the other social attributes. Results are in line with previous research showing that aging is associated with preference toward positive and away from negative information and extend this positivity effect to social perception of faces.
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| 3. |
- Cortes, Diana S., et al.
(författare)
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Effects of aging on emotion recognition from dynamic multimodal expressions and vocalizations
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Age-related differences in emotion recognition have predominantly been investigated using static pictures of facial expressions, and positive emotions beyond happiness have rarely been included. The current study instead used dynamic facial and vocal stimuli, and included a wider than usual range of positive emotions. In Task 1, younger and older adults were tested for their abilities to recognize 12 emotions from brief video recordings presented in visual, auditory, and multimodal blocks. Task 2 assessed recognition of 18 emotions conveyed by non-linguistic vocalizations (e.g., laughter, sobs, and sighs). Results from both tasks showed that younger adults had significantly higher overall recognition rates than older adults. In Task 1, significant group differences (younger > older) were only observed for the auditory block (across all emotions), and for expressions of anger, irritation, and relief (across all presentation blocks). In Task 2, significant group differences were observed for 6 out of 9 positive, and 8 out of 9 negative emotions. Overall, results indicate that recognition of both positive and negative emotions show age-related differences. This suggests that the age-related positivity effect in emotion recognition may become less evident when dynamic emotional stimuli are used and happiness is not the only positive emotion under study.
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| 4. |
- Cortes, Diana S., et al.
(författare)
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Increased dorsomedial prefrontal cortex activity to negative emotion displays in men but not in women
- 2019
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Ingår i: Program.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The neuropeptide oxytocin plays a prominentrole in social and emotional cognition. Findings suggest that exogenous intranasal oxytocin administration facilitates emotion recognition in humans, but individual and contextual differences may have moderating effects. A major caveat in this line of work is that it is predominantly based on young males, which limits current knowledge and potential for generalizability across gender. To uncover potential gender effects, the present study included younger and older men and women. Utilizing a randomized, double-blind, placebo-controlled, within-subjects study design, we investigated the effects of a single-dose of 40 IUs intranasal oxytocin administration on emotion recognition of dynamic positive and negative stimuli in 32 men (mean age 45.78, sd. 22.87) and 39 women (mean 47.87, sd. 47.87), 40 minutes prior to MRI scanning. Preliminary analyses show that oxytocin induced brain activity reductions during exposure to negative (relative to positive) stimuli in women, while increasing brain activity in dorsomedial prefrontal cortex in men. We speculate that the effects of oxytocin on emotion recognition may possibly be related to emotion regulation and mentalization processes, and that oxytocin is related to potential sex-differences in these processes. The results also raise concern that previous oxytocin literature on emotion recognition may be biased as there appears to be gender-differential effects of oxytocin on brain activity across adulthood that have been underestimated. In the next stage of the present study, we will investigate the interaction effects among treatment, sex, age, and presentation modality.
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| 5. |
- Cortes, Diana S., et al.
(författare)
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Memory for faces and voices varies as a function of sex and expressed emotion
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- We investigated how memory for faces and voices (presented separately and in combination) varies as a function of sex and emotional expression (anger, disgust, fear, happiness, sadness, and neutral). At encoding, participants judged the expressed emotion of items in forced-choice tasks, followed by incidental Remember/Know recognition tasks. Results from 600 participants showed that accuracy (hits minus false alarms) was consistently higher for neutral compared to emotional items, whereas accuracy for specific emotions varied across the presentation modalities (i.e., faces, voices, and face-voice combinations). For the subjective sense of recollection (“remember” hits), neutral items received the highest hit rates only for faces, whereas for voices and face-voice combinations anger and fear expressions instead received the highest recollection rates. We also observed better accuracy for items by female expressers, and own-sex bias where female participants displayed memory advantage for female faces and face-voice combinations. Results further suggest that own-sex bias can be explained by recollection, rather than familiarity, rates. Overall, results show that memory for faces and voices may be influenced by the expressions that they carry, as well as by the sex of both items and participants. Emotion expressions may also enhance the subjective sense of recollection without enhancing memory accuracy.
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| 6. |
- Cortes, Diana S., et al.
(författare)
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Mixed support for a causal link between single dose intranasal oxytocin and spiritual experiences: opposing effects depending on individual proclivities for absorption
- 2018
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Ingår i: Social Cognitive and Affective Neuroscience. - : Oxford University Press (OUP). - 1749-5016 .- 1749-5024. ; 13:9, s. 921-932
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Tidskriftsartikel (refereegranskat)abstract
- Intranasal oxytocin (OT) has previously been found to increase spirituality, an effect moderated by OT-related genotypes. This pre-registered study sought to conceptually replicate and extend those findings. Using a single dose of intranasal OT vs placebo (PL), we investigated experimental treatment effects, and moderation by OT-related genotypes on spirituality, mystical experiences, and the sensed presence of a sentient being. A more exploratory aim was to test for interactions between treatment and the personality disposition absorption on these spirituality-related outcomes. A priming plus sensory deprivation procedure that has facilitated spiritual experiences in previous studies was used. The sample (N = 116) contained both sexes and was drawn from a relatively secular context. Results failed to conceptually replicate both the main effects of treatment and the treatment by genotype interactions on spirituality. Similarly, there were no such effects on mystical experiences or sensed presence. However, the data suggested an interaction between treatment and absorption. Relative to PL, OT seemed to enhance spiritual experiences in participants scoring low in absorption and dampen spirituality in participants scoring high in absorption.
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| 7. |
- Cortes, Diana S., et al.
(författare)
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Oxytocin Induces Brain Activity Reductions to Negative Emotional Stimuli in Younger and Older Adults
- 2018
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Konferensbidrag (refereegranskat)abstract
- In recent years, the intranasal administration of the neuropeptide oxytocin has mainly been related to improvements in domains such as emotion recognition and memory, but to date the effects of oxytocin in aging remain largely unknown. A major caveat in oxytocin research is that it is almost exclusively based on young men which may reflect an inadequate picture of the potential benefits of oxytocin administration. In a randomized, double blind, placebo controlled, within-subjects study design, we investigated whether oxytocin affects the recognition of positive and negative stimuli differently in younger and older adults. Forty-four older adults (50% women; M= 69.82) and 44 younger adults (50% women; M= 24.75) participated in this study two times, receiving a single intranasal dose of 40 IUs of placebo and oxytocin in randomized order 40 minutes before engaging in the task. Participants watched short videoclips where actors displayed nine emotions: neutrality, happiness, pride, interest, relief, anger, despair, sadness, and disgust. Preliminary results indicate that oxytocin-induced reductions to negative emotions were found in bilateral fusiform gyrus (Z > 4.16, Family wise error corrected, pFWE < 0.009), hippocampus (Z > 4.53, pFWE < 0.002), insula (Z > 3.69, pFWE < 0.045), and superior temporal gyrus (Z > 4.34, pFWE < 0.008), as well as, right-lateralized reductions in the amygdala (Z = 3.73, pFWE = 0.005). These findings are in line with previous studies showing decreased brain activity to negative stimuli and suggest that this mechanism in not only present in younger adults but it can also be extended to an older population. Future studies should investigate how oxytocin impacts socioemotional and cognitive processes in elderly.
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| 8. |
- Cortes, Diana S., et al.
(författare)
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Oxytocin may facilitate neural recruitment in medial prefrontal cortex and superior temporal gyrus during emotion recognition in young but not older adults
- 2020
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Ingår i: 2020 Cognitive Aging Conference. ; , s. 22-23
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Konferensbidrag (refereegranskat)abstract
- Normal adult aging is associated with decline in some socioemotional abilities, such as the ability to recognize emotions in others, and age-related neurobiological processes may contribute to these deficits. There is increasing evidence that the neuropeptide oxytocin plays a key role in social cognition, including emotion recognition. The mechanisms through which oxytocin promotes emotion recognition are not well understood yet, and particularly in aging. In a randomized, double-blind, placebo-controlled within-subjects design, we investigated the extent to which a single dose of 40 IU of intranasal oxytocin facilitates emotion recognition in 40 younger (M = 24.90 yrs., SD = 2.97, 48% women) and 40 older (M = 69.70 yrs., SD = 2.99, 55% women) men and women. During two fMRI sessions, participants viewed dynamic positive and negative emotional displays. Preliminary analyses show that younger participants recognized positive and negative emotions more accurately than older participants (p < .001), with this behavioral effect not modulated by oxytocin. In the brain data, however, we found an age x treatment interaction in medial prefrontal cortex (xyz [14, 14, 6], p = .007) and superior temporal gyrus (xyz [53, 9, 2], p = .031). In particular, oxytocin (vs. placebo) reduced activity in these regions for older participants, while it enhanced activity in these regions for younger participants. In line with previous research, these findings support the notion that the effects of oxytocin vary by context and individual factors (e.g., social proficiency, age).
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| 9. |
- Cortes S., Diana, et al.
(författare)
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Does single-dose intranasal oxytocin facilitate neural recruitment in younger and older adults during negative compared to positive dynamic multimodal expressions?
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Tidskriftsartikel (refereegranskat)abstract
- Normal adult aging is associated with a decline in socioemotional abilities, and underlying these deficits are age-related neurobiological processes. There is increasing evidence that the neuropeptide oxytocin plays a key role in social cognition, specifically in the ability to recognize emotions. In a randomized, double-blind, placebo controlled within-subjects design, we investigated the extent to which a single dose of 40 IU of intranasal oxytocin facilitates neural recruitment in younger and older adults during negative compared to positive dynamic multimodal expressions. Based on the literature, several regions of interest were selected prior analyses: insula, amygdala, caudate head, fusiform gyrus, superior temporal gyrus, medial prefrontal cortex, medial orbitofrontal cortex, ventral medial prefrontal cortex, and dorsomedial prefrontal cortex. Behavioral data showed that younger adults outperformed older adults. and higher accuracy scores were observed during the PL condition compared to the OT condition. This was further qualified by the brain data, where OT induced brain activity reductions in the fusiform gyrus, dorsomedial prefrontal cortex, and medial orbitofrontal cortex in response to negative compared to positive expressions. Both age groups showed hypoactivity in most regions of interest during auditory stimuli compared to visual and multimodal stimuli. In line with previous research, these findings suggest that the effects of oxytocin may vary due to context, social proficiency, and individual factors (i.e. age). Future studies should target how age, presentation modality, and oxytocin interact.
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| 10. |
- Cortes S., Diana, et al.
(författare)
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Effects of aging on emotion recognition from dynamic multimodal expressions and vocalizations
-
Tidskriftsartikel (refereegranskat)abstract
- Age-related differences in emotion recognition have predominantly been investigated usingstatic pictures of facial expressions. Previous studies have also mainly studied recognition ofnegative emotions, and positive emotions beyond happiness have rarely been included. Thecurrent study instead used dynamic facial and vocal stimuli, and included a wider than usualrange of positive emotions. In Task 1, younger and older adults were tested for their abilities torecognize 12 positive and negative emotions from brief video recordings presented in visual,auditory and multimodal blocks. Task 2 assessed recognition of 18 positive and negativeemotions conveyed by non-linguistic vocalizations (e.g., laughter, sobs, and sighs). Resultsfrom both tasks showed that younger adults had higher overall recognition rates than olderadults. In Task 1, significant age-related differences (younger > older) were only observed inthe auditory condition, and for relief, anger, and irritation. In Task 2, significant groupdifferences were instead observed for most of the emotions. Overall, results indicate thatrecognition of both positive and negative emotions show age-related differences. This suggeststhat the age-related positivity effect in emotion recognition may become less evident whendynamic emotional stimuli are used and happiness is not the only positive emotion under study.
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