| 1. |
- Hadjikhani, Nouchine, 1966, et al.
(författare)
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Look me in the eyes: constraining gaze in the eye-region provokes abnormally high subcortical activation in autism
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Individuals with Autism Spectrum Disorder (ASD) seem to have difficulties looking others in the eyes, but the substrate for this behavior is not well understood. The subcortical pathway, which consists of superior colliculus, pulvinar nucleus of the thalamus, and amygdala, enables rapid and automatic face processing. A specific component of this pathway - i.e., the amygdala - has been shown to be abnormally activated in paradigms where individuals had to specifically attend to the eye-region; however, a direct examination of the effect of manipulating the gaze to the eye-regions on all the components of the subcortical system altogether has never been performed. The subcortical system is particularly important as it shapes the functional specialization of the face-processing cortex during development. Using functional MRI, we investigated the effect of constraining gaze in the eye-region during dynamic emotional face perception in groups of participants with ASD and typical controls. We computed differences in activation in the subcortical face processing system (superior colliculus, pulvinar nucleus of the thalamus and amygdala) for the same stimuli seen freely or with the gaze constrained in the eye-region. Our results show that when constrained to look in the eyes, individuals with ASD show abnormally high activation in the subcortical system, which may be at the basis of their eye avoidance in daily life.
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| 2. |
- Hadjikhani, Nouchine, 1966, et al.
(författare)
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The effect of constraining eye-contact during dynamic emotional face perception-an fMRI study
- 2017
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Ingår i: Social Cognitive and Affective Neuroscience. - : Oxford University Press (OUP). - 1749-5016 .- 1749-5024. ; 12:7, s. 1197-1207
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Tidskriftsartikel (refereegranskat)abstract
- Eye-contact modifies how we perceive emotions and modulates activity in the social brain network. Here, using fMRI, we demonstrate that adding a fixation cross in the eye region of dynamic facial emotional stimuli significantly increases activation in the social brain of healthy, neurotypical participants when compared with activation for the exact same stimuli observed in a free-viewing mode. In addition, using PPI analysis, we show that the degree of amygdala connectivity with the rest of the brain is enhanced for the constrained view for all emotions tested except for fear, and that anxiety and alexithymia modulate the strength of amygdala connectivity for each emotion differently. Finally, we show that autistic traits have opposite effects on amygdala connectivity for fearful and angry emotional expressions, suggesting that these emotions should be treated separately in studies investigating facial emotion processing.
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| 3. |
- Chidlow, Agnieszka, et al.
(författare)
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Internationalization of Service Firms and Their Interactions with Socio-Political Actors : Guest Editors' Introduction
- 2019
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Ingår i: MIR: Management International Review. - : Springer Science and Business Media LLC. - 0938-8249 .- 1861-8901. ; 59:4, s. 499-514
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Although there is extensive research in the field of services and lately on the internationalization of services, the topic of how service firms interact with society and political organizations, during their internationalization process, remains almost untouched. As an answer to the call for further research on the interaction between service firms, society and policy makers, this paper aims to advance the knowledge by proposing an integrative theoretical view. Dissimilar to the earlier research where each study stands on a specific theoretical discipline (economic, behavioural or political science), the proposed theoretical view asserts the need for an interdisciplinary approach. The integration of these three perspectives is vital since business, policy and society have different legitimacy and dependency grounds and yet their goals and objectives have been converging over the years. Isolating these disciplines from each other is, thus, not very helpful in advancing the knowledge and understanding the conditions, motives and consequences of multinational enterprises in foreign markets. Moreover, the internationalization of services and the extent of heterogeneity in service products/solutions, from banking to retailing and e-commerce, create new challenges that need for interaction between these parties; the three pillars of our society.
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| 4. |
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| 5. |
- Hadjikhani, Nouchine, 1966, et al.
(författare)
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Bumetanide for autism: More eye contact, less amygdala activation
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- We recently showed that constraining eye contact leads to exaggerated increase of amygdala activation in autism. Here, in a proof of concept pilot study, we demonstrate that administration of bumetanide (a NKCC1 chloride importer antagonist that restores GABAergic inhibition) normalizes the level of amygdala activation during constrained eye contact with dynamic emotional face stimuli in autism. In addition, eye-tracking data reveal that bumetanide administration increases the time spent in spontaneous eye gaze during in a free-viewing mode of the same face stimuli. In keeping with clinical trials, our data support the Excitatory/Inhibitory dysfunction hypothesis in autism, and indicate that bumetanide may improve specific aspects of social processing in autism. Future double-blind placebo controlled studies with larger cohorts of participants will help clarify the mechanisms of bumetanide action in autism. © 2018 The Author(s).
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| 6. |
- Lassalle, A., et al.
(författare)
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Effect of visual stimuli of pain on empathy brain network in people with and without Autism Spectrum Disorder
- 2018
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Ingår i: European Journal of Neuroscience. - : Wiley. - 0953-816X .- 1460-9568. ; 48:6, s. 2333-2342
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Tidskriftsartikel (refereegranskat)abstract
- The extent to which affective empathy is impaired in Autism Spectrum Disorder (ASD) remains unclear, as some-but not all-previous neuroimaging studies investigating empathy for pain in ASD have shown similar activation levels to those of neurotypicals individuals. These inconsistent results could be due to the use of different empathy-eliciting stimuli. While some studies used pictures of faces exhibiting a painful expression, others used pictures of limbs in painful situations. In this study, we used fMRI to compare activation in areas associated with empathy processing (empathy network) for these two types of stimuli in 31 participants (16 with ASD, 15 controls). We found a group difference in the inferior frontal gyrus (IFG) and the thalamus when participants viewed stimuli of limbs in painful situations, but not when they viewed face stimuli with a painful expression. Both groups of participants activated their empathy network more when viewing pictures of limbs in painful situations than when viewing pictures of faces with a painful expression; this increased activation for limbs versus faces was significantly enhanced in controls relative to ASD participants, especially in the secondary somatosensory cortex (SII). Our findings suggest that empathy defect of people with ASD is contingent upon the type of stimuli used, and may be related to the level of Mirror Neuron System involvement, as brain regions showing group differences (IFG, SII) underlie embodiment. We discuss the potential clinical implications of our findings in terms of developing interventions boosting the empathetic abilities of people with ASD.
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| 7. |
- Martin-Brevet, S., et al.
(författare)
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Quantifying the Effects of 16p11.2 Copy Number Variants on Brain Structure: A Multisite Genetic-First Study
- 2018
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Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223. ; 84:4, s. 253-264
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: 16p11.2 breakpoint 4 to 5 copy number variants (CNVs) increase the risk for developing autism spectrum disorder, schizophrenia, and language and cognitive impairment. In this multisite study, we aimed to quantify the effect of 16p11.2 CNVs on brain structure. METHODS: Using voxel- and surface-based brain morphometric methods, we analyzed structural magnetic resonance imaging collected at seven sites from 78 individuals with a deletion, 71 individuals with a duplication, and 212 individuals without a CNV. RESULTS: Beyond the 16p11.2-related mirror effect on global brain morphometry, we observe regional mirror differences in the insula (deletion. control. duplication). Other regions are preferentially affected by either the deletion or the duplication: the calcarine cortex and transverse temporal gyrus (deletion > control > Cohen's d > -1), the superior and middle temporal gyri (deletion > control > Cohen's d, 21), and the caudate and hippocampus (control > duplication > -0.5 > Cohen's d > -1). Measures of cognition, language, and social responsiveness and the presence of psychiatric diagnoses do not influence these results. CONCLUSIONS: The global and regional effects on brain morphometry due to 16p11.2 CNVs generalize across site, computational method, age, and sex. Effect sizes on neuroimaging and cognitive traits are comparable. Findings partially overlap with results of meta-analyses performed across psychiatric disorders. However, the lack of correlation between morphometric and clinical measures suggests that CNV-associated brain changes contribute to clinical manifestations but require additional factors for the development of the disorder. These findings highlight the power of genetic risk factors as a complement to studying groups defined by behavioral criteria.
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| 8. |
- Zebrowitz, L. A., et al.
(författare)
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Dietary dopamine depletion blunts reward network sensitivity to face trustworthiness
- 2018
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Ingår i: Journal of Psychopharmacology. - : SAGE Publications. - 0269-8811 .- 1461-7285. ; 32:9, s. 965-978
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Tidskriftsartikel (refereegranskat)abstract
- Research demonstrating responsiveness of the neural reward network to face trustworthiness has not assessed whether the effects are mediated by dopaminergic function. We filled this gap in the literature by investigating whether dietary dopamine depletion would blunt the sensitivity of neural activation to faces varying in trustworthiness across reward regions as well as the sensitivity of behavioral responses to those faces. As prolactin release is negatively regulated by dopamine, peripheral prolactin levels confirmed the efficacy of our manipulation. The dopamine depletion manipulation moderated neural activation to face trustworthiness in the amygdala, medial orbital frontal cortex, and ventral medial prefrontal cortex. Control participants (n=20) showed nonlinear and linear neural activation to face trustworthiness in the amygdala and ventral medial prefrontal cortex, and nonlinear activation in the medial orbital frontal cortex, while depleted participants (n=20) showed only a linear effect in the amygdala. Controls also showed stronger amygdala activation to high trustworthy faces than depleted participants. In contrast to effects on neural activation, dopamine depletion did not blunt the sensitivity of behavioral ratings. While this is the first study to demonstrate that dopamine depletion blunts the sensitivity of the neural reward system to social stimuli, namely faces varying in trustworthiness, future research should investigate behavioral measures that may be more responsive to dopaminergic effects than face ratings. Such research would shed further light on the possibility that individual differences in dopaminergic function that were simulated by our manipulation influence social interactions with people who vary in facial trustworthiness.
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| 9. |
- Zebrowitz, L. A., et al.
(författare)
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Older adults' neural activation in the reward circuit is sensitive to face trustworthiness
- 2018
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Ingår i: Cognitive Affective & Behavioral Neuroscience. - : Springer Science and Business Media LLC. - 1530-7026 .- 1531-135X. ; 18:1, s. 21-34
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Tidskriftsartikel (refereegranskat)abstract
- We examined older adult (OA) and younger adult (YA) neural sensitivity to face trustworthiness in reward circuit regions, previously found to respond to trustworthiness in YA. Interactions of face trustworthiness with age revealed effects exclusive to OA in the amygdala and caudate, and an effect that was not moderated by age in the dorsal anterior cingulate cortex (dACC). OA, but not YA, showed a nonlinear amygdala response to face trustworthiness, with significantly stronger activation response to high than to medium trustworthy faces, and no difference between low and medium or high. This may explain why an earlier study investigating OA amygdala activation to trustworthiness failed to find a significant effect, since only the linear low versus high trustworthiness difference was assessed. OA, but not YA, also showed significantly stronger activation to high than to low trustworthy faces in the right caudate, indicating a positive linear effect, consistent with previous YA research, as well as significantly stronger activation to high than to medium but not low trustworthy faces in the left caudate, indicating a nonlinear effect. Activation in dACC across both age groups showed a positive linear effect consistent with previous YA research. Finally, OA rated the faces as more trustworthy than did YA across all levels of trustworthiness. Future research should examine whether the null effects for YA were due to our inclusion of older faces. Research also should investigate possible implications of our findings for more ecologically valid OA responses to people who vary in facial trustworthiness.
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| 10. |
- Zebrowitz, L. A., et al.
(författare)
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The older adult positivity effect in evaluations of trustworthiness: Emotion regulation or cognitive capacity?
- 2017
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- An older adult positivity effect, i.e., the tendency for older adults to favor positive over negative stimulus information more than do younger adults, has been previously shown in attention, memory, and evaluations. This effect has been attributed to greater emotion regulation in older adults. In the case of attention and memory, this explanation has been supported by some evidence that the older adult positivity effect is most pronounced for negative stimuli, which would motivate emotion regulation, and that it is reduced by cognitive load, which would impede emotion regulation. We investigated whether greater older adult positivity in the case of evaluative responses to faces is also enhanced for negative stimuli and attenuated by cognitive load, as an emotion regulation explanation would predict. In two studies, younger and older adults rated trustworthiness of faces that varied in valence both under low and high cognitive load, with the latter manipulated by a distracting backwards counting task. In Study 1, face valence was manipulated by attractiveness (low /disfigured faces, medium, high/fashion models' faces). In Study 2, face valence was manipulated by trustworthiness (low, medium, high). Both studies revealed a significant older adult positivity effect. However, contrary to an emotion regulation account, this effect was not stronger for more negative faces, and cognitive load increased rather than decreased the rated trustworthiness of negatively valenced faces. Although inconsistent with emotion regulation, the latter effect is consistent with theory and research arguing that more cognitive resources are required to process negative stimuli, because they are more cognitively elaborated than positive ones. The finding that increased age and increased cognitive load both enhanced the positivity of trustworthy ratings suggests that the older adult positivity effect in evaluative ratings of faces may reflect age-related declines in cognitive capacity rather than increases in the regulation of negative emotions. © 2017 Zebrowitz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 11. |
- Zebrowitz, L., et al.
(författare)
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Dedifferentiated face processing in older adults is linked to lower resting state metabolic activity in fusiform face area
- 2016
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Ingår i: Brain Research. - : Elsevier BV. - 0006-8993. ; 1644, s. 22-31
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Tidskriftsartikel (refereegranskat)abstract
- We used multimodal brain imaging to examine possible mediators of age-related neural dedifferentiation (less specific neural activation) to different categories of stimuli that had been shown in previous research. Specifically, we examined resting blood flow and brain activation in areas involved in object, place and face perception. We observed lower activation, specificity, and resting blood flow for older adults (OA) than younger adults (YA) in the fusiform face area (FFA) but not in the other regions of interest. Mediation analyses further revealed that FFA resting state blood flow mediated age differences in FFA specificity, whereas age differences in visual and cognitive function and cortical thickness did not. Whole brain analyses also revealed more activated voxels for all categories in, OA, as well as more frontal activation for faces but not for the other categories in OA than YA. Less FFA specificity coupled with more frontal activation when passively viewing faces suggest that OA have more difficulty recruiting specialized face processing mechanisms, and the lower FFA metabolic activity even when faces are not being processed suggests an OA deficiency in the neural substrate underlying face processing. Our data point to a detuning of face-selective mechanisms in older adults.
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