| 1. |
- Fransson, Peter, et al.
(author)
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Limbic justice : Amygdala drives rejection in ultimatum game
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Other publication (other academic/artistic)abstract
- The ultimatum game is a stylized game to study decision making in which a proposer suggests how to split a sum of money either fairly or unfairly. Unfair splits are often rejected by the responder even at a personal cost. Previous research using unspecific stimulus-onsets suggests that such rejections are of cortical origin and involve a change of feeling states. Using an fMRI-design to specifically study early emotional components of decision making and a pharmacological intervention we demonstrate a causal role of the limbic system in the act of rejection. In the placebo-treated group rejection was directly linked to an increased amygdala activity and benzodiazepine treatment decreased rejection rate concomitantly with a suppressed amygdala response to unfair proposals in spite of an unchanged feeling of unfairness. Thus, we segregate the neural basis of rejections associated with the initial reactive emotional response from the slower affective processing associated with awareness.
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| 2. |
- Gospic, Katarina, et al.
(author)
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Altruism costs-the cheap signal from amygdala
- 2014
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In: Social Cognitive & Affective Neuroscience. - : Oxford University Press (OUP). - 1749-5016 .- 1749-5024. ; 9:9, s. 1325-1332
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Journal article (peer-reviewed)abstract
- When people state their willingness to pay for something, the amount usually differs from the behavior in a real purchase situation. The discrepancy between a hypothetical answer and the real act is called hypothetical bias. We investigated neural processes of hypothetical bias regarding monetary donations to public goods using fMRI with the hypothesis that amygdala codes for real costs. Real decisions activated amygdala more than hypothetical decisions. This was observed for both accepted and rejected proposals. The more the subjects accepted real donation proposals the greater was the activity in rostral anterior cingulate cortex-a region known to control amygdala but also neural processing of the cost-benefit difference. The presentation of a charitable donation goal evoked an insula activity that predicted the later decision to donate. In conclusion, we have identified the neural mechanisms underlying real donation behavior, compatible with theories on hypothetical bias. Our findings imply that the emotional system has an important role in real decision making as it signals what kind of immediate cost and reward an outcome is associated with.
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| 3. |
- Gospic, Katarina, et al.
(author)
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Limbic Justice-Amygdala Involvement in Immediate Rejection in the Ultimatum Game
- 2011
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In: PLoS Biology. - : Public Library of Science. - 1545-7885 .- 1544-9173. ; 9:5
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Journal article (peer-reviewed)abstract
- Imaging studies have revealed a putative neural account of emotional bias in decision making. However, it has been difficult in previous studies to identify the causal role of the different sub-regions involved in decision making. The Ultimatum Game (UG) is a game to study the punishment of norm-violating behavior. In a previous influential paper on UG it was suggested that frontal insular cortex has a pivotal role in the rejection response. This view has not been reconciled with a vast literature that attributes a crucial role in emotional decision making to a subcortical structure (i.e., amygdala). In this study we propose an anatomy-informed model that may join these views. We also present a design that detects the functional anatomical response to unfair proposals in a subcortical network that mediates rapid reactive responses. We used a functional MRI paradigm to study the early components of decision making and challenged our paradigm with the introduction of a pharmacological intervention to perturb the elicited behavioral and neural response. Benzodiazepine treatment decreased the rejection rate (from 37.6% to 19.0%) concomitantly with a diminished amygdala response to unfair proposals, and this in spite of an unchanged feeling of unfairness and unchanged insular response. In the control group, rejection was directly linked to an increase in amygdala activity. These results allow a functional anatomical detection of the early neural components of rejection associated with the initial reactive emotional response. Thus, the act of immediate rejection seems to be mediated by the limbic system and is not solely driven by cortical processes, as previously suggested. Our results also prompt an ethical discussion as we demonstrated that a commonly used drug influences core functions in the human brain that underlie individual autonomy and economic decision making.
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| 4. |
- Gospic, Katarina
(author)
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Neural mechanisms of emotional regulation and decision making
- 2011
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Doctoral thesis (other academic/artistic)abstract
- Emotions influence our perception and decision making. It is of great importance to understand the neurophysiology behind these processes as they influence human core functions. Moreover, knowledge within this field is required in order to develop new medical therapies for pathological conditions that involve dysregulation of emotions. In this thesis the neural mechanisms of emotional regulation and decision making were investigated using different pharmacological manipulations and brain imaging. In Study I, we examined whether a CCKb-receptor and a mu-opioid receptor agonist could modulate emotional perception of visual stimuli in opposite directions. In Study II and III, we examined if amygdala, a subcortical structure involved in emotional coding, was involved in social punishment and neural processing of unfairness. The participants played an economic game that examined their proneness to hand out social punishment and their processing of unfairness. Prior to the game, participants had been treated with either an active drug (oxazepam or madopark) or placebo. With this intervention we could manipulate the participants’ behavior and brain activity. Lastly, in Study IV we investigated neural mechanisms of hypothetical bias; that is, the difference between a real decision versus a hypothetical decision. In summary we found, in Study I, that the CCK-opioid system can modulate emotional visual perception in opposite directions. In Study II we demonstrate that amygdala is involved in social punishment and neural processing of unfairness. The degree to which participants gave out social punishment was suppressed with oxazepam without affecting the participants’ perception of unfairness. In Study III we noted that madopark increased amygdala activity in response to unfairness without detectable changes in behavior. In Study IV, we showed that real decisions, in comparison to hypothetical decisions, involve amygdala processing and amygdala activity co-varies positively with the real cost for the participants. In conclusion, this thesis demonstrates that specific neuromodulatory systems participate in emotional regulation and decision making. Our findings also prompt an ethical discussion as we show that a commonly used drug influences core functions in the human brain that underlie individual autonomy and decision making.
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| 5. |
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| 6. |
- Olofsson, Jonas K., et al.
(author)
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Effects of oxazepam on affective perception, recognition, and event-related potentials
- 2011
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In: Psychopharmacology. - : Springer Science and Business Media LLC. - 0033-3158 .- 1432-2072. ; 215:2, s. 301-309
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Journal article (peer-reviewed)abstract
- Background Little is known about how rapid electrocortical responses (event-related potentials; ERPs) to affective pictures are modulated by benzodiazepine agonists. The present study investigated effects of oxazepam (20 mg p.o.) on behavioral measures and ERPs associated with affective picture processing during perception and recognition memory retrieval. Methods Forty-three healthy young adults were given oxazepam or placebo treatment under a double-blind experimental procedure. Affective pictures (negatively arousing or neutral) elicited ERP responses and participants rated pictures for emotionality (during incidental encoding) and recognition. Results Oxazepam did not affect perceptual (P1, P2) or emotional (early posterior negativity and late parietal positivity) ERPs or ratings during perception. However, oxazepam impaired recognition performance and decreased positive mid-frontal ERP component at 420-450 ms for old vs. new pictures. The memory impairment was retained at the delayed memory test. Conclusions Oxazepam does not selectively influence electrocortical or perceptual indexes of emotional perception or emotional memory. Rather, it blocks memory consolidation independent of valence category. These findings indicate that ERPs can be of use in assessing effects of benzodiazepines on memory-related processes.
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