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- Faria, Vanda
(author)
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Mind really does matter : The Neurobiology of Placebo-induced Anxiety Relief in Social Anxiety Disorder
- 2012
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Doctoral thesis (other academic/artistic)abstract
- The placebo effect, a beneficial effect attributable to a treatment containing no specific properties for the condition being treated, has been demonstrated in a variety of medical conditions. This thesis includes four studies aimed at increasing our knowledge on the neurobiology of placebo. Study I, a review of the placebo neuroimaging literature, suggested that the anterior cingulate cortex (ACC) may be a common site of action for placebo responses. However, because placebo neuroimaging studies in clinical disorders are largely lacking, the clinical relevance of this needs further clarification. The subsequent three empirical studies were thus designed from a clinical perspective. Using positron emission tomography (PET) these studies investigated the underlying neurobiology of sustained placebo responses in patients with social anxiety disorder (SAD), a disabling psychiatric condition that nonetheless may be mitigated by placebo interventions. Study II demonstrated that serotonergic gene polymorphisms affect anxiety-induced neural activity and the resultant placebo phenotype. In particular, anxiety reduction resulting from placebo treatment was tied to the attenuating effects of the TPH2 G-703T polymorphism on amygdala activity. Study III further compared the neural response profile of placebo with selective serotonin reuptake inhibitors (SSRIs), i.e the first-line pharmacological treatment for SAD. A similar anxiety reduction was noted in responders of both treatments. PET-data further revealed that placebo and SSRI responders had similar decreases of the neural response in amygdala subregions including the left basomedial/basolateral (BM/BLA) and the right ventrolateral (VLA) sections. To clarify whether successful placebo and SSRI treatments operate via similar or distinct neuromodulatory pathways, study IV focused on the connectivity patterns between the amygdala and prefrontal cortex that may be crucial for normal emotion regulation. In responders of both treatment modalities, the left amygdala (BM/BLA) exhibited negative coupling with the dorsolateral prefrontal cortex and the rostral ACC as well as a shared positive coupling with the dorsal ACC. This may represent shared treatment mechanisms involving improved emotion regulation and decreased rumination. This thesis constitutes a first step towards better understanding of the neurobiology of placebo in the treatment of anxiety, including the neural mechanisms that unite and segregate placebo and SSRI treatment.
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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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| 5. |
- 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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| 6. |
- Vestberg, Torbjorn, et al.
(author)
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Executive Functions Predict the Success of Top-Soccer Players
- 2012
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 7:4
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Journal article (peer-reviewed)abstract
- While the importance of physical abilities and motor coordination is non-contested in sport, more focus has recently been turned toward cognitive processes important for different sports. However, this line of studies has often investigated sport-specific cognitive traits, while few studies have focused on general cognitive traits. We explored if measures of general executive functions can predict the success of a soccer player. The present study used standardized neuropsychological assessment tools assessing players' general executive functions including on-line multi-processing such as creativity, response inhibition, and cognitive flexibility. In a first cross-sectional part of the study we compared the results between High Division players (HD), Lower Division players (LD) and a standardized norm group. The result shows that both HD and LD players had significantly better measures of executive functions in comparison to the norm group for both men and women. Moreover, the HD players outperformed the LD players in these tests. In the second prospective part of the study, a partial correlation test showed a significant correlation between the result from the executive test and the numbers of goals and assists the players had scored two seasons later. The results from this study strongly suggest that results in cognitive function tests predict the success of ball sport players.
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