| 1. |
- Bolstad, Ingeborg, et al.
(författare)
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Aversive event anticipation affects connectivity between the ventral striatum and the orbitofrontal cortex in an fMRI avoidance task
- 2013
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Ingår i: PLOS ONE. - 1932-6203. ; 8:6, s. e68494-
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Tidskriftsartikel (refereegranskat)abstract
- Ability to anticipate aversive events is important for avoiding dangerous or unpleasant situations. The motivation to avoid an event is influenced by the incentive salience of an event-predicting cue. In an avoidance fMRI task we used tone intensities to manipulate salience in order to study the involvement of the orbitofrontal cortex in processing of incentive salience. In the task, cues predicting either aversive or neutral avoidable tones were presented. Ventral striatum, amygdala and anterior insula activations were significantly stronger during presentation of cues for aversive than neutral tones. A psychophysiological interaction analysis showed stronger connectivity between the ventral striatum and the orbitofrontal cortex during aversive than neutral conditions. The present study shows an interaction between the ventral striatum, a structure previously linked to negative incentive salience, and the orbitofrontal cortex supporting a role for this region in processing salience. In addition, this study replicates previous findings suggesting that the task is robust.
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| 2. |
- Bolstad, Ingeborg, et al.
(författare)
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Aversive event anticipation affects connectivity between the ventral striatum and the orbitofrontal cortex in an fMRI avoidance task
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science. - 1932-6203. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- Ability to anticipate aversive events is important for avoiding dangerous or unpleasant situations. The motivation to avoid an event is influenced by the incentive salience of an event-predicting cue. In an avoidance fMRI task we used tone intensities to manipulate salience in order to study the involvement of the orbitofrontal cortex in processing of incentive salience. In the task, cues predicting either aversive or neutral avoidable tones were presented. Ventral striatum, amygdala and anterior insula activations were significantly stronger during presentation of cues for aversive than neutral tones. A psychophysiological interaction analysis showed stronger connectivity between the ventral striatum and the orbitofrontal cortex during aversive than neutral conditions. The present study shows an interaction between the ventral striatum, a structure previously linked to negative incentive salience, and the orbitofrontal cortex supporting a role for this region in processing salience. In addition, this study replicates previous findings suggesting that the task is robust.
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| 3. |
- Bolstad, Ingeborg, et al.
(författare)
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Effects of haloperidol and aripiprazole on the human mesolimbic motivational system : a pharmacological fMRI study
- 2015
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Ingår i: European Neuropsychopharmacology. - 0924-977X .- 1873-7862. ; 25:12, s. 2252-2261
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Tidskriftsartikel (refereegranskat)abstract
- The atypical antipsychotic drug aripiprazole is a partial dopamine (DA) D2 receptor agonist, which differentiates it from most other antipsychotics. This study compares the brain activation characteristic produced by aripiprazole with that of haloperidol, a typical D2 receptor antagonist. Healthy participants received an acute oral dose of haloperidol, aripiprazole or placebo, and then performed an active aversive conditioning task with aversive and neutral events presented as sounds, while blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was carried out. The fMRI task, targeting the mesolimbic motivational system that is thought to be disturbed in psychosis, was based on the conditioned avoidance response (CAR) animal model - a widely used test of therapeutic potential of antipsychotic drugs. In line with the CAR animal model, the present results show that subjects given haloperidol were not able to avoid more aversive than neutral task trials, even though the response times were shorter during aversive events. In the aripiprazole and placebo groups more aversive than neutral events were avoided. Accordingly, the task-related BOLD-fMRI response in the mesolimbic motivational system was diminished in the haloperidol group compared to the placebo group, particularly in the ventral striatum, whereas the aripiprazole group showed task-related activations intermediate of the placebo and haloperidol groups. The current results show differential effects on brain function by aripiprazole and haloperidol, probably related to altered DA transmission. This supports the use of pharmacological fMRI to study antipsychotic properties in humans.
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| 4. |
- Bolstad, Ingeborg, et al.
(författare)
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Effects of haloperidol and aripiprazole on the human mesolimbic motivational system : a pharmacological fMRI study
- 2015
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Ingår i: European Neuropsychopharmacology. - : Elsevier. - 0924-977X .- 1873-7862. ; 25:12, s. 2252-2261
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Tidskriftsartikel (refereegranskat)abstract
- The atypical antipsychotic drug aripiprazole is a partial dopamine (DA) D2 receptor agonist, which differentiates it from most other antipsychotics. This study compares the brain activation characteristic produced by aripiprazole with that of haloperidol, a typical D2 receptor antagonist. Healthy participants received an acute oral dose of haloperidol, aripiprazole or placebo, and then performed an active aversive conditioning task with aversive and neutral events presented as sounds, while blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was carried out. The fMRI task, targeting the mesolimbic motivational system that is thought to be disturbed in psychosis, was based on the conditioned avoidance response (CAR) animal model - a widely used test of therapeutic potential of antipsychotic drugs. In line with the CAR animal model, the present results show that subjects given haloperidol were not able to avoid more aversive than neutral task trials, even though the response times were shorter during aversive events. In the aripiprazole and placebo groups more aversive than neutral events were avoided. Accordingly, the task-related BOLD-fMRI response in the mesolimbic motivational system was diminished in the haloperidol group compared to the placebo group, particularly in the ventral striatum, whereas the aripiprazole group showed task-related activations intermediate of the placebo and haloperidol groups. The current results show differential effects on brain function by aripiprazole and haloperidol, probably related to altered DA transmission. This supports the use of pharmacological fMRI to study antipsychotic properties in humans.
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| 5. |
- Bolstad, Ingeborg, et al.
(författare)
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No difference in frontal cortical activity during an executive functioning task after acute doses of aripiprazole and haloperidol
- 2015
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Ingår i: Frontiers in Human Neuroscience. - 1662-5161 .- 1662-5161. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Aripiprazole is an atypical antipsychotic drug that is characterized by partial dopamine D2 receptor agonism. Its pharmacodynamic profile is proposed to be beneficial in the treatment of cognitive impairment, which is prevalent in psychotic disorders. This study compared brain activation characteristics produced by aripiprazole with that of haloperidol, a typical D2 receptor antagonist, during a task targeting executive functioning.Methods: Healthy participants received an acute oral dose of haloperidol, aripiprazoleor placebo before performing an executive functioning task while blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) was carried out.Results: There was a tendency towards reduced performance in the aripiprazole group compared to the two other groups. The image analysis yielded a strong task related BOLD-fMRI response within each group. An uncorrected between-group analysis showed that aripiprazole challenge resulted in stronger activation in the frontal and temporal gyri and the putamen compared with haloperidol challenge, but after correcting for multiple testing there was no significant group difference.Conclusion: No significant group differences between aripiprazole and haloperidol infrontal cortical activation were obtained when corrected for multiple comparisons.
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| 6. |
- Bolstad, Ingeborg, et al.
(författare)
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No difference in frontal cortical activity during an executive functioning task after acute doses of aripiprazole and haloperidol
- 2015
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Ingår i: Frontiers in Human Neuroscience. - : Frontiers Media S.A.. - 1662-5161. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Aripiprazole is an atypical antipsychotic drug that is characterized by partial dopamine D2 receptor agonism. Its pharmacodynamic profile is proposed to be beneficial in the treatment of cognitive impairment, which is prevalent in psychotic disorders. This study compared brain activation characteristics produced by aripiprazole with that of haloperidol, a typical D2 receptor antagonist, during a task targeting executive functioning. Methods: Healthy participants received an acute oral dose of haloperidol, aripiprazoleor placebo before performing an executive functioning task while blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) was carried out. Results: There was a tendency towards reduced performance in the aripiprazole group compared to the two other groups. The image analysis yielded a strong task related BOLD-fMRI response within each group. An uncorrected between-group analysis showed that aripiprazole challenge resulted in stronger activation in the frontaland temporal gyri and the putamen compared with haloperidol challenge, but after correcting for multiple testing there was no significant group difference. Conclusion: No significant group differences between aripiprazole and haloperidol infrontal cortical activation were obtained when corrected for multiple comparisons.
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| 7. |
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| 8. |
- Carlström, Ingeborg, et al.
(författare)
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Cross-linked gelatin-nanocellulose scaffolds for bone tissue engineering
- 2020
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Ingår i: Materials letters (General ed.). - : Elsevier B.V.. - 0167-577X .- 1873-4979. ; 264
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Tidskriftsartikel (refereegranskat)abstract
- Wood-based cellulose nanofibrils (CNFs) have, in addition to high specific surface area and high surface reactivity, ability to mimic nanostructured collagen in bone extracellular matrix. These properties make CNFs promising materials for bone tissue engineering (BTE). The CNFs degrade slowly in vivo. By blending and cross-linking gelatin (Gel) with CNFs, scaffolds were produced with tuned degradation rate and enhanced mechanical properties, more suitable for BTE applications. This in vitro study aimed to examine initial biological responses of human bone marrow mesenchymal stem cells to cross-linked Gel-CNF scaffolds. The scaffolds were fabricated from 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized CNF blended with Gel and cross-linked either by dehydrothermal treatment (DHT) or by a combination of hexamethylenediamine, genipin, and DHT. CNF scaffolds without cross-linking served as control. The produced scaffolds supported cell attachment, spreading, and osteogenic differentiation. However, the early cell attachment after 1 day and the expression of RUNX2 and SPP1 genes after 7 days were highest in the CNF scaffolds. The results suggest that cross-linked Gel-CNF are cytocompatible and holds potential for BTE applications.
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| 9. |
- Jensen, Jimmy, et al.
(författare)
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Effect of emotional content on brain activation patterns in a reality monitoring task
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Every day we take in large amounts of information from the external world, and we also synthesize representations of things or situations that we have not perceived through our senses. The ability to distinguish between a memory that contains representations from external world and a memory representing an imagined picture is necessary to make sense of the surroundings. This process is called reality monitoring. In the present study we aimed to confirm the existence of the reality monitoring network as reported by previous studies. Further, we wanted to extend these findings by investigating the effect of stimuli aversiveness on the reality monitoring processes and its neural correlates. Twenty-five subjects were included in the study after passing a somatic and psychiatric health screening. The subjects first completed an encoding task of 80 trials outside the scanner. Small descriptions of either an object or a situation (two or three word sentences) were presented on a computer screen. Immediately after the description was shown, a frame that was either empty or containing a picture related to the description was shown for three seconds. The subjects were instructed to look at the picture in the frame or imagine a relevant picture when the frame was empty. The subjects were then instructed to consider whether the pictures were “Unpleasant” or “Not unpleasant” by choosing between the two alternatives on the computer screen. A retrieval task was carried out as Blood-Oxygen Level Dependent (BOLD) fMRI data was collected. During this task the participants were presented with small descriptions that were either presented during the encoding task or they were new. The subjects were to decide whether they previously had viewed a picture associated with the description (a V trial), whether they had imagined a picture associated with the description (an I trial) or whether the description was entirely new (an N trial). The subjects completed a total of 140 randomly presented trials during two runs (20 trials of each category and 20 baseline trials). T2*-weighted functional MRI images were collected on a 3T General Electrics Signa HDx scanner. Data were analysed using SPM8.Overall, most of the trials were considered neutral, and this was true within both the I and the V conditions. Fewer I trials than V trials were considered aversive. The response times were longer in I compared to the V for the aversive trials, and there was a trend for the same effect for the neutral trials. There were no significant differences in response time between neutral and aversive trial. The analysis of the retrieval task behavioural data revealed a higher accuracy rate for aversive trials in the I than the V, while there was no effect for neutral trials. An ANOVA for the corresponding response times showed a main effect of source of encoding where responses were shorter in V than I trials. In paired tests this difference was significant for neutral trials. Paired tests of emotional content within source showed a difference between aversive and neutral trials for I. Successful retrieval and discrimination between sources of encoding generated activations in the left posterior precuneus. Activations of the anterior cingulate were also present. An effect of stimuli aversiveness on brain activation was present in mediolateral prefrontal cortex and the precuneus, indicating a stronger effort of these regions during retrieval of source memory linked to aversive stimuli.In summary, activation patterns in reality monitoring networks were replicated from earlier studies. Further, the results suggest that activations in overlapping networks are increased for aversive stimuli compared to neutral stimuli.
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| 10. |
- Jensen, Jimmy, et al.
(författare)
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Effect of emotional content on brain activation patterns in a reality monitoring task
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Every day we take in large amounts of information from the external world, and we also synthesize representations of things or situations that we have not perceived through our senses. The ability to distinguish between a memory that contains representations from external world and a memory representing an imagined picture is necessary to make sense of the surroundings. This process is called reality monitoring. In the present study we aimed to confirm the existence of the reality monitoring network as reported by previous studies. Further, we wanted to extend these findings by investigating the effect of stimuli aversiveness on the reality monitoring processes and its neural correlates. Twenty-five subjects were included in the study after passing a somatic and psychiatric health screening. The subjects first completed an encoding task of 80 trials outside the scanner. Small descriptions of either an object or a situation (two or three word sentences) were presented on a computer screen. Immediately after the description was shown, a frame that was either empty or containing a picture related to the description was shown for three seconds. The subjects were instructed to look at the picture in the frame or imagine a relevant picture when the frame was empty. The subjects were then instructed to consider whether the pictures were “Unpleasant” or “Not unpleasant” by choosing between the two alternatives on the computer screen. A retrieval task was carried out as Blood-Oxygen Level Dependent (BOLD) fMRI data was collected. During this task the participants were presented with small descriptions that were either presented during the encoding task or they were new. The subjects were to decide whether they previously had viewed a picture associated with the description (a V trial), whether they had imagined a picture associated with the description (an I trial) or whether the description was entirely new (an N trial). The subjects completed a total of 140 randomly presented trials during two runs (20 trials of each category and 20 baseline trials). T2*-weighted functional MRI images were collected on a 3T General Electrics Signa HDx scanner. Data were analysed using SPM8. Overall, most of the trials were considered neutral, and this was true within both the I and the V conditions. Fewer I trials than V trials were considered aversive. The response times were longer in I compared to the V for the aversive trials, and there was a trend for the same effect for the neutral trials. There were no significant differences in response time between neutral and aversive trial. The analysis of the retrieval task behavioural data revealed a higher accuracy rate for aversive trials in the I than the V, while there was no effect for neutral trials. An ANOVA for the corresponding response times showed a main effect of source of encoding where responses were shorter in V than I trials. In paired tests this difference was significant for neutral trials. Paired tests of emotional content within source showed a difference between aversiveand neutral trials for I. Successful retrieval and discrimination between sources of encoding generated activations in the left posterior precuneus. Activations of the anterior cingulate were also present. An effect of stimuli aversiveness on brain activation was present in mediolateral prefrontal cortex and the precuneus, indicating a stronger effort of these regions during retrieval of source memory linked to aversive stimuli. In summary, activation patterns in reality monitoring networks were replicated from earlier studies. Further, the results suggest that activations in overlapping networks are increased for aversive stimuli compared to neutral stimuli.
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| 11. |
- Reckless, Greg E., et al.
(författare)
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Motivation alters response bias and neural activation patterns in a perceptual decision-making task.
- 2013
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Ingår i: Neuroscience. - 0306-4522 .- 1873-7544. ; 238, s. 135-147
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Tidskriftsartikel (refereegranskat)abstract
- Motivation has been demonstrated to affect individuals' response strategies in economic decision-making, however, little is known about how motivation influences perceptual decision-making behavior or its related neural activity. Given the important role motivation plays in shaping our behavior, a better understanding of this relationship is needed. A block-design, continuous performance, perceptual decision-making task where participants were asked to detect a picture of an animal among distractors was used during functional magnetic resonance imaging (fMRI). The effect of positive and negative motivation on sustained activity within regions of the brain thought to underlie decision-making was examined by altering the monetary contingency associated with the task. In addition, signal detection theory was used to investigate the effect of motivation on detection sensitivity, response bias and response time. While both positive and negative motivation resulted in increased sustained activation in the ventral striatum, fusiform gyrus, left dorsolateral prefrontal cortex (DLPFC) and ventromedial prefrontal cortex, only negative motivation resulted in the adoption of a more liberal, closer to optimal response bias. This shift toward a liberal response bias correlated with increased activation in the left DLPFC, but did not result in improved task performance. The present findings suggest that motivation alters aspects of the way perceptual decisions are made. Further, this altered response behavior is reflected in a change in left DLPFC activation, a region involved in the computation of perceptual decisions.
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| 12. |
- Thoresen, Christian, et al.
(författare)
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Arousal Modulates Activity in the Medial Temporal Lobe during a Short-Term Relational Memory Task.
- 2011
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Ingår i: Frontiers in human neuroscience. - 1662-5161. ; 5, s. 177-
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effect of arousal on short-term relational memory and its underlying cortical network. Seventeen healthy participants performed a picture by location, short-term relational memory task using emotional pictures. Functional magnetic resonance imaging was used to measure the blood-oxygenation-level dependent signal relative to task. Subjects' own ratings of the pictures were used to obtain subjective arousal ratings. Subjective arousal was found to have a dose-dependent effect on activations in the prefrontal cortex, amygdala, hippocampus, and in higher order visual areas. Serial position analyses showed that high arousal trials produced a stronger primacy and recency effect than low arousal trials. The results indicate that short-term relational memory may be facilitated by arousal and that this may be modulated by a dose-response function in arousal-driven neuronal regions.
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| 13. |
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| 14. |
- Thoresen, Christian, et al.
(författare)
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Frontotemporal hypoactivity during a reality monitoring paradigm is associated with delusions in patients with schizophrenia spectrum disorders
- 2014
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Ingår i: Cognitive Neuropsychiatry. - 1354-6805 .- 1464-0619. ; 19:2, s. 97-115
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Impaired monitoring of internally generated information has been proposed to be one component in the development and maintenance of delusions. The present study investigated the neural correlates underlying the monitoring processes and whether they were associated with delusions. Methods Twenty healthy controls and 19 patients with schizophrenia spectrum disorders were administrated a reality monitoring paradigm during functional magnetic resonance imaging. During encoding participants were instructed to associate a statement with either a presented (viewed condition) or an imagined picture (imagined condition). During the monitoring session in the scanner, participants were presented with old and new statements and their task was to identify whether a given statement was associated with the viewed condition, imagined condition, or if it was new. Results Patients showed significantly reduced accuracy in the imagined condition with performance negatively associated with degree of delusions. This was accompanied with reduced activity in the left dorsolateral prefrontal cortex and left hippocampus in the patient group. The severity of delusions was negatively correlated with the blood-oxygenation-level dependent response in the left hippocampus. Conclusions The results suggest that weakened monitoring is associated with delusions in patients with schizophrenia spectrum disorder, and that this may be mediated by a frontotemporal dysfunction.
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