| 1. |
- Lycke Brandt, Christine, et al.
(författare)
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Working memory networks and activation patterns in schizophrenia and bipolar disorder : comparison with healthy controls
- 2014
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Ingår i: British Journal of Psychiatry. - 0007-1250 .- 1472-1465. ; 204:4, s. 290-298
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Schizophrenia and bipolar disorder are severe mental disorders with overlapping genetic and clinical characteristics, including cognitive impairments. An important question is whether these disorders also have overlapping neuronal deficits.AIMS: To determine whether large-scale brain networks associated with working memory, as measured with functional magnetic resonance imaging (fMRI), are the same in both schizophrenia and bipolar disorder, and how they differ from those in healthy individuals.METHOD: Patients with schizophrenia (n = 100) and bipolar disorder (n = 100) and a healthy control group (n = 100) performed a 2-back working memory task while fMRI data were acquired. The imaging data were analysed using independent component analysis to extract large-scale networks of task-related activations.RESULTS: Similar working memory networks were activated in all groups. However, in three out of nine networks related to the experimental task there was a graded response difference in fMRI signal amplitudes, where patients with schizophrenia showed greater activation than those with bipolar disorder, who in turn showed more activation than healthy controls. Secondary analysis of the patient groups showed that these activation patterns were associated with history of psychosis and current elevated mood in bipolar disorder.CONCLUSIONS: The same brain networks were related to working memory in schizophrenia, bipolar disorder and controls. However, some key networks showed a graded hyperactivation in the two patient groups, in line with a continuum of neuronal abnormalities across psychotic disorders.
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| 2. |
- Welander-Vatn, Audun, et al.
(författare)
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The neural correlates of cognitive control in bipolar I disorder : an fMRI study of medial frontal cortex activation during a Go/No-go task
- 2013
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Ingår i: Neuroscience Letters. - 0304-3940 .- 1872-7972. ; 549, s. 51-56
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Tidskriftsartikel (refereegranskat)abstract
- In addition to dysregulation of mood, bipolar I disorder (BD I) is characterized by abnormalities in the execution of cognitive control. Hypoactivation of a specific sub-region in the cognitive control network, located in the medial frontal cortex, has been described among BD I patients. The aim of this study was to investigate whether patients with BD I showed decreased activation in this brain region as compared to healthy controls when performing a cognitive control task. Twenty-four BD I patients and 24 healthy controls performed a Go/No-go task during a functional magnetic resonance imaging (fMRI) session. Performance and response times were recorded. The BD I subjects had significantly slower response times and more patients made errors of omission compared to the healthy controls during the task. Both BD I subjects and healthy controls demonstrated activations in the brain region of interest during the task, but analyses revealed no statistically significant differences between groups. Although the patients display some deviances in behavioural measures, this study reveals no significant differences between BD I subjects and healthy controls in recruitment of the medial frontal cortex during a Go/No-go task.
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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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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| 8. |
- 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
-
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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| 9. |
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| 10. |
- Mattingsdal, Morten, et al.
(författare)
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Pathway analysis of genetic markers associated with a functional MRI faces paradigm implicates polymorphisms in calcium responsive pathways
- 2013
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Ingår i: NeuroImage. - 1053-8119 .- 1095-9572. ; 70, s. 143-149
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Tidskriftsartikel (refereegranskat)abstract
- Several lines of evidence suggest that common polygenic variation influences brain function in humans. Combining high-density genetic markers with brain imaging techniques is constricted by the practicalities of collecting sufficiently large brain imaging samples. Pathway analysis promises to leverage knowledge on function of genes to detect recurring signals of moderate effect. We adapt this approach, exploiting the deep information collected on brain function by fMRI methods, to identify molecular pathways containing genetic variants which influence brain activation during a commonly applied experiment based on a face matching task (n=246) which was developed to study neural processing of faces displaying negative emotions. Genetic markers moderately associated (p<10(-4)) with whole brain activation phenotypes constructed by applying principal components to contrast maps, were tested for pathway enrichment using permutation based methods. The most significant pathways are related to post NMDA receptor activation events, driven by genetic variants in calcium/calmodulin-dependent protein kinase II (CAMK2G, CAMK2D) and a calcium-regulated nucleotide exchange factor (RASGRF2) in which all are activated by intracellular calcium/calmodulin. The most significant effect of the combined polygenic model were localized to the left inferior frontal gyrus (p=1.03 × 10(-9)), a region primarily involved in semantic processing but also involved in processing negative emotions. These findings suggest that pathway analysis of GWAS results derived from principal component analysis of fMRI data is a promising method, to our knowledge, not previously described.
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| 11. |
- Moltu, Sissel J., et al.
(författare)
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Arachidonic and docosahexaenoic acid supplementation and brain maturation in preterm infants : a double blind RCT
- 2024
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Ingår i: Clinical Nutrition. - : Elsevier. - 0261-5614 .- 1532-1983. ; 43:1, s. 176-186
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Tidskriftsartikel (refereegranskat)abstract
- Background: Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are important structural components of neural cellular membranes and possess anti-inflammatory properties. Very preterm infants are deprived of the enhanced placental supply of these fatty acids, but the benefit of postnatal supplementation on brain development is uncertain. The aim of this study was to test the hypothesis that early enteral supplementation with ARA and DHA in preterm infants improves white matter (WM) microstructure assessed by diffusion-weighted MRI at term equivalent age.Methods: In this double-blind, randomized controlled trial, infants born before 29 weeks gestational age were allocated to either 100 mg/kg ARA and 50 mg/kg DHA (ARA:DHA group) or medium chain triglycerides (control). Supplements were started on the second day of life and provided until 36 weeks postmenstrual age. The primary outcome was brain maturation assessed by diffusion tensor imaging (DTI) using Tract-Based Spatial Statistics (TBSS) analysis.Results: We included 120 infants (60 per group) in the trial; mean (range) gestational age was 26+3 (22+6 - 28+6) weeks and postmenstrual age at scan was 41+3 (39+1 - 47+0) weeks. Ninety-two infants underwent MRI imaging, and of these, 90 had successful T1/T2 weighted MR images and 74 had DTI data of acceptable quality. TBSS did not show significant differences in mean or axial diffusivity between the groups, but demonstrated significantly higher fractional anisotropy in several large WM tracts in the ARA:DHA group, including corpus callosum, the anterior and posterior limb of the internal capsula, inferior occipitofrontal fasciculus, uncinate fasciculus, and the inferior longitudinal fasciculus. Radial diffusivity was also significantly lower in several of the same WM tracts in the ARA:DHA group.Conclusion: This study suggests that supplementation with ARA and DHA at doses matching estimated fetal accretion rates improves WM maturation compared to control treatment, but further studies are needed to ascertain any functional benefit.Clinical trial registration: www.clinicaltrials.gov; ID:NCT03555019.
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| 12. |
- Ousdal, Olga Therese, et al.
(författare)
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Effect of relevance on amygdala activation and association with the ventral striatum.
- 2012
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Ingår i: NeuroImage. - 1053-8119 .- 1095-9572. ; 62:1, s. 95-101
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Tidskriftsartikel (refereegranskat)abstract
- While the amygdala historically has been implicated in emotional stimuli processing, recent data suggest a general role in parceling out the relevance of stimuli, regardless of their emotional properties. Using functional magnetic resonance imaging, we tested the relevance hypothesis by investigating human amygdala responses to emotionally neutral stimuli while manipulating their relevance. The task was operationalized as highly relevant if a subsequent opportunity to respond for a reward depended on response accuracy of the task, and less relevant if the reward opportunity was independent of task performance. A region of interest analysis revealed bilateral amygdala activations in response to the high relevance condition compared to the low relevance condition. An exploratory whole-brain analysis yielded robust similar results in bilateral ventral striatum. A subsequent functional connectivity analysis demonstrated increased connectivity between amygdala and ventral striatum for the highly relevant stimuli compared to the less relevant stimuli. These findings suggest that the amygdala's processing profile goes beyond detection of emotions per se, and directly support the proposed role in relevance detection. In addition, the findings suggest a close relationship between amygdala and ventral striatal activity when processing relevant stimuli. Thus, the results may indicate that human amygdala modulates ventral striatum activity and subsequent behaviors beyond that observed for emotional cues, to encompass a broader range of relevant stimuli.
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| 13. |
- Ousdal, Olga T., et al.
(författare)
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Increased amygdala and visual cortex activity and functional connectivity towards stimulus novelty is associated with state anxiety
- 2014
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Ingår i: PLOS ONE. - 1932-6203. ; 9:4, s. e96146-
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Tidskriftsartikel (refereegranskat)abstract
- Novel stimuli often require a rapid reallocation of sensory processing resources to determine the significance of the event, and the appropriate behavioral response. Both the amygdala and the visual cortex are central elements of the neural circuitry responding to novelty, demonstrating increased activity to new as compared to highly familiarized stimuli. Further, these brain areas are intimately connected, and thus the amygdala may be a key region for directing sensory processing resources to novel events. Although knowledge regarding the neurocircuit of novelty detection is gradually increasing, we still lack a basic understanding of the conditions that are necessary and sufficient for novelty-specific responses in human amygdala and the visual cortices, and if these brain areas interact during detection of novelty. In the present study, we investigated the response of amygdala and the visual cortex to novelty, by comparing functional MRI activity between 1st and 2nd time presentation of a series of emotional faces in an event-related task. We observed a significant decrease in amygdala and visual cortex activity already after a single stimulus exposure. Interestingly, this decrease in responsiveness was less for subjects with a high score on state anxiety. Further, novel faces stimuli were associated with a relative increase in the functional coupling between the amygdala and the inferior occipital gyrus (BA 18). Thus, we suggest that amygdala is involved in fast sensory boosting that may be important for attention reallocation to novel events, and that the strength of this response depends on individual state anxiety.
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| 14. |
- Ousdal, Olga T., et al.
(författare)
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Increased amygdala and visual cortex activity and functional connectivity towards stimulus novelty is associated with state anxiety
- 2014
-
Ingår i: PLoS ONE. - : Public Library of Science. - 1932-6203. ; 9:4
-
Tidskriftsartikel (refereegranskat)abstract
- Novel stimuli often require a rapid reallocation of sensory processing resources to determine the significance of the event, and the appropriate behavioral response. Both the amygdala and the visual cortex are central elements of the neural circuitry responding to novelty, demonstrating increased activity to new as compared to highly familiarized stimuli. Further, these brain areas are intimately connected, and thus the amygdala may be a key region for directing sensory processing resources to novel events. Although knowledge regarding the neurocircuit of novelty detection is gradually increasing, we still lack a basic understanding of the conditions that are necessary and sufficient for novelty-specific responses in human amygdala and the visual cortices, and if these brain areas interact during detection of novelty. In the present study, we investigated the response of amygdala and the visual cortex to novelty, by comparing functional MRI activity between 1st and 2nd time presentation of a series of emotional faces in an event-related task. We observed a significant decrease in amygdala and visual cortex activity already after a single stimulus exposure. Interestingly, this decrease in responsiveness was less for subjects with a high score on state anxiety. Further, novel faces stimuli were associated with a relative increase in the functional coupling between the amygdala and the inferior occipital gyrus (BA 18). Thus, we suggest that amygdala is involved in fast sensory boosting that may be important for attention reallocation to novel events, and that the strength of this response depends on individual state anxiety.
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| 15. |
- Ousdal, Olga Therese, et al.
(författare)
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The human amygdala encodes value and space during decision making
- 2014
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Ingår i: NeuroImage. - 1053-8119 .- 1095-9572. ; 101, s. 712-719
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Tidskriftsartikel (refereegranskat)abstract
- Valuable stimuli are invariably localized in space. While our knowledge regarding the neural networks supporting value assignment and comparisons is considerable, we lack a basic understanding of how the human brain integrates motivational and spatial information. The amygdala is a key structure for learning and maintaining the value of sensory stimuli and a recent non-human primate study provided initial evidence that it also acts to integrate value with spatial location, a question we address here in a human setting. We measured hemodynamic responses (fMRI) in amygdala while manipulating the value and spatial configuration of stimuli in a simple stimulus-reward task. Subjects responded significantly faster and showed greater amygdala activation when a reward was dependent on a spatial specific response, compared to when a reward required less spatial specificity. Supplemental analysis supported this spatial specificity by demonstrating that the pattern of amygdala activity varied based on whether subjects responded to a motivational target presented in the ipsilateral or contralateral visual space. Our data show that the human amygdala integrates information about space and value, an integration of likely importance for assigning cognitive resources towards highly valuable stimuli in our environment.
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| 16. |
- Ousdal, Olga Therese, et al.
(författare)
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The human amygdala encodes value and space during decision making
- 2014
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Ingår i: NeuroImage. - : Academic Press Inc.. - 1053-8119 .- 1095-9572. ; 101, s. 712-719
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Tidskriftsartikel (refereegranskat)abstract
- Valuable stimuli are invariably localized in space. While our knowledge regarding the neural networks supporting value assignment and comparisons is considerable, we lack a basic understanding of how the human brain integrates motivational and spatial information. The amygdala is a key structure for learning and maintaining the value of sensory stimuli and a recent non-human primate study provided initial evidence that it also acts to integrate value with spatial location, a question we address here in a human setting. We measured hemodynamic responses (fMRI) in amygdala while manipulating the value and spatial configuration of stimuli in a simple stimulus-reward task. Subjects responded significantly faster and showed greater amygdala activation when a reward was dependent on a spatial specific response, compared to when a reward required less spatial specificity. Supplemental analysis supported this spatial specificity by demonstrating that the pattern of amygdala activity varied based on whether subjects responded to a motivational target presented in the ipsilateral or contralateral visual space. Our data show that the human amygdala integrates information about space and value, an integration of likely importance for assigning cognitive resources towards highly valuable stimuli in our environment.
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| 17. |
- Reckless, Greg E., et al.
(författare)
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Negative symptoms in schizophrenia are associated with aberrant striato-cortical connectivity in a rewarded perceptual decision-making task
- 2015
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Ingår i: NeuroImage. - 0353-8842 .- 2213-1582. ; 8, s. 290-297
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundNegative symptoms in schizophrenia have been associated with structural and functional changes in the prefrontal cortex. They often persist after treatment with antipsychotic medication which targets, in particular, the ventral striatum (VS). As schizophrenia has been suggested to arise from dysfunctional connectivity between neural networks, it is possible that residual aberrant striato-cortical connectivity in medicated patients plays a role in enduring negative symptomology. The present study examined the relationship between striato-cortical connectivity and negative symptoms in medicated schizophrenia patients.MethodsWe manipulated motivation in a perceptual decision-making task during functional magnetic resonance imaging. Comparing healthy controls (n = 21) and medicated patients with schizophrenia (n = 18) we investigated how motivation-mediated changes in VS activation affected functional connectivity with the frontal cortex, and how changes in connectivity strength from the neutral to motivated condition related to negative symptom severity.ResultsA pattern of aberrant striato-cortical connectivity was observed in the presence of intact VS, but altered left inferior frontal gyrus (IFG) motivation-mediated activation in patients. The more severe the patient's negative symptoms, the less the connectivity strength between the right VS and left IFG changed from the neutral to the motivated condition. Despite aberrant striato-cortical connectivity and altered recruitment of the left IFG among patients, both patients and healthy controls adopted a more liberal response strategy in the motivated compared to the neutral condition.ConclusionsThe present findings suggest that there is a link between dysfunctional striato-cortical connectivity and negative symptom severity, and offer a possible explanation as to why negative symptoms persist after treatment with antipsychotics.
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| 18. |
- Reckless, Greg E., et al.
(författare)
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Negative symptoms in schizophrenia are associated with aberrant striato-cortical connectivity in a rewarded perceptual decision-making task
- 2015
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Ingår i: NeuroImage Clinical. - : Elsevier BV. - 0353-8842 .- 2213-1582. ; 8, s. 290-297
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Tidskriftsartikel (refereegranskat)abstract
- Background Negative symptoms in schizophrenia have been associated with structural and functional changes in the prefrontal cortex. They often persist after treatment with antipsychotic medication which targets, in particular, the ventral striatum (VS). As schizophrenia has been suggested to arise from dysfunctional connectivity between neural networks, it is possible that residual aberrant striato-cortical connectivity in medicated patients plays a role in enduring negative symptomology. The present study examined the relationship between striato-cortical connectivity and negative symptoms in medicated schizophrenia patients. Methods We manipulated motivation in a perceptual decision-making task during functional magnetic resonance imaging. Comparing healthy controls (n = 21) and medicated patients with schizophrenia (n = 18) we investigated how motivation-mediated changes in VS activation affected functional connectivity with the frontal cortex, and how changes in connectivity strength from the neutral to motivated condition related to negative symptom severity. Results A pattern of aberrant striato-cortical connectivity was observed in the presence of intact VS, but altered left inferior frontal gyrus (IFG) motivation-mediated activation in patients. The more severe the patient's negative symptoms, the less the connectivity strength between the right VS and left IFG changed from the neutral to the motivated condition. Despite aberrant striato-cortical connectivity and altered recruitment of the left IFG among patients, both patients and healthy controls adopted a more liberal response strategy in the motivated compared to the neutral condition. Conclusions The present findings suggest that there is a link between dysfunctional striato-cortical connectivity and negative symptom severity, and offer a possible explanation as to why negative symptoms persist after treatment with antipsychotics.
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| 19. |
- Reckless, Greg E., et al.
(författare)
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The left inferior frontal gyrus is involved in adjusting response bias during a perceptual decision-making task
- 2014
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Ingår i: Brain and Behavior. - 2162-3279 .- 2162-3279. ; 4:3, s. 398-407
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionChanging the way we make decisions from one environment to another allows us to maintain optimal decision-making. One way decision-making may change is how biased one is toward one option or another. Identifying the regions of the brain that underlie the change in bias will allow for a better understanding of flexible decision-making.MethodsAn event-related, perceptual decision-making task where participants had to detect a picture of an animal amongst distractors was used during functional magnetic resonance imaging. Positive and negative financial motivation were used to affect a change in response bias, and changes in decision-making behavior were quantified using signal detection theory.ResultsResponse bias became relatively more liberal during both positive and negative motivated trials compared to neutral trials. For both motivational conditions, the larger the liberal shift in bias, the greater the left inferior frontal gyrus (IFG) activity. There was no relationship between individuals' belief that they used a different strategy and their actual change in response bias.ConclusionsThe present findings suggest that the left IFG plays a role in adjusting response bias across different decision environments. This suggests a potential role for the left IFG in flexible decision-making.
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| 20. |
- Reckless, Greg E., et al.
(författare)
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The left inferior frontal gyrus is involved in adjusting response bias during a perceptual decision-making task
- 2014
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Ingår i: Brain and Behavior. - : John Wiley and Sons Inc.. - 2162-3279. ; 4:3, s. 398-407
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Changing the way we make decisions from one environment to another allows us to maintain optimal decision-making. One way decision-making may change is how biased one is toward one option or another. Identifying the regions of the brain that underlie the change in bias will allow for a better understanding of flexible decision-making. Methods An event-related, perceptual decision-making task where participants had to detect a picture of an animal amongst distractors was used during functional magnetic resonance imaging. Positive and negative financial motivation were used to affect a change in response bias, and changes in decision-making behavior were quantified using signal detection theory. Results Response bias became relatively more liberal during both positive and negative motivated trials compared to neutral trials. For both motivational conditions, the larger the liberal shift in bias, the greater the left inferior frontal gyrus (IFG) activity. There was no relationship between individuals' belief that they used a different strategy and their actual change in response bias. Conclusions The present findings suggest that the left IFG plays a role in adjusting response bias across different decision environments. This suggests a potential role for the left IFG in flexible decision-making.
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| 21. |
- 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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| 22. |
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| 23. |
- 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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| 24. |
- Welander-Vatn, Audun S, et al.
(författare)
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No altered dorsal anterior cingulate activation in bipolar II disorder patients during a Go/No-go task : an fMRI study.
- 2009
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Ingår i: Bipolar Disorders. - 1398-5647 .- 1399-5618. ; 11:3, s. 270-279
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: It has been reported that one of the core features in patients with bipolar disorder II (BD II) is increased impulsivity. The aim of this study was to investigate whether patients with BD II showed decreased activation in the dorsal anterior cingulate cortex (dACC) as compared to healthy controls when performing a task sensitive to impulsivity.METHODS: Twenty-seven BD II patients and 28 healthy controls performed a Go/No-go task during a functional magnetic resonance imaging (fMRI) session. Eleven of the patients were unmedicated, and possible group differences between medicated and unmedicated patients were also assessed. Results: The groups did not differ in behavioral performance on the Go/No-go task. Both BD II subjects and healthy controls demonstrated dACC activity during the task, and analyses revealed no statistically significant group differences. Medicated and unmedicated patients also did not differ in the degree of fMRI activation.CONCLUSIONS: These findings do not support the hypothesis of abnormal dACC activity during a Go/No-go task in BD II patients.
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| 25. |
- Welander-Vatn, Audun, et al.
(författare)
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The neural correlates of cognitive control in bipolar I disorder : an fMRI study of medial frontal cortex activation during a Go/No-go task
- 2013
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Ingår i: Neuroscience Letters. - : Elsevier Ireland Ltd. - 0304-3940 .- 1872-7972. ; 549, s. 51-56
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Tidskriftsartikel (refereegranskat)abstract
- In addition to dysregulation of mood, bipolar I disorder (BD I) is characterized by abnormalities in the execution of cognitive control. Hypoactivation of a specific sub-region in the cognitive control network, located in the medial frontal cortex, has been described among BD I patients. The aim of this study was to investigate whether patients with BD I showed decreased activation in this brain region as compared to healthy controls when performing a cognitive control task. Twenty-four BD I patients and 24 healthy controls performed a Go/No-go task during a functional magnetic resonance imaging (fMRI) session. Performance and response times were recorded. The BD I subjects had significantly slower response times and more patients made errors of omission compared to the healthy controls during the task. Both BD I subjects and healthy controls demonstrated activations in the brain region of interest during the task, but analyses revealed no statistically significant differences between groups. Although the patients display some deviances in behavioural measures, this study reveals no significant differences between BD I subjects and healthy controls in recruitment of the medial frontal cortex during a Go/No-go task.
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