| 1. |
- Böhme, Rebecca, et al.
(författare)
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Aberrant Salience Is Related to Reduced Reinforcement Learning Signals and Elevated Dopamine Synthesis Capacity in Healthy Adults
- 2015
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Ingår i: Journal of Neuroscience. - : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 35:28, s. 10103-10111
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Tidskriftsartikel (refereegranskat)abstract
- The striatum is known to play a key role in reinforcement learning, specifically in the encoding of teaching signals such as reward prediction errors (RPEs). It has been proposed that aberrant salience attribution is associated with impaired coding of RPE and heightened dopamine turnover in the striatum, and might be linked to the development of psychotic symptoms. However, the relationship of aberrant salience attribution, RPE coding, and dopamine synthesis capacity has not been directly investigated. Here we assessed the association between a behavioral measure of aberrant salience attribution, the salience attribution test, to neural correlates of RPEs measured via functional magnetic resonance imaging while healthy participants (n = 58) performed an instrumental learning task. A subset of participants (n = 27) also underwent positron emission tomography with the radiotracer [18F]fluoro-l-DOPA to quantify striatal presynaptic dopamine synthesis capacity. Individual variability in aberrant salience measures related negatively to ventral striatal and prefrontal RPE signals and in an exploratory analysis was found to be positively associated with ventral striatal presynaptic dopamine levels. These data provide the first evidence for a specific link between the constructs of aberrant salience attribution, reduced RPE processing, and potentially increased presynaptic dopamine function.
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| 2. |
- Böhme, Rebecca, et al.
(författare)
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Distinction of self-produced touch and social touch at cortical and spinal cord levels
- 2019
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 116:6, s. 2290-2299
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Tidskriftsartikel (refereegranskat)abstract
- Differentiation between self-produced tactile stimuli and touch by others is necessary for social interactions and for a coherent concept of "self." The mechanisms underlying this distinction are unknown. Here, we investigated the distinction between self-and other-produced light touch in healthy volunteers using three different approaches: fMRI, behavioral testing, and somatosensory-evoked potentials (SEPs) at spinal and cortical levels. Using fMRI, we found self-other differentiation in somatosensory and sociocognitive areas. Other-touch was related to activation in several areas, including somatosensory cortex, insula, superior temporal gyrus, supramarginal gyrus, striatum, amygdala, cerebellum, and prefrontal cortex. During self-touch, we instead found deactivation in insula, anterior cingulate cortex, superior temporal gyrus, amygdala, parahippocampal gyrus, and prefrontal areas. Deactivation extended into brain areas encoding low-level sensory representations, including thalamus and brainstem. These findings were replicated in a second cohort. During self-touch, the sensorimotor cortex was functionally connected to the insula, and the threshold for detection of an additional tactile stimulus was elevated. Differential encoding of self-vs. other-touch during fMRI correlated with the individual self-concept strength. In SEP, cortical amplitudes were reduced during self-touch, while latencies at cortical and spinal levels were faster for other-touch. We thus demonstrated a robust self-other distinction in brain areas related to somatosensory, social cognitive, and interoceptive processing. Signs of this distinction were evident at the spinal cord. Our results provide a framework for future studies in autism, schizophrenia, and emotionally unstable personality disorder, conditions where symptoms include social touch avoidance and poor self-vs.-other discrimination.
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| 3. |
- Böhme, Rebecca, et al.
(författare)
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Reversal learning strategy in adolescence is associated with prefrontal cortex activation
- 2017
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Ingår i: European Journal of Neuroscience. - : WILEY-BLACKWELL. - 0953-816X .- 1460-9568. ; 45:1, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- Adolescence is a critical maturation period for human cognitive control and executive function. In this study, a large sample of adolescents (n=85) performed a reversal learning task during functional magnetic resonance imaging. We analyzed behavioral data using a reinforcement learning model to provide individually fitted parameters and imaging data with regard to reward prediction errors (PE). Following a model-based approach, we formed two groups depending on whether individuals tended to update expectations predominantly for the chosen stimulus or also for the unchosen one. These groups significantly differed in their problem behavior score obtained using the child behavior checklist (CBCL) and in a measure of their developmental stage. Imaging results showed that dorsolateral striatal areas covaried with PE. Participants who relied less on learning based on task structure showed less prefrontal activation compared with participants who relied more on task structure. An exploratory analysis revealed that PE-related activity was associated with pubertal development in prefrontal areas, insula and anterior cingulate. These findings support the hypothesis that the prefrontal cortex is implicated in mediating flexible goal-directed behavioral control.
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| 4. |
- Deserno, Lorenz, et al.
(författare)
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Ventral striatal dopamine reflects behavioral and neural signatures of model-based control during sequential decision making
- 2015
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:5, s. 1595-1600
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Tidskriftsartikel (refereegranskat)abstract
- Whether humans make choices based on a deliberative “model-based” or a reflexive “model-free” system of behavioral control remains an ongoing topic of research. Dopamine is implicated in motivational drive as well as in planning future actions. Here, we demonstrate that higher presynaptic dopamine in human ventral striatum is associated with more pronounced model-based behavioral control, as well as an enhanced coding of model-based signatures in lateral prefrontal cortex and diminished coding of model-free learning signals in ventral striatum. Our study links ventral striatal presynaptic dopamine to a balance between two distinct modes of behavioral control in humans. The findings have implications for neuropsychiatric diseases associated with alterations of dopamine neurotransmission and a disrupted balance of behavioral control.Dual system theories suggest that behavioral control is parsed between a deliberative “model-based” and a more reflexive “model-free” system. A balance of control exerted by these systems is thought to be related to dopamine neurotransmission. However, in the absence of direct measures of human dopamine, it remains unknown whether this reflects a quantitative relation with dopamine either in the striatum or other brain areas. Using a sequential decision task performed during functional magnetic resonance imaging, combined with striatal measures of dopamine using [18F]DOPA positron emission tomography, we show that higher presynaptic ventral striatal dopamine levels were associated with a behavioral bias toward more model-based control. Higher presynaptic dopamine in ventral striatum was associated with greater coding of model-based signatures in lateral prefrontal cortex and diminished coding of model-free prediction errors in ventral striatum. Thus, interindividual variability in ventral striatal presynaptic dopamine reflects a balance in the behavioral expression and the neural signatures of model-free and model-based control. Our data provide a novel perspective on how alterations in presynaptic dopamine levels might be accompanied by a disruption of behavioral control as observed in aging or neuropsychiatric diseases such as schizophrenia and addiction.
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| 5. |
- Gleich, Tobias, et al.
(författare)
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Prefrontal and Striatal Glutamate Differently Relate to Striatal Dopamine : Potential Regulatory Mechanisms of Striatal Presynaptic Dopamine Function?
- 2015
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Ingår i: Journal of Neuroscience. - : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 35:26, s. 9615-9621
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Tidskriftsartikel (refereegranskat)abstract
- Theoretical and animal work has proposed that prefrontal cortex (PFC) glutamate inhibits dopaminergic inputs to the ventral striatum (VS) indirectly, whereas direct VS glutamatergic afferents have been suggested to enhance dopaminergic inputs to the VS. In the present study, we aimed to investigate relationships of glutamate and dopamine measures in prefrontostriatal circuitries of healthy humans. We hypothesized that PFC and VS glutamate, as well as their balance, are differently associated with VS dopamine. Glutamate concentrations in the left lateral PFC and left striatum were assessed using 3-Tesla proton magnetic resonance spectroscopy. Striatal presynaptic dopamine synthesis capacity was measured by fluorine-18-l-dihydroxyphenylalanine (F-18-FDOPA) positron emission tomography. First, a negative relationship was observed between glutamate concentrations in lateral PFC and VS dopamine synthesis capacity (n = 28). Second, a positive relationship was revealed between striatal glutamate and VS dopamine synthesis capacity (n = 26). Additionally, the intraindividual difference between PFC and striatal glutamate concentrations correlated negatively with VS dopamine synthesis capacity (n = 24). The present results indicate an involvement of a balance in PFC and striatal glutamate in the regulation of VS dopamine synthesis capacity. This notion points toward a potential mechanism how VS presynaptic dopamine levels are kept in a fine-tuned range. A disruption of this mechanism may account for alterations in striatal dopamine turnover as observed in mental diseases (e.g., in schizophrenia).SIGNIFICANCE STATEMENT The present work demonstrates complementary relationships between prefrontal and striatal glutamate and ventral striatal presynaptic dopamine using human imaging measures: a negative correlation between prefrontal glutamate and presynaptic dopamine and a positive relationship between striatal glutamate and presynaptic dopamine are revealed. The results may reflect a regulatory role of prefrontal and striatal glutamate for ventral striatal presynaptic dopamine levels. Such glutamate–dopamine relationships improve our understanding of neurochemical interactions in prefrontostriatal circuits and have implications for the neurobiology of mental disease.
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| 6. |
- Mcintyre, Sarah, et al.
(författare)
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Affective touch communication in close adult relationships
- 2019
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Ingår i: 2019 IEEE WORLD HAPTICS CONFERENCE (WHC). - : IEEE. - 9781538694619 - 9781538694626 ; , s. 175-180
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Konferensbidrag (refereegranskat)abstract
- Inter-personal touch is a powerful aspect of social interaction that we expect to he particularly important for emotional communication. We studied the capacity of closely acquainted humans to signal the meaning of several word cues (e.g. gratitude, sadness) using touch sensation alone. Participants communicated all cues with above chance performance. We show that emotionally close people can accurately signal the meaning of different words through touch, and that performance is affected by the amount of contextual information available. Even with minimal context and feedback, both attention-getting and love were communicated surprisingly well. Neither the type of close relationship, nor self-reported comfort with touch significantly affected performance.
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| 7. |
- Nickchen, Katharina, et al.
(författare)
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Reversal learning reveals cognitive deficits and altered prediction error encoding in the ventral striatum in Huntingtons disease
- 2017
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Ingår i: Brain Imaging and Behavior. - : SPRINGER. - 1931-7557 .- 1931-7565. ; 11:6, s. 1862-1872
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Tidskriftsartikel (refereegranskat)abstract
- Huntingtons disease (HD) is an autosomal dominant neurodegenerative condition characterized by a triad of movement disorder, neuropsychiatric symptoms and cognitive deficits. The striatum is particularly vulnerable to the effects of mutant huntingtin, and cell loss can already be found in presymptomatic stages. Since the striatum is well known for its role in reinforcement learning, we hypothesized to find altered behavioral and neural responses in HD patients in a probabilistic reinforcement learning task performed during functional magnetic resonance imaging. We studied 24 HD patients without central nervous system (CNS)-active medication and 25 healthy controls. Twenty HD patients and 24 healthy controls were able to complete the task. Computational modeling was used to calculate prediction error values and estimate individual parameters. We observed that gray matter density and prediction error signals during the learning task were related to disease stage. HD patients in advanced disease stages appear to use a less complex strategy in the reversal learning task. In contrast, HD patients in early disease stages show intact encoding of learning signals in the degenerating left ventral striatum. This effect appears to be lost with disease progression.
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| 8. |
- Pankow, Anne, et al.
(författare)
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Aberrant Salience Is Related to Dysfunctional Self-Referential Processing in Psychosis
- 2016
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Ingår i: Schizophrenia Bulletin. - : Oxford University Press. - 0586-7614 .- 1745-1701. ; 42:1, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- Background. A dysfunctional differentiation between self-relevant and irrelevant information may affect the perception of environmental stimuli as abnormally salient. The aberrant salience hypothesis assumes that positive symptoms arise from an attribution of salience to irrelevant stimuli accompanied by the feeling of self-relevance. Self-referential processing relies on the activation of cortical midline structures which was demonstrated to be impaired in psychosis. We investigated the neural correlates of self-referential processing, aberrant salience attribution, and the relationship between these 2 measures across the psychosis continuum. Methods. Twenty-nine schizophrenia patients, 24 healthy individuals with subclinical delusional ideation, and 50 healthy individuals participated in this study. Aberrant salience was assessed behaviorally in terms of reaction times to task irrelevant cues. Participants performed a self-reference task during fMRI in which they had to apply neutral trait words to them or to a public figure. The correlation between self-referential processing and aberrant salience attribution was tested. Results. Schizophrenia patients displayed increased aberrant salience attribution compared with healthy controls and individuals with subclinical delusional ideation, while the latter exhibited intermediate aberrant salience scores. In the self-reference task, schizophrenia patients showed reduced activation in the ventromedial prefrontal cortex (vmPFC), but individuals with subclinical delusional ideation did not differ from healthy controls. In schizophrenia patients, vmPFC activation correlated negatively with implicit aberrant salience attribution. Conclusions. Higher aberrant salience attribution in schizophrenia patients is related to reduced vmPFC activation during self-referential judgments suggesting that aberrant relevance coding is reflected in decreased neural self-referential processing as well as in aberrant salience attribution.
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| 9. |
- Raufelder, Diana, et al.
(författare)
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Does Feedback-Related Brain Response during Reinforcement Learning Predict Socio-motivational (In-)dependence in Adolescence?
- 2016
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Ingår i: Frontiers in Psychology. - Lausanne, Switzerland : Frontiers Research Foundation. - 1664-1078. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- This multi-methodological study applied functional magnetic resonance imaging to investigate neural activation in a group of adolescent students (N = 88) during a probabilistic reinforcement learning task. We related patterns of emerging brain activity and individual learning rates to socio-motivational (in-)dependence manifested in four different motivation types (MTs): (1) peer-dependent MT, (2) teacher-dependent MT, (3) peer-and-teacher-dependent MT, (4) peer-and-teacher-independent MT. A multinomial regression analysis revealed that the individual learning rate predicts students’ membership to the independent MT, or the peer-and-teacher-dependent MT. Additionally, the striatum, a brain region associated with behavioral adaptation and flexibility, showed increased learning-related activation in students with motivational independence. Moreover, the prefrontal cortex, which is involved in behavioral control, was more active in students of the peer-and-teacher-dependent MT. Overall, this study offers new insights into the interplay of motivation and learning with (1) a focus on inter-individual differences in the role of peers and teachers as source of students’ individual motivation and (2) its potential neurobiological basis.
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