Read by QxMD icon Read

Computational psychiatry

shared collection
50 papers 25 to 100 followers
By Abraham Nunes Psychiatry resident interested in computational neuroscience, forensic psychiatry, and neuropsychiatry.
Juliet Y Davidow, Karin Foerde, Adriana Galván, Daphna Shohamy
Adolescents are notorious for engaging in reward-seeking behaviors, a tendency attributed to heightened activity in the brain's reward systems during adolescence. It has been suggested that reward sensitivity in adolescence might be adaptive, but evidence of an adaptive role has been scarce. Using a probabilistic reinforcement learning task combined with reinforcement learning models and fMRI, we found that adolescents showed better reinforcement learning and a stronger link between reinforcement learning and episodic memory for rewarding outcomes...
October 5, 2016: Neuron
Jenna M Reinen, Jared X Van Snellenberg, Guillermo Horga, Anissa Abi-Dargham, Nathaniel D Daw, Daphna Shohamy
BACKGROUND: Recent findings demonstrate that patients with schizophrenia are worse at learning to predict rewards than losses, suggesting that motivational context modulates learning in this disease. However, these findings derive from studies in patients treated with antipsychotic medications, D2 receptor antagonists that may interfere with the neural systems that underlie motivation and learning. Thus, it remains unknown how motivational context affects learning in schizophrenia, separate from the effects of medication...
April 22, 2016: Schizophrenia Bulletin
Alec Solway, Carlos Diuk, Natalia Córdova, Debbie Yee, Andrew G Barto, Yael Niv, Matthew M Botvinick
Human behavior has long been recognized to display hierarchical structure: actions fit together into subtasks, which cohere into extended goal-directed activities. Arranging actions hierarchically has well established benefits, allowing behaviors to be represented efficiently by the brain, and allowing solutions to new tasks to be discovered easily. However, these payoffs depend on the particular way in which actions are organized into a hierarchy, the specific way in which tasks are carved up into subtasks...
August 2014: PLoS Computational Biology
Lauren R Godier, Sanne de Wit, Anthony Pinto, Joanna E Steinglass, Ashley L Greene, Jessica Scaife, Claire M Gillan, B Timothy Walsh, Helen-Blair Simpson, Rebecca J Park
Anorexia Nervosa (AN) is a disorder characterised by compulsive behaviour, such as self-starvation and excessive exercise, which develop in the pursuit of weight-loss. Recent theory suggests that once established, compulsive weight-loss behaviours in AN may become habitual. In two parallel studies, we measured whether individuals with AN showed a bias toward habits using two outcome-devaluation tasks. In Study 1, 23 women with AN (restrictive and binge/purge subtypes), and 18 healthy controls (HC) completed the slips-of-action paradigm, designed to assess reward-based habits...
October 30, 2016: Psychiatry Research
Tiago V Maia, Michael J Frank
We propose that schizophrenia involves a combination of decreased phasic dopamine responses for relevant stimuli and increased spontaneous phasic dopamine release. Using insights from computational reinforcement-learning models and basic-science studies of the dopamine system, we show that each of these two disturbances contributes to a specific symptom domain and explains a large set of experimental findings associated with that domain. Reduced phasic responses for relevant stimuli help to explain negative symptoms and provide a unified explanation for the following experimental findings in schizophrenia, most of which have been shown to correlate with negative symptoms: reduced learning from rewards; blunted activation of the ventral striatum, midbrain, and other limbic regions for rewards and positive prediction errors; blunted activation of the ventral striatum during reward anticipation; blunted autonomic responding for relevant stimuli; blunted neural activation for aversive outcomes and aversive prediction errors; reduced willingness to expend effort for rewards; and psychomotor slowing...
June 1, 2016: Biological Psychiatry
Rumana Chowdhury, Marc Guitart-Masip, Christian Lambert, Peter Dayan, Quentin Huys, Emrah Düzel, Raymond J Dolan
Senescence affects the ability to utilize information about the likelihood of rewards for optimal decision-making. Using functional magnetic resonance imaging in humans, we found that healthy older adults had an abnormal signature of expected value, resulting in an incomplete reward prediction error (RPE) signal in the nucleus accumbens, a brain region that receives rich input projections from substantia nigra/ventral tegmental area (SN/VTA) dopaminergic neurons. Structural connectivity between SN/VTA and striatum, measured by diffusion tensor imaging, was tightly coupled to inter-individual differences in the expression of this expected reward value signal...
May 2013: Nature Neuroscience
Marc Guitart-Masip, Marcos Economides, Quentin J M Huys, Michael J Frank, Rumana Chowdhury, Emrah Duzel, Peter Dayan, Raymond J Dolan
RATIONALE: Decision-making involves two fundamental axes of control namely valence, spanning reward and punishment, and action, spanning invigoration and inhibition. We recently exploited a go/no-go task whose contingencies explicitly decouple valence and action to show that these axes are inextricably coupled during learning. This results in a disadvantage in learning to go to avoid punishment and in learning to no-go to obtain a reward. The neuromodulators dopamine and serotonin are likely to play a role in these asymmetries: Dopamine signals anticipation of future rewards and is also involved in an invigoration of motor responses leading to reward, but it also arbitrates between different forms of control...
March 2014: Psychopharmacology
Dirk E M Geurts, Quentin J M Huys, Hanneke E M den Ouden, Roshan Cools
Adaptive decision-making involves interaction between systems regulating Pavlovian and instrumental control of behavior. Here we investigate in humans the role of serotonin in such Pavlovian-instrumental transfer in both the aversive and the appetitive domain using acute tryptophan depletion, known to lower central serotonin levels. Acute tryptophan depletion attenuated the inhibiting effect of aversive Pavlovian cues on instrumental behavior, while leaving unaltered the activating effect of appetitive Pavlovian cues...
November 27, 2013: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Miriam Sebold, Lorenz Deserno, Stephan Nebe, Stefan Nebe, Daniel J Schad, Maria Garbusow, Claudia Hägele, Jürgen Keller, Elisabeth Jünger, Norbert Kathmann, Michael N Smolka, Michael Smolka, Michael A Rapp, Florian Schlagenhauf, Andreas Heinz, Quentin J M Huys
BACKGROUND: Human and animal work suggests a shift from goal-directed to habitual decision-making in addiction. However, the evidence for this in human alcohol dependence is as yet inconclusive. METHODS: Twenty-six healthy controls and 26 recently detoxified alcohol-dependent patients underwent behavioral testing with a 2-step task designed to disentangle goal-directed and habitual response patterns. RESULTS: Alcohol-dependent patients showed less evidence of goal-directed choices than healthy controls, particularly after losses...
2014: Neuropsychobiology
Maria Garbusow, Daniel J Schad, Miriam Sebold, Eva Friedel, Nadine Bernhardt, Stefan P Koch, Bruno Steinacher, Norbert Kathmann, Dirk E M Geurts, Christian Sommer, Dirk K Müller, Stephan Nebe, Sören Paul, Hans-Ulrich Wittchen, Ulrich S Zimmermann, Henrik Walter, Michael N Smolka, Philipp Sterzer, Michael A Rapp, Quentin J M Huys, Florian Schlagenhauf, Andreas Heinz
In detoxified alcohol-dependent patients, alcohol-related stimuli can promote relapse. However, to date, the mechanisms by which contextual stimuli promote relapse have not been elucidated in detail. One hypothesis is that such contextual stimuli directly stimulate the motivation to drink via associated brain regions like the ventral striatum and thus promote alcohol seeking, intake and relapse. Pavlovian-to-Instrumental-Transfer (PIT) may be one of those behavioral phenomena contributing to relapse, capturing how Pavlovian conditioned (contextual) cues determine instrumental behavior (e...
May 2016: Addiction Biology
Christian A Webb, Daniel G Dillon, Pia Pechtel, Franziska K Goer, Laura Murray, Quentin J M Huys, Maurizio Fava, Patrick J McGrath, Myrna Weissman, Ramin Parsey, Benji T Kurian, Phillip Adams, Sarah Weyandt, Joseph M Trombello, Bruce Grannemann, Crystal M Cooper, Patricia Deldin, Craig Tenke, Madhukar Trivedi, Gerard Bruder, Diego A Pizzagalli
Major depressive disorder (MDD) is clinically, and likely pathophysiologically, heterogeneous. A potentially fruitful approach to parsing this heterogeneity is to focus on promising endophenotypes. Guided by the NIMH Research Domain Criteria initiative, we used source localization of scalp-recorded EEG resting data to examine the neural correlates of three emerging endophenotypes of depression: neuroticism, blunted reward learning, and cognitive control deficits. Data were drawn from the ongoing multi-site EMBARC study...
January 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Ulrich Kirk, Xiaosi Gu, Ann H Harvey, Peter Fonagy, P Read Montague
Neuroimaging research has demonstrated that ventromedial prefrontal cortex (vmPFC) encodes value signals that can be modulated by top-down cognitive input such as semantic knowledge, price incentives, and monetary favors suggesting that such biases may have an identified biological basis. It has been hypothesized that mindfulness training (MT) provides one path for gaining control over such top-down influences; yet, there have been no direct tests of this hypothesis. Here, we probe the behavioral and neural effects of MT on value signals in vmPFC in a randomized longitudinal design of 8 weeks of MT on an initially naïve subject cohort...
October 15, 2014: NeuroImage
Ulrich Kirk, P Read Montague
Reinforcement learning models have demonstrated that phasic activity of dopamine neurons during reward expectation encodes information about the predictability of reward and cues that predict reward. Self-control strategies such as those practiced in mindfulness-based approaches is claimed to reduce negative and positive reactions to stimuli suggesting the hypothesis that such training may influence basic reward processing. Using a passive conditioning task and fMRI in a group of experienced mindfulness meditators and age-matched controls, we tested the hypothesis that mindfulness meditation influence reward and reward prediction error (PE) signals...
2015: Frontiers in Psychology
David Arkadir, Angela Radulescu, Deborah Raymond, Naomi Lubarr, Susan B Bressman, Pietro Mazzoni, Yael Niv
It has been difficult to link synaptic modification to overt behavioral changes. Rodent models of DYT1 dystonia, a motor disorder caused by a single gene mutation, demonstrate increased long-term potentiation and decreased long-term depression in corticostriatal synapses. Computationally, such asymmetric learning predicts risk taking in probabilistic tasks. Here we demonstrate abnormal risk taking in DYT1 dystonia patients, which is correlated with disease severity, thereby supporting striatal plasticity in shaping choice behavior in humans...
2016: ELife
Stephanie C Y Chan, Yael Niv, Kenneth A Norman
UNLABELLED: The orbitofrontal cortex (OFC) has been implicated in both the representation of "state," in studies of reinforcement learning and decision making, and also in the representation of "schemas," in studies of episodic memory. Both of these cognitive constructs require a similar inference about the underlying situation or "latent cause" that generates our observations at any given time. The statistically optimal solution to this inference problem is to use Bayes' rule to compute a posterior probability distribution over latent causes...
July 27, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Karl Friston, Harriet R Brown, Jakob Siemerkus, Klaas E Stephan
Twenty years have passed since the dysconnection hypothesis was first proposed (Friston and Frith, 1995; Weinberger, 1993). In that time, neuroscience has witnessed tremendous advances: we now live in a world of non-invasive neuroanatomy, computational neuroimaging and the Bayesian brain. The genomics era has come and gone. Connectomics and large-scale neuroinformatics initiatives are emerging everywhere. So where is the dysconnection hypothesis now? This article considers how the notion of schizophrenia as a dysconnection syndrome has developed - and how it has been enriched by recent advances in clinical neuroscience...
October 2016: Schizophrenia Research
Raphaël Le Bouc, Lionel Rigoux, Liane Schmidt, Bertrand Degos, Marie-Laure Welter, Marie Vidailhet, Jean Daunizeau, Mathias Pessiglione
UNLABELLED: Motor dysfunction (e.g., bradykinesia) and motivational deficit (i.e., apathy) are hallmarks of Parkinson's disease (PD). Yet, it remains unclear whether these two symptoms arise from a same dopaminergic dysfunction. Here, we develop a computational model that articulates motor control to economic decision theory, to dissect the motor and motivational functions of dopamine in humans. This model can capture different aspects of the behavior: choice (which action is selected) and vigor (action speed and intensity)...
June 22, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Helene Haker, Maya Schneebeli, Klaas Enno Stephan
Diagnosis and individualized treatment of autism spectrum disorder (ASD) represent major problems for contemporary psychiatry. Tackling these problems requires guidance by a pathophysiological theory. In this paper, we consider recent theories that re-conceptualize ASD from a "Bayesian brain" perspective, which posit that the core abnormality of ASD resides in perceptual aberrations due to a disbalance in the precision of prediction errors (sensory noise) relative to the precision of predictions (prior beliefs)...
2016: Frontiers in Psychiatry
Andrea Mf Reiter, Hans-Jochen Heinze, Florian Schlagenhauf, Lorenz Deserno
Despite its clinical relevance and the recent recognition as a diagnostic category in the DSM-5, Binge Eating Disorder (BED) has rarely been investigated from a cognitive neuroscientific perspective targeting a more precise neurocognitive profiling of the disorder. BED patients suffer from a lack of behavioral control during recurrent binge eating episodes and thus, fail to adapt their behavior in the face of negative consequences, eg, high risk for obesity. To examine impairments in flexible reward-based decision-making, we exposed BED patients (n=22) and matched healthy individuals (n=22) to a reward-guided decision-making task during functional resonance imaging (fMRI)...
June 15, 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
Renaud Jardri, Kenneth Hugdahl, Matthew Hughes, Jérôme Brunelin, Flavie Waters, Ben Alderson-Day, Dave Smailes, Philipp Sterzer, Philip R Corlett, Pantelis Leptourgos, Martin Debbané, Arnaud Cachia, Sophie Denève
This review from the International Consortium on Hallucinations Research intends to question the pertinence of the excitatory-to-inhibitory (E/I) imbalance hypothesis as a model for hallucinations. A large number of studies suggest that subtle impairments of the E/I balance are involved in neurological and psychiatric conditions, such as schizophrenia. Emerging evidence also points to a role of the E/I balance in maintaining stable perceptual representations, suggesting it may be a plausible model for hallucinations...
September 2016: Schizophrenia Bulletin
2016-06-10 01:35:24
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"