scholarly journals Short-term mindfulness practice attenuates reward prediction errors signals in the brain

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ulrich Kirk ◽  
Giuseppe Pagnoni ◽  
Sébastien Hétu ◽  
Read Montague
Keyword(s):  
Mindfulness Practice ◽  
Prediction Errors ◽  
Short Term ◽  
Reward Prediction ◽  
The Brain

scholarly journals Nicotinic and Cholinergic Modulation of Reward Prediction Error Computations in the Ventral Tegmental Area: a Minimal Circuit Model

2018 ◽  
Author(s):  
Nicolas Deperrois ◽  
Boris Gutkin
Keyword(s):  
Ventral Tegmental Area ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Prediction Errors ◽  
Mediated Effects ◽  
Reward Prediction ◽  
Gaba Neuron ◽  
Ventral Tegmental ◽  
Reward Information ◽  
The Brain

AbstractDopamine (DA) neurons in the ventral tegmental area (VTA) are thought to encode reward prediction errors (RPE) by comparing actual and expected rewards. In recent years, much work has been done to identify how the brain uses and computes this signal.While several lines of evidence suggest the the interplay of he DA and the inhibitory interneurons in the VTA implements the RPE computaiton, it still remains unclear how the DA neurons learn key quantities, for example the amplitude and the timing of primary rewards during conditioning tasks. Furthermore, exogenous nicotine and endogenous acetylcholine, acting on both VTA DA and GABA (γ - aminobutyric acid) neurons via nicotinic-acetylcholine receptors (nAChRs), also likely affect these computations. To explore the potential circuit-level mechanisms for RPE computations during classical-conditioning tasks, we developed a minimal computational model of the VTA circuitry. The model was designed to account for several reward-related properties of VTA afferents and recent findings on VTA GABA neuron dynamics during conditioning.With our minimal model, we showed that the RPE can be learned by a two-speed process computing reward timing and magnitude. Including a model of nAChR-mediated currents in the VTA DA-GABA circuit, we also showed that nicotine should reduce the acetylcholine action on the VTA GABA neurons by receptor desensitization and therefore potentially boost the DA responses to reward information. Together, our results delineate the mechanisms by which RPE are computed in the brain, and suggest a hypothesis on nicotine-mediated effects on reward-related perception and decision-making.

scholarly journals The contribution of striatal pseudo-reward prediction errors to value-based decision-making

2017 ◽  
Author(s):  
Ernest Mas-Herrero ◽  
Guillaume Sescousse ◽  
Roshan Cools ◽  
Josep Marco-Pallarés
Keyword(s):  
Decision Making ◽  
Choice Behavior ◽  
Prediction Errors ◽  
Life Outcomes ◽  
Stimulus Response ◽  
Hierarchical Reinforcement Learning ◽  
Reward Prediction ◽  
Fmri Study ◽  
Reward Contingencies ◽  
The Brain

AbstractMost studies that have investigated the brain mechanisms underlying learning have focused on the ability to learn simple stimulus-response associations. However, in everyday life, outcomes are often obtained through complex behavioral patterns involving a series of actions. In such scenarios, parallel learning systems are important to reduce the complexity of the learning problem, as proposed in the framework of hierarchical reinforcement learning (HRL). One of the key features of HRL is the computation of pseudo-reward prediction errors (PRPEs) which allow the reinforcement of actions that led to a sub-goal before the final goal itself is achieved. Here we wanted to test the hypothesis that, despite not carrying any rewarding value per se, pseudo-rewards might generate a bias in choice behavior when reward contingencies are not well-known or uncertain. Second, we also hypothesized that this bias might be related to the strength of PRPE striatal representations. In order to test these ideas, we developed a novel decision-making paradigm to assess reward prediction errors (RPEs) and PRPEs in two studies (fMRI study: n = 20; behavioural study: n = 19). Our results show that overall participants developed a preference for the most pseudo-rewarding option throughout the task, even though it did not lead to more monetary rewards. fMRI analyses revealed that this preference was predicted by individual differences in the relative striatal sensitivity to PRPEs vs RPEs. Together, our results indicate that pseudo-rewards generate learning signals in the striatum and subsequently bias choice behavior despite their lack of association with actual reward.

Polychlorinated biphenyl induced hepatocyte alterations

1987 ◽  
Vol 45 ◽  
pp. 716-717
Author(s):  
D.N. Collins ◽  
J.N. Turner ◽  
K.O. Brosch ◽  
R.F. Seegal
Keyword(s):  
Lipid Droplets ◽  
Wistar Rats ◽  
Homovanillic Acid ◽  
Polychlorinated Biphenyl ◽  
Corn Oil ◽  
Environmental Pollutants ◽  
Short Term ◽  
Pcb Congeners ◽  
Urinary Levels ◽  
The Brain

Polychlorinated biphenyls (PCBs) are a ubiquitous class of environmental pollutants with toxic and hepatocellular effects, including accumulation of fat, proliferated smooth endoplasmic recticulum (SER), and concentric membrane arrays (CMAs) (1-3). The CMAs appear to be a membrane storage and degeneration organelle composed of a large number of concentric membrane layers usually surrounding one or more lipid droplets often with internalized membrane fragments (3). The present study documents liver alteration after a short term single dose exposure to PCBs with high chlorine content, and correlates them with reported animal weights and central nervous system (CNS) measures. In the brain PCB congeners were concentrated in particular regions (4) while catecholamine concentrations were decreased (4-6). Urinary levels of homovanillic acid a dopamine metabolite were evaluated (7).Wistar rats were gavaged with corn oil (6 controls), or with a 1:1 mixture of Aroclor 1254 and 1260 in corn oil at 500 or 1000 mg total PCB/kg (6 at each level).

Morphological Changes in the Brain of Acutely Ill and Weight-Recovered Patients with Anorexia Nervosa

2014 ◽  
Vol 42 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Jochen Seitz ◽  
Katharina Bühren ◽  
Georg G. von Polier ◽  
Nicole Heussen ◽  
Beate Herpertz-Dahlmann ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Cognitive Deficits ◽  
Time Course ◽  
Morphological Changes ◽  
Meta Analysis ◽  
Short Term ◽  
Clinical Prognosis ◽  
Qualitative Review ◽  
Brain Changes ◽  
The Brain

Objective: Acute anorexia nervosa (AN) leads to reduced gray (GM) and white matter (WM) volume in the brain, which however improves again upon restoration of weight. Yet little is known about the extent and clinical correlates of these brain changes, nor do we know much about the time-course and completeness of their recovery. Methods: We conducted a meta-analysis and a qualitative review of all magnetic resonance imaging studies involving volume analyses of the brain in both acute and recovered AN. Results: We identified structural neuroimaging studies with a total of 214 acute AN patients and 177 weight-recovered AN patients. In acute AN, GM was reduced by 5.6% and WM by 3.8% compared to healthy controls (HC). Short-term weight recovery 2–5 months after admission resulted in restitution of about half of the GM aberrations and almost full WM recovery. After 2–8 years of remission GM and WM were nearly normalized, and differences to HC (GM: –1.0%, WM: –0.7%) were no longer significant, although small residual changes could not be ruled out. In the qualitative review some studies found GM volume loss to be associated with cognitive deficits and clinical prognosis. Conclusions: GM and WM were strongly reduced in acute AN. The completeness of brain volume rehabilitation remained equivocal.

Temporal Prediction Errors Affect Short-Term Memory Scanning Response Time

2016 ◽  
Vol 63 (6) ◽  
pp. 333-342
Author(s):  
Roberto Limongi ◽  
Angélica M. Silva
Keyword(s):  
Response Time ◽  
Short Term Memory ◽  
Estimation Error ◽  
Predictive Coding ◽  
Time Estimation ◽  
Prediction Errors ◽  
Memory Scanning ◽  
Short Term ◽  
Term Memory ◽  
Temporal Prediction

Abstract. The Sternberg short-term memory scanning task has been used to unveil cognitive operations involved in time perception. Participants produce time intervals during the task, and the researcher explores how task performance affects interval production – where time estimation error is the dependent variable of interest. The perspective of predictive behavior regards time estimation error as a temporal prediction error (PE), an independent variable that controls cognition, behavior, and learning. Based on this perspective, we investigated whether temporal PEs affect short-term memory scanning. Participants performed temporal predictions while they maintained information in memory. Model inference revealed that PEs affected memory scanning response time independently of the memory-set size effect. We discuss the results within the context of formal and mechanistic models of short-term memory scanning and predictive coding, a Bayes-based theory of brain function. We state the hypothesis that our finding could be associated with weak frontostriatal connections and weak striatal activity.

Reward Prediction Errors Drive Declarative Learning Irrespective of Agency

2020 ◽  
Author(s):  
Kate Ergo ◽  
Luna De Vilder ◽  
Esther De Loof ◽  
Tom Verguts
Keyword(s):  
Learning Theory ◽  
Learning Effect ◽  
Steady Increase ◽  
Prediction Errors ◽  
Experimental Paradigm ◽  
Reward Prediction ◽  
Declarative Learning

Recent years have witnessed a steady increase in the number of studies investigating the role of reward prediction errors (RPEs) in declarative learning. Specifically, in several experimental paradigms RPEs drive declarative learning; with larger and more positive RPEs enhancing declarative learning. However, it is unknown whether this RPE must derive from the participant’s own response, or whether instead any RPE is sufficient to obtain the learning effect. To test this, we generated RPEs in the same experimental paradigm where we combined an agency and a non-agency condition. We observed no interaction between RPE and agency, suggesting that any RPE (irrespective of its source) can drive declarative learning. This result holds implications for declarative learning theory.

scholarly journals Expression Analysis of Zinc Transporters in Nervous Tissue Cells Reveals Neuronal and Synaptic Localization of ZIP4

2021 ◽  
Vol 22 (9) ◽  
pp. 4511
Author(s):  
Chiara A. De Benedictis ◽  
Claudia Haffke ◽  
Simone Hagmeyer ◽  
Ann Katrin Sauer ◽  
Andreas M. Grabrucker
Keyword(s):  
Brain Function ◽  
Zinc Homeostasis ◽  
Zinc Transporters ◽  
Excitatory Synapses ◽  
Short Term ◽  
Synaptic Localization ◽  
Zinc Levels ◽  
Rat Astrocyte ◽  
Cellular Zinc ◽  
The Brain

In the last years, research has shown that zinc ions play an essential role in the physiology of brain function. Zinc acts as a potent neuromodulatory agent and signaling ions, regulating healthy brain development and the function of both neurons and glial cells. Therefore, the concentration of zinc within the brain and its cells is tightly controlled. Zinc transporters are key regulators of (extra-) cellular zinc levels, and deregulation of zinc homeostasis and zinc transporters has been associated with neurodegenerative and neuropsychiatric disorders. However, to date, the presence of specific family members and their subcellular localization within brain cells have not been investigated in detail. Here, we analyzed the expression of all zinc transporters (ZnTs) and Irt-like proteins (ZIPs) in the rat brain. We further used primary rat neurons and rat astrocyte cell lines to differentiate between the expression found in neurons or astrocytes or both. We identified ZIP4 expressed in astrocytes but significantly more so in neurons, a finding that has not been reported previously. In neurons, ZIP4 is localized to synapses and found in a complex with major postsynaptic scaffold proteins of excitatory synapses. Synaptic ZIP4 reacts to short-term fluctuations in local zinc levels. We conclude that ZIP4 may have a so-far undescribed functional role at excitatory postsynapses.

Changes of PACAP levels in the brain show gender differences following short-term water and food deprivation

2007 ◽  
Vol 152 (2-3) ◽  
pp. 225-230 ◽  
Author(s):  
P. Kiss ◽  
D. Reglődi ◽  
A. Tamás ◽  
A. Lubics ◽  
I. Lengvári ◽  
...  
Keyword(s):  
Gender Differences ◽  
Food Deprivation ◽  
Short Term ◽  
The Brain

scholarly journals Mindfulness Research Update: 2008

2009 ◽  
Vol 14 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Jeffrey M. Greeson
Keyword(s):  
Quality Of Life ◽  
Stress Reduction ◽  
Mindfulness Meditation ◽  
Stress Hormones ◽  
Theoretical Work ◽  
The Body ◽  
Mindfulness Practice ◽  
Optimal Health ◽  
The Brain

Objective: To briefly review the effects of mindfulness on the mind, the brain, the body, and behavior. Methods: Selective review of MEDLINE, PsycINFO, and Google Scholar databases (2003—2008) using the terms ``mindfulness,'' ``meditation,'' ``mental health,'' ``physical health,'' ``quality of life,'' and ``stress reduction.'' A total of 52 exemplars of empirical and theoretical work were selected for review. Results: Both basic and clinical research indicate that cultivating a more mindful way of being is associated with less emotional distress, more positive states of mind, and better quality of life. In addition, mindfulness practice can influence the brain, the autonomic nervous system, stress hormones, the immune system, and health behaviors, including eating, sleeping, and substance use, in salutary ways. Conclusion: The application of cutting-edge technology toward understanding mindfulness— an ``inner technology''—is elucidating new ways in which attention, awareness, acceptance, and compassion may promote optimal health—in mind, body, relationships, and spirit.

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