scholarly journals The role of dopaminergic nuclei in predicting and experiencing gains and losses: A 7T human fMRI study

2019 ◽  
Author(s):  
Laura Fontanesi ◽  
Sebastian Gluth ◽  
Jörg Rieskamp ◽  
Birte U. Forstmann
Keyword(s):  
Animal Studies ◽  
Dopamine Neurons ◽  
7 Tesla ◽  
Ultrahigh Field ◽  
Reward Prediction ◽  
Fmri Study ◽  
Human Participants ◽  
Gains And Losses ◽  
Human Neuroimaging

AbstractThe ability to predict the outcomes of actions based on experience is crucial for making successful decisions in new or dynamic environments. In animal studies using electrophysiology, it was found that dopamine neurons, located in the substantia nigra (SN) and the ventral tegmental area (VTA), have a crucial role in feedback-based learning. However, human neuroimaging studies have provided inconclusive results. The present work used ultrahigh field (7 Tesla) structural and functional MRI and optimized protocols to extract SN and VTA signals in human participants. In a number-guessing task, we found significant correlations with reward prediction error and risk in both the SN and the VTA and no correlation with expected value. We also found a surprise signal in the SN. These results are in line with a recent framework that proposed a differential role for the VTA and the SN in, respectively, learning of values and surprise.

scholarly journals Reward prediction error in the ERP following unconditioned aversive stimuli

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Harry J. Stewardson ◽  
Thomas D. Sambrook
Keyword(s):  
Reinforcement Learning ◽  
Prediction Error ◽  
Dopamine Neurons ◽  
Prediction Errors ◽  
Temporal Difference ◽  
Dopamine System ◽  
Reward Prediction Error ◽  
Reward Prediction ◽  
Midbrain Dopamine ◽  
Human Participants

AbstractReinforcement learning in humans and other animals is driven by reward prediction errors: deviations between the amount of reward or punishment initially expected and that which is obtained. Temporal difference methods of reinforcement learning generate this reward prediction error at the earliest time at which a revision in reward or punishment likelihood is signalled, for example by a conditioned stimulus. Midbrain dopamine neurons, believed to compute reward prediction errors, generate this signal in response to both conditioned and unconditioned stimuli, as predicted by temporal difference learning. Electroencephalographic recordings of human participants have suggested that a component named the feedback-related negativity (FRN) is generated when this signal is carried to the cortex. If this is so, the FRN should be expected to respond equivalently to conditioned and unconditioned stimuli. However, very few studies have attempted to measure the FRN’s response to unconditioned stimuli. The present study attempted to elicit the FRN in response to a primary aversive stimulus (electric shock) using a design that varied reward prediction error while holding physical intensity constant. The FRN was strongly elicited, but earlier and more transiently than typically seen, suggesting that it may incorporate other processes than the midbrain dopamine system.

scholarly journals Distinct signals in medial and lateral VTA dopamine neurons modulate fear extinction at different times

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Lili X Cai ◽  
Katherine Pizano ◽  
Gregory W Gundersen ◽  
Cameron L Hayes ◽  
Weston T Fleming ◽  
...  
Keyword(s):  
Deep Learning ◽  
Prediction Error ◽  
Fear Extinction ◽  
Freezing Behavior ◽  
Dopamine Neurons ◽  
Reward Prediction Error ◽  
Reward Prediction ◽  
Time Period ◽  
Temporal Dependencies

Dopamine (DA) neurons are thought to encode reward prediction error (RPE), in addition to other signals, such as salience. While RPE is known to support learning, the role of salience in learning remains less clear. To address this, we recorded and manipulated VTA DA neurons in mice during fear extinction. We applied deep learning to classify mouse freezing behavior, eliminating the need for human scoring. Our fiber photometry recordings showed DA neurons in medial and lateral VTA have distinct activity profiles during fear extinction: medial VTA activity more closely reflected RPE, while lateral VTA activity more closely reflected a salience-like signal. Optogenetic inhibition of DA neurons in either region slowed fear extinction, with the relevant time period for inhibition differing across regions. Our results indicate salience-like signals can have similar downstream consequences to RPE-like signals, although with different temporal dependencies.

scholarly journals Distinct signals in medial and lateral VTA dopamine neurons modulate fear extinction at different times

2020 ◽  
Author(s):  
Lili X. Cai ◽  
Katherine Pizano ◽  
Gregory W. Gundersen ◽  
Cameron L. Hayes ◽  
Weston T. Fleming ◽  
...  
Keyword(s):  
Deep Learning ◽  
Prediction Error ◽  
Fear Extinction ◽  
Freezing Behavior ◽  
Dopamine Neurons ◽  
Reward Prediction Error ◽  
Reward Prediction ◽  
Time Period ◽  
Temporal Dependencies

Dopamine (DA) neurons are known to encode reward prediction error (RPE), in addition to other signals, such as salience. While RPE is known to support learning, the role of salience in supporting learning remains less clear. To address this, we recorded and manipulated VTA DA neurons in mice during fear extinction, a behavior we observed to generate spatially segregated RPE and salience signals. We applied deep learning to classify mouse freezing behavior, eliminating the need for human scoring. Our fiber photometry recordings showed that DA neurons in medial and lateral VTA have distinct activity profiles during fear extinction: medial VTA activity more closely reflected RPE, while lateral VTA activity more closely reflected a salience-like signal. Optogenetic inhibition of DA neurons in either region slowed fear extinction, with the relevant time period for inhibition differing across regions. Our results indicate that salience-like signals can have similar downstream consequences to RPE-like signals, although with different temporal dependencies.

Comprehensive Income: which potential effects on firms' performance evaluation and users' decision process?

2016 ◽  
pp. 55-94
Author(s):  
Pier Luigi Marchini ◽  
Carlotta D'Este
Keyword(s):  
Performance Evaluation ◽  
Decision Process ◽  
Financial Analysts ◽  
Listed Companies ◽  
Financial Statement ◽  
Comprehensive Income ◽  
Other Comprehensive Income ◽  
Gains And Losses ◽  
The Impact

The reporting of comprehensive income is becoming increasingly important. After the introduction of Other Comprehensive Income (OCI) reporting, as required by the 2007 IAS 1-revised, the IASB is currently seeking inputs from investors on the usefulness of unrealized gains and losses and on the role of comprehensive income. This circumstance is of particular relevance in code law countries, as local pre-IFRS accounting models influence financial statement preparers and users. This study aims at investigating the role played by unrealized gains and losses reporting on users' decision process, by examining the impact of OCI on the Italian listed companies RoE ratio and by surveying a sample of financial analysts, also content analysing their formal reports. The results show that the reporting of comprehensive income does not affect the financial statement users' decision process, although it statistically affects Italian listed entities' performance.

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 Hypoxia and Mitochondrial Dysfunction in Pregnancy Complications

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 405 ◽  
Author(s):  
Xiang-Qun Hu ◽  
Lubo Zhang
Keyword(s):  
Pregnancy Complications ◽  
Intrauterine Growth Restriction ◽  
Animal Studies ◽  
Major Effect ◽  
Causative Role ◽  
Therapeutic Approaches ◽  
Maternal Complications ◽  
Mitochondrial Ros ◽  
Subsequent Risk

Hypoxia is a common and severe stress to an organism’s homeostatic mechanisms, and hypoxia during gestation is associated with significantly increased incidence of maternal complications of preeclampsia, adversely impacting on the fetal development and subsequent risk for cardiovascular and metabolic disease. Human and animal studies have revealed a causative role of increased uterine vascular resistance and placental hypoxia in preeclampsia and fetal/intrauterine growth restriction (FGR/IUGR) associated with gestational hypoxia. Gestational hypoxia has a major effect on mitochondria of uteroplacental cells to overproduce reactive oxygen species (ROS), leading to oxidative stress. Excess mitochondrial ROS in turn cause uteroplacental dysfunction by damaging cellular macromolecules, which underlies the pathogenesis of preeclampsia and FGR. In this article, we review the current understanding of hypoxia-induced mitochondrial ROS and their role in placental dysfunction and the pathogenesis of pregnancy complications. In addition, therapeutic approaches selectively targeting mitochondrial ROS in the placental cells are discussed.

scholarly journals Including the animal standpoint in critical public relations research

2021 ◽  
Vol 10 (2) ◽  
pp. 139-161
Author(s):  
Núria Almiron ◽  
Laura Fernández
Keyword(s):  
Political Economy ◽  
Public Relations ◽  
Animal Studies ◽  
Critical Animal Studies ◽  
Essential Step ◽  
Challenges And Opportunities ◽  
Discourse Studies ◽  
Theoretical Paper ◽  
Short Explanation

In this paper we argue that adopting critical animal studies perspectives in critical public relations can not only be very fruitful, but that it is also a necessity if the aims of the latter are to be achieved. To this end, this text introduces the challenges and opportunities that the field of critical animal studies brings to critical public relations studies. First, a short explanation of what critical animal studies is and why it can contribute to critical public relations studies is provided. Then the main fields of research where this contribution can be most relevant are discussed, including ethics, discourse studies and political economy. The final aim of this theoretical paper is to expand research within the field of critical public relations by including a critical animal studies approach. Eventually, the authors suggest that embracing the animal standpoint in critical public relations is an essential step to furthering the study of power, hegemony, ideology, propaganda or social change and to accomplishing the emancipatory role of research.

scholarly journals Oxidative Stress as a Possible Target in the Treatment of Toxoplasmosis: Perspectives and Ambiguities

2021 ◽  
Vol 22 (11) ◽  
pp. 5705
Author(s):  
Karolina Szewczyk-Golec ◽  
Marta Pawłowska ◽  
Roland Wesołowski ◽  
Marcin Wróblewski ◽  
Celestyna Mila-Kierzenkowska
Keyword(s):  
Oxidative Stress ◽  
Animal Studies ◽  
Treatment Options ◽  
Natural Antioxidants ◽  
Redox Status ◽  
Host Cells ◽  
Common Disease ◽  
Parasite Viability

Toxoplasma gondii is an apicomplexan parasite causing toxoplasmosis, a common disease, which is most typically asymptomatic. However, toxoplasmosis can be severe and even fatal in immunocompromised patients and fetuses. Available treatment options are limited, so there is a strong impetus to develop novel therapeutics. This review focuses on the role of oxidative stress in the pathophysiology and treatment of T. gondii infection. Chemical compounds that modify redox status can reduce the parasite viability and thus be potential anti-Toxoplasma drugs. On the other hand, oxidative stress caused by the activation of the inflammatory response may have some deleterious consequences in host cells. In this respect, the potential use of natural antioxidants is worth considering, including melatonin and some vitamins, as possible novel anti-Toxoplasma therapeutics. Results of in vitro and animal studies are promising. However, supplementation with some antioxidants was found to promote the increase in parasitemia, and the disease was then characterized by a milder course. Undoubtedly, research in this area may have a significant impact on the future prospects of toxoplasmosis therapy.

Animal studies on the role of 50/60-hertz magnetic fields in carcinogenesis

Life Sciences ◽  
1994 ◽  
Vol 54 (21) ◽  
pp. 1531-1543 ◽  
Author(s):  
Wolfgang Löscher ◽  
Meike Mevissen
Keyword(s):  
Magnetic Fields ◽  
Animal Studies
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