scholarly journals Specific effect of a dopamine partial agonist on counterfactual learning: evidence from Gilles de la Tourette syndrome

2016 ◽  
Author(s):  
Alexandre Salvador ◽  
Yulia Worbe ◽  
Cécile Delorme ◽  
Giorgio Coricelli ◽  
Raphaël Gaillard ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Healthy Subjects ◽  
Partial Agonist ◽  
Specific Effect ◽  
Learning Task ◽  
Learning Performance ◽  
Healthy Controls ◽  
Dopamine Receptor Antagonists ◽  
Direct Learning ◽  
Simple Action

AbstractThe dopamine partial agonist aripiprazole is increasingly used to treat pathologies for which other antipsychotics are indicated because it displays fewer side effects, such as sedation and depression-like symptoms, than other dopamine receptor antagonists. Previously, we showed that aripiprazole may protect motivational function by preserving reinforcement-related signals used to sustain reward-maximization behaviour in a simple action-outcome learning task. However, the effect of aripiprazole on more cognitive facets of human reinforcement learning, such as learning from the hypothetical outcomes of alternative courses of action (i.e., counterfactual learning), is unknown.To test the influence of aripiprazole on counterfactual learning, we administered a reinforcement-learning task that involves both direct learning from obtained outcomes and indirect learning from forgone outcomes to two groups of Gilles de la Tourette (GTS) patients, one consisting of patients who were completely unmedicated and the other consisting of patients who were receiving aripiprazole monotherapy, and to healthy subjects. We replicated a previous finding showing that aripiprazole does not affect direct learning from obtained outcomes in GTS. We also found that whereas learning performance improved in the presence of counterfactual feedback in both healthy controls and unmedicated GTS patients, this was not the case in aripiprazole-medicated GTS patients.Our results suggest that whereas aripiprazole preserves direct learning of action-outcome associations, it may impair more complex inferential processes, such as counterfactual learning, from forgone outcomes.

scholarly journals Attention and reinforcement learning in Parkinson’s disease

2020 ◽  
Author(s):  
Brónagh McCoy ◽  
Rebecca P. Lawson ◽  
Jan Theeuwes
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Reinforcement Learning ◽  
Interactive Effect ◽  
Learning Task ◽  
Brain Regions ◽  
Learning Performance ◽  
Activation Patterns ◽  
Probabilistic Classification ◽  
Dorsolateral Prefrontal

ABSTRACTDopamine is known to be involved in several important cognitive processes, most notably in learning from rewards and in the ability to attend to task-relevant aspects of the environment. Both of these features of dopaminergic signalling have been studied separately in research involving Parkinson’s disease (PD) patients, who exhibit diminished levels of dopamine. Here, we tie together some of the commonalities in the effects of dopamine on these aspects of cognition by having PD patients (ON and OFF dopaminergic medication) and healthy controls (HCs) perform two tasks that probe these processes. Within-patient behavioural measures of distractibility, from an attentional capture task, and learning performance, from a probabilistic classification reinforcement learning task, were included in one model to assess the role of distractibility during learning. Dopamine medication state and distractibility level were found to have an interactive effect on learning performance; less distractibility in PD ON was associated with higher accuracy during learning, and this was altered in PD OFF. Functional magnetic resonance imaging (fMRI) data acquired during the learning task furthermore allowed us to assess multivariate patterns of positive and negative outcomes in fronto-striatal and visual brain regions involved in both learning processes and the executive control of attention. Here, we demonstrate that while PD ON show a clearer distinction between outcomes than OFF in dorsolateral prefrontal cortex (DLPFC) and putamen, PD OFF show better distinction of activation patterns in visual regions that respond to the stimuli presented during the task. These results demonstrate that dopamine plays a key role in modulating the interaction between attention and learning at the level of both behaviour and activation patterns in the brain.

Neuroevolution approach for reinforcement learning task applied to control system of a cart pole system

2019 ◽  
Author(s):  
Marco Boaretto ◽  
Gabriel Chaves Becchi ◽  
Luiza Scapinello Aquino ◽  
Aderson Cleber Pifer ◽  
Helon Vicente Hultmann Ayala ◽  
...  
Keyword(s):  
Control System ◽  
Reinforcement Learning ◽  
Learning Task ◽  
Pole System

Model-Based and Model-Free Social Cognition

2019 ◽  
Author(s):  
Leor M Hackel ◽  
Jeffrey Jordan Berg ◽  
Björn Lindström ◽  
David Amodio
Keyword(s):  
Reinforcement Learning ◽  
Social Cognition ◽  
Learning Strategies ◽  
Memory Systems ◽  
Learning Task ◽  
Financial Advisors ◽  
Model Based ◽  
Model Free ◽  
Systems Model ◽  
Task Assessment

Do habits play a role in our social impressions? To investigate the contribution of habits to the formation of social attitudes, we examined the roles of model-free and model-based reinforcement learning in social interactions—computations linked in past work to habit and planning, respectively. Participants in this study learned about novel individuals in a sequential reinforcement learning paradigm, choosing financial advisors who led them to high- or low-paying stocks. Results indicated that participants relied on both model-based and model-free learning, such that each independently predicted choice during the learning task and self-reported liking in a post-task assessment. Specifically, participants liked advisors who could provide large future rewards as well as advisors who had provided them with large rewards in the past. Moreover, participants varied in their use of model-based and model-free learning strategies, and this individual difference influenced the way in which learning related to self-reported attitudes: among participants who relied more on model-free learning, model-free social learning related more to post-task attitudes. We discuss implications for attitudes, trait impressions, and social behavior, as well as the role of habits in a memory systems model of social cognition.

Over-expression of IL-6 coding gene in the peripheral blood of migraine with aura patients

2021 ◽  
pp. 1-5
Author(s):  
Mahdi Ramezani ◽  
Alireza Komaki ◽  
Mohammad Mahdi Eftekharian ◽  
Mehrdokht Mazdeh ◽  
Soudeh Ghafouri-Fard
Keyword(s):  
Migraine With Aura ◽  
Peripheral Blood ◽  
Healthy Subjects ◽  
Migraine Without Aura ◽  
P Value ◽  
Healthy Controls ◽  
Over Expression ◽  
Significant Difference ◽  
Male Patients ◽  
Years Lived With Disability

Migraine is a common disorder which is placed among the top ten reasons of years lived with disability. Cytokines are among the molecules that contribute in the pathophysiology of migraine. In the current study, we evaluated expression levels of IL-6 coding gene in the peripheral blood of 120 migraine patients (54 migraine without aura and 66 migraine with aura patients) and 40 healthy subjects. No significant difference was detected in expression of IL-6 between total migraine patients and healthy controls (Posterior beta = 0.253, P value = 0.199). The interaction effect between gender and group was significant (Posterior beta =-1.274, P value = 0.011), therefore, we conducted subgroup analysis within gender group. Such analysis revealed that while expression of this gene is not different between male patients and male controls (Posterior beta =-0.371, P value > 0.999), it was significantly over-expressed in female patients compared with female controls (Posterior beta = 0.86, P= 0.002). Expression of IL-6 was significantly higher in patients with aura compared with controls (Posterior beta = 0.63, adjusted P value = 0.019). However, expression of this cytokine coding gene was not different between patients without aura and healthy subjects (Posterior beta = 0.193, adjusted P value = 0.281). Therefore, IL-6 might be involved in the pathophysiology of migraine among females and migraine with aura among both sexes.

scholarly journals No sex differences in learning in wild bumblebees

2021 ◽  
Author(s):  
Felicity Muth ◽  
Amber D Tripodi ◽  
Rene Bonilla ◽  
James P Strange ◽  
Anne S Leonard
Keyword(s):  
Sex Differences ◽  
Associative Learning ◽  
Sierra Nevada ◽  
Comparative Cognition ◽  
Natural Populations ◽  
Interspecific Variation ◽  
Learning Task ◽  
Learning Ability ◽  
Learning Performance ◽  
Males And Females

Abstract Females and males often face different sources of selection, resulting in dimorphism in morphological, physiological, and even cognitive traits. Sex differences are often studied in respect to spatial cognition, yet the different ecological roles of males and females might shape cognition in multiple ways. For example, in dietary generalist bumblebees (Bombus), the ability to learn associations is critical to female workers, who face informationally rich foraging scenarios as they collect nectar and pollen from thousands of flowers over a period of weeks to months to feed the colony. While male bumblebees likely need to learn associations as well, they only forage for themselves while searching for potential mates. It is thus less clear whether foraging males would benefit from the same associative learning performance as foraging females. In this system, as in others, cognitive performance is typically studied in lab-reared animals under captive conditions, which may not be representative of patterns in the wild. In the first test of sex and species differences in cognition using wild bumblebees, we compared the performance of Bombus vancouverensis nearcticus (formerly bifarius) and Bombus vosnesenskii of both sexes on an associative learning task at Sierra Nevada (CA) field sites. Across both species, we found that males and females did not differ in their ability to learn, although males were slower to respond to the sucrose reward. These results offer the first evidence from natural populations that male bumblebees may be equally as able to learn associations as females, supporting findings from captive colonies of commercial bees. The observed interspecific variation in learning ability opens the door to using the Bombus system to test hypotheses about comparative cognition.

scholarly journals Cardiovascular magnetic resonance-determined left ventricular myocardium impairment is associated with C-reactive protein and ST2 in patients with paroxysmal atrial fibrillation

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Lei Zhao ◽  
Songnan Li ◽  
Chen Zhang ◽  
Jie Tian ◽  
Aijia Lu ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Healthy Subjects ◽  
T1 Mapping ◽  
Circumferential Strain ◽  
Myocardial Strain ◽  
Left Ventricular ◽  
Healthy Controls ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Native T1

Abstract Background Myocardial strain assessed with cardiovascular magnetic resonance (CMR) feature tracking can detect early left ventricular (LV) myocardial deformation quantitatively in patients with a variety of cardiovascular diseases, but this method has not yet been applied to quantify myocardial strain in patients with atrial fibrillation (AF) and no coexistent cardiovascular disease, i.e., the early stage of AF. This study sought to compare LV myocardial strain and T1 mapping indices in AF patients and healthy subjects, and to investigate the associations of a portfolio of inflammation, cardiac remodeling and fibrosis biomarkers with LV myocardial strain and T1 mapping indices in AF patients with no coexistent cardiovascular disease. Methods The study consisted of 80 patients with paroxysmal AF patients and no coexistent cardiovascular disease and 20 age- and sex-matched healthy controls. Left atrial volume (LAV), LV myocardial strain and native T1 were assessed with CMR, and compared between the AF patients and healthy subjects. Biomarkers of C-reactive protein (CRP), transforming growth factor beta-1 (TGF-β1), collagen III N-terminal propeptide (PIIINP), and soluble suppression of tumorigenicity 2 (sST2) were obtained with blood tests, and compared between the AF patients and healthy controls. Associations of these biomarkers with those CMR-measured parameters were analyzed for the AF patients. Results For the CMR-measured parameters, the AF patients showed significantly larger LAV and LV end-systolic volume, and higher native T1 than the healthy controls (max P = 0.027). The absolute values of the LV peak systolic circumferential strain and its rate as well as the LV diastolic circumferential strain rate were all significantly reduced in the AF patients (all P < 0.001). For the biomarkers, the AF patients showed significantly larger CRP (an inflammation biomarker) and sST2 (a myocardium stiffness biomarker) than the controls (max P = 0.007). In the AF patients, the five CMR-measured parameters of LAV, three LV strain indices and native T1 were all significantly associated with these two biomarkers of CRP and sST2 (max P = 0.020). Conclusions In patients with paroxysmal AF and no coexistent cardiovascular disease, LAV enlargement and LV myocardium abnormalities were detected by CMR, and these abnormalities were associated with biomarkers that reflect inflammation and myocardial stiffness.

MO477SERUM C-REACTIVE PROTEIN AND PROCALCITONIN LEVELS IN HEMODIALYSIS AND INTRADIALYTIC ALTERATIONS

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Makrouhi Sonikian ◽  
Aggeliki Barbatsi ◽  
Eugenia Karakou ◽  
Theodoros Chiras ◽  
Jacob Skarakis ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Control Group ◽  
Healthy Controls ◽  
C Reactive Protein ◽  
Polysulfone Membrane ◽  
Reactive Protein ◽  
Markers Of Inflammation ◽  
Dialysate Flow Rate ◽  
Significant Difference ◽  
Serum Crp

Abstract Introduction C-reactive protein (CRP) and procalcitonin (PCT) are widely used as markers of inflammation and infection in general population and in chronic hemodialysis (HD) as well. However, in dialysis (D) patients, serum CRP and PCT levels may be elevated even in the absence of inflammatory or infectious disease and diagnostic process is a challenge in such cases. We studied HD patients' laboratory profile concerning CRP and PCT. Subjects and Methods We studied 25 stable HD patients, M/F=22/3, aged 68(44-89) years, dialyzed thrice weekly for 55(6-274) months with a dialysate flow rate of 700 ml/min, with a residual daily diuresis less than 200 ml, Kt/V values of 1,44±0,3 and no signs of infection. Patients were classified in two groups. Group A included 10 patients on pre-dilution online hemodiafiltration (HDF). Group B consisted of 15 patients on conventional HD with low-flux polysulfone membrane. Twenty healthy subjects formed a control group C. Serum CRP and PCT levels were measured in duplicate in A and B groups before and at the end of mid-week dialysis sessions and also in C group. Results Pre-D serum CRP values in the total of patients were higher than those in healthy controls (10,89±19,29 vs 2,54±1,28 mg/L-p=0,004). Compared with group C, pre-D CRP values were higher only in B group (15,98±24,54 mg/L-p=0,001) but not in A group (4,09±3,33 mg/L-p=NS). There was a significant difference in pre-D serum CRP values between A and B groups (p=0,028). At the end of D session serum CRP values showed a tendency to increase in both groups A (5,16±4,81 mg/L) and B (17,00±27,00 mg/L) but differences were not significant. Pre-D serum PCT values in the total of patients were higher than those in healthy controls (0,82±0,9 vs 0,29±0,55 ng/ml-p&lt;0,001). Compared with group C, pre-D PCT values were higher in both A group (0,52±0,15 ng/ml-p&lt;0,001) and B group (1,01±1,13 ng/ml-p=0,006). There was no significant difference in pre-D serum PCT values between A and B groups (p=0,261). At the end of D session serum PCT values decreased in A group (0,32±0,11 ng/ml-p&lt;0,001) and increased in B group (1,12±1,21 ng/ml-p=0,014). Conclusions In patients on both conventional low-flux HD and online HDF pre-D serum CRP and PCT levels were higher than those in healthy subjects. Dialysis modality and membrane flux did not affect post-D serum CRP values, but post-PCT values decreased in online HDF. PCT usefulness might be limited in dialysis with high-flux membranes. Cut-off values have to be established for both markers to eliminate confusion in diagnosis of inflammatory and infectious diseases in hemodialyzed patients.

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