Decision and dopaminergic system: an ERPs study of Iowa gambling task in Parkinson's disease

Influence of rhythmic-movement activity intervention on hot executive function of 5- to 6-year-old children

Hot Executive Function (hot EF) refers to cognitive process involved in high emotion or motivation, and the operation of this function is related to the activities of the ventromedial prefrontal lobe and orbitofrontal lobe. Meanwhile, rhythmic-movement activity is a musical activity in which one expresses and feels music with one's own body movements which involves cognitive abilities such as adjusting and understanding emotions among children. To explore how rhythmic-movement activity with rewards influences the development of hot EF in children of 5-6 years old, the organization principles of rhythmic-movement activity with rewards intervention on hot EF were designed, and 62 children of 5-6 years old in a kindergarten in Yantai of China were selected as research participants (M = 5.80 years old, SD = 0.37 years old) for pre-test and post-test experimental design. The experimental group received rhythmic-movement activity with rewards three times a week for 6 weeks, while the control group did not. The gift delay task and the children's gambling task were used to measure two sub-components of hot EF before and after the intervention, and the results show that rhythmic-movement activity with rewards has a significant effect on gratification delay and affective decision-making ability of children. Finally, the effects and enlightenment of rhythmic-movement activity with rewards on hot EF are discussed.

[Features of decision-making in patients with alcohol dependence]

OBJECTIVE

To identify electroencephalographic correlates of decision-making features in patients with alcohol dependence.

MATERIAL AND METHODS

Forty men with alcohol dependence were examined as the main group. Thirty people were examined as a control group. The Cambridge Gambling Task and the Iowa Gambling Task were used to study decision-making functions. Additionally, a background electroencephalogram was recorded with the calculation of absolute spectral power indicators.

RESULTS

In the main group, the relatively higher indicators of decision-making logic (65 [50; 80]%, p<0.05) were associated with larger values of the spectral power of the theta and alpha rhythm of the electroencephalogram in the central and parietal-occipital leads (R=0.426, p=0.019; R=0.418, p=0.022; R=0.394, p=0.028 and R=0.445, p=0.014; R=0.458, p=0.011; R=0.382, p=0.035, respectively). Difficulties in making decisions based on emotional learning in patients with alcohol dependence were associated with larger values of the spectral power of the beta rhythm of the electroencephalogram in the temporal leads.

CONCLUSIONS

The study showed that the deficit of decision-making functions in patients with alcohol dependence may be due to an imbalance of the excitation/inhibition mechanisms in the brain.

Effects of subjective and objective task difficulties for feedback- related brain potentials in social situations: An electroencephalogram study

In this study, the relationship between two types of feedback task difficulties and feedback-related brain potentials, such as feedback-related negativity (FRN), reward positivity (RewP), and P300, was investigated in social situations where participants performed a task simultaneously by a pair. The electroencephalogram activity was measured while participants answered four-choice questions with their partners. Participants were informed about the general accuracy rate of the question (objective task difficulty) before responding to the questionnaire. The feedback outcome was definitely correct when the participants had the knowledge to answer the questions correctly. Therefore, the subjective task difficulty depended on the knowledge of the participant and differed from the objective task difficulty. In the task, the participants selected the choice they deemed correct. Before checking the answers, participants responded to the preceding question's subjective task difficulty. As one of the social factors, the task consisted of two types of conditions: one, in which one's response affected partner's reward, and another, in which it did not. The second social factor was the order of feedback outcomes; in our experiment, these outcomes were presented sequentially to pairs of participants. The effects of subjective and objective task difficulties and social factors on feedback-related brain potentials were comprehensively analyzed. The study showed that subjective task difficulty sensitively modulated the amplitude of gain-related P300, suggesting that it is sensitive to modulation in the allocation of attentional resources to own feedback outcome. The objective task difficulty sensitively modulated the amplitude of RewP after receiving the partner's incorrect feedback outcome. RewP was more sensitive to positive affective valence, such as feelings of superiority over the partner, than to task-dependent rewards received by the participants themselves. In contrast, FRN was more negative in the joint condition than in the individual condition, suggesting sensitivity to social responsibility felt by participants toward their partners.

Decision making in Parkinson's disease: An analysis of the studies using the Iowa Gambling Task

In Parkinson's disease (PD) impairments in decision making can occur, in particular because of the tendency toward risky and rewarding options. The Iowa Gambling Task has been widely used to investigate decision processes involving these options. The task assesses the ability to manage risk and to learn from feedback. The present paper aims at critically examining those studies in which this task has been administered to PD patients, in order to understand possible anomalies in patients' decision processes and which variables are responsible for that. A meta‐analysis has been conducted as well. Features of the task, sociodemographic and clinical aspects (including daily drugs intake), cognitive conditions and emotional disorders of the patients have been taken into account. Neural correlates of decision‐making competences were considered. It emerged that PD patients show a trend of preference toward risky choices, probably due to an impairment in anticipating the unrewarding consequences or to an insensitiveness to punishment. The possible role played by dopamine medications in decision making under uncertain conditions, affecting basal ganglia and structures involved in the limbic loop, was discussed. Attention has been focused on some aspects that need to be investigated in further research, in order to delve into this issue and promote patients' quality of life.

Learning With and Without Feedback in Children With Developmental Language Disorder

Purpose Intervention provided to school-age children with developmental language disorder often relies on the provision of performance feedback, yet it is unclear whether children with this disorder benefit from feedback-based learning. The study evaluates the effect of performance feedback on learning in children with developmental language disorder. Method Thirteen 8- to 12-year-old children with developmental language disorder and 14 age- and gender-matched children with typical language development completed two learning tasks whose objective was to pair nonword novel names with novel objects. The two tasks differed in the presence of performance feedback to guide learning. Learning outcomes on immediate and follow-up tests were compared between the feedback-based and feedback-free tasks. Additionally, an electrophysiological marker of feedback processing was compared between children with and without developmental language disorder. Results Children with developmental language disorder demonstrated poorer learning outcomes on both tasks when compared with their peers, but both groups achieved better accuracy on the feedback-free task when compared with the feedback-based task. Within the feedback-based task, children were more likely to repeat a correct response than to change it after positive feedback but were as likely to repeat an error as they were to correct it after receiving negative feedback. While children with typical language elicited a feedback-related negativity with greater amplitude to negative feedback, this event-related potential had no amplitude differences between positive and negative feedback in children with developmental language disorder. Conclusions Findings indicate that 8- to 12-year-old children benefit more from a feedback-free learning environment and that negative feedback is not as effective as positive feedback in facilitating learning in children. The behavioral and electrophysiological data provide evidence that feedback processing is impaired in children with developmental language disorders. Future research should evaluate feedback-based learning in children with this disorder using other learning paradigms.

Is there a Neurobiological Rationale for the Utility of the Iowa Gambling Task in Parkinson's Disease?

Up to 23% of newly diagnosed, non-demented, Parkinson’s disease (PD) patients experience deficits in executive functioning (EF). In fact, EF deficits may occur up to 39-months prior to the onset of motor decline. Optimal EF requires working memory, attention, cognitive flexibility, and response inhibition underlying appropriate decision-making. The capacity for making strategic decisions requires inhibiting imprudent decisions and are associated with noradrenergic and dopaminergic signaling in prefrontal and orbitofrontal cortex. Catecholaminergic dysfunction and the loss of noradrenergic and dopaminergic cell bodies early in PD progression in the aforementioned cortical areas likely contribute to EF deficits resulting in non-strategic decision-making. Thus, detecting these deficits early in the disease process could help identify a significant portion of individuals with PD pathology (14–60%) before frank motor impairment. A task to evaluate EF in the domain of non-strategic decision-making might be useful to indicate the moderate loss of catecholamines that occurs early in PD pathology prior to motor decline and cognitive impairment. In this review, we focus on the potential utility of the Iowa Gambling Task (IGT) for this purpose, given significant overlap between in loss of dopaminergic and noradrenergic cells bodies in early PD and the deficits in catecholamine function associated with decreased EF. As such, given the loss of catecholamines already well-underway after PD diagnosis, we evaluate the potential utility of the IGT to identify the risk of therapeutic non-compliance and a potential companion approach to detect PD in premotor stages.

FRN and P3 during the Iowa gambling task: The importance of gender

Previous research has shown gender-related psychobiological differences in risky and competitive strategies that affect win and loss outcomes. In addition, some studies have found differences in the decision-making process, with women taking longer to reach the same performance as men. However, the underlying neural mechanisms remain unclear. The present study aimed to investigate gender differences in behavioral performance and neural correlates during a decision-making task, the Iowa Gambling Task (IGT). Forty healthy young adults (23 men and 17 women) performed the IGT while the feedback-related negativity (FRN) and P3 were recorded as neural correlates of feedback processing. No gender differences were observed in the behavioral performance on the IGT after 100 and 150 trials, or in the P3 component. In women, but not in men, the FRN component showed a greater amplitude for losses than for wins. There were no significant gender-related differences in behavioral performance, and men and women revealed a similar learning process on the IGT. At the neural level, no direct differences between men and women were observed in the feedback processing stage for the FRN or P3. However, our results indicate that women showed greater sensitivity to losses than to wins during the decision-making task, as reflected in the FRN component.

Behavioral and Neural Arguments of Motivational Influence on Decision Making During Uncertainty

The scientific world is increasingly interested in motivation, primarily due to the suspected impact on decision-making abilities, particularly in uncertain conditions. To explore this plausible relationship, 28 healthy participants were included in the study and performed decision-making and motivational tasks while their neural activity was recorded. All participants performed the Iowa Gambling Task (IGT) and were split into two groups based on their score, one favorable group with 14 participants who performed advantageously and one undecided group with 14 participants who failed to develop the correct strategy on the IGT. In addition, all participants performed the Effort Expenditure for Reward Task (EEfRT), which defines the motivational level of each participant by the effort that participants agree to do in function of reward magnitudes and probabilities to receive these reward (10, 50, and 90%). The completion of both tasks allowed for the exploration of the relationship between the motivational level and decision-making abilities. The EEfRT was adapted to electroencephalography (EEG) recordings to explore how motivation could influence reward experience. Behavioral results showed no difference in EEfRT performances on the whole task between the two groups’ performances on the IGT. However, there was a negative correlation between the difficulty to develop an optimal strategy on the IGT and the percentage of difficult choices at the 90% condition on the EEfRT. Each probability condition has been previously associated to different motivational and emotional states, with the 90% condition associated to the reward sensitivity. This behavioral result leads to the hypothesis that reward sensitivity may induce an inability to develop an optimal strategy on the IGT. Group analysis demonstrated that only the undecided group showed a P300 during the processing of the outcome, whereas the favorable group showed a blunted P300. Similarly, there was a negative correlation between the P300 amplitude and the ability to develop an optimal strategy on the IGT. In conclusion, behavioral and neuronal data provides evidence that the propensity to focus only on the immediate outcomes is related to the development of an inefficient strategy on the IGT, without influence of motivation.

Electrophysiological Measurement of Emotion and Somatic State Affecting Ambiguity Decision: Evidences From SCRs, ERPs, and HR

Twenty-three years ago, the Somatic Marker Hypothesis (SMH) proposed by Damasio was introduced to explain the role of emotion in decision-making, and provided a unique neuroanatomical framework for decision-making and its influence by emotion. The core idea of the SMH is that decision-making is a process that is affected by somatic state signals, including those that express themselves in emotion and feeling. In order to verify the SMH, the Iowa Gambling Task (IGT) was originally designed by Bechara et al. and the skin conductance responses (SCRs) was recorded during the IGT. The initial confirmatory results showed that normal subjects would generate anticipatory SCRs when they received reward or punishment, but patients of the VMPFC lesion entirely failed to generate anticipatory SCRs prior to their selection of a card. With the further development of the SMH–related researches, other electrophysiological methods of measuring somatic state was gradually used to test the SMH, including event-related potentials (ERPs), and heart rate (HR). In this mini review article, we summarize the extant electrophysiological research on the SMH and decision-making under ambiguity, propose an integrative perspective for employing different electrophysiological measurement methods, and indicate the application of electrophysiological measurement based on the SMH in daily social decision-making.

Applied strategy in the Iowa Gambling Task: Comparison of individuals with Parkinson's disease to healthy controls

INTRODUCTION

Decision-making impairments in Parkinson's disease (PD) have frequently been measured using the Iowa Gambling Task (IGT), though results have been inconsistent. At present, task performance has primarily been evaluated based on the total IGT score, and there is a need for further analysis of the strategy of older individuals with PD and healthy control (HC) participants in IGT.

OBJECTIVE

The present study aims to explore possible impairments in IGT performance in individuals with PD compared to healthy controls using strategy analysis, extending previous results on this subject, and to discuss potential effects of medication on task performance.

METHODS

67 individuals with PD and 29 HC participants completed the IGT. Results were analyzed to evaluate impairments, applied strategies, presence of subgroups, and potential effects of medication on performance.

RESULTS

Both groups obtained a low overall IGT score and individuals with PD had significantly lower total IGT scores compared to HC participants. Regression analysis showed a small, but significant relationship between levodopa and dopamine agonist dosage and total IGT score, indicating that medication level could be a marker of level of executive functions. Subgroups of advantageous and disadvantageous choosers differed significantly in deck preferences for both groups.

CONCLUSION

Individuals with PD were significantly impaired in IGT performance, both in overall scores and in detailed analyses, and they utilized an inefficient strategy during task performance. However, HC participants also presented with a suboptimal strategy and results suggest the presence of subgroups in both individuals with PD and HC participants, which may reflect age-related changes. These results are in line with previous research on performance of older individuals and alternative deck preferences in the IGT and underline the importance of considering the applied strategy in the evaluation of IGT performance.

Behavioral and Neuroanatomical Account of Impulsivity in Parkinson's Disease

Impulse control disorder (ICD) is a major non-motor complication of Parkinson's disease (PD) with often devastating consequences for patients' quality of life. In this study, we aimed to characterize the phenotype of impulsivity in PD and its neuroanatomical correlates.

Methods: Thirty-seven PD patients (15 patients with ICD, 22 patients without ICD) and 36 healthy controls underwent a neuropsychological battery. The test battery consisted of anxiety and depression scales, self-report measures of impulsivity (Barratt scale and UPPS-P), behavioral measures of impulsive action (Go/No-Go task, Stop signal task) and impulsive choice (Delay discounting, Iowa gambling task), and measures of cognitive abilities (working memory, attention, executive function). Patients and controls underwent structural MRI scanning.

Results: Patients with ICD had significantly higher levels of self-reported impulsivity (Barratt scale and Lack of perseverance from UPPS-P) in comparison with healthy controls and non-impulsive PD patients, but they performed similarly in behavioral tasks, except for the Iowa gambling task. In this task, patients with ICD made significantly less risky decisions than patients without ICD and healthy controls. Patients without ICD did not differ from healthy controls in self-reported impulsivity or behavioral measurements. Both patient groups were more anxious and depressive than healthy controls. MRI scanning revealed structural differences in cortical areas related to impulse control in both patient groups. Patients without ICD had lower volumes and cortical thickness of bilateral inferior frontal gyrus. Patients with ICD had higher volumes of right caudal anterior cingulate and rostral middle frontal cortex.

Conclusions: Despite the presence of ICD as confirmed by both clinical follow-up and self-reported impulsivity scales and supported by structural differences in various neural nodes related to inhibitory control and reward processing, patients with ICD performed no worse than healthy controls in various behavioral tasks previously hypothesized as robust impulsivity measures. These results call for caution against impetuous interpretation of behavioral tests, since various factors may and will influence the ultimate outcomes, be it the lack of sensitivity in specific, limited ICD subtypes, excessive caution of ICD patients during testing due to previous negative experience rendering simplistic tasks insufficient, or other, as of now unknown aspects, calling for further research.

Analysis of Decision-Making Process Using Methods of Quantitative Electroencephalography and Machine Learning Tools

The electroencephalographic activity of particular brain areas during the decision making process is still little known. This paper presents results of experiments on the group of 30 patients with a wide range of psychiatric disorders and 41 members of the control group. All subjects were performing the Iowa Gambling Task that is often used for decision process investigations. The electroencephalographical activity of participants was recorded using the dense array amplifier. The most frequently active Brodmann Areas were estimated by means of the photogrammetry techniques and source localization algorithms. The analysis was conducted in the full frequency as well as in alpha, beta, gamma, delta, and theta bands. Next the mean electric charge flowing through each of the most frequently active areas and for each frequency band was calculated. The comparison of the results obtained for the subjects and the control groups is presented. The difference in activity of the selected Brodmann Areas can be observed in all variants of the task. The hyperactivity of amygdala is found in both the patients and the control group. It is noted that the somatosensory association cortex, dorsolateral prefrontal cortex, and primary visual cortex play an important role in the decision-making process as well. Some of our results confirm the previous findings in the fMRI experiments. In addition, the results of the electroencephalographic analysis in the broadband as well as in specific frequency bands were used as inputs to several machine learning classifiers built in Azure Machine Learning environment. Comparison of classifiers' efficiency is presented to some extent and finding the most effective classifier may be important for planning research strategy toward finding decision-making biomarkers in cortical activity for both healthy people and those suffering from psychiatric disorders.

ERP correlates of cognitive control and food-related processing in normal weight and severely obese candidates for bariatric surgery: Data gathered using a newly designed Simon task

Although there have been suggestions that altered cognitive control and food reward sensitivity contribute to overeating in obese individuals, neurophysiological correlates of these mechanisms have been poorly investigated. The current study investigated event-related potentials (ERP) in 24 severely obese and 26 normal weight individuals in fasting condition, using a novel Simon task with food and object distractors. The study showed that conflict in the Simon task for the food distractor increased with hunger in both groups but was larger with respect to a neutral condition only in the obese individuals. ERP showed higher N1amplitudes in both groups for food distractor, reflecting early food processing. The P2 latency was delayed and the effect of distractors on N2 amplitude was smaller in the obese subjects, reflecting altered neural mechanisms associated with selective attention and cognitive control, all contributing hypothetically to delay response selection of these individuals faced with food distractor.

Behavioral and Electrophysiological Arguments in Favor of a Relationship between Impulsivity, Risk-Taking, and Success on the Iowa Gambling Task

The aim of the present study was to investigate the relationship between trait impulsivity, risk-taking, and decision-making performance. We recruited 20 healthy participants who performed the Iowa Gambling Task (IGT) and the Balloon Analog Risk Task (BART) to measure decision-making and risk-taking. The impulsivity was measured by the Barratt Impulsiveness Scale. Resting-state neural activity was recorded to explore whether brain oscillatory rhythms provide important information about the dispositional trait of impulsivity. We found a significant correlation between the ability to develop a successful strategy and the propensity to take more risks in the first trials of the BART. Risk-taking was negatively correlated with cognitive impulsivity in participants who were unable to develop a successful strategy. Neither risk-taking nor decision-making was correlated with cortical asymmetry. In a more exploratory approach, the group was sub-divided in function of participants’ performances at the IGT. We found that the group who developed a successful strategy at the IGT was more prone to risk, whereas the group who failed showed a greater cognitive impulsivity. These results emphasize the need for individuals to explore their environment to develop a successful strategy in uncertain situations, which may not be possible without taking risks.

Iowa Gambling Task Performance in Parkinson Disease Patients with Impulse Control Disorders

OBJECTIVE

A subgroup of patients with Parkinson disease (PD) develops impulse control disorders (ICD) associated with their dopamine replacement therapy. Patients and their families may be reluctant to report ICD symptoms or unaware these symptoms are related to PD medication, which can make detecting an ICD difficult for clinicians. Ideally, a behavioral measure that is sensitive to ICD could be employed to ensure that patients with these behaviors are identified and treated. The Iowa Gambling Task (IGT), a standardized decision-making task, has proven sensitive in other populations with impulse control problems. We hypothesized that the IGT would differentiate between PD patients with and without ICD.

METHODS

We compared IGT performance and disease variables in 24 PD patients with ICD and 24 PD patients without ICD. Patient groups were matched in terms of age, sex, and duration of PD.

RESULTS

There were no significant differences in IGT scores between PD groups. IGT performance declined with increasing age, but the majority of patients performed within normal limits based on published age- and education-corrected normative data.

CONCLUSIONS

The IGT did not distinguish between PD patients with and without ICD. Increasing age negatively impacted performance in both groups. Other studies have found that IGT performance may decline in normal aging. Our results suggest that the IGT lacks the sensitivity and specificity needed to differentiate between age-related deficits and disruption in frontal-subcortical circuits underlying ICD associated with PD medications. Therefore, the IGT is not an appropriate behavioral measure for ICD in PD patients.

Event-related potentials in response to feedback following risk-taking in the hot version of the Columbia Card Task

Given the importance of risk-taking in individuals' personal and professional life, several behavioral tasks for measuring the construct have been developed. Recently, a new task was introduced, the Columbia Card Task (CCT). This task measures participants' risk levels and establishes how sensitive participants are to gains, losses, and probabilities when taking risk. So far, the CCT has been examined in behavioral studies and in combination with several (neuro)biological techniques. However, no electroencephalography (EEG) research has been done on the task. The present study fills this gap and helps to validate this relatively new experimental task. To this end, n = 126 students were asked to complete self-reports (reward responsiveness, impulsiveness, and sensation-seeking) and to perform the CCT (and other risk tasks) in an EEG setup. The results show that feedback appraisal after risky decision-making in the CCT was accompanied by a feedback-related negativity (FRN) and a P300, which were stronger in response to negative than positive feedback. Correlations between the FRN and P300 difference wave on the one hand and risk-related self-reports and behavior on the other were nonsignificant and small, but were mostly in the expected direction. This pattern did not change after excluding participants with psychiatric/neurological disorders and outliers. Excluding participants with reversed (positive > negative) difference waves strengthened FRN correlations. The impact such individuals can have on the data should be taken into account in future studies. Regarding the CCT in particular, future studies should also address its oddball structure and its masking of true values (censoring).

Gambling behavior in Parkinson's Disease: Impulsivity, reward mechanism and cortical brain oscillations

Psychopathological components, such as reward sensitivity and impulsivity, and dopaminergic treatment are crucial characteristics related to the development of Pathological Gambling (PG) in Parkinson's Disease (PD). The aim of the present study is to investigate the differences in decision-making in PD patients with or without PG considering both neurophysiological and behavioral aspects. The IOWA Gambling Task (IGT) and electroencephalographic (EEG) activity were considered to elucidate the decision and post-feedback processes in PG. The sample included fifty-two PD patients, divided in three groups: 17 PD patients with active gambling behavior (PD Gamblers, PDG); 15 PD patients who remitted from PG (PD Non-Gamblers, PDNG); and a Control Group (CG) composed by 20 patients with PD only. EEG and IGT performance were recorded during decision and post-feedback phase. Results showed worse performance and an increase of the low frequency bands in the frontal area for the PDG group compared to the other two groups. In addition, higher BAS (Behavioral Activation System) and BIS-11 (Barratt Impulsiveness Scale) personality components were correlated to groups' behavioral response. These results show an anomalous behavioral (IGT) and cortical response of PDG patients related to their inability to use adequate control mechanisms during a decision-making task where reward mechanisms (BAS) and impulsivity (BIS-11) are relevant.

Event-Related Potentials in Relation to Risk-Taking: A Systematic Review

Event-related potentials (ERPs) have been used to investigate neural mechanisms underlying risk-related decisions over the last 16 years. We aimed to systematically evaluate associations between risk-taking and ERP components elicited during decisions and following feedback. A total of 79 articles identified from PsychINFO and PubMed databases met the inclusion criteria. Selected articles assessed early ERP components (feedback-related negativity/FRN, error-related negativity/ERN, and medial frontal negativity/MFN) and the mid-latency P3 component, all using gambling paradigms that involved selecting between choices of varying risk (e.g., Iowa Gambling Task, Balloon Analogue Risk Task, and two-choice gambling tasks). The P3 component was consistently enhanced to the selection of risky options and when positive feedback (as compared to negative feedback) was provided. Also consistently, the early negative components were found to be larger following feedback indicating monetary losses as compared to gains. In the majority of studies reviewed here, risk was conceptualized in the context of simple economical decisions in gambling tasks. As such, this narrow concept of risk might not capture the diversity of risky decisions made in other areas of everyday experience, for example, social, health, and recreational risk-related decisions. It therefore remains to be seen whether the risk-sensitivity of the ERP components reviewed here generalizes to other domains of life.

Meta-Analytic Evidence for a Reversal Learning Effect on the Iowa Gambling Task in Older Adults

Iowa Gambling Task (IGT) is one of the most widely used tools to assess economic decision-making. However, the research tradition on aging and the Iowa Gambling Task (IGT) has been mainly focused on the overall performance of older adults in relation to younger or clinical groups, remaining unclear whether older adults are capable of learning along the task. We conducted a meta-analysis to examine older adults' decision-making on the IGT, to test the effects of aging on reversal learning (45 studies) and to provide normative data on total and block net scores (55 studies). From the accumulated empirical evidence, we found an average total net score of 7.55 (±25.9). We also observed a significant reversal learning effect along the blocks of the IGT, indicating that older adults inhibit the prepotent response toward immediately attractive options associated with high losses, in favor of initially less attractive options associated with long-run profit. During block 1, decisions of older adults led to a negative gambling net score, reflecting the expected initial pattern of risk-taking. However, the shift toward more safe options occurred between block 2 (small-to-medium effect size) and blocks 3, 4, 5 (medium-to-large effect size). These main findings highlight that older adults are able to move from the initial uncertainty, when the possible outcomes are unknown, to decisions based on risk, when the outcomes are learned and may be used to guide future adaptive decision-making.

Diagnosing mild cognitive impairment in Parkinson's disease: which tests perform best in the Italian population?

Mild cognitive impairment (MCI) is common in patients with Parkinson's disease (PD) and should be recognized early because it represents a predictor of PD-related dementia and worse disease course. Diagnostic criteria for PD-related MCI (PD-MCI) have recently been defined by a Movement Disorders Society (MDS) task force. The present study explored which neuropsychological tests perform best for a level II (i.e., comprehensive neuropsychological assessment) diagnosis of PD-MCI according to the MDS task force criteria in Italian-speaking PD patients. To this aim, we assessed a comprehensive 23-item neuropsychological battery, derived the best-performing 10-test battery (i.e., two tests per domain for each of the five cognitive domains), and explored its accuracy for diagnosing PD-MCI in comparison to the full battery in a group of PD patients. A secondary aim was to explore the role of this battery for subtyping PD-MCI according to single-domain vs. multiple-domain involvement. The 10-test battery showed 73% sensitivity and 100% specificity for diagnosing PD-MCI, and 69% sensitivity and 100% specificity for PD-MCI subtyping. In patients older than 70 years, we derived a slightly different 10-test battery with 84% sensitivity and 100% specificity for PD-MCI diagnosis, and 86% sensitivity and 100% specificity for PD-MCI subtyping. These 10-item neuropsychological batteries might represent a good trade-off between diagnostic accuracy and time of application, and their role in PD-MCI diagnosis and subtyping should be further explored in future prospective studies.

Aging and risky decision-making: New ERP evidence from the Iowa Gambling Task

Several pieces of evidence have highlighted the presence of an age-related decline in risky decision-making (DM), but the reason of this decline is still unclear. The aim of the present study was to investigate the neural correlates of feedback processing in risky DM. Twenty-one younger (age <50 years) and 15 older (age >50 years) adults were tested with the Iowa Gambling Task (IGT) during Event Related Potentials (ERP) recording. The analysis was focused on the feedback-related negativity (FRN) and P3, two ERP components that represent different stages of feedback processing. Behavioral results revealed that older adults, despite showing a significant learning trend, completed the IGT with a gain of a smaller amount of money compared to the younger ones. ERP results revealed that while the FRN response was comparable in the two groups, the P3 amplitude was significantly reduced after negative feedback in older adults, compared with the younger ones. Furthermore, the difference in the P3 amplitude evoked by positive and negative feedback was significantly correlated with age. Hence, the present findings suggest that older adults seem to be less willing to shift attention from positive to negative information, and that this relevant change in the later stages of feedback processing could be the cause of a poor performance in risky DM contexts.

Pathophysiology of Motor Dysfunction in Parkinson's Disease as the Rationale for Drug Treatment and Rehabilitation

Cardinal motor features of Parkinson's disease (PD) include bradykinesia, rest tremor, and rigidity, which appear in the early stages of the disease and largely depend on dopaminergic nigrostriatal denervation. Intermediate and advanced PD stages are characterized by motor fluctuations and dyskinesia, which depend on complex mechanisms secondary to severe nigrostriatal loss and to the problems related to oral levodopa absorption, and motor and nonmotor symptoms and signs that are secondary to marked dopaminergic loss and multisystem neurodegeneration with damage to nondopaminergic pathways. Nondopaminergic dysfunction results in motor problems, including posture, balance and gait disturbances, and fatigue, and nonmotor problems, encompassing depression, apathy, cognitive impairment, sleep disturbances, pain, and autonomic dysfunction. There are a number of symptomatic drugs for PD motor signs, but the pharmacological resources for nonmotor signs and symptoms are limited, and rehabilitation may contribute to their treatment. The present review will focus on classical notions and recent insights into the neuropathology, neuropharmacology, and neurophysiology of motor dysfunction of PD. These pieces of information represent the basis for the pharmacological, neurosurgical, and rehabilitative approaches to PD.

Apathy and noradrenaline: silent partners to mild cognitive impairment in Parkinson's disease?

PURPOSE OF REVIEW

Mild cognitive impairment (MCI) is a comorbid factor in Parkinson's disease. The aim of this review is to examine the recent neuroimaging findings in the search for Parkinson's disease MCI (PD-MCI) biomarkers to gain insight on whether MCI and specific cognitive deficits in Parkinson's disease implicate striatal dopamine or another system.

RECENT FINDINGS

The evidence implicates a diffuse pathophysiology in PD-MCI rather than acute dopaminergic involvement. On the one hand, performance in specific cognitive domains, notably in set-shifting and learning, appears to vary with dopaminergic status. On the other hand, motivational states in Parkinson's disease along with their behavioral and physiological indices suggest a noradrenergic contribution to cognitive deficits in Parkinson's disease. Finally, Parkinson's disease's pattern of neurodegeneration offers an avenue for continued research in nigrostriatal dopamine's role in distinct behaviors, as well as the specification of dorsal and ventral striatal functions.

SUMMARY

The search for PD-MCI biomarkers has employed an array of neuroimaging techniques, but still yields divergent findings. This may be due in part to MCI's broad definition, encompassing heterogeneous cognitive domains, only some of which are affected in Parkinson's disease. Most domains falling under the MCI umbrella include fronto-dependent executive functions, whereas others, notably learning, rely on the basal ganglia. Given the deterioration of the nigrostriatal dopaminergic system in Parkinson's disease, it has been the prime target of PD-MCI investigation. By testing well defined cognitive deficits in Parkinson's disease, distinct functions can be attributed to specific neural systems, overcoming conflicting results on PD-MCI. Apart from dopamine, other systems such as the neurovascular or noradrenergic systems are affected in Parkinson's disease. These factors may be at the basis of specific facets of PD-MCI for which dopaminergic involvement has not been conclusive. Finally, the impact of both dopaminergic and noradrenergic deficiency on motivational states in Parkinson's disease is examined in light of a plausible link between apathy and cognitive deficits.

Screening for Mild Cognitive Impairment in Parkinson's Disease: Comparison of the Italian Versions of Three Neuropsychological Tests

Mild cognitive impairment (MCI) is frequent in Parkinson's disease (PD). Recently proposed criteria for MCI in PD (PD-MCI) indicate level I diagnosis based on abbreviated assessment and level II based on comprehensive neuropsychological evaluation. The study explored the sensitivity and specificity of the Italian versions of three neuropsychological tests for level I diagnosis of PD-MCI. We recruited 100 consecutive PD patients. After screening for inclusion criteria, 43 patients were included. The sensitivity and specificity of the Mini Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), and the Addenbrooke's Cognitive Examination Revised (ACE-R) in comparison to level II diagnosis of PD-MCI were examined. PD-MCI was diagnosed (level II) in 51% of patients. Disease duration was significantly longer and PD motor scales were more severely impaired in MCI group. The receiver-operator characteristics curve documented nonsignificant difference in the performance of the three tests, with slight advantage of MMSE (corrected data). The time of administration favored MMSE. In Italian-speaking PD patients, MMSE might represent a good screening tool for PD-MCI, because of the shorter time of administration and the performance comparable to those of MoCA and ACE-R. Further studies are needed to validate the new PD-MCI criteria across different languages and cultures.

Neural Correlates of Successful and Unsuccessful Strategical Mechanisms Involved in Uncertain Decision-Making

The ability to develop successful long-term strategies in uncertain situations relies on complex neural mechanisms. Although lesion studies have shown some of the mechanisms involved, it is still unknown why some healthy subjects are able to make the right decision whereas others are not. The aim of our study was to investigate neurophysiological differences underlying this ability to develop a successful strategy in a group of healthy subjects playing a monetary card game called the Iowa Gambling Task (IGT). In this task, subjects have to win and earn money by choosing between four decks of cards, two were advantageous in the long term and two disadvantageous. Twenty healthy right-handed subjects performed the IGT while their cerebral activity was recorded by electroencephalography. Based on their behavioral performances, two groups of subjects could clearly be distinguished: one who selected the good decks and thus succeeded in developing a Favorable strategy (9 subjects) and one who remained Undecided (11 subjects). No neural difference was found between each group before the selection of a deck, but in both groups a greater negativity was found emerging from the right superior frontal gyrus 600 ms before a disadvantageous selection. During the processing of the feedback, an attenuation of the P200 and P300 waveforms was found for the Undecided group, and a P300 originating from the medial frontal gyrus was found in response to a loss only in the Favorable group. Our results suggest that undecided subjects are hyposensitive to the valence of the cards during gambling, which affects the feedback processing.

Betting on DBS: Effects of subthalamic nucleus deep brain stimulation on risk taking and decision making in patients with Parkinson's disease

OBJECTIVE

Concerns persist that deep brain stimulation (DBS) for Parkinson's disease (PD) increases impulsivity or induces excessive reward seeking. We report here the performance of PD patients with implanted subthalamic nucleus electrodes, with stimulation on and off, on 3 laboratory tasks of risk taking and decision making. They are compared with PD patients maintained on medication and healthy participants.

METHODS AND RESULTS

In the Game of Dice Task, a test of "risky" decision making, PD patients with or without DBS made highest risk bets more often and ended up with less money than did healthy participants. There was a trend for DBS stimulation to ameliorate this effect. Deal or No-Deal is an "ambiguous" decision-making task that assessed preference for risk (holding on to one's briefcase) over a "sure thing" (accepting the banker's offer). Here, DBS patients were more conservative with stimulation on than with it off. They accepted smaller offers from the banker and won less money in the DBS-on condition. Overall, the 2 PD groups won less money than did healthy participants. The Framing Paradigm assessed willingness to gamble on a fixed (unambiguous) prize depending on whether the reward was "framed" as a loss or a gain. Nonsurgical PD patients tended to be more risk-averse than were healthy participants, whereas DBS patients were more willing to gamble for gains as well as losses both on and off stimulation.

CONCLUSIONS

On risky decision-making tasks, DBS patients took more risks than did healthy participants, but stimulation may temper this tendency. In contrast, in an ambiguous-risk situation, DBS patients were more risk-averse (conservative) than were healthy participants, and this tendency was greatest with stimulation.

Cognition and emotional decision-making in chronic low back pain: an ERPs study during Iowa gambling task

Previous reports documented abnormalities in cognitive functions and decision-making (DM) in patients with chronic pain, but these changes are not consistent across studies. Reasons for these discordant findings might include the presence of confounders, variability in chronic pain conditions, and the use of different cognitive tests. The present study was aimed to add evidence in this field, by exploring the cognitive profile of a specific type of chronic pain, i.e., chronic low back pain (cLBP). Twenty four cLBP patients and 24 healthy controls underwent a neuropsychological battery and we focused on emotional DM abilities by means of Iowa gambling task (IGT). During IGT, behavioral responses and the electroencephalogram (EEG) were recorded in 12 patients and 12 controls. Event-related potentials (ERPs) were averaged offline from EEG epochs locked to the feedback presentation (4000 ms duration, from 2000 ms before to 2000 ms after the feedback onset) separately for wins and losses and the feedback-related negativity (FRN) and P300 peak-to-peak amplitudes were calculated. Among cognitive measures, cLBP patients scored lower than controls in the modified card sorting test (MCST) and the score in this test was significantly influenced by pain duration and intensity. Behavioral IGT results documented worse performance and the absence of a learning process during the test in cLBP patients compared to controls, with no effect of pain characteristics. ERPs findings documented abnormal feedback processing in patients during IGT. cLBP patients showed poor performance in the MCST and the IGT. Abnormal feedback processing may be secondary to impingement of chronic pain in brain areas involved in DM or suggest the presence of a predisposing factor related to pain chronification. These abnormalities might contribute to the impairment in the work and family settings that often cLBP patients report.