Xingui Chen

Dissociation of decision making under ambiguity and decision making under risk: a neurocognitive endophenotype candidate for obsessive-compulsive disorder.

Evidence in the literature suggests that executive dysfunction is regarded as an endophenotype candidate for obsessive-compulsive disorder (OCD). Decision making is an important domain of executive function. However, few studies that have investigated whether decision making is a potential endophenotype for OCD have produced inconsistent results. Differences in the findings across these studies may be attributed to several factors: different study materials, comorbidity, medication, etc. There are at least two types of decision making that differ mainly in the degree of uncertainty and how much useful information about consequences and their probabilities are provided to the decision maker: decision making under ambiguity and decision making under risk. The aim of the present study was to simultaneously examine decision making under ambiguity as assessed by the Iowa Gambling Task (IGT) and decision making under risk as measured by the Game of Dice Task (GDT) in OCD patients and their unaffected first-degree relative (UFDR) for the first time. The study analyzed 55 medication-naïve, non-depressed OCD patient probands, 55 UFDRs of the OCD patients and 55 healthy matched comparison subjects (CS) without a family history of OCD with the IGT, the GDT and a neuropsychological test battery. While the OCD patients and the UFDRs performed worse than the CS on the IGT, they were unimpaired on the GDT. Our study supports the claim that decision making under ambiguity differs from decision making under risk and suggests that dissociation of decision making under ambiguity and decision making under risk may qualify to be a neurocognitive endophenotypes for OCD.

Decision-making impairments in breast cancer patients treated with tamoxifen

The selective estrogen receptor modulator tamoxifen (TAM) is most commonly prescribed for patients with hormone-sensitive breast cancer. Although TAM can bind to estrogen receptors in the nervous system, it is unknown whether it acts as an estrogen agonist or antagonist in the human brain. Several studies have reported the negative effects of TAM on cognitive function; however, its effects on decision-making function have not been previously explored. The present study aimed to investigate the decision-making function under ambiguity and risk in breast cancer patients treated with TAM. Participants included breast cancer patients taking TAM (TAM, n=47) and breast cancer patients not taking TAM (non-TAM, n=45) as well as their matched healthy controls (HC, n=50). All participants were given the Iowa Gambling Task (IGT) to assess their decision-making under conditions involving ambiguity, the Game of Dice Task (GDT) to assess their decision-making under conditions involving risk, and a battery of neuropsychological tests. Our results indicated that patients in the TAM group were significantly impaired as assessed by both the IGT and GDT and performed significantly worse on some aspects of various tasks involving memory and information processing. Furthermore, we found that decreased performance on verbal memory testing significantly correlated with IGT performance, and executive dysfunction was associated with poor GDT performance in breast cancer patients undergoing TAM treatment. This study demonstrates that breast cancer patients taking TAM have several decision-making impairments. These findings may support the idea that TAM resulting in cognitive changes plays an antagonistic role in the areas of the brain where estrogen receptors are present, including the prefrontal cortex, hippocampus and amygdala.

Dissociation of decision making under ambiguity and decision making under risk in breast cancer patients receiving adjuvant chemotherapy: a neuropsychological study.

There is evidence that women with breast cancer show a cognitive impairment after having undergone chemotherapy treatment; this cognitive impairment may result in behavioral deficits. However, the neural mechanism of this cognitive impairment remains unclear. The present study investigated the neural basis of the cognitive impairment caused by chemotherapy treatment by exploring the decision-making function of the executive subcomponents under ambiguity and risk in breast cancer survivors. Participants included breast cancer patients who had undergone chemotherapy (CT, N=63) or patients who did not undergo chemotherapy (non-CT, N=62), as well as matched healthy controls (HC, N=61). All participants were examined using the Iowa Gambling Task (IGT) to assess their decision-making under ambiguity, the Game of Dice Task (GDT) to assess their decision-making under risk and neuropsychological background tests. Our results indicated that during the IGT test, the chemotherapy-treated breast cancer patients selected from the disadvantageous decks with a higher frequency than the non-treated breast cancer patients or healthy controls, whereas all three groups performed at the same level when performing the GDT. The CT group demonstrated significantly lower scores in several cognitive tasks, including attention, memory, executive functions and cognitive processing, when compared with the other two groups. In addition, within the CT group, significant correlations were found between the IGT performance and information processing, as well as with working memory. This study demonstrated that breast cancer survivors treated with chemotherapy may have selective reductions in IGT performance but unimpaired GDT performance and that these deficits may result from dysfunctions in the limbic loop rather than in the dorsolateral prefrontal loop.

Selective impairment of attention networks in breast cancer patients receiving chemotherapy treatment

Complaints about attention disorders are common among breast cancer survivors who have undergone chemotherapy treatment. However, it is not known whether these complaints indicate a global attention deficit or the selective impairment of attention networks.

Trait Anxiety Has Effect on Decision Making under Ambiguity but Not Decision Making under Risk

Previous studies have reported that trait anxiety (TA) affects decision making. However, results remain largely inconsistent across studies. The aim of the current study was to further address the interaction between TA and decision making. 304 subjects without depression from a sample consisting of 642 participants were grouped into high TA (HTA), medium TA (MTA) and low TA (LTA) groups based on their TA scores from State Trait Anxiety Inventory. All subjects were assessed with the Iowa Gambling Task (IGT) that measures decision making under ambiguity and the Game of Dice Task (GDT) that measures decision making under risk. While the HTA and LTA groups performed worse on the IGT compared to the MTA group, performances on the GDT between the three groups did not differ. Furthermore, the LTA and HTA groups showed different individual deck level preferences in the IGT: the former showed a preference for deck B indicating that these subjects focused more on the magnitude of rewards, and the latter showed a preference for deck A indicating significant decision making impairment. Our findings suggest that trait anxiety has effect on decision making under ambiguity but not decision making under risk and different levels of trait anxiety related differently to individual deck level preferences in the IGT.

Decision-Making in Patients with Hyperthyroidism: A Neuropsychological Study.

Introduction Cognitive and behavioral impairments are common in patients with abnormal thyroid function; these impairments cause a reduction in their quality of life. The current study investigates the decision making performance in patients with hyperthyroidism to explore the possible mechanism of their cognitive and behavioral impairments. Methods Thirty-eight patients with hyperthyroidism and forty healthy control subjects were recruited to perform the Iowa Gambling Task (IGT), which assessed decision making under ambiguous conditions. Results Patients with hyperthyroidism had a higher score on the Zung Self-Rating Anxiety Scale (Z-SAS), and exhibited poorer executive function and IGT performance than did healthy control subjects. The patients preferred to choose decks with a high immediate reward, despite a higher future punishment, and were not capable of effectively using feedback information from previous choices. No clinical characteristics were associated with the total net score of the IGT in the current study. Conclusions Patients with hyperthyroidism had decision-making impairment under ambiguous conditions. The deficits may result from frontal cortex and limbic system metabolic disorders and dopamine dysfunction.

How does gaze direction affect facial processing in social anxiety? —An ERP study

Previous behavioral studies have demonstrated an effect of eye gaze direction on the processing of emotional expressions in adults with social anxiety. However, specific brain responses to the interaction between gaze direction and facial expressions in social anxiety remain unclear. The present study aimed to explore the time course of such interaction using event-related potentials (ERPs) in participants with social anxiety. High socially anxious individuals and low socially anxious individuals were asked to identify the gender of angry or neutral faces with direct or averted gaze while their behavioral performance and electrophysiological data were monitored. We found that identification of angry faces with direct but not averted gaze elicited larger N2 amplitude in high socially anxious individuals compared to low socially anxious individuals, while identification of neutral faces did not produce any gaze modulation effect. Moreover, the N2 was correlated with increased anxiety severity upon exposure to angry faces with direct gaze. Therefore, our results suggest that gaze direction modulates the processing of threatening faces in social anxiety. The N2 component elicited by angry faces with direct gaze could be a state-dependent biomarker of social anxiety and may be an important reference biomarker for social anxiety diagnosis and intervention.

Exploring Biological Motion Processing in Parkinson's Disease Using Temporal Dilation.

Biological motion (BM) perception is the compelling ability of the visual system to perceive complex animated movements effortlessly and promptly. A recent study has shown that BM can automatically lengthen perceived temporal duration independent of global configuration. The present study aimed mainly to investigate this temporal dilation effect of BM signals in Parkinson’s disease (PD) patients. We used the temporal dilation effect as an implicit measure of visual processing of BM. In all, 32 PD patients (under off-therapy conditions) and 32 healthy controls (HCs) participated in our study. In each trial, an upright BM sequence and an inverted BM sequence were presented within an interval in the center of the screen. We tested both canonical and scrambled BM sequences; the scrambled ones were generated by disturbing the global configuration of the canonical ones but preserving exactly the same local motion components. Observers were required to make a verbal two-alternative forced choice response to indicate which interval (the first or the second) appeared longer. Statistical analyses were conducted on the points of subjective equality (PSEs). We found that the temporal dilation effect was significantly reduced for PD patients compared with HCs in both canonical and scrambled BM conditions. Moreover, no temporal dilation effects of scrambled BM were shown in both early- and late-stage PD patients, while the temporal dilation effect of canonical BM was relatively preserved in the early stages.

External Error Monitoring in Subclinical Obsessive-Compulsive Subjects: Electrophysiological Evidence from a Gambling Task

Background Feedback-related negativity (FRN) is believed to be an important electrophysiology index of “external” negative feedback processing. Previous studies on FRN in obsessive-compulsive (OC) individuals are scarce and controversial. In these studies, anxiety symptoms were not evaluated in detail. However, OC disorders have a number of radical differences from anxiety disorders. It is necessary to study FRN and its neuroanatomical correlates in OC individuals without anxious symptoms. Methods A total of 628 undergraduate students completed an OC questionnaire. We chose 14 students who scored in the upper 10% and 14 students who scored in the lowest 10% without anxiety symptoms as a subclinical OC group (SOC) and a low obsessive-compulsive group (LOC). The students all performed the revised Iowa Gambling Task. We used the event-related potentials (ERP) and standardized low-resolution brain electromagnetic tomography (sLORETA) to track external negative feedback processing and its substrate in the brain. Results Our study revealed poorer decision-making ability and greater FRN amplitudes in SOC subjects compared with LOC controls. The SOC subjects displayed anterior prefrontal cortex (aPFC) hyperactivation during the loss feedback condition. Specifically, we found an intercorrelation of current source density during the loss condition between the dorsal anterior cingulate cortex (dACC) and aPFC in the LOC subjects but not in the SOC group. Conclusions Our results support the notion that overactive external feedback error processing may reflect a candidate endophenotype of OC. We also provide important information on the dysfunction in the interaction between aPFC and dACC in populations with OC. Nevertheless, the findings support that OC may be distinguished from other anxiety disorders using a new electrophysiology perspective.

The neural substrates of response inhibition to negative information across explicit and implicit tasks in GAD patients: electrophysiological evidence from an ERP study

Background: It has been established that the inability to inhibit a response to negative stimuli is the genesis of anxiety. However, the neural substrates of response inhibition to sad faces across explicit and implicit tasks in general anxiety disorder (GAD) patients remain unclear. Methods: Electrophysiological data were recorded when subjects performed two modified emotional go/no-go tasks in which neutral and sad faces were presented: one task was explicit (emotion categorization), and the other task was implicit (gender categorization). Results: In the explicit task, electrophysiological evidence showed decreased amplitudes of no-go/go difference waves at the N2 interval in the GAD group compared to the control group. However, in the implicit task, the amplitudes of no-go/go difference waves at the N2 interval showed a reversed trend. Source localization analysis on no-go/N2 components revealed a decreased current source density (CSD) in the right dorsal lateral prefrontal cortex in GAD individuals relative to controls. In the implicit task, the left superior temporal gyrus and the left inferior parietal lobe showed enhanced activation in GAD individuals and may compensate for the dysfunction of the right dorsal lateral prefrontal cortex. Conclusion: These findings indicated that the processing of response inhibition to socially sad faces in GAD individuals was interrupted in the explicit task. However, this processing was preserved in the implicit task. The neural substrates of response inhibition to sad faces were dissociated between implicit and explicit tasks.