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1.  Impaired social decision making in patients with major depressive disorder 
Brain and Behavior  2012;2(4):415-423.
Research on how depression influences social decision making has been scarce. This study investigated how people with depression make decisions in an interpersonal trust-reciprocity game. Fifty female patients diagnosed with major depressive disorders (MDDs) and 49 healthy women participated in this study. The experiment was conducted on a one-to-one basis. Participants were asked to play the role of a trustee responsible for investing money given to them by an anonymous female investor playing on another computer station. In each trial, the investor would send to a participant (the trustee) a request for a certain percentage of the appreciated investment (repayment proportion). Since only the participant knew the exact amount of the appreciated investment, she could decide to pay more (altruistic act), the same, or less (deceptive act) than the requested amount. The participant's money acquired in the trial would be confiscated if her deceptive act was caught. The frequency of deceptive or altruistic decisions and relative monetary gain in each decision choice were examined. People with depression made fewer deceptive and fewer altruistic responses than healthy controls in all conditions. Moreover, the specific behavioral pattern presented by people with depression was modulated by the task factors, including the risk of deception detection and others’ intentions (benevolence vs. malevolence). Findings of this study contribute to furthering our understanding of the specific pattern of social behavioral changes associated with depression.
doi:10.1002/brb3.62
PMCID: PMC3432964  PMID: 22950045
Affective disorders; altruism; deception; depression; risky decision making; trust
2.  I want to lie about not knowing you, but my precuneus refuses to cooperate 
Scientific Reports  2013;3:1636.
Previously identified neural correlates of deception, such as the prefrontal, anterior cingulate, and parietal regions, have proven to be unreliable neural markers of deception, most likely because activity in these regions reflects executive processes that are not specific to deception. Herein, we report the first fMRI study that provides strong preliminary evidence that the neural activity associated with perception but not executive processes could offer a better marker of deception with regard to face familiarity. Using a face-recognition task, activity in the left precuneus during the perception of familiar faces accurately marked 11 of 13 subjects who lied about not knowing faces that were in fact familiar to them. This level of classification accuracy is much higher than the level predicted by chance and agrees with other findings by experts in lie detection.
doi:10.1038/srep01636
PMCID: PMC3622132  PMID: 23572081
3.  Increased gray matter volume in the right angular and posterior parahippocampal gyri in loving-kindness meditators 
Previous voxel-based morphometry (VBM) studies have revealed that meditation is associated with structural brain changes in regions underlying cognitive processes that are required for attention or mindfulness during meditation. This VBM study examined brain changes related to the practice of an emotion-oriented meditation: loving-kindness meditation (LKM). A 3 T magnetic resonance imaging (MRI) scanner captured images of the brain structures of 25 men, 10 of whom had practiced LKM in the Theravada tradition for at least 5 years. Compared with novices, more gray matter volume was detected in the right angular and posterior parahippocampal gyri in LKM experts. The right angular gyrus has not been previously reported to have structural differences associated with meditation, and its specific role in mind and cognitive empathy theory suggests the uniqueness of this finding for LKM practice. These regions are important for affective regulation associated with empathic response, anxiety and mood. At the same time, gray matter volume in the left temporal lobe in the LKM experts appeared to be greater, an observation that has also been reported in previous MRI meditation studies on meditation styles other than LKM. Overall, the findings of our study suggest that experience in LKM may influence brain structures associated with affective regulation.
doi:10.1093/scan/nss076
PMCID: PMC3541494  PMID: 22814662
temporo-parietal junction; voxel-based morphometry; metta meditation; empathy; affective regulation
4.  Distinct Neural Activity Associated with Focused-Attention Meditation and Loving-Kindness Meditation 
PLoS ONE  2012;7(8):e40054.
This study examined the dissociable neural effects of ānāpānasati (focused-attention meditation, FAM) and mettā (loving-kindness meditation, LKM) on BOLD signals during cognitive (continuous performance test, CPT) and affective (emotion-processing task, EPT, in which participants viewed affective pictures) processing. Twenty-two male Chinese expert meditators (11 FAM experts, 11 LKM experts) and 22 male Chinese novice meditators (11 FAM novices, 11 LKM novices) had their brain activity monitored by a 3T MRI scanner while performing the cognitive and affective tasks in both meditation and baseline states. We examined the interaction between state (meditation vs. baseline) and expertise (expert vs. novice) separately during LKM and FAM, using a conjunction approach to reveal common regions sensitive to the expert meditative state. Additionally, exclusive masking techniques revealed distinct interactions between state and group during LKM and FAM. Specifically, we demonstrated that the practice of FAM was associated with expertise-related behavioral improvements and neural activation differences in attention task performance. However, the effect of state LKM meditation did not carry over to attention task performance. On the other hand, both FAM and LKM practice appeared to affect the neural responses to affective pictures. For viewing sad faces, the regions activated for FAM practitioners were consistent with attention-related processing; whereas responses of LKM experts to sad pictures were more in line with differentiating emotional contagion from compassion/emotional regulation processes. Our findings provide the first report of distinct neural activity associated with forms of meditation during sustained attention and emotion processing.
doi:10.1371/journal.pone.0040054
PMCID: PMC3419705  PMID: 22905090
5.  Adiponectin protects rat hippocampal neurons against excitotoxicity 
Age  2010;33(2):155-165.
Adiponectin exerts multiple regulatory functions in the body and in the hypothalamus primarily through activation of its two receptors, adiponectin receptor1 and adiponectin receptor 2. Recent studies have shown that adiponectin receptors are widely expressed in other areas of the brain including the hippocampus. However, the functions of adiponectin in brain regions other than the hypothalamus are not clear. Here, we report that adiponectin can protect cultured hippocampal neurons against kainic acid-induced (KA) cytotoxicity. Adiponectin reduced the level of reactive oxygen species, attenuated apoptotic cell death, and also suppressed activation of caspase-3 induced by KA. Pretreatment of hippocampal primary neurons with an AMPK inhibitor, compound C, abolished adiponectin-induced neuronal protection. The AMPK activator, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside, attenuated KA-induced caspase-3 activity. These findings suggest that the AMPK pathway is critically involved in adiponectin-induced neuroprotection and may mediate the antioxidative and anti-apoptotic properties of adiponectin.
doi:10.1007/s11357-010-9173-5
PMCID: PMC3127462  PMID: 20842535
Adiponectin; Neuroprotection; Hippocampus; Kainic acid; AMPK
6.  Identification and Classification of Facial Familiarity in Directed Lying: An ERP Study 
PLoS ONE  2012;7(2):e31250.
Recognizing familiar faces is essential to social functioning, but little is known about how people identify human faces and classify them in terms of familiarity. Face identification involves discriminating familiar faces from unfamiliar faces, whereas face classification involves making an intentional decision to classify faces as “familiar” or “unfamiliar.” This study used a directed-lying task to explore the differentiation between identification and classification processes involved in the recognition of familiar faces. To explore this issue, the participants in this study were shown familiar and unfamiliar faces. They responded to these faces (i.e., as familiar or unfamiliar) in accordance with the instructions they were given (i.e., to lie or to tell the truth) while their EEG activity was recorded. Familiar faces (regardless of lying vs. truth) elicited significantly less negative-going N400f in the middle and right parietal and temporal regions than unfamiliar faces. Regardless of their actual familiarity, the faces that the participants classified as “familiar” elicited more negative-going N400f in the central and right temporal regions than those classified as “unfamiliar.” The P600 was related primarily with the facial identification process. Familiar faces (regardless of lying vs. truth) elicited more positive-going P600f in the middle parietal and middle occipital regions. The results suggest that N400f and P600f play different roles in the processes involved in facial recognition. The N400f appears to be associated with both the identification (judgment of familiarity) and classification of faces, while it is likely that the P600f is only associated with the identification process (recollection of facial information). Future studies should use different experimental paradigms to validate the generalizability of the results of this study.
doi:10.1371/journal.pone.0031250
PMCID: PMC3283635  PMID: 22363597
7.  Lying about the Valence of Affective Pictures: An fMRI Study 
PLoS ONE  2010;5(8):e12291.
The neural correlates of lying about affective information were studied using a functional magnetic resonance imaging (fMRI) methodology. Specifically, 13 healthy right-handed Chinese men were instructed to lie about the valence, positive or negative, of pictures selected from the International Affective Picture System (IAPS) while their brain activity was scanned by a 3T Philip Achieva scanner. The key finding is that the neural activity associated with deception is valence-related. Comparing to telling the truth, deception about the valence of the affectively positive pictures was associated with activity in the inferior frontal, cingulate, inferior parietal, precuneus, and middle temporal regions. Lying about the valence of the affectively negative pictures, on the other hand, was associated with activity in the orbital and medial frontal regions. While a clear valence-related effect on deception was observed, common neural regions were also recruited for the process of deception about the valence of the affective pictures. These regions included the lateral prefrontal and inferior parietal regions. Activity in these regions has been widely reported in fMRI studies on deception using affectively-neutral stimuli. The findings of this study reveal the effect of valence on the neural activity associated with deception. Furthermore, the data also help to illustrate the complexity of the neural mechanisms underlying deception.
doi:10.1371/journal.pone.0012291
PMCID: PMC2928271  PMID: 20811624
8.  Sex-Related Differences in Neural Activity during Risk Taking: An fMRI Study 
Cerebral Cortex (New York, NY)  2008;19(6):1303-1312.
This study explored sex effects on the process of risk-taking. We observed that the female participants (n = 10) showed stronger activation in the right insula and bilateral orbitofrontal cortex (OFC) than did the male participants (n = 12) while they were performing in the Risky-Gains task. The female participants also showed stronger activations in the precentral, postcentral, and paracentral regions after receiving punishment feedback. In addition, the strength of neural activity in the insula correlated with the rate of risky behaviors for the female participants but not for the male participants. Similarly, the percent signal changes in the right OFC correlated negatively with the rate of selecting risky choices for the female group. These findings strongly suggest a sex-related influence modulating brain activity during risk-taking tasks. When taking the same level of risk, relative to men, women tend to engage in more neural processing involving the insula and the OFC to update and valuate possible uncertainty associated with risk-taking decision making. These results are consistent with the value-based decision-making model and offer insights into the possible neural mechanisms underlying the different risk-taking attitudes of men and women.
doi:10.1093/cercor/bhn172
PMCID: PMC2677650  PMID: 18842666
insula; neuroimaging; orbitofrontal cortex; risk taking; sex differences
9.  Age-related differences in neural activities during risk taking as revealed by functional MRI 
Previous research has clearly documented that risky decision making is different in young and older adults. Yet, there has been a relative dearth of research that seeks to understand such age-related changes in the neural activities associated with risk taking. To address this research issue, 21 men (12 young men, mean age 29.9 ± 6.2 years and 9 older men, mean age 65.2 ± 4.2 years) performed a risky-gains task while their brain activities were monitored by an fMRI scanner. The older adults, relative to their younger peers, presented with contralateral prefrontal activity, particularly at the orbitofrontal cortex. Furthermore, stronger activation of the right insula was observed for the older-aged participants compared to the younger-aged adults. The findings of this study are consistent with the a priori speculations established in accordance with the HAROLD model as well as previous findings. Findings of this study suggest that when making risky decisions, there may be possible neuropsychological mechanisms underlying the change in impulsive and risk-taking behaviors during the course of natural ageing.
doi:10.1093/scan/nsm033
PMCID: PMC2569821  PMID: 19015090
risk taking; ageing; insula; orbitofrontal cortex; prefrontal cortex; neuroimaging
10.  The Relevance of Short-Range Fibers to Cognitive Efficiency and Brain Activation in Aging and Dementia 
PLoS ONE  2014;9(4):e90307.
The integrity of structural connectivity in a functional brain network supports the efficiency of neural processing within relevant brain regions. This study aimed to quantitatively investigate the short- and long-range fibers, and their differential roles in the lower cognitive efficiency in aging and dementia. Three groups of healthy young, healthy older adults and patients with Alzheimer's disease (AD) participated in this combined functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) study on prospective memory (PM). Short- and long-range fiber tracts within the PM task engaged brain networks were generated. The correlation between the fMRI signal change, PM performance and the DTI characters were calculated. FMRI results showed that the PM-specific frontal activations in three groups were distributed hierarchically along the rostrocaudal axis in the frontal lobe. In an overall PM condition generally activated brain network among the three groups, tractography was used to generate the short-range fibers, and they were found impaired in both healthy older adults and AD patients. However, the long-range fiber tracts were only impaired in AD. Additionally, the mean diffusivity (MD) of short-range but not long-range fibers was positively correlated with fMRI signal change and negatively correlated with the efficiency of PM performance. This study suggests that the disintegrity of short-range fibers may contribute more to the lower cognitive efficiency and higher compensatory brain activation in healthy older adults and more in AD patients.
doi:10.1371/journal.pone.0090307
PMCID: PMC3973665  PMID: 24694731
11.  Hippocampal Neurogenesis and Dendritic Plasticity Support Running-Improved Spatial Learning and Depression-Like Behaviour in Stressed Rats 
PLoS ONE  2011;6(9):e24263.
Exercise promotes hippocampal neurogenesis and dendritic plasticity while stress shows the opposite effects, suggesting a possible mechanism for exercise to counteract stress. Changes in hippocampal neurogenesis and dendritic modification occur simultaneously in rats with stress or exercise; however, it is unclear whether neurogenesis or dendritic remodeling has a greater impact on mediating the effect of exercise on stress since they have been separately examined. Here we examined hippocampal cell proliferation in runners treated with different doses (low: 30 mg/kg; moderate: 40 mg/kg; high: 50 mg/kg) of corticosterone (CORT) for 14 days. Water maze task and forced swim tests were applied to assess hippocampal-dependent learning and depression-like behaviour respectively the day after the treatment. Repeated CORT treatment resulted in a graded increase in depression-like behaviour and impaired spatial learning that is associated with decreased hippocampal cell proliferation and BDNF levels. Running reversed these effects in rats treated with low or moderate, but not high doses of CORT. Using 40 mg/kg CORT-treated rats, we further studied the role of neurogenesis and dendritic remodeling in mediating the effects of exercise on stress. Co-labelling with BrdU (thymidine analog) /doublecortin (immature neuronal marker) showed that running increased neuronal differentiation in vehicle- and CORT-treated rats. Running also increased dendritic length and spine density in CA3 pyramidal neurons in 40 mg/kg CORT-treated rats. Ablation of neurogenesis with Ara-c infusion diminished the effect of running on restoring spatial learning and decreasing depression-like behaviour in 40 mg/kg CORT-treated animals in spite of dendritic and spine enhancement. but not normal runners with enhanced dendritic length. The results indicate that both restored hippocampal neurogenesis and dendritic remodelling within the hippocampus are essential for running to counteract stress.
doi:10.1371/journal.pone.0024263
PMCID: PMC3174166  PMID: 21935393

Results 1-11 (11)