Institute of Psychology,Chinese Academy Of Sciences
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Linking challenge and hindrance stress to safety performance: The moderating effect of core self-evaluation
No full textThe buffering effect of core self-evaluation (CSE) in stress research has received academic attention. However, most research in this area focused on its moderating effect on well-being. In the present study, we take a closer look at the moderating role of CSE in the relationship between challenge/hindrance stress and safety performance. Results indicated that challenge and hindrance stress were both negatively related to safety performance. More importantly, CSE acted as a buffer in the negative relationships between challenge stress and safety compliance and between hindrance stress and safety participation. Contrary to our prediction, the negative relationship between hindrance stress and safety participation was stronger for people higher on CSE. Based on our findings, we discuss the theoretical implications for personality and safety research. (C) 2014 Elsevier Ltd. All rights reserved
The time course of contrast adaptation measured with a new method: Detection of ramped contrast
No full textThe present study introduces a new method to measure contrast detection thresholds before and after adaptation to contrast. A sinusoidal testing grating increased contrast at a constant rate from an initial subthreshold level. Subjects indicated when the grating was just visible, which terminated its presentation. The stimulus contrast at the time of response was taken as a measure of relative threshold. We used the method to measure the time courses of changes in threshold following adaptation, for several adapting contrasts (9, 19, 29, or 39 dB, ref. 1%) and adapting durations (10, 100, or 1000 s). The buildup and decay of adaptation to contrast was described well by a power function of time. These results agree with previous findings, but are more efficient in terms of subject time. This method promises to be a useful tool for studying the dynamics of adaptation to spatial contrast
Dopaminergic pathway polymorphisms and heroin addiction: further support for association of CSNK1E variants
No full textBackground & aim: The dopaminergic pathways have been implicated in the etiology of drug addictions. The aim of this study was to determine if variants in dopaminergic genes are associated with heroin addiction. Materials & methods: The study includes 828 former heroin addicts and 232 healthy controls, of predominantly European ancestry. Ninety seven SNPs (13 genes) were analyzed. Results: Nine nominally significant associations were observed at CSNK1E, ANKK1, DRD2 and DRD3. Conclusion: The results support our previous report of association of CSNK1E SNP rs1534891 with protection from heroin addiction. CSNK1E interacts with circadian rhythms and DARPP-32 and has been implicated in negative regulation of sensitivity to opioids in rodents. It may be a target for drug addiction treatment
A General Exponential Framework for Dimensionality Reduction
No full textAs a general framework, Laplacian embedding, based on a pairwise similarity matrix, infers low dimensional representations from high dimensional data. However, it generally suffers from three issues: 1) algorithmic performance is sensitive to the size of neighbors; 2) the algorithm encounters the well known small sample size (SSS) problem; and 3) the algorithm de-emphasizes small distance pairs. To address these issues, here we propose exponential embedding using matrix exponential and provide a general framework for dimensionality reduction. In the framework, the matrix exponential can be roughly interpreted by the random walk over the feature similarity matrix, and thus is more robust. The positive definite property of matrix exponential deals with the SSS problem. The behavior of the decay function of exponential embedding is more significant in emphasizing small distance pairs. Under this framework, we apply matrix exponential to extend many popular Laplacian embedding algorithms, e. g., locality preserving projections, unsupervised discriminant projections, and marginal fisher analysis. Experiments conducted on the synthesized data, UCI, and the Georgia Tech face database show that the proposed new framework can well address the issues mentioned above
Four Days of Visual Contrast Deprivation Reveals Limits of Neuronal Adaptation
No full textSensory systems continuously adjust their function to match changes in the environment. Such adaptation produces large perceptual effects, and its pervasiveness makes it a key part of understanding cortical function generally [1-3]. In visual contrast adaptation, for example, brief exposure to vertical stripes can dramatically alter the apparent orientation and intensity of similarly oriented patterns (e. g., [4-7]). However, many environmental changes are long lasting. How does the visual system adjust to such challenges? Most past work on contrast adaptation has adapted subjects for just a few minutes. Only a few studies have examined durations greater than 1 hr [8-12], and none have exceeded 1 day. Here, we measured perceptual effects of adaptation in humans who viewed a world lacking vertical information for 4 days continuously. As expected, adaptation increased in magnitude during the first day, but it then showed a drop in strength. The decrease in adaptation is surprising because the adapting environment remained constant, and in short-term work, adaptation always strengthens or at least is maintained under such conditions. It indicates that the classical effects of contrast adaptation, which arise largely in primary visual cortex [13-18], are not maintained after approximately 1 day. Results from day 2 through day 4 further showed that slower adaptive processes can overcome this limit. Because adaptation is generally beneficial overall, its limits argue that the brain is sensitive to costs that arise when the neural code changes [19, 20]. These costs may determine when and how cortex can alter its function
Effects of 5-hydroxytryptamine 2C receptor agonist MK212 and 2A receptor antagonist MDL100907 on maternal behavior in postpartum female rats
No full textMaternal behavior in rats is a highly motivated and well-organized social behavior. Given the known roles of serotonin (5-HT) in emotion, motivation, social behavior, and major depression - and its known interaction with dopamine - it is likely that serotonin also plays a crucial role in this behavior. So far, there are surprisingly few studies focusing on 5-HT in maternal behavior, except for maternal aggression. In the present study, we examined the effects of 5-HT2C receptor agonism and 5-HT2A receptor antagonism on maternal behavior in postpartum female rats. We hypothesized that activation of 5-HT2C receptors and blockade of 5-HT2A receptors would produce a functionally equivalent disruption of maternal behavior because these two receptor subtypes often exert opposite effects on various brain functions and psychological processes relevant to rat maternal behavior. On postpartum Days 5, 7, and 9, Sprague-Dawley mother rats were given a single injection of 0.9% NaCl solution, the 5-HT2C agonist MK212 (0.5, 1.0 or 2.0 mg/kg, ip), or the 5-HT2A antagonist MDL100907 (0.05, 0.5 or 2.0 mg/kg, ip). Maternal behavior was tested 30 min before and 30 min, 120 min, 240 min after injection. Acute injection of MK212 significantly disrupted pup retrieval, pup licking, pup nursing, and nest building in a dose-dependent fashion. At the tested doses, MDL100907 had little effect on various components of rat maternal behavior. Across the 3 days of testing, no apparent sensitization or tolerance associated with repeated administration of MK212 and MDL100907 was found. We concluded that rat maternal performance is critically dependent on 5-HT2C receptors, while the role of 5-HT2A receptors is still inconclusive. Possible behavioral mechanisms of actions of 5-HT2C receptor in maternal behavior are discussed. (C) 2013 Elsevier Inc. All rights reserved
Anhedonia and Pain Avoidance in the Suicidal Mind: Behavioral Evidence for Motivational Manifestations of Suicidal Ideation in Patients With Major Depressive Disorder
No full textObjectives: Psychological pain may be helpful in conceptualizing suicidal behavior, in that high motivation to avoid pain combined with painful feelings may contribute to an increased risk of suicide. However, no experimental study has tested this hypothesis. The aim of the present study is to provide empirical evidence for the relationship between anhedonia, pain avoidance motivation, and suicidal ideation. Method: The sample comprised 40 depressed outpatients and 20 healthy control subjects. All participants completed the Beck Scale for Suicide Ideation (BSS), Beck Depression Inventory, Psychache Scale, Three-Dimensional Psychological Pain Scale, the monetary incentive delay (MID), and affective incentive delay (AID) tasks. Based on BSS scores, clinical participants were divided into high suicidal ideation (HSI) and low suicidal ideation (LSI) groups. Results: In the AID task, the HSI group had longer response times (RTs) under the reward condition than those under the punishment condition (p = .002). The LSI and control groups had shorter RTs under the reward condition compared with those under the neural condition (p < .001 and p = .008, respectively). The LSI group also had shorter RTs under the reward condition than under the punishment condition (p = .003). Pain arousal (r = -.33, p < .01) and BSS scores were significantly negatively correlated with differences in RTs between neutral and reward conditions. Pain avoidance (r = .35, p < .01) and BSS scores were positively correlated with differences in RTs between neutral and punishment conditions. Conclusions: The AID task was more sensitive than the MID task for the detection of participants' motivation in approaching hedonic experiences and avoiding pain. A suicidal mindset is manifested as decreased motivation to experience hedonia and increased motivation to avoid pain, which could be strong predictors of suicidal behavior. (C) 2013 Wiley Periodicals, Inc
Unraveling the Miswired Connectome: A Developmental Perspective
No full textThe vast majority of mental illnesses can be conceptualized as developmental disorders of neural interactions within the connectome, or developmental miswiring. The recent maturation of pediatric in vivo brain imaging is bringing the identification of clinically meaningful brain-based biomarkers of developmental disorders within reach. Even more auspicious is the ability to study the evolving connectome throughout life, beginning in utero, which promises to move the field from topological phenomenology to etiological nosology. Here, we scope advances in pediatric imaging of the brain connectome as the field faces the challenge of unraveling developmental miswiring. We highlight promises while also providing a pragmatic review of the many obstacles ahead that must be overcome to significantly impact public health
Human Brain Responses to Concomitant Stimulation of A delta and C Nociceptors
No full textIntense radiant heat pulses concomitantly activate A delta-and C-fiber skin nociceptors, and elicit a typical double sensation: an initial A delta-related pricking pain is followed by a C-related prolonged burning sensation. It has been repeatedly reported that C-fiber laser-evoked potentials (C-LEPs) become detectable only when the concomitant activation of A delta-fibers is avoided or reduced. Given that the saliency of the eliciting stimulus is a major determinant of LEPs, one explanation for these observations is that the saliency of the C-input is smaller than that of the preceding A delta-input. However, even if the saliency of the C-input is reduced because of the preceding A delta-input, a C-LEP should still be visible even when preceded by an A delta-LEP response. Here we tested this hypothesis by applying advanced signal processing techniques (peak alignment and time-frequency decomposition) to electroencephalographic data collected in two experiments conducted in 34 and 96 healthy participants. We show that, when using optimal stimulus parameters (delivering >80 stimuli within a small skin territory), C-LEPs can be reliably detected in most participants. Importantly, C-LEPs are observed even when preceded by A delta-LEPs, both in average waveforms and single trials. By providing quantitative information about several response properties of C-LEPs (latency jitter, stimulus-response and perception-response functions, dependency on stimulus repetitions and stimulated area), these results define optimal parameters to record C-LEPs simply and reliably. These findings have important clinical implications for assessing small-fiber function in neuropathies and neuropathic pain
The Dula Dangerous Driving Index in China: An investigation of reliability and validity
No full textThe aim of this study was to translate the Dula Dangerous Driving Index (DDDI) into Chinese and to verify its reliability and validity. A total of 246 drivers completed the Chinese version of the DDDI and the Driver Behavior Questionnaire (DBQ). Specific sociodemographic variables and traffic violations were also measured. A confirmatory factor analysis confirmed the internal structure of the DDDI, and the four-factor model was supported in China. Measures of convergent and criterion validity demonstrated that the Chinese DDDI was valid. Its convergent validity was supported by its positive relationship with the DBQ, and its criterion validity was tested using its relationship with self-reported accident involvement and traffic violations. Finally, score comparisons between different demographic groups revealed significant differences, thereby linking age and driving years to dangerous driving. (C) 2013 Elsevier Ltd. All rights reserved
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