Decision-making style explains the withdrawal behavior of shy individuals: evidence from Chinese college students

Few studies have examined the mechanisms linking motivated behavior and reward-punishment stimuli in shy individuals. This study was designed to probe these mechanisms by examining shy and non-shy college student responses to both monetary rewards and penalties in the Iowa Gambling Task (IGT). Specifically, out of the 280 undergraduates surveyed in East China, 45 participants (18 boys) identified as shy and 45 (19 boys) identified as non-shy based on their shyness questionnaire scores were selected to participate in the IGT. Results revealed that shy participants selected favorable low-risk seeking decks (deck C) more frequently and adverse high-risk seeking decks (deck B) less frequently and were more inclined to change deck selection after incurring a net loss. Furthermore, the net score of shy students was higher than that of nonshy students. Results demonstrated that shy people were the winners of IGT games, indicating that they are more likely to exhibit risk-averse behaviors when making decisions. The results are discussed from the perspective of the decision-making style and practical implications of shy individuals.

Precarious Job Makes Me Withdraw? The Role of Job Insecurity and Negative Affect

An expanding "gig" economy has changed the nature of employment; thus, researchers have recently focused on exploring the role of job precariousness in the workplace. However, little research attention has been given to understanding why, how and when job precariousness leads to employees' negative behavioral outcomes in the service-oriented industry. In the current study, we examined job insecurity as a mediator and employees' negative affect as a moderator in the relationship between job precariousness and employees' withdrawal behavior. Using a sample of 472 employees working in Chinese hotels, we found that job precariousness is positively related to employees' withdrawal behavior by increasing their job insecurity. Moreover, this mediating relationship is conditional on the moderator variable of employees' negative affect for the path from job insecurity to withdrawal behavior. The importance of these findings for understanding the undesirable behavior outcomes of job precariousness is discussed.

Leader Humility, and Subordinates' Organizational Citizenship Behavior and Withdrawal Behavior: Exploring the Mediating Mechanisms of Subordinates' Psychological Capital

As a bottom-up leadership style, leader humility has received considerable attention from researchers. Among the abundant studies revealing the positive impact of leader humility on employees' work attitude and behaviors, there is less knowledge on how leader humility influences subordinates' organizational citizenship behavior (OCB) and withdrawal behavior. On the basis of the social information processing theory, this study proposed a cross-level mediation model and examined the direct impact of leader humility on subordinates' OCB and withdrawal behavior. We also further explored the underlying psychological mechanism and examined the mediating effect of psychological capital on these relationships. Using a two-wave panel design and 274 employees' questionnaire data, the empirical analysis found that: (1) leader humility was positively related to subordinates' OCB and negatively related to subordinates' withdrawal behavior; (2) leader humility was positively related to subordinates' psychological capital; and (3) psychological capital played a cross-level mediating role in the leader humility-subordinates' OCB relationship and the leader humility-subordinates' withdrawal behavior relationship. Theoretical and practical implications, limitations, and suggestions for future research are also discussed.

Mapping the sequence of brain events in response to disgusting food

Warning signals indicating that a food is potentially dangerous may evoke a response that is not limited to the feeling of disgust. We investigated the sequence of brain events in response to visual representations of disgusting food using a dynamic image analysis. Functional MRI was acquired in 30 healthy subjects while they were watching a movie showing disgusting food scenes interspersed with the scenes of appetizing food. Imaging analysis included the identification of the global brain response and the generation of frame-by-frame activation maps at the temporal resolution of 2 s. Robust activations were identified in brain structures conventionally associated with the experience of disgust, but our analysis also captured a variety of other brain elements showing distinct temporal evolutions. The earliest events included transient changes in the orbitofrontal cortex and visual areas, followed by a more durable engagement of the periaqueductal gray, a pivotal element in the mediation of responses to threat. A subsequent core phase was characterized by the activation of subcortical and cortical structures directly concerned not only with the emotional dimension of disgust (e.g., amygdala-hippocampus, insula), but also with the regulation of food intake (e.g., hypothalamus). In a later phase, neural excitement extended to broad cortical areas, the thalamus and cerebellum, and finally to the default mode network that signaled the progressive termination of the evoked response. The response to disgusting food representations is not limited to the emotional domain of disgust, and may sequentially involve a variety of broadly distributed brain networks. Hum Brain Mapp 39:369-380, 2018. © 2017 Wiley Periodicals, Inc.

Homolog of protein kinase Mζ maintains context aversive memory and underlying long-term facilitation in terrestrial snail Helix

It has been shown that a variety of long-term memories in different regions of the brain and in different species are quickly erased by local inhibition of protein kinase Mζ (PKMζ), a persistently active protein kinase. Using antibodies to mammalian PKMζ, we describe in the present study the localization of immunoreactive molecules in the nervous system of the terrestrial snail Helix lucorum. Presence of a homolog of PKMζ was confirmed with transcriptomics. We have demonstrated in behavioral experiments that contextual fear memory disappeared under a blockade of PKMζ with a selective peptide blocker of PKMζ zeta inhibitory peptide (ZIP), but not with scrambled ZIP. If ZIP was combined with a “reminder” (20 min in noxious context), no impairment of the long-term contextual memory was observed. In electrophysiological experiments we investigated whether PKMζ takes part in the maintenance of long-term facilitation (LTF) in the neural circuit mediating tentacle withdrawal. LTF of excitatory synaptic inputs to premotor interneurons was induced by high-frequency nerve stimulation combined with serotonin bath applications and lasted at least 4 h. We found that bath application of 2 × 10⁻⁶ M ZIP at the 90th min after the tetanization reduced the EPSP amplitude to the non-tetanized EPSP values. Applications of the scrambled ZIP peptide at a similar time and concentration didn’t affect the EPSP amplitudes. In order to test whether effects of ZIP are specific to the synapses, we performed experiments with LTF of somatic membrane responses to local glutamate applications. It was shown earlier that serotonin application in such an “artificial synapse” condition elicits LTF of responses to glutamate. It was found that ZIP had no effect on LTF in these conditions, which may be explained by the very low concentration of PKMζ molecules in somata of these identified neurons, as evidenced by immunochemistry. Obtained results suggest that the Helix homolog of PKMζ might be involved in post-induction maintenance of long-term changes in the nervous system of the terrestrial snail.

Nitric oxide in central amygdala potentiates expression of conditioned withdrawal induced by morphine

Objective:

The aim of this study was to evaluate if nitric oxide (NO) in the central amygdala (CeA) is involved in the expression of withdrawal aspects induced by morphine.

Materials and Methods:

Male Wistar rats (weighing 200-250 g) were bilaterally cannulated in the CeA and conditioned to morphine using an unbiased paradigm. Morphine (2.5-10 mg/kg) was subcutaneously injected once a day throughout the conditioning phase of the procedure. This phase also included 3-saline paired sessions. Naloxone (0.1-0.4 mg/kg, intraperitoneally [i.p.]), an antagonist of opioid receptors, was administered i.p. 10 min prior to testing of morphine-induced withdrawal features. The NO precursor, L-arginine (0.3-3 μg/rat) was intra-CeA injected prior to testing of naloxone response. To evaluate the involvement of NO system an inhibitor of NO synthase (NOS), N^G-nitro-L-arginine methyl ester (L-NAME) (0.3-3 μg/rat), was injected ahead of L-arginine. Control group received saline solely instead of drug. As a complementary study, the activation of NOS was studied by nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d).

Results:

Morphine induced a significant increase in wet dog shaking and grooming behaviors compared with controls. Injection of naloxone pre-testing of morphine response significantly reversed the response to morphine. However, pre-microinjection of L-arginine intra-CeA recovered the response to morphine. Injection of L-NAME intra-CeA ahead of L-arginine though had no effect behaviorally, but, inhibited the NOS which has been evidenced by NADPH-d.

Conclusion:

The present study shows that NO in the CeA potentiates the expression of conditioned withdrawal induced by morphine paired with naloxone.