The orienting of spatial attention to backward masked fearful faces is associated with variation in the serotonin transporter gene

Threat signals facilitate spatial attention, even when awareness of these signals has been restricted through the use of backward masking. However, unrestricted/unmasked threat cues tend to delay the disengagement of attention, whereas restricted/masked threat facilitates orienting, suggesting different underlying mechanisms. Within the general population, the serotonin transporter gene polymorphism (5HTTLPR) is associated with one's allocation of attention to unmasked threat signals. However, it is unclear to what extent the 5HTTLPR gene may be involved in nonconscious biases to masked threat, and whether or not such biases are driven by facilitated orienting or delayed disengagement. Participants were genotyped and performed a dot-probe task with backward masked fearful and neutral faces. Results indicate that short-allele carriers of the 5HTTLPR gene nonconsciously orient spatial attention to masked fearful faces. On the other hand, homozygous long-allele individuals tended to direct attention away from masked fearful faces. All participants' performance was at chance in a posttask assessment of awareness for the masked faces. The results add to current literature on the 5HTTLPR and attention biases, and suggest that threat signals facilitate the orienting of attention in short-allele carriers of the 5HTTLPR gene even under restricted processing conditions.     

Could stress cause psychosis in individuals vulnerable to schizophrenia?

It has long been considered that psychosocial stress plays a role in the expression of symptoms in schizophrenia (SZ), as it interacts with latent neural vulnerability that stems from genetic liability and early environmental insult. Advances in the understanding of the neurobiology of the stress cascade in both animal and human studies lead to a plausible model by which this interaction may occur: through neurotoxic effects on the hippocampus that may involve synaptic remodeling. Of late, the neurodevelopmental model of SZ etiology has been favored. But an elaboration of this schema that credits the impact of postnatal events and considers a role for neurodegenerative changes may be more plausible, given the evidence for gene-environment interaction in SZ expression and progressive structural changes observed with magnetic resonance imaging. Furthermore, new insights into nongliotic neurotoxic effects such as apoptosis, failure of neurogenesis, and changes in circuitry lead to an expansion of the time frame in which environmental effects may mediate expression of SZ symptoms.     

Acute stress eliminates female advantage in detection of ambiguous negative affect

The human stress response evolved to maximize an individual's probability of survival when threatened. The present study addressed whether physical danger modulates perception of an unrelated ambiguous threat and, if so, to what extent this response is sex- specific. The authors utilized a first-time tandem skydive as a stressor, which had been previously validated as producing a highly-controlled, genuinely stressful environment. In a counter-balanced within-subjects design, participants wore a virtual reality helmet to complete an emotion-identification task during the plane's ascent (stress condition) and in the laboratory (control condition). Participants were presented static male faces morphed between 20-80% aggression, which gradually emerged from degraded images. Using a binary forced-choice design, participants identified each ambiguous face as aggressive or neutral. Results showed that participants characterized emotion more rapidly under stress versus control conditions. Unexpectedly, the results also show that while women were more sensitive to affect ambiguity than men under control conditions, they exhibited a marked decrease in sensitivity equivalent to men while under stress.     

Trait reappraisal is associated with resilience to acute psychological stress

Life is full of stressful events. However, while some individuals are negatively affected by stress, others are more resilient to its effects. The factors that contribute to variability in stress resilience are not fully understood. Here, we tested the hypothesis that trait reappraisal would be associated with greater stress resilience to a first-time tandem skydive. Specifically, we expected measures of “anxiety” to be lower and measures of “euphoria” to be higher in high trait reappraising individuals. Our findings that trait reappraisal is negatively correlated with stress reactivity as measured by cortisol, heart rate, and self-report state anxiety, but positively correlated with self-report state euphoria suggest that individuals high in trait reappraisal are more stress resilient.     

Are cognitive symptoms of schizophrenia mediated by abnormalities in emotional arousal?

We tested 28 individuals with schizophrenia (SZ) and 16 healthy individuals on a test of logical reasoning and "cognitive gating," defined as the ability to discriminate between relevant and irrelevant information in confirming or disconfirming a given belief. The Logical Reasoning and Cognitive Gating Task tests both processes under neutral and affect-laden conditions. This is done by presenting formally identical constructs using benign and emotionally arousing language. When separated by symptom profiles, we found statistically significant differences for performance and arousal response between patients with delusions, patients with formal thought disorder, and patients with neither delusions nor formal thought disorder, as well as between patients and healthy controls. When analyzed by error type, we found that nearly all errors by delusional patients were caused by overly restrictive information choice, a pattern that may be related to a delusional patient's tendency to "jump to conclusions" on Bayesian probabilistic tasks. This is in contrast to patients with formal thought disorder, whose low performance resulted also from overly extensive information choice. The tendencies towards restriction were exacerbated by arousal, which is consistent with studies on cognition and arousal in healthy individuals. After briefly examining research on emotional arousal and SZ, and the interaction between emotional arousal and restriction of perceptual cues in healthy individuals, we conclude by suggesting a model which accounts for the distinctive cognitive characteristics of delusional patients by their possessing distinct vulnerabilities to emotional arousal. Specifically, these results suggest the possibility that delusional patients process information in a manner that is essentially intact. However, delusional patients may possess an acute vulnerability to emotional arousal that might cause delusional individuals to behave cognitively as if they were healthy individuals under significantly more severe forms of stress.