Dynamic Measures of Anxiety-Related Threat Bias: Links to Stress Reactivity.

Exaggerated attention to threatening information, or the threat bias, has been implicated in the development and maintenance of anxiety disorders. Recent research has highlighted methodological limitations in threat bias measures, such as temporal insensitivity, leading to the development of novel metrics that capture change and variability in threat bias over time. These metrics, however, have rarely been examined in non-clinical samples. The present study aimed to explore the utility of these trial-level metrics in predicting anxiety-related stress reactivity (stress-induced negative mood state) in trait anxious adults (N = 52). Following a stressor, participants completed the dot probe task to generate threat bias scores. Stress reactivity was measured via stress-induced changes in subjective mood state. More variability in trial-level bias scores and greater bias away from threat (both mean and peak negative trial-level bias scores) predicted increased stress reactivity. The temporal characteristics of threat bias and implications for clinically-relevant measurement are discussed.

Hick-Hyman Law is Mediated by the Cognitive Control Network in the Brain.

The Hick-Hyman law describes a linear increase in reaction time (RT) as a function of the information entropy of response selection, which is computed as the binary logarithm of the number of response alternatives. While numerous behavioral studies have provided evidence for the Hick-Hyman law, its neural underpinnings have rarely been examined and are still unclear. In this functional magnetic resonance imaging study, by utilizing a choice reaction time task to manipulate the entropy of response selection, we examined brain activity mediating the input and the output, as well as the connectivity between corresponding regions in human participants. Beyond confirming the Hick-Hyman law in RT performance, we found that activation of the cognitive control network (CCN) increased and activation of the default mode network (DMN) decreased, both as a function of entropy. However, only the CCN, but not the DMN, was involved in mediating the relationship between entropy and RT. The CCN was involved in both stages of uncertainty representation and response generation, while the DMN was mainly involved at the stage of uncertainty representation. These findings indicate that the CCN serves as a core entity underlying the Hick-Hyman law by coordinating uncertainty representation and response generation in the brain.

Neurocognitive assessment of emotional context sensitivity.

Sensitivity to emotional context is an emerging construct for characterizing adaptive or maladaptive emotion regulation, but few measurement approaches exist. The current study combined behavioral and neurocognitive measures to assess context sensitivity in relation to self-report measures of adaptive emotional flexibility and well-being. Sixty-six adults completed an emotional go/no-go task using happy, fearful, and neutral faces as go and no-go cues, while EEG was recorded to generate event-related potentials (ERPs) reflecting attentional selection and discrimination (N170) and cognitive control (N2). Context sensitivity was measured as the degree of emotional facilitation or disruption in the go/no-go task and magnitude of ERP response to emotion cues. Participants self-reported on emotional flexibility, anxiety, and depression. Overall participants evidenced emotional context sensitivity, such that when happy faces were go stimuli, accuracy improved (greater behavioral facilitation), whereas when fearful faces were no-go stimuli, errors increased (disrupted behavioral inhibition). These indices predicted emotional flexibility and well-being: Greater behavioral facilitation following happy cues was associated with lower depression and anxiety, whereas greater disruption in behavioral inhibition following fearful cues was associated with lower flexibility. ERP indices of context sensitivity revealed additional associations: Greater N2 to fear go cues was associated with less anxiety and depression, and greater N2 and N170 to happy and fear no-go cues, respectively, were associated with greater emotional flexibility and well-being. Results suggest that pleasant and unpleasant emotions selectively enhance and disrupt components of context sensitivity, and that behavioral and ERP indices of context sensitivity predict flexibility and well-being.

Repeated recall and PKMζ maintain fear memories in juvenile rats.

We examined the neural substrates of fear memory formation and maintenance when repeated recall was used to prevent forgetting in young animals. In contrast to adult rats, juveniles failed to show contextual fear responses at 4 d post-fear conditioning. Reconsolidation sessions 3 and 6 d after conditioning restored contextual fear responses in juveniles 7 d after initial training. In juveniles that received reconsolidation sessions, protein kinase M zeta (PKMζ) increased in the amygdala, but not in the hippocampus. These data suggest that repeated reminders and increased PKMζ maintain fear responses in juvenile animals that otherwise would not exhibit this behavior.

The Capacity of Cognitive Control Estimated from a Perceptual Decision Making Task.

Cognitive control refers to the processes that permit selection and prioritization of information processing in different cognitive domains to reach the capacity-limited conscious mind. Although previous studies have suggested that the capacity of cognitive control itself is limited, a direct quantification of this capacity has not been attempted. In this behavioral study, we manipulated the information rate of cognitive control by parametrically varying both the uncertainty of stimul measured as information entropy and the exposure time of the stimuli. We used the relationship between the participants' response accuracy and the information rate of cognitive control (in bits per second, bps) in the model fitting to estimate the capacity of cognitive control. We found that the capacity of cognitive control was approximately 3 to 4 bps, demonstrating that cognitive control as a higher-level function has a remarkably low capacity. This quantification of the capacity of cognitive control may have significant theoretical and clinical implications.

Neuroanatomical Alterations in High-Functioning Adults with Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is a pervasive neurodevelopmental condition, affecting cognition and behavior throughout the life span. With recent advances in neuroimaging techniques and analytical approaches, a considerable effort has been directed toward identifying the neuroanatomical underpinnings of ASD. While gray-matter abnormalities have been found throughout cortical, subcortical, and cerebellar regions of affected individuals, there is currently little consistency across findings, partly due to small sample-sizes and great heterogeneity among participants in previous studies. Here, we report voxel-based morphometry of structural magnetic resonance images in a relatively large sample of high-functioning adults with ASD (n = 66) and matched typically-developing controls (n = 66) drawn from multiple studies. We found decreased gray-matter volume in posterior brain regions, including the posterior hippocampus and cuneus, as well as increased gray-matter volume in frontal brain regions, including the medial prefrontal cortex, superior and inferior frontal gyri, and middle temporal gyrus in individuals with ASD. We discuss our results in relation to findings obtained in previous studies, as well as their potential clinical implications.

For whom the bell tolls: Neurocognitive individual differences in the acute stress-reduction effects of an attention bias modification game for anxiety.

The efficacy of attention bias modification training (ABMT) for anxiety is debated, in part because individual differences in task engagement and pre-training threat bias impact training efficacy. In the present study, an engaging, gamified ABMT mobile application, or "app," was utilized in 42 (21 females) trait-anxious adults. EEG was recorded during pre- and post-training threat bias assessment to generate scalp-recorded event-related potentials (ERPs) reflecting neurocognitive responses to threat. Following app play (ABMT versus placebo), subjective anxiety and stress responses (observed and self-reported) were measured. ABMT, versus placebo, resulted in improved behavioral performance during the stress task for females, and in potentiation of the N2 ERP to threat for males, suggesting increased attention control. Training groups did not differ in self-reported anxiety. ABMT also resulted in improved performance during the stress task among those evidencing specific pre-training ERP responses: decreased P1, suggesting less attention allocation, but potentiated N170, suggesting enhanced attention selection and discrimination. Differences in behavioral threat bias did not moderate training effects. Results suggest that efficient allocation of attention to threat combined with enhanced discrimination between threat and non-threat may facilitate stress-reduction effects of ABMT. Targeting neurocognitive responses to threat to personalize ABMT and develop more effective methods of treatment delivery, such as gamification, are discussed.