Faculty Bibliography

Previous research across species has shown that the amygdala is critical for learning about aversive outcomes, while the striatum is involved in reward-related processing. Less is known, however, about the role of the amygdala and the striatum in learning how to exert control over emotions and avoid negative outcomes. One potential mechanism for active avoidance of stressful situations is postulated to involve amygdala-striatal interactions. The goal of this study was to investigate the physiological and neural correlates underlying avoidance learning in humans. Specifically, we used a classical conditioning paradigm where three different conditioned stimuli (CS) were presented. One stimulus predicted the delivery of a shock upon stimulus offset (CS+), while another predicted no negative consequences (CS-). A third conditioned cue also predicted delivery of a shock, but participants were instructed that upon seeing this stimulus, they could avoid the shock if they chose the correct action (AV+). After successful learning, participants could then easily terminate the shock during subsequent stimulus presentations (AV-). Physiological responses (as measured by skin conductance responses) confirmed a main effect of conditioning, particularly showing higher arousal responses during pre (AV+) compared to post (AV-) learning of an avoidance response. Consistent with animal models, amygdala-striatal interactions were observed to underlie the acquisition of an avoidance response. These results support a mechanism of active coping with conditioned fear that allows for the control over emotional responses such as fears that can become maladaptive and influence our decision-making

A specific polymorphism of the brain-derived neurotrophic factor (BDNF) gene is associated with alterations in brain anatomy and memory; its relevance to the functional connectivity of brain networks, however, is unclear. Given that altered hippocampal function and structure has been found in adults who carry the methionine (met) allele of the BDNF gene and the molecular studies elucidating the role of BDNF in neurogenesis and synapse formation, we examined the association between BDNF gene variants and neural resting connectivity in children and adolescents. We observed a reduction in hippocampal and parahippocampal to cortical connectivity in met-allele carriers within both default-mode and executive networks. In contrast, we observed increased connectivity to amygdala, insula and striatal regions in met-carriers, within the paralimbic network. Because of the known association between the BDNF gene and neuropsychiatric disorder, this latter finding of greater connectivity in circuits important for emotion processing may indicate a new neural mechanism through which these gene-related psychiatric differences are manifest. Here we show that the BDNF gene, known to regulate synaptic plasticity and connectivity in the brain, affects functional connectivity at the neural systems level. In addition, we demonstrate that the spatial topography of multiple high-level resting state networks in healthy children and adolescents is similar to that observed in adults.

Fear arousal, initiated by an environmental threat, leads to activation of the stress response, a state of alarm that promotes an array of autonomic and endocrine changes designed to aid self-preservation. The stress response includes the release of glucocorticoids from the adrenal cortex and catecholamines from the adrenal medulla and sympathetic nerves. These stress hormones, in turn, provide feedback to the brain and influence neural structures that control emotion and cognition. To illustrate this influence, we focus on how it impacts fear conditioning, a behavioral paradigm widely used to study the neural mechanisms underlying the acquisition, expression, consolidation, reconsolidation, and extinction of emotional memories. We also discuss how stress and the endocrine mediators of the stress response influence the morphological and electrophysiological properties of neurons in brain areas that are crucial for fear-conditioning processes, including the amygdala, hippocampus, and prefrontal cortex. The information in this review illuminates the behavioral and cellular events that underlie the feedforward and feedback networks that mediate states of fear and stress and their interaction in the brain

This study examines the independent impact of bullying on suicide risk. Bullying was assessed by peer nomination in a prospective study of 1,655 7th and 8th grade Korean students, and suicide by youth self-report. Odds Ratios (ORs) of bullying for suicidal risks were computed, controlling for other suicide risk factors. Victim-Perpetrators and female Victims at baseline showed increased risk for persistent suicidality (OR: 2.4-9.8). Male Incident Victims exhibited increased risk for suicidal behaviors and ideations (OR = 4.4, 3.6). Female Persistent Perpetrators exhibited increased risks for suicidal behaviors; male Incident Perpetrators had increased risk for suicidal ideations (OR = 2.7, 2.3). Baseline-only male Victim-Perpetrators showed increased risk for suicidal ideations. (OR = 6.4). Bullying independently increased suicide risks

Cognitive deficits are frequent consequences of acquired brain injury (ABI) and often require intervention. We review the theoretical and empirical literature on cognitive rehabilitation in a variety of treatment domains including attention, memory, unilateral neglect, speech and language, executive functioning, and family involvement/education. Because there are more well-designed studies examining the efficacy of cognitive rehabilitation in adults with brain injury, the major findings from this body of literature are also highlighted. In addition, given that similar cognitive and behavioral concerns are often apparent in children with certain neurodevelopmental disorders, selected literature focusing on interventions for these groups of children is included. Limitations and challenges inherent in examining cognitive interventions in children with ABI are also discussed. Overall, despite the growing body of literature examining the efficacy of cognitive rehabilitation in children with ABI, there continues to be a great need to develop well-designed studies to examine the efficacy of these interventions.