Faculty Bibliography

In the water maze, mice are trained to navigate to an escape platform located below the water's surface, and spatial learning is most commonly evaluated in a probe test in which the platform is removed from the pool. While contemporary tracking software provides precise positional information of mice for the duration of the probe test, existing performance measures (e.g., percent quadrant time, platform crossings) fail to exploit fully the richness of this positional data. Using the concept of entropy (H), here we develop a new measure that considers both how focused the search is and the degree to which searching is centered on the former platform location. To evaluate how H performs compared to existing measures of water maze performance we compiled five separate databases, containing more than 1600 mouse probe tests. Random selection of individual trials from respective databases then allowed us to simulate experiments with varying sample and effect sizes. Using this Monte Carlo-based method, we found that H outperformed existing measures in its ability to detect group differences over a range of sample or effect sizes. Additionally, we validated the new measure using three models of experimentally induced hippocampal dysfunction: (1) complete hippocampal lesions, (2) genetic deletion of alphaCaMKII, a gene implicated in hippocampal behavioral and synaptic plasticity, and (3) a mouse model of Alzheimer's disease. Together, these data indicate that H offers greater sensitivity than existing measures, most likely because it exploits the richness of the precise positional information of the mouse throughout the probe test.

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.