October 5, 2012
2-4pm, Alumni Center Pavilion, Northeastern University [view maps & directions]
Kevin S. LaBar
Professor of Psychology & Neuroscience and Psychiatry & Behavioral Sciences
Center for Cognitive Neuroscience, Duke University, Durham, NC
Title: Perceptual and Conceptual Contributions to Fear Generalization
Abstract: The ability to generalize information across different experiences is paramount to adaptive behavior. This ability can prove maladaptive, however, if acquired knowledge is applied too broadly. For instance, following a highly aversive experience, individuals often overgeneralize fear behaviors towards stimuli or situations related to the initial experience. Overgeneralization of fear is symptomatic of anxiety disorders like posttraumatic stress disorder. Here, we present results from functional neuroimaging experiments in healthy adults designed to examine the neural systems that mediate fear generalization on the basis of both perceptual and conceptual similarity. First, we examined generalization of conditioned fear among stimuli that perceptually resembled a learned threat. During fear learning, a face expressing a moderate amount of fear (conditioned stimulus, CS+) signaled delivery of a mildly aversive electric shock (unconditioned stimulus, US), whereas the same face with a neutral expression was unreinforced. In a subsequent generalization test, subjects were presented with faces expressing more or less fear intensity than the CS+. Behaviorally, subjects retrospectively misidentified a learned threat as expressing more intense fear than its actual value and generated greater skin conductance responses (SCR) to generalized stimuli expressing higher fear intensity. Brain activity related to intensity-based generalization was observed in the striatum, insula, and thalamus. Generalized SCRs were correlated with activity in the amygdala, and connectivity between the amygdala and fusiform gyrus was correlated with trait anxiety levels. In a separate experiment, we examined fear generalization across exemplars of conceptually related objects. Objects from one category (e.g. animals) were paired with a shock US whereas those from another category (e.g. tools) was unreinforced. Category-based fear learning modulated activity in category-selective brain regions in the occipital-temporal cortex, as well areas associated with emotional learning (e.g. the amygdala and insula). We discovered a mechanistic account for the spread of conceptual fear based on hippocampal signaling of object typicality, which was reflected in greater functional coupling with the amygdala early in learning. Finally, we used multivariate statistical analyses to show experience-dependent alterations in the cortical representations of the object categories. In sum, these studies provide human neuroimaging evidence for perceptual and conceptual factors supporting fear generalization. These results add new insights to neurobiologically-based models of human anxiety disorders that go beyond basic conditioning processes.
An ASI Monthly Speaker Series Event
April 26, 2012, 3-5pm: Adam Anderson, The Affect and Cognition Laboratory, Psychology, University of Toronto.
Title: Opposition in facial expression form and function.
Abstract: Facial expressions are instrumental in externalizing one’s internal emotional state and thus in regulating social interactions. Darwin hypothesized that emotional expressions originated in a less appreciated functional role to modify preparedness for perception and action. We provide evidence for two of Darwin’ original principles of emotional expressive behavior in humans: 1) the principle of function— expressions serve adaptive functions for the sender, and 2) the principle of form— expressions with opposite functions are opposites in form. Specifically, we show facial expressions afford a primitive sensory regulatory opposition to increase or decrease sensory intake. We further provide evidence for the exaptation or co-opting of expression opposition for the purposes of social regulation and its use across cultures from the East and West. These convergent sources of evidence suggest facial expressions are not distinct classes, as suggested by Darwin’s modern interpreters, but rather arise from opposing dimensions potentially originating from a primitive sensory regulatory function.
Location: Henderson Executive Suite, 450 Dodge Hall. [Maps, Directions, and Parking]
February 24, 2012: Hideki Ohira, Nagoya University, Japan
Title: Functional association of brain and body in affective decision making
Abstract: Though traditional microeconomics has supposed that human decisions are based on logical and exact computation of cost-benefit balances or efficacies, studies in behavioral economics and psychology have shown that humans sometimes make irrational decisions driven by affects, especially when values of options and contingencies between options and outcomes are uncertain. Some theorists argued that one important source of such affective drives influencing decision making is bodily responses which are represented in brain regions such as the insula and anterior cingulate cortex. In this talk, empirical evidence for the functional associations of the brain and body accompanying affective decision making will be shown as follows. (1) Heart rate responses and concentration of inflammatory cytokine (IL-6) can predict acceptance or rejection to an unfair offer in an economical negotiation game, the Ultimatum Game. Activation of the anterior insula mediates this phenomenon. (2) Enhancement of interoception by biofeedback technique affects decision making with risk. (3) Sympathetic responses reflected by secretion of epinephrine are represented in brain regions such as the midbrain, anterior cingulate cortex, and anterior insula, and furthermore can determine randomness of decision making in a situation where action-outcome contingency is stochastic and unstable.
January 20, 2012: George Bonanno, The Loss, Trauma, and Emotion Laboratory, Columbia University
with discussant Susan Nolen-Hoeksema, Yale Depression and Cognition Program
Title: Beyond Resilience and PTSD: Predicting the Heterogeneity of Responses to Potential Trauma
Abstract: Potentially traumatic events (PTEs) are more common than is usually assumed. Until recently, responses to such events have been understood almost exclusively in terms of extreme reactions (e.g., PTSD) or in terms of measures of central tendency (e.g., average group differences). Although both approaches have been useful, neither captures the true heterogeneity of responses to PTEs and both underestimate the prevalence of human resilience. In this talk I describe studies from our research program that map individual trajectories of adjustment following such demanding life events as terrorist disaster, combat, traumatic injury, bereavement, bio-epidemic, and cancer surgery. I also examine the predictors of these trajectories, and emphasize the important role of emotional context sensitivity, flexibility in coping and emotion regulation, and positive emotional expression.