Oct 07, 2015
12:00 PM
149 13th Street (Building 149), main second floor seminar room (2204)

Marta Peciña Iturbe, MD, PhD
Research Assistant Professor
Department of Psychiatry and Depression Center, University of Michigan

Talk title: Molecular and Functional Mechanisms of Placebo Effects: Towards the Validation of Biomarkers in Clinical Trials.

Abstract: Endogenous opioid and non-opioid mechanisms [e.g. dopamine (DA), endocannabinoids  (eCB)] have been implicated in the formation of placebo effects, with initial reports dating back three-decades. Besides the perspective that placebo effects confound randomized clinical trials (RCTs), the information so far acquired points to neurobiological systems that when activated by positive expectations and maintained through conditioning and reward learning are capable of inducing physiological changes that lead to the experience of analgesia and improvements in emotional state. Functional and molecular neuroimaging techniques with positron emission tomography (PET) and the selective μ-opioid and D2/D3 radiotracers [11C]carfentanil and [11C]raclopride have significantly contributed to our understanding of the neurobiological systems involved in the formation of placebo effects. This line of research has described neural and neurotransmitter networks implicated in placebo responses and provided the technical tools to examine inter-individual differences in the function of placebo responsive mechanisms, and potential surrogate markers. As a consequence, the formation of biological placebo effects is now being linked to the concept of resiliency mechanisms, partially determined by genetic factors, and uncovered by the cognitive emotional integration of the expectations created by the therapeutic environment and its maintenance through learning mechanisms. Further work needs to extend this research into clinical conditions where the rates of placebo responses are high and its neurobiological mechanisms have been largely unexplored (e.g. mood and anxiety disorders, persistent pain syndromes, or even Parkinson Disease and multiple sclerosis). Moreover, current progress in our understanding of the biological bases of placebo effects should be use to inform future clinical trial designs as well as potential biological targets that have not been contemplated in traditional drug development.

Co-Sponsored by the Program in Placebo Studies/BIDMC/HMS

Oct 14, 2015
12:00 PM
149 13th Street (Building 149), main second floor seminar room (2204)

R. Matthew Hutchison, PhD

Postdoctoral Fellow

Department of Psychology, Harvard University

Talk title: Do you see what I see? Brain responses to free viewing of dynamic social and non-social object interactions

Abstract: Explorations of neurophysiological response properties in naturalistic and less controlled settings have historically played a major role in discovering organizational and functional properties in the visual and reward systems. Recently, functional MRI analyses of humans viewing naturalistic scenes and complex streams of stimuli have yielded robust responses that are stable across participants and capture dynamics that are not evident in constrained paradigms. Motivated by this background, we conducted an extensive exploration of response properties during movie viewing of scenes depicting different levels of social interaction: (1) only inanimate objects, (2) individual people interacting with inanimate objects, and (3) more than one person interacting. In addition to results demonstrating consistent effects of movie type, there was tremendous variability in the responses to individual movies across every region analyzed, variance that was reproduced between independent subject groups and across individual subjects. Hemispheric specialization, changes in regional network membership, and a stereotyped evolution of whole brain activity were also observed across subjects. Taken together, the results suggest that dynamic social stimulus conditions, despite the seemingly uncontrolled nature of the task, evoke highly consistent and time-locked brain activity that may be leveraged to better probe large-scale brain patterns.