Wednesday, October 29, 2014

Elizabeth Phelps

CNS seminar Tuesday November 4th at noon, 3rd floor McGill Hall conference room (Psychology Dept)

Changing Fear


Animal models of fear learning provide a basis for understanding human fears.  This research has demonstrated that the amygdala is necessary for the acquisition, storage and expression of fear learning.  This talk will explore how the neural mechanisms identified in animal models are consistent with human brain function and extend this research to the complex learning situations more typical of human experience.  I will first describe how the mechanisms of simple associative fear learning extend to the social acquisition of fear in humans.  I will then focus on how fear, once acquired, can be diminished.  Extinction and emotion regulation, techniques adapted in cognitive behavioral therapy, can be used to control fear via inhibitory signals from the ventromedial prefrontal cortex to the amygdala.  One drawback of these techniques is that fears are only inhibited and can return, with one factor being stress.  A more lasting means to control fear may be to target the fear memory itself through influencing reconsolidation.  I will present evidence suggesting that the behavioral interference of reconsolidation in humans persistently inhibits fear and diminishes involvement of the prefrontal cortex inhibitory circuitry.    

Sunday, September 28, 2014

David Jentsch

CNS seminar Tuesday October 7th at noon, 3rd floor McGill Hall conference room (Psychology Dept)

Title: Reward, interrupted: Inhibitory control and its relevance to addictions

Professor of Psychology

Abstract: Amongst the biobehavioral risk factors for drug misuse, abuse and dependence, particular attention has been paid to impulsivity: a trait-like proclivity to engage in excessive reward pursuit or consumption. Impulsivity may result from unusually strong motivational urges to obtain the reward and/or difficulty with reasoning about the consequences of, or suppressing, reward-related behaviors. High levels of impulsivity segregate with preclinical and clinically-impairing drug use in humans, are effects of experience with stimulant drugs of abuse in animal models and are reported to predict susceptibility for relatively greater drug self-administration in both humans and animal models. This talk will feature behavioral pharmacological, neuroimaging and genetic studies that reveal the crucial role for deficient dopamine D2-receptor mediated transmission in inhibitory control impairments. It will highlight how systems genetics approaches can reveal new relationships between biological mechanisms and addiction-related susceptibility phenotypes, including impulsivity.

Tuesday, May 13, 2014

Tom Hnasko

Tuesday 20th May @noon
Tom Hnasko

Midbrain dopamine and glutamate neurons in behavioral reinforcement and beyond.

Dopamine neurons in the ventral tegmental area (VTA) have been well characterized and are potent modulators of reward seeking.  But in addition to dopamine neurons, the VTA contains populations of GABA and glutamate neurons, some of which co-release dopamine.  Recent advances have highlighted divergent behavioral roles for discrete VTA circuits based on transmitter heterogeneity and projection target.  I will describe our recent work aimed at defining the contribution of glutamate-releasing neurons in the VTA to mesolimbic circuit function using conditional knockout and optogenetic approaches.

Monday, April 28, 2014

Ed Connor Seminar Postponed

The CNS seminar on Tuesday with Ed Connor has been postponed until May 27th.

Thursday, April 24, 2014

Ed Connor

Tuesday, April 29th @Noon
Crick Conference Room

Ed Connor
Mind/Brain Institute
Johns Hopkins University

A channel for 3D environmental shape in ventral pathway visual cortex

We use adaptive stimulus algorithms to study high-level shape processing in the final stages of the monkey ventral pathway in IT (inferotemporal cortex). IT is conventionally treated as a single, homogeneous region dedicated to object vision, but connectivity analysis reveals anatomically distinct channels, through ventral superior temporal sulcus (STSv) and dorsal/ventral inferotemporal gyrus (TEd, TEv). We studied shape processing in the STSv and TEd channels with evolving 3D abstract shapes ranging in scale and topology from small, closed, bounded objects to large, open, unbounded environments (landscape-like surfaces and cave-like interiors). In STSv, most neurons were more responsive to objects, as expected. In TEd, surprisingly, most neurons were more responsive to 3D environmental shape. Previous studies have localized visual “place” information to posterior cortical modules. Our results show it is also channeled through the anterior ventral pathway, where object and environmental shape information could be integrated to support scene vision.

Friday, April 18, 2014

Mike Wehr

Tuesday, April 22nd 12pm

Mike Wehr
Dept of Psychology
University of Oregon

What does inhibitory circuitry do in auditory cortex?

In the past decade we've learned a great deal about the broad roles of synaptic inhibition in auditory cortex, but little is known about the functions of specific subtypes of inhibitory interneurons. I'll tell you about our recent work on specific interneuron types (mainly parvalbumin-expressing cells, but also somatostatin-expressing cells), and how they affect auditory receptive fields, perception, and learning.

Thursday, March 27, 2014

Robert Bilder

Research Domains Criteria: Can We Build Models from Genome to Syndrome?

Robert Bilder, PhD

Recent initiatives aim to change the current diagnostic taxonomy of mental disorders, replacing this with better biologically validated dimensions. The NIMH Research Domains Criteria Initiative (RDoC) consensus meetings have operationalized target dimensions for cognitive systems (attention, perception, working memory, declarative memory, language, and cognitive [effortful] control), positive and negative valence systems, systems for social processes, and arousal and regulatory systems. The RDoC initiative explicitly defines constructs (domains) that span many levels (units) of analysis from basic molecular genetic through intermediate levels of measurement involving molecules, cells, circuits, physiology, and behavior, and finally to self-reports.  By specifying measures at different levels, RDoC implies theoretical models of associations across levels. The representation of the RDoC matrix elements (comprising domains intersected with levels) does not specify the precise nature of associations across levels, but the theoretical models that underlie selection of measures involve deterministic links to connect levels. Existing evidence, however, generally falls short of specifying causality across levels, so the implied structures lack validation, and appropriate targets for intervention remain underspecified. Examples from the RDoC “Working Memory” constructs are used to illustrate both challenges and opportunities. There is so far no validated causal path specifying traversals across levels from “genome-to-syndrome,” but selected pairwise links from level to level enable hypotheses about domain-based interventions. What kinds of informatics infrastructure, conventions for data aggregation and modeling across studies, and novel experimental designs will best support the development of evidence-based target specification?  We will describe a neural circuit description framework that reflects an effort to bridge some current gaps. What experimental evidence would persuade us that some of the manifold paths from genome to syndrome are true? We will describe a recently initiated project that aims to integrate EEG, MRI, cognitive and higher-level behavior to better specify these multi-level traversals.

Wednesday, March 5, 2014

Nicole Rust

CNS Seminar
Tuesday, March 11th

Nicole Rust
Dept of Psychology
University of Pennsylvania

The neural mechanisms involved in finding visual targets

Abstract: Finding visual targets requires our brains to flexibly compare working memory information about what we are looking for with visual information about what we are looking at to produce signals that indicate when we have found a “target match”. To investigate how target match signals are computed, we recorded the responses of neural populations in inferotemporal (IT) and perirhinal (PRH) cortex as subjects performed a task that required them to find targets within sequences of distractors. Our results suggest that target match signals are computed via a two-stage process in which visual and working memory signals are first combined to produce a largely nonlinearly separable or “tangled” IT representation of whether a target is in view, followed by “untangling” computations in perirhinal cortex that produce a target match representation that is more accessible to a linear population read-out. These perirhinal untangling computations are well-described by a linear-nonlinear (LN) functional model analogous to the well-known Energy model for V1 complex cells, consistent with suggestions that a generalized canonical computational framework may be useful for understanding signal processing throughout the brain.

Wednesday, February 19, 2014

Mimi Liljeholm

Neural bases of goals and habits
Crick, Tuesday, Feb 25th

Mimi Liljeholm
UC Irvine
Dept Cognitive Science

Two distinct strategies have been proposed to support action selection in humans and other animals: 1) a goal-directed strategy that generates decisions based on deliberate evaluation of the consequences of actions, and 2) a habitual strategy that relies on a more reflexive elicitation of actions by environmental stimuli.  Although considerable evidence has substantiated this theoretical distinction, very little is still known about what factors induce the use of one strategy over the other and how the two strategies are respectively implemented by the human brain.  In this talk I will present behavioral and functional neuroimaging (fMRI) data in support of the outcome divergence hypothesis – the notion that shifts between decision strategies are driven by the degree to which alternative actions yield distinct outcomes.  I will show that striatal and cortical BOLD activity discriminates between conditions of high and low outcome divergence, predicts individual differences in habitual performance, and does so differentially across the development versus deployment of goal-directed and habitual behavioral control.  Moreover, I will show that many of these effects are preserved across experiential and vicarious learning domains. Taken together, my results indicate a broad division between neural systems mediating the processing of stimulus-response and action-outcome relationships.