The D.O. Hebb Lecture Series was initiated in 1989 in memory of Hebb’s contribution to the science of behavior. Invited speakers of the D.O. Lecture series are scientists who have made distinguished empirical contributions to basic research in all areas of psychology. It is currently made possible by the generous support of the D.O. Hebb Endowment Memorial Fund.
Most speakers also deliver an informal seminar held in the morning.
All main lectures from 3.30 - 5:00 pm. Lectures are followed by a Wine and Cheese Reception in the Atrium of the Bellini Life Sciences Complex (3649 Promenade Sir William Osler). Admission is free.
2018 - 2019 Hebb Lectures
September 21, 2018 - Location: MCMED 522
Department of Human Development and Quantitative Methodology, University of Maryland, College Park
Professor, Measurement, Statistics and Evaluation Program
Title: Measurement modeling in psychology: construct validation in nested settings
Abstract: In social science research, latent constructs are often inferred from sets of items intended to measure those constructs. When data are collected in multilevel settings (e.g., students within schools or children within families) the construct of interest might exist at multiple levels. In this talk, I will consider how researchers might approach construct meaning and construct validation when working with data that are nested. I will first present extensions of the single-level confirmatory factor analysis (CFA) approach to a simple multilevel CFA (MCFA) when data are nested. I then will wade through the murky conceptual landscape that exists when considering measurement models at both the individual and cluster levels and introduce conceptual distinctions between constructs across levels and among different types of constructs at the cluster level. Specifically, I will discuss how items might be used to measure “shared” and “configural” cluster-level constructs. While shared constructs would reflect a shared element of the cluster (wherein individuals would be viewed as exchangeable within a cluster), configural constructs represent aggregation of characteristics of the individuals within the cluster. Additionally, an often-overlooked characteristic of configural constructs would be an evaluation of differential dispersion within clusters. Although empirical data may show cluster dependency, theoretically the construct may be an individual level one only but the data reflect a spurious intraclass correlation (ICC) or a spurious contextual effect due to measurement non-invariance. The appropriate CFA modeling approach will depend on the hypothesized constructs to be measured; examples based on empirical data and simulated data will be shown.
October 12, 2018 - Location: MCMED 522
Department of Psychology, McGill University
Title: Music-making, social interaction, and group synchrony
Music-making is a fundamentally human experience. Music exists across human cultures and across our lifespan. Its uses include enjoyment, social bonding, and mood regulation. Our work in the cognitive neuroscience of music addresses how and why musical sound influences our brains and bodies. I will describe experiments with musicians and nonmusicians singing, moving, and synchronizing with a beat as we investigate how individual differences or “signatures” in music-making affect electrophysiology and cognition, and why a physical model of coupled oscillations among individuals predicts group synchrony. These findings shed light on the relationship of music-making to social interaction and health.
Caroline Palmer is a Professor in the Department of Psychology at McGill University. Internationally recognized for her interdisciplinary research in auditory cognition, Dr. Palmer holds the Canada Research Chair in Cognitive Neuroscience of Performance and she directs the NSERC-Create training network in Complex Dynamics of Brain and Behaviour. Her pioneering work uncovered temporal relationships among interpretation, expression, emotion and meaning in music performance and speech prosody. Those findings have altered our understanding of how complex acoustics communicate information among musicians, speakers, and listeners. As founder of two national training networks, Palmer has translated laboratory science into industrial and health-care workplace experience across Canada and North America.
November 9, 2018 - Location: MCMED 522
Scott Waddell, Ph.D.
Professor of Neurobiology, Wellcome Principal Research Fellow
Center for Neural Circuits & Behaviour
Morning seminar (10:00am, MC 461):
Title: Mechanisms of Memory Formation and Re-evaluation in Drosophila
Memory is a fundamental property of the brain. Drosophila can learn to associate odors with reward or punishment. The resulting memories direct odor-specific approach or avoidance behaviors. Recent progress has revealed a straightforward model for learning in which specific dopaminergic neurons assign valence to odor representations in the neural ensemble of the mushroom bodies. Dopamine directed synaptic depression alters the route of odor-driven activity through the mushroom body output network. This learned configuration guides relevant behaviour. Following retrieval, these memories can be updated through the processes of extinction and reconsolidation. Our latest studies provide mechanistic neural circuit-based explanations for these fascinating and conserved phenomena.
Afternoon lecture (3:30pm, MCMED 522):
Title: Dopaminergic Control of Motivated Behaviour in the Fruit Fly
Motivational systems provide some of the control that allows animals to seek resources at the appropriate time. Behavioral expression of food-associated memory in fruit flies is constrained by satiety and promoted by hunger. Expression of water- memory is similarly dependent on thirst. We have uncovered some of the key neural elements of the respective motivational control mechanisms. In the hungry and thirsty conditions, broadly released neuropeptides inhibit the function of anatomically-restricted dopaminergic neurons to release memory expression. In the case of hunger, dopamine alters the level of GABA-ergic feedforward inhibition within the fly’s mushroom bodies. Directly stimulating or inhibiting the relevant neurons in each layer of the circuit can promote memory performance in satiated flies. Normal state-dependent control therefore emerges from a neural architecture of hierarchical inhibition. I will also discuss our most recent work, in which we have broken the system and formed memories that lead to compulsive behavior.
November 30, 2018 - Location: Rutherford Physics Building, Room 112
(Address: 3600 University Street)
(Macnamara Lecture - Reception to follow at 2001 McGill College)
Department of Psychology
Title: Preschoolers' changing minds
Abstract: During the preschool years, children’s explicit understandings of the world go through dramatic changes. I will review the work that we have done investigating how neurobiological factors interact with particular kinds of experience to promote change in children’s naive psychological understandings, or their “theory of mind.” These findings provide evidence that neurodevelopmental factors act as a rate-limiting factor on the extent to which preschoolers can use their experiences to drive conceptual change. However, I will also present some recent evidence from our lab suggesting that, at least with respect to theory of mind understandings, biology and experience might be even more tightly integrated. Specifically, some kinds of experience may induce biological changes that support theory of mind reasoning both transiently and in the long term. Together, these findings help us to understand how deep connections between biology and experience shape conceptual development during the preschool years.
February 1, 2019 - Location: MCMED 522
(Reception to follow at 2001 McGill College)
Department of Psychology, Columbia University,
New York, New York
Title: Emotional Brain Development and the Role of Early Experiences
Abstract: Human brain development is very slow, thus maximizing its chances of being influenced by environmental factors. Variations in early species-typical experiences, such as parental caregiving, reveal the profound effects on the development of neurocircuitry involved in affective learning and regulation (e.g., amygdala, hippocampus, medial prefrontal cortex). This talk will focus on both typical development as well as development following caregiver deprivation showing that early life early environments may influence development through learning as well as altering developmental pacing of this circuitry. These age-related changes will be discussed in terms of potential developmental sensitive periods for environmental influence.
April 5, 2019 - Location: MCMED 522
Department of Psychology, Carnegie Mellon University, Pittsburgh, PA
Title: Face and words recognition: Flip sides of the same coin?
Understanding the process by which the cerebral hemispheres reach their mature functional organization remains challenging. We propose a theoretical account in which, in the domain of vision, faces and words come to be represented adjacent to retinotopic cortex by virtue of the need to discriminate among homogeneous exemplars. Orthographic representations are further constrained to be proximal to typically left-lateralized language-related information to minimize connectivity length between visual and language areas. As reading is acquired, orthography comes to rely more heavily (albeit not exclusively) on the left fusiform region to bridge between vision and language. Consequently, due to competition from emerging word representations, face representations that were initially bilateral become lateralized to the right fusiform region (albeit, again, not exclusively). In this talk, I will summarize empirical evidence from a variety of studies (behavioral, evoked response potential, functional imaging) across different populations (children, adolescents and adults, left-handers and individuals with developmental dyslexia) that supports the claims that hemispheric lateralization is graded rather than binary and that this graded organization emerges dynamically over the course of development. Perturbations of this system either during development or in adulthood provide further insights into the principles governing hemispheric organization.
Title: A broader vision of object recognition: beyond ventral cortex
The neural correlates of object recognition are typically assumed to be under the purview of the ventral pathway of the cortical visual system. Decades of empirical studies using neuroimaging as well as single unit recording in awake behaving non-human primates have supported this conclusion. I will describe some recent studies from my lab that examine the nature of these ventral neural representations including investigations that permit the reconstruction of the images displayed to the observer using fMRI data acquired from ventral cortex. I will then go on to argue that signals associated with object recognition extend beyond ventral cortex and that representations in the dorsal visual pathway and even in subcortical regions are tuned to represent shape and identity properties of objects. I will describe several studies using fMRI and psychophysics in both normal and brain-damaged individuals that support the role of these other regions in the recognition of visual objects. I will suggest that objects are widely represented in the brain and the challenge is to understand the necessity and sufficiency of these representations.