Opening Ceremonies and Keynote Address - Making Memories in Mice
Sheena Josselyn, Hospital for Sick Children (SickKids) and University of Toronto
Understanding how the brain uses information is a fundamental goal of neuroscience. Several human disorders (ranging from autism spectrum disorder to PTSD to Alzheimer’s disease) may stem from disrupted information processing. Therefore, this basic knowledge is not only critical for understanding normal brain function, but also vital for the development of new treatment strategies for these disorders. Memory may be defined as the retention over time of internal representations gained through experience, and the capacity to reconstruct these representations at later times. Long-lasting physical brain changes (‘engrams’) are thought to encode these internal representations. The concept of a physical memory trace likely originated in ancient Greece, although it wasn’t until 1904 that Richard Semon first coined the term ‘engram’. Despite its long history, finding a specific engram has been challenging, likely because an engram is encoded at multiple levels (epigenetic, synaptic, cell assembly). My lab is interested in understanding how specific neurons are recruited or allocated to an engram, and how neuronal membership in an engram may change over time or with new experience. Here I will describe data in our efforts to understand memories in mice.
The 30th Annual George A. Miller Prize in Cognitive Neuroscience (GAM) - Hippocampus: Action at a Distance
Lynn Nadel, Ph.D., University of Arizona
The hippocampal formation provides the core of a context-based memory system that enables actions at both spatial and temporal removes. It does this by creating representations of context – what O'Keefe and I labelled 'cognitive maps', that are critical to acting at a distance. Most simply, these internal maps allow organisms to act on the basis of entities (objects, people, goals, etc) that are at some distance, and not within visible, audible or olfactory range. Context representations support environment re-identification, allowing animals to correctly link up information gathered in the same environment over multiple occasions separated by significant temporal gaps. They support, as well, retrieval of contextually-appropriate knowledge, bringing information gathered in the past to bear on present behavior and future planning. My talk will review evidence in support of these assertions about the hippocampus, and consider various implications of its role in action at a distance.
The 13th Annual Fred Kavli Distinguished Career Contributions Award (DCC) - Focus through Time
Kia Nobre, Ph.D., Wu Tsai Institute and Department of Psychology, Yale University
The ability to focus on important and interesting signals is at the core of selective attention, driving its functions for anticipating, selecting, prioritizing, and gating information to support adaptive behavior. In my lecture, I will explore three notions of how the attentional focus has shifted through time over the recent decades, highlighting discoveries and contributions from our research group. (1) From a static starting point, focus became highly dynamic. Attention functions, from proactive anticipation to action preparation, ebb and flow according to predictable and relevant timings of events. We have learned that a growing variety of temporal structures - based on associations, probabilities, rhythms, and sequences – extracted over short periods to long-term memories – can fuel the dynamics of attention. (2) Focus transcended the present situation. In addition to modulating perception and action in the moment, focus applies internally to contents available only in the mind. Through focus, mental contents are selected, prioritized, and gated dynamically to enhance relevant retrieval and guide future-oriented behavior. (3) Over time, focus has acquired more dimensions and perspectives. Embracing temporal dynamics and considering the past to future domains, the treatment of focus is breaking away from simple dichotomies. A much richer field of investigation lies ahead, allowing us to understand the nature and role of focus as a fundamental cornerstone across the gamut of cognition.
Young Investigator Award Lectures
YIA 1: The neural circuit underlying subjective perception
Peter Kok, Ph.D., Wellcome Centre for Human Neuroimaging, University College London Queen Square Institute of Neurology, University College London
The way we perceive the world is strongly influenced by our expectations about what we are likely to see at any given moment. However, the neural mechanisms by which the brain achieves this remarkable feat have yet to be established. To understand the neural mechanisms underlying the interplay between sensory inputs and prior expectations, we need to investigate the way these signals flow at the level of cortical circuits, e.g. through the different cortical layers. Until recently, it was not possible to do this in non-invasive studies of humans, because the typical voxel size in fMRI is bigger than the full thickness of the cortex. I will discuss recent work in which we met this challenge by using fMRI at ultra-high field (7T) to obtain BOLD signals at very high resolution to disambiguate signals from the different cortical layers. This approach has allowed us to probe the neural circuitry underlying effects of expectation and subjective perception. I will also discuss the role of the hippocampus as a potential generator of top-down expectation effects in visual cortex, focusing on predictive stimulus representations in hippocampal subfields and informational connectivity with the visual cortex. Together, this work aims to shed new light on the neural circuitry underlying our perception of the world.
Insights from studying people with congenital sensorimotor deprivation
Ella Striem-Amit, Ph.D., Department of Neuroscience, Georgetown University Medical Center, Washington, DC.
What is the balance between nature and nurture in determining the function of cortical areas? A key way to answer this question is by studying people with congenital deprivation. What plasticity is evident when a brain area is deprived from birth of its typical input or outputs, and what can this tell us about cognitive representations? Furthermore, does deprivation affect every deprived brain similarly, or are plasticity patterns diverse across individuals? I will present a series of studies examining the role of sensory and motor experience and specific sensorimotor features in the neural representations of objects and actions. Combining evidence from studies of people born blind and people born without hands, I will show how plasticity in these individuals’ brains allows us to infer the cognitive abstractness of neural representations along the cortical hierarchies. Beyond broader patterns of plasticity, I will show evidence for a larger diversity of brain patterns in blindness and deafness, which opens new questions about differential developmental trajectories and functions for the deprived cortex, and how these may affect restoration of function on an individual level. Throughout, I will highlight the different ways that studying congenital deprivation across domains can illuminate the cognitive neuroscience of the typically developed brain.
