Colloquia

Spring 2019

Banishing Ghosts of Process from the Neural Machinery of Human Memory: A Representational Account of Cognition

April 18, 2019

12–1:30 p.m., International Lounge, Usdan

Dr. Rosie Cowell, University of Massachusetts, Amherst

Abstract:  Accounts of cognition often assume that the brain is organized along lines of cognitive process, for example, with recollection mediated by one neural substrate and familiarity by another. We argue that cognitive processes – introspectively-identifiable mental events like recollection – are inadequate labels for characterizing neural mechanisms, because they conflate lower-level components of the mechanisms we seek to identify. Recollection involves both a neurocomputational operation (pattern completion) and a neural representation (high-dimensional, associative content). To uncover memory's mechanisms, we must decompose cognitive processes into their operations and representations, asking how each separately, and their interaction, gives rise to neural and behavioral phenomena. I will present theoretical and empirical work ‒ including connectionist simulations and fMRI data ̶ that implies we can replace process-based accounts of memory with a representational account. In other words, rather than explaining what different brain regions do by appeal to cognitive processes (e.g., recollection happens in hippocampus and familiarity in neocortex), we should appeal to representational content (high-dimensional representations are supported by hippocampus and lower-dimensional representations by neocortex).

"Measuring and overcoming cognitive challenge in speech comprehension"

March 14, 2019

12–1:30 p.m.

  • Dr. Jonathan Peelle, Washington University in St. Louis

International Lounge, Usdan

Abstract: How does acoustic clarity affect the way our brains process speech, and how might this change with adult aging? I will review data from behavioral and brain imaging studies that speak to the added cognitive demands associated with acoustic challenge. Findings support a shared resource framework of speech comprehension in which domain-general cognitive processes are required for both auditory and linguistic processing. The specific patterns of neural activity depend on the difficulty of the speech being heard, as well as the hearing and cognitive ability of each individual listener. I will also talk about some preliminary work looking at how we might be able to help listeners compensate for cognitive challenges and improve their understanding of what they are hearing.

"Memory networks in the human brain"

March 7, 2019

12–1:30 p.m.

  • Dr. Mike Kahana, UPenn

International Lounge, Usdan

Abstract: Human memory function is highly variable, fluctuating between periods of high and low performance even within a given person. Neurosurgical patients with indwelling electrodes present a unique opportunity to study the neural correlates of this variability and to define both the features of neural activity at a given brain location and the functional connections between brain regions that predict variability in memory encoding and retrieval. Here, I will describe our recent efforts to characterize brain networks that support memory via correlative (passive neural recording) and causal (direct electrical stimulation) approaches. Throughout the brain, we find that low-frequency networks exhibit reduced local power but stronger functional connectivity during successful episodic encoding and retrieval. Furthermore, many canonical memory regions emerge as hubs of such low-frequency connections, including the lateral frontotemporal cortices, the parahippocampal gyrus – and within it – the entorhinal cortex. High-frequency bands (i.e. gamma, 30+ Hz) almost exclusively exhibit desynchronization during successful memory operations. We recently extended these correlative studies and used intracranial stimulation to ask whether functional connections imply causality. We confirmed that electrical stimulation evokes increases in theta power at remote regions, as predicted by the strength of low-frequency functional connections. This relation was strongest when stimulation occurred in or near white matter. These findings demonstrate the importance of low-frequency connectivity to episodic memory, integrating these findings over spatial scales and through causal and correlative approaches.

Developmental tuning of action selection

January 17, 2019

12–1:30 p.m., International Lounge, Usdan

Dr. Catherine Hartley, NYU

Abstract:  Computational reinforcement learning models provide a framework for understanding how individuals can evaluate which actions are beneficial and which are best avoided. To date, these models have primarily been leveraged to understand learning and decision-making in adults. In this talk, I will present studies characterizing developmental changes, from childhood to adulthood, in the cognitive representations and computations engaged to evaluate and select actions. I will discuss how these changes may optimize behavior for an individual’s developmental stage and unique life experiences.

Fall 2018

The nose is not enough: re-evaluating our typology of the chemosensory systems

September 27, 2018

12–1:30 p.m.

  • Dr. Donald Katz, Brandeis University

International Lounge, Usdan

Social by default: Outlining the social psychological functions of the default network

November 1, 2018

12–1:30 p.m.

  • Dr. Meghan Meyer, Dartmouth

Location: Levine-Ross, Hassenfeld

Functional Imaging of the Human Brain: A Window into the Architecture of the Mind

November 29, 2018

12–1:30 p.m.

  • Dr. Nancy Kanwisher, McGovern Institute for Brain Research at MIT

Location: International Lounge, Usdan

Previous Colloquiums

Special Colloquium: How do Culture and Race Impact the Brain, Body, and Behavior?

January 25, 2018

12–1:30 p.m.

Featuring talks by:

  • Dr. Valerie Purdie Greenaway, Columbia University

  • Dr. Jiyoung Park, University of Texas at Dallas

Location: Rapaporte Treasure Hall, Goldfarb Library

A special talk sponsored by the Chief Diversity Officer, Provost, and the Dean of Arts and Sciences, Heller, and IBS.

A Diversity, Equity and Inclusion Program

Exercising Your Brain and Mind

February 8, 2018

12–1:30 p.m.

  • Arthur F. Kramer, PhD, University of Illinois at Urbana-Champaign

Location: Alumni Lounge, Usdan

Learning and Attention in Infants: The Importance of Prediction in Development

March 22, 2018

12–1:30 p.m.

  • Dr. Richard N. Aslin, Yale University

Location: Luria 1-3, Hassenfeld

Age Effects on the Neural Processing of Value-Based Decisions

March 29, 2018

12–1:30 p.m.

  • Dr. Joshua O. Goh, National Taiwan University

Location: Luria 1-3, Hassenfeld