Functional MRI Speaker Series

Most years our laboratory provides opportunities for our users and researchers to learn about advances in fields related to Functional MRI.

No RSVP is required. To be added to the Speaker Series email group and receive notifications about the speaker series talks, please contact the Administrator.

Video of past presentations can be accessed here.

Academic Year 2018-2019 Speaker Series

October 9, 2018

Dr. Caterina Gratton, Northwestern University

Topic: States and Stability in Human Brain Networks

Humans can easily and flexibly accomplish a wide variety of tasks, with different perceptual and cognitive demands, depending on their goals. This ability appears to depend on the coordinated interactions between brain regions that are organized into large-scale networks. In my research, I am interested in characterizing how human brain networks are organized, how they contribute to the myriad goal-directed behaviors that are essential to our daily lives, and how these processes break down. In my talk, I will present an overview of my research, highlighting three recent projects centered on understanding brain network organization and how it changes over different timescales. The first section will use dense measurements of brain networks from 10 individual subjects to examine how networks vary across individuals, days, and task states. In the second part of the talk, I will discuss how brain networks are affected by progressive neurodegeneration in Parkinson’s Disease. Finally, I will describe findings from a recent initiative into characterizing trait-like variation in brain networks. Jointly, these projects add to our understanding of brain organization and function, and how this organization contributes to complex behaviors.

March 12, 2019

Dr. Jessica Cohen, University of North Carolina Chapel Hill

Topic: Functional Brain Network Organization and Dynamics in Health and Disease

The brain’s ability to adaptively engage different functional networks in the face of a changing environment is an important characteristic that enables a wide variety of behaviors. The goal of my research program is to understand how distinct brain networks interact with each other and flexibly reconfigure when confronted with a dynamic environment, as well as how network integration contributes to individual differences in behavior in both health and disease. In my talk, I will first discuss adaptive reconfiguration of functional brain network organization in response to changes in cognitive demands, followed by a depiction of situations in which stable brain network organization is adaptive. I will end by describing how dysfunctional brain network organization in ADHD underlies symptoms and cognitive deficits. Together, this research provides evidence that the healthy brain systematically reconfigures to adapt to current demands, and that dysfunction in this dynamic network behavior underlies ADHD.

April 2, 2019

Dr. Thomas Liu, University of California San Diego

Topic: The Global Signal, Vigilance Fluctuations, and Nuisance Regression in Resting State fMRI

Resting-state fMRI (rsfMRI) is now a widely used method to assess the functional connectivity (FC) of the brain. However, the mechanisms underlying rsfMRI are still poorly understood. In this talk I will address several related aspects of the rsfMRI signal. The first is the global signal, which represents the whole brain average signal and has been widely used as a regressor for removing the effects of global variations in resting-state activity. I will discuss the controversy surrounding global signal regression and describe new approaches for minimizing global signal effects. A related topic concerns the origins of global activity in the brain. There is growing evidence that a considerable portion of this global activity arises from fluctuations in vigilance and arousal. I will discuss the recent findings in this area and discuss the implications for the analysis and interpretation of rsfMRI studies. Finally, I will describe recent empirical and theoretical work demonstrating the limitations of regression based methods that are widely used to minimize the effects of nuisance components in rsfMRI studies.

April 9, 2019

Dr. Morgan Barense, University of Toronto

Topic: Understanding memory disorders: At the level of cognitive process representational content?

How does perception of an object relate to subsequent memory for that object? A central assumption in most modern theories of memory is that memory and perception are functionally and anatomically segregated. For example, amnesia resulting from medial temporal lobe (MTL) lesions is traditionally considered to be a selective deficit in long-term declarative memory with no effect on perceptual processes. This view is consistent with a popular paradigm in cognitive neuroscience, in which the brain is understood in terms of a modular organization of function based on cognitive process. The work I will present offers a new perspective. Guided by computational modelling complemented with neuropsychology and neuroimaging, I will provide support for the notion that memory and perception are inextricably intertwined throughout the MTL, relying on shared neural representations and computational mechanisms. I will then describe how this new framework can improve basic understanding of cognitive impairments observed in Alzheimer’s disease, as well as guide development of new diagnostic procedures for those at risk for dementia.