Sepideh Sadaghiani, Assistant Professor of Psychology, Neuroscience, & Bioengineering at Illinois, lectured on “The functional connectome across temporal scales” at 4:00 pm in 2269 Beckman Institute and on Zoom October 26, 2022. Ryan Miller, MBM trainee and PhD candidate in Chemical & Biomolecular Engineering, gave an introduction.
The lecture was free and open to the public courtesy of the Miniature Brain Machinery Program.
The view of human brain function has drastically shifted over the last decade, owing to the observation that most brain activity is intrinsic rather than driven by external stimuli or cognitive demands. Specifically, all brain regions continuously communicate in spatiotemporally organized patterns that constitute the functional connectome, with consequences for cognition and behavior.
In this talk, I will argue that another shift is underway, driven by new insights from synergistic interrogation of the functional connectome using different acquisition methods. The human functional connectome is typically investigated with functional magnetic resonance imaging (fMRI) that relies on the indirect hemodynamic signal, thereby emphasizing very slow connectivity across brain regions. Conversely, more recent methodological advances demonstrate that fast connectivity within the whole-brain connectome can be studied with real-time methods such as electroencephalography (EEG).
Our findings show that combining fMRI with scalp or intracranial EEG in humans, especially when recorded concurrently, paints a multiplex picture of neural communication across the connectome. Specifically, the connectome comprises both fast, oscillation-based connectivity observable with EEG, as well as extremely slow processes best captured by fMRI. While the fast and slow processes share an important degree of spatial organization, these processes unfold in a temporally independent manner.
Our observations suggest that infraslow connectivity (measured in fMRI) and rapid connectivity of various frequency bands (measured by EEG) constitute multiple dynamic trajectories through a shared state space of discrete connectome configurations. The multitude of flexible trajectories may enable any given brain region to concurrently connect to multiple sets of other regions.
About the Sadaghiani Lab:
Distant brain regions are in constant communication with each other. This communication, also called functional connectivity, is foundational to all cognition. Functional connectivity is spatially organized into many large brain networks. But how this network organization is maintained and modulated in the service of flexible cognition is poorly understood. Sepideh Sadaghiani’s lab is studying connectivity and cognitive functions of large-scale brain networks. Her lab is most interested in networks involved in cognitive control functions such as alertness and attention (cognitive control networks).
One research line of the lab seeks to delineate the function of different cognitive control networks. This research investigates how cognitive control networks modulate processes in “lower-order” brain areas such as perception in sensory cortices.
Another research line focuses on the functional role of intrinsic (spontaneous) network activity. Neural activity and communication across brain networks are continuously ongoing independent of external stimuli or tasks. Sadaghiani’s research aims at understanding why this intrinsic activity and functional connectivity exists and how it affects behavior.
Sepideh Sadaghiani’s lab combines various techniques to address these questions in the human brain including functional magnetic resonance imaging (fMRI), electroencephalography (EEG), simultaneous EEG-fMRI and genetic analyses in healthy participants and neurological patients.