2023-2024 Psychology Department

Colloquium Speaker Series

presents

 Adam Steel

Postdoctoral Fellow

Dartmouth College

Mechanisms Underlying Perceptual and Mnemonic Interaction in the Brain

Natural behaviors require perceptual and mnemonic information to dynamically interact. For example, when navigating, we continuously exchange information about the current percept with our memory of the surrounding environment. What neural mechanisms allow perceptual and mnemonic representations to interact in the brain? Here, I address this question in the domain of visual scenes using fMRI. First, I describe a topographic dissociation between the brain areas supporting perception and memory of scenes. Specifically, a set of scene-memory related brain areas fall anterior and adjacent to areas involved in scene perception. These memory areas selectively co-fluctuate with the hippocampus during naturalistic scene understanding, constituting a bridge between perceptual and visuospatial representations. Second, using a combination of fMRI and immersive virtual reality, I show that these scene-memory areas uniquely process the extent of known visuospatial context currently outside of view, consistent with a role in jointly representing perceptual and mnemonic information. Finally, I show that a low-level coding mechanism, retinotopy, scaffolds the scene-perception and memory areas’ interaction, such that retinotopic populations in scene perception and memory areas exhibit retinotopically-specific opponent responses during bottom-up perception and top-down recall. Together, these studies provide a novel framework for understanding how perceptual and mnemonic information coexist and interact in the brain, and suggest that perceptual-grounded neural codes play an important role in structuring interregional interaction outside of sensory cortex.

Thursday, February 8, 2024

3:30pm

301 Gilmer Hall

2023-2024 Psychology Department

Colloquium Speaker Series

presents

Lauren DiNicola

Postdoctoral Fellow

Harvard University

Examining the Organization and Functions of Parallel Networks in the Human Brain 

Every day, we recall past experiences, consider others’ feelings, imagine future plans, and communicate. These cognitive abilities are hallmarks of our species, and all have been linked to regions of association cortex (furthest from primary sensory and motor areas). Association regions also show disproportionate evolutionary expansion and prolonged postnatal development in humans, making them intriguing targets for understanding the flexible forms of thought that emerge and mature as we grow. Recently, precision neuroscience techniques have revealed multiple interwoven networks within association zones. My work uses within-individual approaches to measure these networks with high anatomical precision and explore functional properties across tasks designed to dissociate and unpack cognitive processes. In this talk, I will describe our discoveries that multiple, parallel networks in human association cortex are distinctly specialized to support memory, social and language functions. Right next to these are additional distributed networks supporting domain-flexible functions, like cognitive control. All of these networks feature side-by-side regions, forming clusters in a repeating organization across the brain. These surprising results help revise our understanding of how interwoven networks support different facets of cognition and provide the foundation for new questions about how parallel organization arises in the cortex, which specific processes these networks support, and how functional roles might be sculpted across development, including during periods with high risk for psychopathology. 

Monday, February 19, 2024

12:30pm

390 Gilmer Hall