The Snyder laboratory studies small circuits underlying cognition in the non-human primate model. Currently, the lab has projects involving spatial representation, memory and movement; eye-hand and bimanual coordination; and correlation-based functional connectivity. In the past the lab has worked on topics including effector-selective circuits underlying movement, cognitive switch costs, and neuronal correlates of rewards.
Spatial representation and memory
How are locations in space are represented in the cerebral cortex, and how those representations are used to guide eye and arm movements. More generally, how is sensory spatial information transformed into commands for movement? And, given a system in which this occurs, how can we analyze that transformation?
Parietal cortex has long been implicated in the transformation of visual sensory information into motor commands. A patient with unilateral parietal damage may ignore objects in one half of the world, clothe only half of their body or eat from only half of their plate. Spatial memory is affected, and there are often motor deficits as well. In order to understand the role of the parietal cortex in representing space and subserving movement, we record from individual neurons in macaque monkeys while they perform complex visuo-motor tasks. The animals are trained to look at and reach for colored spots of light – a monkey video game. We ask how the locations of these spots are represented by neural activity in the brain. What frame of reference is used? Is there a single, generic representation or multiple special purpose representations? How is spatial information from other sensory systems combined with visually-derived information? How does the nature of the task, and what the animal intends to do, affect parietal processing? Is parietal cortex specifically involved in the learning of new sensory-motor mappings? How do rewards affect processing?
Frontal cortex has long been implicated in spatial memory. The lab has been asking whether those memories are effector-specific or effector-general, and what are the computational principles underlying the actual circuits subserving memory.
Eye-hand and bimanual coordination: We easily combine movements of our two arms and eyes in order to manipulate objects in the world. What circuits are responsible for this coordination? To what extent does each hemisphere control a single arm, with communication across the hemispheres subserving bimanual coordination? What are the patterns of eye movements that accompany arm movements to two different locations, and is there anything special about the circuitry driving those movements?
Correlation-based functional connectivity. Resting state functional connectivity using fMRI has greatly advanced our understanding of brain architecture. We still do not know, however, exactly what drives these correlations in blood oxygen levels and whether the correlations play an important role in cognition. The lab recently developed oxygen polarography so that we can simultaneously record oxygen across multiple brain networks, LFP and spiking activity. The lab has learned much about the manifestations of functional connectivity correlation in these modalities, and are begin to put together a mechanistic understanding of these processes.
- Mooshagian E, Holmes CD, Snyder LH. Local field potentials in the parietal reach region reveal mechanisms of bimanual coordination. Nature Communications. 2021; 12(1):2514. doi: 10.1038/s41467-021-22701-3.
- Papadimitriou C, Holmes CD, Snyder LH. Primate spatial memory cells become tuned early and lose tuning at cell-specific times. Cerebral Cortex. 2021; 31(9):4206-4219. doi: 10.1093/cercor/bhab079.
- Mooshagian E, Wang C, Holmes CD, Snyder LH. Single units in the posterior parietal cortex encode patterns of bimanual coordination. Cereb Cortex. 2018; 28(5):1549-1567.
- Papadimitriou C, White RL 3rd, Snyder LH. Ghosts in the machine II: Neural correlates of memory interference from the previous trial. Cereb Cortex. 2017; 27(4):2513-2527.
- Bentley WJ, Li JM, Snyder AZ, Raichle ME, Snyder LH. Oxygen level and LFP in task-positive and task-negative areas: Bridging BOLD fMRI and electrophysiology. Cereb Cortex. 2016; 26(1):346-57.
- Patel GH, Yang D, Jamerson EC, Snyder LH, Corbetta M, Ferrera VP. Functional evolution of new and expanded attention networks in humans. Proc Natl Acad Sci U S A. 2015; 112:9454-9.
- Li JM, Bentley WJ, Snyder AZ, Raichle ME, Snyder LH. Functional connectivity arises from a slow rhythmic mechanism. Proc Natl Acad Sci U S A. 2015; 112:E2527-35.
- Liu YQ, Yttri EA, Snyder LH. Intention and attention: different functional roles for LIPd and LIPv. Nature Neurosci. 2010; 13:495-500.
- Stoet G, Snyder LH. Neural correlates of executive control functions in the monkey. Trends Cogn Sci. 2009; 13(5):228-34.
See a complete list of Dr. Snyder’s publications on PubMed.
1982, AB, English Princeton University
1992, MD, Medicine University of Rochester
1992, PhD, Physiology University of Rochester
1998-1999 Washington University/Howard Hughes Medical Institute Award
1998-2000 Sloan Foundation Research Fellowship
2001 Klingenstein Fellow
2000-2024 National Eye Institute Investigator
2004 EJLB Foundation Scholar Research Programme Award Recipient
2009-2019 National Mental Heath Institute Investigator
2012-2017 Co-Director, Washington University Neuroscience Program
2014-2019 Editorial Board, Journal of Neurophysiology
2015-2018 Program Committee, Society for Neuroscience