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Rachel Denison, An Vu, David Feinberg, Michael Silver; fMRI of the magnocellular and parvocellular subdivisions of human LGN. Journal of Vision 2012;12(9):77. doi: 10.1167/12.9.77.
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© ARVO (1962-2015); The Authors (2016-present)
Parallel processing in the visual system is particularly well-defined in the lateral geniculate nucleus (LGN) of the thalamus, which has distinct anatomical subdivisions with complementary functional properties. In particular, the magnocellular subdivision of the LGN is selective for high temporal frequencies and low spatial frequencies, while the parvocellular subdivision is selective for low temporal frequencies, high spatial frequencies, and color. Despite their distinctive functional characteristics and critical position in the visual processing pathway from retina to cortex, the subdivisions of the LGN have rarely been studied in humans. Research has been limited by the difficulty of measuring neural responses from LGN subdivisions due to their small size and their location deep in the brain. We used high-resolution fMRI, combined with presentation of visual stimuli designed to differentially activate magnocellular and parvocellular neuronal responses, to functionally localize the magnocellular and parvocellular subdivisions in humans. Preliminary results suggest that specific combinations of spatial, temporal, luminance contrast, and chromatic stimulus factors selected to preferentially evoke BOLD responses in either magnocellular or parvocellular layers allow functional localization of these subdivisions. The ability to reliably localize the magnocellular and parvocellular subdivisions of the LGN in humans will facilitate investigations into the role of these specialized early visual pathways in human visual perception, attention, and cognition.
Meeting abstract presented at VSS 2012
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