Study of Post-stimulus BOLD Undershoots between Lateral Geniculate Nucleus and Primary Visual Cortex in Cat Brain
Zhu X, Zhang Y, Chen W, Zhang N, Park J
CMRR, Radiology Department, University of Minneasota Medical School
One well observed phenomenon in the fMRI study of visual stimulation is a prolonged post-stimulus BOLD undershoot in the activated visual cortex (V1) although whether the undershoot is due to the delayed CBV or CMRO2 recovery compared to that of CBF is still under debated. It is interesting to examine if the same phenomena also exists in the sub-cortical lateral geniculate nuclei (LGN), which is the first stage for processing visual information. We have conducted an fMRI study using a cat model and flicking visual stimulation to examine the BOLD undershoots in both LGN and V1. We only observed undershoot in V1 but not in LGN indicating the dissociation of BOLD dynamics between them.