Direct comparison of visual cortex activation in human and non-human primates using functional magnetic resonance imaging

Publisher Summary This chapter presents the direct comparison of visual cortex activation in human and nonhuman primates using functional magnetic resonance imaging. fMRI has revolutionized in vivo brain imaging allowing safe, noninvasive mapping of areas of functional neuronal activation in response to a specific task or stimulus. The signals measured with fMRI arise from a complex interaction of regional changes in local cerebral blood flow, blood volume, and oxygen saturation in response to changes in neural activity. For best signal to noise and contrast to noise in the MR image, it is important to optimize the pulse sequence for the relaxation parameters of the tissues of interest. The field strength dependency of the relaxation rates means that imaging sequence parameters should be optimized at a higher field to account for this. A number of anesthetic combinations have been proposed for primate fMRI. The optimal choice of agents depends on the area of cortex under investigation. It is found that unfolding of the sulcal architecture allows the neocortex to be represented as the smooth surface of an idealized balloon-like inflated brain. The retinotopic mapping in monkey and human visual cortex is also elaborated in this chapter.