Correlation of activation sizes between lateral geniculate nucleus and primary visual cortex in humans

It is well established that the lateral geniculate nucleus (LGN) and the pr imary visual cortex (V1) are retinotopically organized. This similarity is expected to reflect a correlation of activation sizes between V1 and LGN du ring visual stimulation. However, it is a challenge to determine this funct ional correlation experimentally in the human brain using most neuroimaging techniques due to their low sensitivity for detecting small LGN activation in the thalamus. The purpose of this study was to examine the functional c orrelation of activation sizes between LGN and V1 during fullfield and hemi field visual stimulation using a large visual field and high-resolution fMR I technique at 4 Tesla. The correlation was determined by comparing the V1 and LGN activation size ratios between the left and right hemispheres of th e same subjects. The results reveal 1) a linear correlation of functional a ctivation size ratio between LGN and V1 with a correlation coefficient of 0 .96, and 2) the capability of fMRI for quantifying spatial correlation betw een cortical and subcortical activation. Magn Reson Med 45:202-205, 2001, ( C) 2001 Wiley-Liss, Inc.