LATERAL GENICULATE ACTIVATIONS CAN BE DETECTED USING INTERSUBJECT AVERAGING AND FMRI

Applications of fMRI in functional brain imaging are mainly confined t o single subject designs, prohibiting the assessment of subject or gro up by condition interactions (i.e., differential activations) or areas of conjoint activation, In this paper a framework for fMRI group desi gns, using statistical parametric mapping, is introduced, It is genera lly believed that intersubject averaging, which requires spatial norma lization and smoothing, will decrease the effective spatial resolution of fMRI or its sensitivity, A subcortical activation of the lateral g eniculate nucleus (LGN) was therefore chosen to demonstrate the feasib ility and power of intersubject averaging in the context of fMRI. Seve n volunteers were studied, while looking at a blank screen or radially moving dots, LGN activation was demonstrated in all single subject an alyses and in the group analysis.