OBJECTIVE: We aimed to probe for regional cerebral effects of S-ketamine on in vivo GABA-A-receptor binding in healthy human subjects. METHODS: We investigated I-123-iomazenil SPECT before, during and after administration of S-ketamine in a blinded placebo-controlled study design (n = 12 in both groups). Analyses of SPECT were performed with voxel-based statistical parametric mapping (SPM), and...