MAGNETIC IMAGING IN HUMAN CLASSICAL-CONDITIONING

MAGNETOENCEPHALOGRAPHY (MEG) was recorded during aversive classical co nditioning in an attempt to elucidate the temporal coding of primary s omatosensory cortex (SI) activation previously found with positron emi ssion tomography. Four healthy volunteers participated in the experime nt. The reinforced conditioned stimulus was displayed on a screen for 2 s, and as it disappeared an unconditioned electric shock to the righ t middle finger followed. A control stimulus, not paired with a shock was also presented. With MEG, we observed a conditioned magnetic respo nse located in the SI. The conditioned response predated the shock pre sentation and is interpreted as evidence for functional control of noc iception mediated by corticothalamic projections