Using a computerized image processing method, the metabolic activity of the unfolded molecular and pyramidal layers of the piriform cortex was studied in rats during odorous stimulation. Animals were either intact or had sustained a bilateral transection of the lateral olfactory tract. 2-DG labelling was observed in corresponding areas across these two layers. No spatial pattern of 2-DG uptake could be seen in correlation with the odorant quality. These results are discussed with respect to the known anatomical and functional properties of the piriform cortex.