Odor recognition memory in humans: role of right temporal and orbitofrontal regions

Odor memory was studied in 121 patients with unilateral cerebral excision from temporal, frontal, frontotemporal, or centroparietal areas, and 20 control subjects. Odors were presented birhinally, and half were named, to examine the effect of verbal labelling. Testing was by yes-no recognition immediately after presentation, 20 min later, and after 24 hr, using eight different targets and eight new foils each time. The results showed impairment only after excision from the right temporal or right orbitofrontal cortex. All groups showed significant forgetting over time, and verbalized odors were recognized more efficiently than unlabelled ones. The findings, suggesting a right hemisphere predominance in odor memory, support similar results for odor discrimination.