Our purpose was to evaluate the utility of functional MRI (fMRI) in the investigation of olfactory function. fMRI of the brain was performed on 12 healthy subjects and in 5 patients. Coronal sections were selected through the mid- to anterior temporal region of the brain. Significant activation was noted especially in the frontal and temporal lobes. Some of these activated regions corresponded to the orbitofrontal, entorhinal and pyriform cortical areas. Additional regions of activation were also observed in other areas of the frontal and temporal lobes. Imagination of smell produced less activation than active stimulation. Areas of negative activation were also noted in the frontal and temporal lobes. Patients demonstrated either abnormal patterns of activation, or no activation, depending on the nature of their dysfunction. These studies indicate that MRI may be used to demonstrate olfactory cortex activation.

The purpose of this study was to evaluate the feasibility of functional MRI (fMRI) in the investigation of transient global amnesia (TGA). MRI of the brain was performed on normal subjects and a patient with TGA. fMR images were obtained of left temporal and frontal regions of the brain. A 55-year-old woman was studied during a 6-h period of amnesia and again 2 weeks later, when memory had returned to normal. In all cases, memory testing was conducted during fMRI using a version of the Hopkins Verbal Learning Test. During TGA, the patient showed little or no activation during list learning or recognition testing. After her TGA had resolved, she demonstrated normal list learning and recognition. As in the healthy subjects, activation in the temporal region occurred during both list learning and recognition, whereas frontal activation was seen more often during recognition testing.