Figure legends
Figure 1: Patients wore a specialized 32-channel electroencephalogram monitoring device compatible with the MRI environment. MRI scans were performed with a 3T scanner using an 8-channel head coil. Odorants and odorless air were presented to patients via a nasal canula.
Figure 2: In all panels: control mean in blue, patients in another color and all error bars are SD. Scores at olfactory threshold(T), discrimination(D), and identification(I) using the sniffin sticks test. All patients were classified as anosmic on the olfactory function test. (Patient A: threshold 1, discrimination 6, identification 4, total 11; Patient B: threshold 1, discrimination 3, identification 4, total 8; Patient C: threshold 1, discrimination 5, identification 4, total 10; Patient D: threshold 1, discrimination 2, identification 3, total 6; Patient E: threshold 1, discrimination 4, identification 3, total 8; Patient F: threshold 1, discrimination 7, identification 4, total 12)
Figure 3: T2-weighted pre-contrast coronal section MRI scans. In normal patients, an olfactory bulb (yellow arrow) and sulci (yellow arrowhead) can be found. However, in patients A and B, the olfactory bulb (red arrow, orange arrow) and olfactory sulci (red arrowhead, orange arrowhead) could not be visualized bilaterally.
Figure 4: Olfactory functional MRI of a normal patient revealed bilateral activation in the orbitofrontal cortex, right uncus, and left primary olfactory cortex in the CIT (citral) session, and mild activation in the gyrus recti in the BME (β-mercaptoethanol) session. OERPs were recorded in both session as seening that the P2 waves were visible.
(A) In the first patient, no activation was observed in the primary olfactory cortex in the CIT session, but activation was seen in the left basal frontal lobe (orbitofrontal cortex), bilateral insula, left inferior frontal operculum, and the right inferior parietal lobule (uncorrected comparison, P < 0.01). In the BME session, diffuse activation was seen, possibly due to noise (uncorrected comparison, P < 0.01). No OERP was recorded.
(B) In the second patient, activation was observed in the primary olfactory cortex and orbitofrontal cortex in the CIT session. In the BME session, no activation was seen. OERP was recorded in CIT session.