Table 1. Brain areas included in fOCN.
| Brain region | Right side | Left side | ||
|---|---|---|---|---|
| AAL | Harvard Oxford | AAL | Harvard Oxford | |
| Primary olfactory areas | ||||
| Piriform cortices | 7% | * | 8% | * |
| Amygdala | 27% | 24% | 37% | 45% |
| Secondary olfactory areas | ||||
| Putamen | 17% | 17% | 9% | 6% |
| Pallidum | 0% | 3% | 0% | 1% |
| Parahippocampus | 0% | 0% | 7% | 3% |
| Hippocampus | < 1% | 0% | 6% | < 1% |
| Orbitofrontal Cortex | 0% | 5% | 0% | 0% |
| Atlas-definition differences | ||||
| Un-named grey matter areas | — | ~37% | — | 35% |
| White matter** | — | ~15% | — | 12% |
| Not contained in atlas** | 50% | — | 32% | — |
To investigate the percentage of overlap of the fOCN on non-primary olfactory areas, the fOCN was added to both the AAL atlas and the Harvard-Oxford atlas. This conformed the initial AAL results, that the cluster contained large quantities of non-primary olfactory areas. The voxels of the fOCN cluster were subtracted from the original AAL parcellation, as any measure of connectivity to these regions would otherwise contain a nonsense measure of connection within a voxel. The fOCN did not completely overlap any AAL regions. *These areas are not defined in the Harvard-Oxford atlas, but are contained within the larger “Cerebral Cortex” parcellation. **White matter regions are only included in parcellations of the Harvard-Oxford atlas.