ZFA/Uberon issues: subcommissural organ

[gouttegd]

In ZFA, 'subcommissural organ' (hereafter SCO) is part_of the synencephalon, itself part_of the diencephalon (~ forebrain).

The corresponding Uberon term is part_of the 'midbrain tectum' and therefore of the mindbrain.

This is a direct contradiction and a violation of the spatial disjointness between diencephalon and midbrain in Uberon.

According to Corales et al. 2022, the SCO is “located in the dorsocaudal region of the third ventricle at the entrance of the aqueduct of Sylvius”. The third ventricle is part_of the diencephalon, while the aqueduct of Sylvius (known in Uberon as the midbrain cerebral aqueduct) is part_of the mindbrain. But “at the entrance of” does not imply “inside”, so I think this supports ZFA’s claim that the SCO should be considered a part of the diencephalon rather than the midbrain.

According to McKinley, Clarke & Oldfield 2004, the SCO is “situated on the rostral and ventral surfaces of the posterior commissure and forms the initial part of the midline dorsal roof of the aqueduct of Sylvius”. The posterior commissure is again part_of the diencephalon, further supporting a diencephalic location for the SCO.

Alternatively, it could be argued that if the SCO “forms the initial part of midline dorsal roof of the aqueduct of Sylvia”, then it is also a part of that aqueduct, which would means that it spans both the diecencephalon and the midbrain (which would mean it can’t be part of either, since we say those two regions are spatially disjoint). But I am inclined to follow ZFA here.