The dorsal part of the nervous system typically gives rise to sensory structures, and the ventral part gives rise to motor structures. Because the central sulcus marks such a functional boundary, I had assumed it was an example of this zonation ... however, recently I didn't find any source to defend this position. (I would have been sure that hunting for "fate map" and "central sulcus" would pull up something informative...) Some of the embryology, in which I think a trace of a central sulcus might be apparent quite early, can be seen at UNSW, but none of the embryology images I considered really seem usable to answer the question.

*Note: "Central sulcus" is referenced as a visible marker for the boundary between motor and sensory functions. Answers that trace the origin of this boundary in species where it is not marked by a sulcus are also welcome.


1 Answer 1


The basal and alar plates have an important sensorimotor separation of duties in the spinal cord. I don't see any reason to apply this to the cerebral cortex that develops from the forebrain - you're probably not finding anything about this because people don't concern themselves with alar/basal plates in the front of the brain.

Importantly, the neocortex is pretty evolutionarily new. You're placing strong developmental purpose on a sulcus that doesn't even exist in the evolutionary ancestors of humans. There is no such separation between sensory and motor cortex in a mouse, for example.

See this sagittal view of a forebrain:

enter image description here

(image from Medina L. (2009) Evolution and Embryological Development of Forebrain. In: Binder M.D., Hirokawa N., Windhorst U. (eds) Encyclopedia of Neuroscience. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-29678-2_3112)

The neocortex is just a small slice situated at the dorsal surface of the forebrain (yes, it does wrap around the entire dorsal surface and extends along the lateral sides, but that doesn't make it anything but dorsal). There is no trace of any dorsal or ventral embryonic origin within the neocortex. The dashed line that roughly separates the dorsal and ventral parts of the CNS ends in the diencephalon; in this view, all of the neocortex, including motor cortex, is part of the dorsal "sensory" part of the brain.

  • $\begingroup$ From the papers and images I'm seeing online, such as this one, I have the impression that the mouse forebrain has a relatively similar overall organization with motor areas in a frontal lobe. (The motor barrel is specific to whiskers, and RFA's exact nature seems to be subject to interpretation, but the overall emphasis seems the same) Also, I don't see how you can say the region is entirely dorsal but also that there is no trace of dorsal embryonic origin. $\endgroup$ Jul 9, 2021 at 1:01
  • $\begingroup$ @MikeSerfas Yes they have a motor cortex. They do not have a central sulcus, or really any sulci or gyri besides one, the rhinal fissure. The general positions are like humans but there are no "lobes", we only call them that to reference primate brains. I'm saying there's no dorsal/ventral origin separation for cortex. It's not relevant. If you find somewhere that says it's relevant, great, but you shouldn't just look at pictures and guess. $\endgroup$
    – Bryan Krause
    Jul 9, 2021 at 3:23
  • $\begingroup$ Well, that's why I asked here. :) $\endgroup$ Jul 9, 2021 at 6:21

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