As I understand, sensory nerve cells in the dorsal root ganglion are pseudounipolar neurons, with a sole protrusion from the soma branching into a central axon (or functional axon) and peripheral axon (or functional dendrite). Depending on the kind of nerve fiber, the peripheral axon may be myelinated to various degrees, and even not myelinated at all.
Now in an online lexicon (which is in German, unfortunately: http://flexikon.doccheck.com/de/Pseudounipolare_Nervenzelle), it is asserted, that while the peripheral axons (signalling from the periphery to the dorsal root) are usually myelinated, the central axon (signalling from the dorsal root to the posterior horn of the spinal cord) is usually NOT myelinated. The claim is unsourced. In spite of thorough research on the internet, I have not been able to find any notion whatsoever on the central axon being myelinated or not. So my question:
Is there any evidence that in dorsal root pseudounipolar neurons central axons are typically unmyelinated even when the peripheral axon is? Evidence on human neurons is preferred, but evidence on other species is welcome as well.