“Highlights of neuroanatomical discoveries of the mammalian gonadotropin-releasing hormone system” is an interesting and well-written review paper. It shows GnRH neurons' anatomy morphology and physiology from a historical perspective. It highlights both historical and more recent discoveries critical for understanding the role of GnRH neurons in the control of reproductive functions. Importantly, it also presents unresolved questions and opportunities for future neuroanatomical research on this population of neurons. The review takes the reader on a fascinating journey back to the time when anatomical studies that began in the late 1930’ allowed scientists to prove the concept of neurosecretion to modern time using genetic manipulations, viral-mediated tracking, RNA scope technique, 3D neuronal reconstructions, and nanotechnology. Of particular interest are parts of this paper, which explained how single discoveries led to progress in the field of reproduction. Worthwhile are also parts describing in detail specific techniques. e.g., FOS staining or advances and disadvantages of using particular fixatives.
Moreover, the review contains a table and three complex and high-quality figures, which add to the text.
This review is of potential interest not only for researchers working in reproductive biology, veterinary and medicine but also for scientists interested in using particular techniques in their experimental work.

I have only several comments and minor revisions, which are mentioned below:
1. While the historical perspective is fascinating and essential for this paper, I think it is worth mentioning that the GnRH neurons “received a Nobel prize.” See: https://www.nobelprize.org/prizes/medicine/1977/summary/
2. Of interest for potential readers, at least in my opinion, could be also a section describing the GnRH neurons migrations in the early stages of the development, which is a fascinating topic, as well as a section on abnormalities in GnRH neurons system, e.g., in Kallmann syndrome.
3. In spite that the GnRH neurons are decidedly not different in males and females, there are markedly different physiologies of gonadotropin secretion. Could authors add several paragraphs on this topic? On the other hand, it could be interesting to mention marked sex differences in KNDy neurons.
4. P. 9 line 262: Please delete “.” after “Distinct regulation zones”
5. P. 9 lines 283 and 288. Please insert spaces between numbers and units:
“50-150um” and 50um”
6. P. 11 line 327: Please delete “.” after “Function-related morphological plasticity”
7. P.11 line 357: Please insert a space between “semaphoring” and “7A”
8. P.14 line 442: Please delete the extra space in front of the sentence: “Importantly, both the changes in synaptic input and glial ensheathment were only in GnRH cells and not in adjacent non-identified neurons in the POA.”
9. P.14 line 456: Please provide the full name before the abbreviation “PCOS”.
10. P.17 line 541: Please insert a space between “(16 × 6 μm)” and “(42)”
11. P.17 lines 556-557: “As described in different species (42, 118), several circumventricular organs, including the median eminence, the organum vasculosum laminae terminalis….. please add abbreviations (ME) and (OVLT) and use them later in the text.
12. P.18 lines 569-571: Please consider also introducing and using later abbreviations for peptides names in the sentence “In humans, these descending 570 GnRH fibers are accompanied and occasionally contacted by other peptidergic fibers containing kisspeptin, neurokinin B and Substance P (121).”
13. P. 19 lines 595-596: Please also consider abbreviation for the arcuate nucleus and preoptic area. P. 21 – here again, the abbreviation for estrogen receptors could be used
14. P.22 lines 723-724: “Recently our laboratory has provided a more comprehensive characterization of extrahypothalamic GnRH neurons…..”, please specify the laboratory, as several authors wrote the review,
15. P. 25 line 794: Please use italic for “in vivo”
16. P.26 line 803: in the sentence: “Diversity of distribution of GnRH Neurons in Mammals,” use “mammals”
17. P. 26. Since Figure 1 is reproduced from reference 30, I wonder if permission is needed for the publisher. Authors are asked to check it.
18. P. 27, line 822: Please add a comma after “Bar =10 μm”
19. P. 27, line 824: Please add a comma after “spiny protrusion”

Dear Authors,
my comments and question have been addressed.
Congratulation on your manuscripts !