The effect of ablation of the olfactory pits on the development of the habenular nuclei in Rana pipiens.
The habenular nuclei in the diencephalon of the frog, Rana pipiens, are asymmetrical structures: two discrete cell groups develop on the left side (as medial and lateral nuclei), while a single nucleus is formed on the right side. Experimental animals were subjected to bilateral removal of the olfactory pits at an early embryonic stage, and were maintained with normal control animals until metamorphosis was complete. The length, relative volume and cell number for each of the three nuclei were determined in the control and experimental animals at regular intervals during larval development. In the control animals, the left medial nucleus developed similarly to the right nucleus spatially and temporally; however, the left lateral nucleus was significantly different in its development in the three parameters measured. In the experimental animals the left medial and the right habenular nuclei were alone affected by the removal of the olfactory pits. The results provide experimental evidence that the right and left medial, but not the left lateral, habenular nuclei are centers receiving afferent olfactory fibers.
D000818:Animals; D001001:Anura; D002452:Cell Count; D009434:Neural Pathways / Q000196:embryology / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D009830:Olfactory Bulb / Q000196:embryology*; D011894:Rana pipiens / Q000196:embryology*; D013787:Thalamic Nuclei / Q000033:anatomy & histology / Q000196:embryology* / Q000502:physiology