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Figure 3 | Frontiers in Zoology

Figure 3

From: Development of the retinotectal system in the direct-developing frog Eleutherodactylus coqui in comparison with other anurans

Figure 3

Tectal development in E. coqui and D. pictus . (A, B) Morphometric analysis of tectal development. Volume of the entire optic tectum (light blue) or of its cellular layer (dark blue) is plotted against developmental age. In addition, a proliferative index indicating the PCNA positive proportion of the cellular layer is shown in green. Each symbol represents a measurement from a single individual (there are less data points for the proliferative index than for area measurements because PCNA staining was not apparent in each individual). Curves are drawn through mean values in case more than one individual per stage was analyzed. For each species, timing of first outgrowth of tectofugal fibers, first ingrowth of optic (retinofugal) fibers into the tectum, the formation of tectal layers 7–9, 5, and 1–4, and the coverage of the entire surface of the tectum by optic fibers is indicated in red. Phases of development are depicted as described in Fig. 2. (C) Overview of tectal development in E. coqui and D. pictus based on camera lucida drawings of sections through the central tectum of different developmental stages. Hatched line indicates border between cellular layers adjacent to the ventricle and peripheral fiber layers. Within the tectum, the hatched line indicates border between layers 1–6 (mostly cellular) and layers 7–9 (mostly fibers). Stippling indicates PCNA-positive regions.

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