One approach to elucidating the principles of regeneration is to investigate mechanisms that regenerate a target organ. Planarian eyes are discrete, visible structures that are dispensable for viability, making them powerful for studying the logic of regeneration. Fate specification in eye regeneration occurs in stem cells (neoblasts), generating eye progenitors. Eye progenitor production is not responsive to the presence or absence of the eye, with regeneration explained by constant progenitor production in the appropriate positional environment. Eye progenitors display coarse spatial specification. A combination of eye-extrinsic cues and self-organization with differentiated eye cells dictate where migratory eye progenitors target. Finally, guidepost-like cells influence regenerating axons to facilitate the restoration of eye circuitry. These findings from the eye as a case study present a model that explains how regeneration can occur.

阐明再生原理的一种方法是研究再生目标器官的机制。涡虫的眼睛是离散的、可见的结构，对于生存能力来说是可有可无的，这使得它们对于研究再生的逻辑非常有用。眼睛再生的命运规范发生在干细胞（成骨细胞）中，产生眼睛祖细胞。眼睛祖细胞的产生对眼睛的存在或不存在没有反应，再生解释为在适当的位置环境中恒定的祖细胞产生。眼祖细胞显示粗略的空间规格。眼睛外在线索和自组织与分化的眼细胞的组合决定了迁移眼祖细胞的目标。最后，路标样细胞影响再生轴突以促进眼电路的恢复。