An evaluation of the hypothesis of shifting terminals in goldfish optic tectum

摘要: It has been proposed that the terminal arbors of retinal ganglion cells continually shift positions in optic tectum as a natural consequence growth larval amphibians and teleost fish. Here, we develop detailed anatomical model this process, based on recent observations goldfish. The predicts some unusual structural features axons tectum. was tested two ways by use tracer, horseradish peroxidase (HRP). In first, were visualized anterogradely transported HRP applied nerve or retina. As predicted, had three parts: (1) fascicular segment (in stratum opticum), (2) extrafascicular synaptic neuropil), (3) arbor (also neuropil). extended up to 1 mm caudally from fascicle through which it entered At its terminus, restricted single lamina branched extensively over an elliptical area with major axes between 100 200 micron long. second test, cell bodies labeled retrogradely manner intended label all terminals vicinity. pattern locations varied, depending where applied, accord model's predictions. close agreement supports hypothesis shifting terminals.