In vitro reconstruction and functional development of the superior colliculus in the retinotectal pathway

• Published in: Neuroscience letters 2013-06, Vol.545, p.96-101
• Main Authors: Hirota, Shinya, Moriguchi, Hiroyuki, Saito, Atsushi, Inoue, Kousuke, Murakami, Akitoshi, Kotani, Kiyoshi, Jimbo, Yasuhiko
• Format: Article
• Language: English
• Subjects: Animals; Cells, Cultured; Co-culture; Coculture Techniques - methods; Development; Microelectrode array (MEA) substrates; Nerve Net - physiology; Neuronal Plasticity - physiology; Organ Culture Techniques - methods; Rats; Rats, Wistar; Retinal Ganglion Cells - physiology; Spontaneous activity; Superior Colliculi - physiology; Superior colliculus (SC); Visual Pathways - physiology
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2013.04.020

•Retinotectal pathways were reconstructed on MEA substrates by co-cultures.•Spontaneous activities of co-cultured retinas and SCs were recorded for one month.•Functional connections between co-cultured retinas and SCs were formed.•The signal input from retina affects the functional development of SC. In order to examine the formation of a neural network and the functional development of a visual pathway, we performed in vitro reconstruction of the retinotectal pathway using organotypic explants and co-culture methods. Retinas and superior colliculus (SC) slices obtained from embryonic rats were co-cultured on microelectrode array (MEA) substrates for four weeks. We observed retinal ganglion cell neurites innervating SC slices that evoked responses in retinas or SC slices after applying electrical stimulation. Functional connections between retinas and SC slices were formed in the cultures. At the same time, spontaneous electrical activities were recorded from both the retinas and SC slices over the four weeks. In the co-cultured SC slices, sporadic firings were initially observed at 3–4 days in vitro (DIV), and thereafter the frequency of spontaneous firing increased and synchronized activities occurred after two weeks in vitro (WIV). In most of the single-cultured SC slices, however, only sporadic firings were observed over four weeks. In addition, the retinas and SC slices were co-cultured to enable the exchange of soluble factors with each other via culture medium but not via direct neural connections. The activity patterns resembled ones of single-cultured SC slices. These results suggest that signal inputs from retinas through direct neural connections affect the development of SCs in the retinotectal pathway.