Synapse elimination in olivo-cerebellar explants occurs during a critical period and leaves an indelible trace in Purkinje cells
Proceedings of the National Academy of Sciences. 2009-08-03; 106(33): 14102-14107
DOI: 10.1073/pnas.0902820106
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During developmental synaptogenesis, the pre- and postsynaptic cells undergo
specific interactions that lead to the establishment of the mature circuit. We
have studied the roles of the pre- and postsynaptic cells in establishing this
mature innervation by using an in vitro model of synaptic development. We
describe climbing fiber (CF)-Purkinje cell (PC) synaptogenesis in cultured mouse
hindbrain explants and show that synaptic competition occurs during early
development in vitro. By manipulating the maturation stage of each of the
synaptic partners in a coculture experimental paradigm, we found that
multi-innervation does not occur when both synaptic partners are mature and have
already experienced synapse elimination; in contrast, mature PCs can be
multi-innervated when they have never experienced synapse elimination and/or when
CFs are immature. However in these cases, the normal process of synapse
elimination is impaired. These results show that CF-synapse elimination occurs
only during a PC-dependant critical period and triggers indelible signals that
prevent synapse competition in the mature system.