Events

Before hearing onset, neuronal activity in developing auditory pathways is dominated by rhythmic patterns of spontaneous action potentials. It has remained controversial whether this stereotypic pattern is important for the development or refinement of central auditory pathways. I will present recent results which demonstrate that genetic ablation of cholinergic neurotransmission to developing cochlear hair cells alters the temporal fine structure without affecting the overall level of spontaneous activity. These abnormal activity patterns interfered with the tonotopic refinement of an inhibitory sound localization pathway. Altered activity patterns impaired both synaptic silencing and strengthening which occurs before hearing onset and axonal pruning that normally occurs after hearing onset, resulting in an less precise topographic organization. Our study provides evidence that the exact temporal pattern of prehearing spontaneous activity guides the formation of precise tonotopy, the major organizing principle of central auditory pathways.