Activity-dependent development of intrinsic network in the central nucleus of the inferior colliculus

Through experience, sensory circuits learn and adapt, optimizing their network organization in accordance to the external sensory inputs, to help the organism better recognize, better navigate and better survive in the world. How are these dynamic changes happen in the brain? This is the question constantly being pursued. In this thesis, I followed this everlasting pursuit by asking how is the fundamental architecture of the intrinsic synaptic connectivity of the central nucleus of the inferior colliculus (CNIC) shaped through experience. In Chapter II, I investigated how the precise temporal pattern of prehearing spontaneous activity influences the prehearing establishment and post-hearing development of the CNIC intrinsic synaptic connectivity onto GABAergic neurons. I showed that the precise temporal pattern of prehearing spontaneous activity is required to prepare the CNIC intrinsic network into a configuration that permits acoustic experience-dependent network refinement to take place. In Chapter III and IV, I investigated how acoustic experience influences the development and organization the CNIC intrinsic synaptic connectivity onto both GABAergic neurons and glutamatergic neurons. I showed that acoustic experience-dependent network refinement centers on GABAergic CNIC populations. Inhibition plays an essential role in shaping the CNIC intrinsic network configuration. Based on the intrinsic synaptic connectivity, I proposed an inhibition-centered functional organization of the CNIC intrinsic network, in which inhibition not only sculpts, but also governs how the CNIC represents the acoustic world.