Regulation of inhibitory synapse function in the developing auditory CNS

Auditory processing requires a balanced participation of synaptic inhibition and excitation. This balance is achieved during development, in part, through the refinement of inhibitory connections and the regulation of inhibitory functional properties. Here, we make the case that spontaneous and experience-driven activity contributes to these maturational events in the auditory brainstem and cortex. Using brain slice preparations, we selectively assessed the physiology and plasticity of central inhibitory transmission. Together, the results demonstrate that inhibitory synapse function is regulated at every central location examined. The sites of regulation involve presynaptic factors such as transmitter synthesis and release properties, as well as postsynaptic factors such as receptor subunit kinetics, KCC2 function, and long-term depression. We propose that reduced inhibitory strength following disuse is due to delayed development, and this may contribute the enhanced excitability.