Neurons in the inferior colliculus (IC) have long been thought to have stable response characteristics. Yet, some forms of acoustic stimulation will transiently enhance sound evoked discharge rate in IC neurons, effectively shifting these characteristics. Such short-term changes in gain can directly impact a neuron?s ability to integrate successive stimuli, and thus define its temporal sensitivity. The goal of this project is to identify the cellular mechanisms of this acoustic gain effect, by performing whole-cell patch-clamp recordings of IC neurons in a brain slice preparation. Preliminary patch-clamp data show that inhibitory synaptic stimulation of the lateral lemniscus can condition a single IC neuron to a temporary state of higher gain, which recovers within seconds. To examine the specific cellular changes underlying this form of short term plasticity, a series of experiments using pharmacological and voltage manipulation in an IC slice are proposed. The effect of synaptic stimulation on current-evoked action potentials will be used to facilitate comparison with in vivo phenomena. Deficits in auditory temporal processing may be a source of specific language impairment, or delayed cognitive development. Identification of temporal sensitivity mechanisms provides a focus for alleviation of such impairments. Optimization of auditory prostheses could also benefit from a better understanding of synaptic mechanisms that underlie central auditory computations.
| Miko, Ilona J; Sanes, Dan H (2009) Transient gain adjustment in the inferior colliculus is serotonin- and calcium-dependent. Hear Res 251:39-50 |
