Temporal processing in the superior olivary complex: impact of deafness and peripheral electrical stimulation strategies

大脑可以利用时间或时间信息来提取声音的频率和位置。时间信息是由与声波周期相匹配的脑细胞反应模式编码的。这些反应可以用小电压尖峰或动作电位来测量。将这些反应从一个大脑处理部位整合到另一个大脑处理部位，依赖于一群因声音而被激活的细胞之间精确（在时间上匹配）的放电。声音定位依赖于来自双耳的信息的时间整合。具体来说，这些信息的整合依赖于双耳输入的平衡，它根据声音在空间中的位置保持适当的时间窗口。最近的证据表明，在耳聋中，这种整合过程被破坏，这可能是由于无法调节细胞的连贯激活。这对人工耳蜗使用者有影响，他们处理时间信息的能力由于先前耳聋导致的时间编码能力的丧失而受到损害。在这个项目中，我们将测量上橄榄复合体细胞内发生的电压变化，上橄榄复合体包含一组整合双耳输入的结构。我们将检查这些细胞在正常和耳聋条件下处理时间信息的能力。这项研究不仅有助于理解听觉编码的基本机制，而且有助于改进人工耳蜗植入患者的电刺激策略。

The brain can use timing or temporal information to extract the frequency and location of sound. Timing information is coded by the pattern of responses of brain cells that match the period of the sound wave. These responses can be measured as small voltage spikes or action potentials. Integration of these responses from one brain-processing site to another relies on precise (temporally matched) firing among a population of cells that are activated in response to sound. Sound localisation relies on this temporal integration from information coming from both ears. Specifically, the integration of this information relies on the balance of incoming inputs from both ears, which maintains an appropriate time window depending on the location of sound in space. Recent evidence suggests that in deafness this process of integration is disrupted which may be possibly due to an inability to regulate the coherent activation of cells. This has implications for cochlear implant users whose ability to process temporal information is compromised by a loss of temporal coding ability resulting from prior deafness. In this project we will measure voltage changes occurring inside cells of the superior olivary complex, which contains a group of structures that integrate input from both ears. We will examine the ability of these cells to process temporal information in normal and deafened conditions. This study will lead not only to an understanding of basic mechanisms for auditory coding but also to improved electrical stimulation strategies for patients with cochlear implants.