Rahne Torsten, Sussman Elyse
Department of Experimental Audiology and Medical Physics, Otto-von-Guericke-University, Magdeburg, Germany.
Eur J Neurosci. 2009 Jan;29(1):205-11. doi: 10.1111/j.1460-9568.2008.06561.x. Epub 2008 Dec 12.
The auditory scene is dynamic, changing from 1 min to the next as sound sources enter and leave our space. How does the brain resolve the problem of maintaining neural representations of the distinct yet changing sound sources? We used an auditory streaming paradigm to test the dynamics of multiple sound source representation, when switching between integrated and segregated sound streams. The mismatch negativity (MMN) component of event-related potentials was used as index of change detection to observe stimulus-driven modulation of the ongoing sound organization. Probe tones were presented randomly within ambiguously organized sound sequences to reveal whether the neurophysiological representation of the sounds was integrated (no MMN) or segregated (MMN). The pattern of results demonstrated context-dependent responses to a single tone that was modulated in dynamic fashion as the auditory environment rapidly changed from integrated to segregated sounds. This suggests a rapid form of auditory plasticity in which the longer-term sound context influences the current state of neural activity when it is ambiguous. These results demonstrate stimulus-driven modulation of neural activity that accommodates to the dynamically changing acoustic environment.
听觉场景是动态的，随着声源进入和离开我们的空间，每分钟都在变化。大脑如何解决维持不同但不断变化的声源的神经表征这一问题呢？我们使用了一种听觉流范式来测试在整合和分离的声流之间切换时多个声源表征的动态变化。事件相关电位的失配负波（MMN）成分被用作变化检测指标，以观察正在进行的声音组织的刺激驱动调制。探测音在组织模糊的声音序列中随机呈现，以揭示声音的神经生理表征是整合的（无MMN）还是分离的（有MMN）。结果模式表明，对单个音调的上下文相关反应会随着听觉环境从整合声音迅速转变为分离声音而以动态方式受到调制。这表明存在一种快速的听觉可塑性形式，即在模糊不清时，长期的声音上下文会影响神经活动的当前状态。这些结果证明了刺激驱动的神经活动调制，这种调制能够适应动态变化的声学环境。
