Neuroimaging studies of auditory perception and attention

我们的听觉环境通常由无数的声音组成，但很少有人研究声音“对象”如何在大脑中呈现，以及在嘈杂环境中如何将注意力分配到特定的声音对象上。确定注意力在复杂的听觉场景中是如何分配的是有实际意义和理论意义的。在实践方面，这些信息可以指导制定训练方案，帮助有注意力问题的个人。在理论方面，它可以提供对调节听觉知觉、注意力和认知的神经机制的洞察。拟议的研究计划结合了行为技术和事件相关脑电位(ERPs)的头皮记录，并围绕两个截然不同但相互交错的主题开发：(1)使用变化检测范式评估记忆中并发声音对象的表征，(2)评估注意在嘈杂环境中的部署。我们将研究听众在听觉场景中发现显著变化(即改变耳聋)的惊人失败。这种改变耳聋可能是由于未能正确编码存储器中的各种声音对象和/或在比较各种场景时出现问题而发生的。我们将通过比较与编码和保持过程相关的神经活动来检验这些假说。此外，我们还将研究变盲和变聋在神经活动方面的异同。将通过要求参与者指出听觉场景是否由预定义的目标声音(以及在不同位置同时发生的其他声音)组成来调查听觉场景中注意力的分配。我们预计，听觉注意的部署将以目标位置对侧的神经活动增强为特征，并且当注意力指向声音身份(例如，说话者的声音)时，与分配给位置(即，说话者的位置)的注意相比，这种神经活动将不同。我们将使用从这些研究中获得的知识来完善我们目前基于对象的听觉注意描述。

Our auditory environment is often comprised of a myriad of sounds and yet there has been a paucity of work investigating how sound "objects" are represented in the brain and how attention is deployed to a particular sound object within a noisy environment. Determining how attention is allocated in complex auditory scenes is of interest for both practical and theoretical reasons. On the practical side, this information can guide the development of training regimens to help individuals with attention problems. On the theoretical side, it can provide insight into the neural mechanisms mediating auditory perception, attention, and cognition. The proposed research program combines behavioural techniques with scalp-recording of event-related brain potentials (ERPs) and is developed around two distinct but interleaved themes: (1) assessing the representation of concurrent sound objects in memory using a change detection paradigm, and (2) assessing the deployment of attention within a noisy environment. We will examine the surprising failure of listeners to detect salient changes in auditory scenes (i.e., change deafness). This change deafness may occur because of a failure to properly encode various sound objects in memory and/or a problem in comparing various scenes. We will examine these hypotheses by comparing the neural activity associated with the encoding and retention processes. In addition, we will examine the similarities and differences in neural activity for change blindness and change deafness. The deployment of attention during auditory scenes will be investigated by asking participants to indicate whether an auditory scene is comprised of a predefined target sound (among other sounds occurring simultaneously at various locations). We anticipate that the deployment of auditory attention will be characterized by enhanced neural activity contralateral to the target location and that this neural activity will differ when attention is directed to sound identity (e.g., talker's voice) compared to attention allocated to location (i.e., talker's location). We will use the knowledge gained from these studies to refine our current object-based account of auditory attention.