Understanding the brain mechanisms that regulate attention to auditory memory

人类的口头交流受到我们的能力的限制，即使在存在其他噪音的情况下，我们也能听到说话者的声音，无论是其他人说话还是其他声源(例如，音乐、机械引擎的声音)。要做到这一点，通常需要重播一个人刚刚说过的话，在脑海中回想起那些在短期记忆中仍然可以理解的口语。也就是说，刚刚听到但不再存在的声音成为我们关注的对象。我们知道，选择性注意力会影响我们的记忆，而且熟悉的人比不熟悉的人更容易理解。然而，我们并不完全了解让我们在短期记忆中注意声音的大脑机制，也不知道现有的记忆是如何偏向这种注意力的。这项研究计划的目的是：(I)描述允许人们将注意力集中在听觉记忆上的神经结构；(Ii)确定当听者反思刚刚听到的声音的时间、内容或地点时，大脑过程有何不同；(Iii)考察对记忆的注意如何增强对退化语音的处理；(Iv)描述长期记忆如何引导注意力；以及(V)确定在不利的听力条件下，长期记忆中的信息如何与正在进行的知觉处理相结合。所有研究都包括健康的年轻人，并实施了行为、计算和脑成像技术的仔细组合，以便绘制出这些过程中涉及的时间进程和大脑区域。对短期记忆的自上而下的注意是使用所谓的延迟匹配到样本范式来研究的。在这样的任务中，在呈现刺激序列之后，会出现一个(追溯)提示，告诉参与者应该在记忆中保留哪个项目(S)(内部定向注意)。我们预测，对记忆的注意将涉及一个广泛分布的大脑区域的神经网络，其中包括听觉皮质和对集中注意力重要的区域。注意力和听觉长期记忆之间的相互作用是用一种学习范式来研究的，这种学习范式旨在建立两个听觉刺激之间的强烈联系。我们预计，现有的语境记忆将通过重新激活最初在学习过程中涉及的大脑区域来偏向注意力并优化感知。结果将使我们能够通过考虑到关注来自我们内部和外部世界的事件的适当和不断变化的平衡来改进注意力模型。确定如何将注意力分配到听觉记忆上，可以指导制定训练方案，以提高正常人群一生中的注意力，也可以改善大脑受损、健康状况和/或学习障碍的人的注意力，这些疾病会影响他们注意记忆的能力。

Human oral communication is constrained by our ability to “hear” a speaker even in the presence of other noise, whether that be other people talking or other sound sources (e.g., music, mechanical engine sounds). Doing this often requires a sort of replay of what a person just said by going back in one’s mind to those spoken words still accessible in short-term memory. That is, the sounds just heard, but no longer present, become the object of our attention. We know that selective attention influences what we remember, and that it is easier to understand a familiar talker than an unfamiliar one. However, we do not fully understand the brain mechanisms that allow us to attend to sounds in short-term memory nor do we know how existing memories bias that attention. The aims of this research program are to: (i) characterize the neural architecture that allows people to focus their attention to auditory memory; (ii) determine how brain processes differ when listeners are reflecting on the when, what, or where of the sound just heard; (iii) examine how attention to memory enhances processing of degraded speech; (iv) characterize how long-term memory steers attention; and (v) identify how information in long term memory is integrated with ongoing perceptual processing in adverse listening conditions. All studies include healthy young adults and implement a careful combination of behavioral, computational, and brain imaging techniques in order to map out the time course and brain areas involved in these processes. Top-down attention to short-term memory is studied using what is called a delayed match-to-sample paradigm. In such tasks, a (retro)cue telling participants which item(s) to maintain in memory (internally oriented attention) appears after the stimulus array is presented. We predict that attention to memory will engage a widely distributed neural network of brain regions that include the auditory cortex and regions important for focusing attention. The interplay between attention and auditory long-term memory is investigated using a learning paradigm designed to create a strong association between two auditory stimuli. We anticipate that existing contextual memories will bias attention and optimize perception by re-activating brain areas originally involved during learning. The results will allow us to advance models of attention by taking into account the proper and changing balance of attending to events from our internal and external worlds. Determining how attention is allocated to auditory memory can guide the development of training regimens to improve attention in normal populations across the life span and also in people within brain damage, medical conditions and/or learning disabilities which affect their ability to attend to memory.