Neural Mechanisms of the Representation, Prioritization, and Manipulation of Visual Working Memory

为了完成许多日常任务，比如在繁忙的街道上开车，有必要在信息不在视线范围内时，把它记在“在线”上。负责在短时间内将信息保存在记忆中的认知过程被称为视觉工作记忆。然而，这种能力是非常有限的；在视觉工作记忆中不可能保存无限量的信息。因此，先前的研究表明，当你在网上保存更多的信息时，所保存的信息的质量就会变得非常不稳定：也就是说，虽然有些记忆非常详细，但其他记忆的分辨率却很低。我们过去的工作已经证明，选择性地关注某些项目可以预测人们对这些信息的记忆程度。注意力“偏向”记忆，这种由注意力引起的记忆偏差似乎可以解释为什么当需要记住更多的东西时，记忆性能会下降：当需要记住很多东西时，注意力分散在所有的东西上，记忆性能就会受到影响。

In order to perform many everyday tasks, such as driving down a busy street, it is necessary to hold information in mind “on-line” when it is no longer in view. The cognitive process responsible for holding information in memory for short periods of time is referred to as visual working memory. This ability is extremely limited, however; it is not possible to hold an unlimited amount of information in visual working memory. Consequently, previous studies have demonstrated that when you hold more information on-line, the quality of the information maintained becomes quite variable: that is, while some memories are very detailed, others have very low-resolution. Our past work has established that selectively attending to some items predicts how well people will remember that information. Attention “biases” memory, and this biasing of memory by attention appears to provide an explanation for why memory performance decreases when more items have to be remembered: when many items have to be remembered, attention is split across all items, and memory performance suffers. The current proposal builds on our previous research, and aims to identify the neural mechanisms that support the top-down biasing of visual working memory by attention. In particular, we are using fMRI and EEG and measure neural activity while healthy young adults perform visual working memory tasks, in order to understand how the brain can use attention to select and enhance the memories for some visual objects. We are also using TMS to causally disrupt brain functioning in areas thought to support this process, so that we can more accurately identify their role in this behaviour. Finally, we are also going to examine whether the process of selecting and enhancing some items in memory is similar to the processes involved when performing manipulations on the contents of memory (e.g., if you have to rotate an object in your mind). This research is important to people who study the brain, such as psychologists, neuroscientists and neurologists, as it will better help us understand how the brain supports short-term memory for visual objects. In particular, because this process is so limited, it will help to clarify how the brain manages to cope with these limits on information processing. By better understanding how the brain works, this research may help inform how behavioural interventions can support individuals who may suffer from short-term memory impairments.