Stop Thinking About It!: Cognitive and Neural Mechanisms of the Removal and Inhibition of Information in Memory

How can we as scientists determine when someone has stopped thinking of something? Said differently, how can we find an experimental signature of a thought that no longer exists? In this talk I will discuss our behavioral and neuroimaging research that addresses this question to elucidate the cognitive control mechanisms that allow information in working memory to be actively removed. Our approach, using a marriage of functional neuroimaging and machine learning techniques (including multi-voxel pattern analysis), along with behavioral experiments has been able to follow the trace of a thought and then verify that it has indeed been removed. Moreover, this research provides evidence of at least three distinct ways of removing information from working memory: by replacing it with something else, by specifically targeting it for suppression, and by clearing the mind of all thought. In this talk, I will discuss a) the neural mechanisms that enable each of these three types of operations, b) provide evidence regarding the time course of each removal operation, and c) elucidate the consequences of these removal operations for the encoding of new information, which is critical for new learning. I will briefly discuss the implications of this work for psychological and psychiatric disorders, many of which are characterized by recurrent or intrusive thoughts that individuals cannot remove from the current focus of attention.