Attention and memory in real time

Abstract

Information streams towards the brain at every moment. The nervous system is responsible for processing this information without substantial delays, in order to attend to important information and store memories for future use. Accordingly, for neuroscientists, I propose that it is not sufficient to be able to deduce what was happening in the brain, but we should also understand what is happening in the moment. Real-time neural analyses offer the opportunity to do so, by closing the loop between experimenter and participant.

By tracking neural processes in real time, we can return rapid feedback to modify cognition, such as attention and memory. In Chapter 1, I used this approach to track and provide feedback about fluctuations of sustained attention in real time. When asked to sustain our attention to something, attention naturally fluctuates. I developed a paradigm to deliver real-time feedback about fluctuations of attention concurrent to task performance. Then, I observed how and whether this feedback modified cognitive abilities. This novel approach of closed-loop neurofeedback benefited attention performance and increased the neural discriminability of the attended information.

In addition to providing feedback, real-time analyses can also be used to optimize experimental design and influence memory encoding. Information encoded when attention is lapsing is much less likely to be later remembered. In Chapter 2, by monitoring fluctuations of attention, the delivery of information was timed to be at the right or wrong moment, when attention was measured to be high or low. This manipulation affected later memory and contributed to our understanding of the tight link between attention and memory.

Finally, after memories have already been encoded, their retrieval can also be manipulated. The retrieval of a memory is facilitated when it occurs in the same context as was present when the memory was initially encoded. In Chapter 3, I used real-time neurofeedback to guide participants closer or farther away from the original encoding context during retrieval, influencing what and how much they remembered.

The work presented in this dissertation opens up several avenues to explore and perturb attentional and mnemonic processes and the neural mechanisms that support them.