'Zoning out' during our daily tasks is typically considered a waste of time, as when an inattentive student daydreams during a lecture. But to the contrary, moments of inattention to our surroundings may be essential to the formation of memory. This project will test the hypothesis that even when we seem to be sitting still and doing nothing, the mind and brain are continuously switching between two distinct states - one in which we are focused on processing our immediate external environment (an 'online' state), and another during which we ignore our immediate surroundings and turn our attention toward internally generated activity, including thinking of the past and planning for the future (an 'offline' state). This project tests the hypothesis that the early stages of memory processing occur specifically during moments of this offline state, interspersed throughout our day. By developing new methods of measuring these waking states and their function, this work will help to move us toward a more accurate understanding of wakefulness as an oscillation between distinct processing modes that are essential for the formation and retention of long-term memories. As a part of NSF's RUI (Research in Undergraduate Institutions) program, this project will also provide high-quality research training for approximately 12 undergraduate students across the course of 3 years, including members of underrepresented minority groups and students from underserved public high schools in South Carolina.
Studies of human memory have typically treated wakefulness as a homogenous state. But to the contrary, moment-to-moment alternation between online attention to the current environment and offline attention to internally generated thought and imagery may be a fundamental feature of the waking state, occurring even in the absence of a directed cognitive task. Although we all experience such attentional fluctuations throughout the day, the structure and function of these short bouts of offline time remain almost entirely unknown. The objective of the current project is to model this temporal microstructure of wakefulness in human subjects, assessing the functional relevance of fluctuation between online and offline attentional states to memory processing. The central hypothesis is that the early stages of memory consolidation occur specifically during these offline moments interspersed throughout the day. This hypothesis is based in part on the researcher's preliminary data describing features of these proposed states of wakefulness using simultaneous high-density EEG, pupillometry, behavioral, and subjective report measures. To test the hypotheses, the research team will pursue two specific aims. Aim 1 will model the transition between online and offline waking states at seconds-level temporal resolution, using simultaneous high-density EEG, pupillometry, behavioral, and subjective report measures. Aim 2 will assess the contribution of spontaneous offline time to memory consolidation. Together, these studies will test the novel hypothesis that a fast-timescale alternation between online and offline attentional states is essential for memory consolidation to occur. This work thus challenges the traditional view of wakefulness as a unified state, instead describing wake as an oscillation between statistically discriminable cortical states, each with different cognitive functions.
We anticipate that this work will lead to two main scientific advances. First, this project will develop a new, data-driven model of the alternation between waking states in human subjects. The classification algorithms to be developed will allow future investigators to more easily and objectively detect and measure offline time, while providing a uniquely comprehensive description of the heterogeneous structure of wakefulness. Second, the project will test the relevance of fluctuation between waking states to memory consolidation, resolving a continued uncertainty in the field of memory research regarding the brain state(s) during which consolidation occurs, and the timescale(s) on which it operates. Finally, as a part of NSF's RUI (Research in Undergraduate Institutions) program, this project will also strengthen the undergraduate STEM pipeline in an underserved region of the country, providing high-quality research training to approximately 12 undergraduate students, including members of underrepresented minorities and local high school students in South Carolina.
This project is jointly funded by the Perception Action & Cognition Program, the Cognitive Neuroscience Program, and the Established Program to Stimulate Competitive Research (EPSCoR).
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
