The role of prestimulus oscillatory brain dynamics in auditory memory

项目总结：wisniewski项目

PROJECT SUMMARY: WISNIEWSKI PROJECT Ongoing brain dynamics impact memory for events as they occur. This is evident in nonhuman and human neuroelectromagnetic recordings (e.g., electroencephalography - EEG) where prestimulus oscillatory brain states have been shown to determine neural plasticity and predict later memory retrieval. However, a reliance on correlational data, restrictive memory paradigms, outdated analysis techniques, and a bias to use visual and/or language stimuli has left open questions in the state of knowledge. It is still not clear whether prestimulus brain states causally impact memory, whether their impacts are related to the cortical source of oscillatory activity, and whether effects only apply to a subset of tasks. This makes it difficult to develop approaches that use prestimulus brain dynamics with health-relevant goals (e.g., systems that induce brain dynamics that can facilitate memory). The proposed research employs innovative methodological approaches to examine the central hypothesis that oscillatory prestimulus brain dynamics impact memory for sound. The data produced will fill gaps in the state of knowledge and identify directions that can be taken to exploit prestimulus brain dynamics to produce positive health outcomes. Aim 1 will determine how prestimulus oscillatory EEG dynamics relate to auditory memory performance. High-density (104 channel) EEG will be recorded while subjects encode sounds in memory tasks with the capability of assessing memory accuracy and precision. Analyses will reveal the prestimulus EEG oscillatory dynamics that are predictive of these memory performance metrics. Source modeling will reveal the cortical areas responsible for these effects and allow a characterization of how interactions among different sources influence memory. Aim 2 will modulate prestimulus brain dynamics and measure resulting impacts on memory. Both a sensory entrainment and repetitive transcranial magnetic stimulation (rTMS) protocol will be used to induce oscillatory brain states in subjects. Because brain states will be purposefully manipulated, this will provide a causal viewpoint on prestimulus oscillatory activity regarding memory performance. This project stands to produce theoretical insights on the functional roles of oscillatory brain activity in memory processes. For instance, it is directly relevant to theory on alpha (~8-13 Hz) oscillations which proposes that the phase and power of ongoing alpha should gate the processing of incoming events. Methods that allow causal inference will inform the ongoing debate in neuroscience as to whether oscillations play a functional role in processing or are merely epiphenomenal. Through its use of multiple methods (EEG, sensory entrainment, rTMS), the project also stands to identify the most useful directions to take in the development of rehabilitative/assistive devices. The project will link with all three of CNAP Phase 2 crosscutting themes (The Neurobiology of Learning and Memory, Neuromodulation and Assessment, and Advanced Computational Modeling) and will rely on the Neuroinformatics and Cognitive Neuroscience Cores.