Sleep; Neural reactivation; Neural decoding; MRI; Learning and Memory; Emotion; Neural plasticity; EEG; Reward; Synaptic downscaling; Homeostasis; Affective processes
Sterpenich Virginie, Perogamvros Lampros, Tononi Giulio, Schwartz Sophie (2019), Fear in dreams and in wakefulness: Evidence for day/night affective homeostasis, in Human Brain Mapping
Perogamvros Lampros, Park Hyeong-Dong, Bayer Laurence, Perrault Aurore A., Blanke Olaf, Schwartz Sophie (2019), Increased heartbeat-evoked potential during REM sleep in nightmare disorder, in NeuroImage: Clinical
, 22, 101701-101701.
Miendlarzewska Ewa A., Ciucci Sara, Cannistraci Carlo V., Bavelier Daphne, Schwartz Sophie (2018), Reward-enhanced encoding improves relearning of forgotten associations, in Scientific Reports
, 8(1), 8557-8557.
Bolton Thomas A. W., Tarun Anjali, Sterpenich Virginie, Schwartz Sophie, Van De Ville Dimitri (2018), Interactions Between Large-Scale Functional Brain Networks are Captured by Sparse Coupled HMMs, in IEEE Transactions on Medical Imaging
, 37(1), 230-240.
Sterpenich Virginie, Ceravolo Leonardo, Schwartz Sophie (2017), Sleep deprivation disrupts the contribution of the hippocampus to the formation of novel lexical associations, in Brain and Language
, 167, 61-71.
Debarnot Ursula, Rossi Marta, Faraguna Ugo, Schwartz Sophie, Sebastiani Laura (2017), Sleep does not facilitate insight in older adults, in Neurobiology of Learning and Memory
, 140, 106-113.
Carl Aberg Kristoffer, Doell Kimberly C., Schwartz Sophie (2016), Linking Individual Learning Styles to Approach-Avoidance Motivational Traits and Computational Aspects of Reinforcement Learning, in PLOS ONE
, 11(11), e0166675-e0166675.
Aberg Kristoffer Carl, Doell Kimberly C., Schwartz Sophie (2016), The “Creative Right Brain” Revisited: Individual Creativity and Associative Priming in the Right Hemisphere Relate to Hemispheric Asymmetries in Reward Brain Function, in Cerebral Cortex
, 27(10), 4946-4959.
Aberg Kristoffer Carl, Doell Kimberly Crystal, Schwartz Sophie (2016), The left hemisphere learns what is right: Hemispatial reward learning depends on reinforcement learning processes in the contralateral hemisphere, in Neuropsychologia
, 89, 1-13.
Miendlarzewska Ewa A., Bavelier Daphne, Schwartz Sophie (2016), Influence of reward motivation on human declarative memory, in Neuroscience & Biobehavioral Reviews
, 61, 156-176.
Aberg K. C., Doell K. C., Schwartz S. (2015), Hemispheric Asymmetries in Striatal Reward Responses Relate to Approach-Avoidance Learning and Encoding of Positive-Negative Prediction Errors in Dopaminergic Midbrain Regions, in Journal of Neuroscience
, 35(43), 14491-14500.
Recent research provides evidence for memory reactivation during both wakefulness and sleep. The spontaneous reactivation of recent memory traces may contribute to their consolidation. We hypothesize that this mechanism enhances the neural integration and representation of the most important information to optimize future behavior. The overarching aim of the project is to test this hypothesis by using a combination of advanced high-density EEG (hdEEG), functional MRI (fMRI) measurements, and neural decoding. This approach offers an unprecedented opportunity to study the spontaneous reemergence of patterns of neural activity corresponding to specific past experience across distinct vigilance states in humans. A first main goal of the present project is to test whether information with a high relevance for future behavior is favored in the competition for reactivation. We and others recently showed that stimuli or behaviors with an affective relevance (e.g., aversively conditioned or rewarded information) reach improved memory representation at both the cognitive and neural levels after a period of sleep, suggesting that they undergo privileged offline reprocessing during sleep. However, to our knowledge, there is no direct evidence for such selectivity in spontaneous neural replay and its causal role in memory consolidation processes. In the present project, we propose to experimentally manipulate the affective relevance of a task and assess the reactivation of associated brain activity patterns by using neural decoding methods. Applied to activity and connectivity neuroimaging measures with a high spatial and temporal resolution (i.e., fMRI and hdEEG), this approach offers unique insights into the type of neural information that may be reactivated. A second main goal of the project is to decipher how neural reactivation operates across wakefulness and distinct stages of sleep, and how it affects the integration of new information into existing networks of representation. Ruminations and counter-factual thoughts are often reported at sleep onset, whereas the replay of rewarded memories may predominate during slow-wave sleep (SWS). Yet, these phenomena have never been investigated in the same experiment, their neural underpinnings remain unclear, and how they differentially contribute to memory processes is unsettled. We also expect to observe inter-individual differences since, for example, anxious individuals often report ruminations at sleep-onset, which may cause insomnia. A third goal of the project is to investigate another major indicator of experience-dependent local neural plasticity, namely synaptic homeostasis, which can be measured by slow-wave activity (SWA). Whether the emotional relevance of a learning task may also influence the spatial and temporal distribution of SWA during subsequent sleep is unknown. Importantly, while neural replay and synaptic homeostasis may both predominate during SWS, their possible cooperation and respective contributions to overnight brain changes need to be better understood. This project proposal is designed to optimally address each of these goals. The methodological approach proposed is original, reliable, and timely. In particular, it exploits some recent developments in the domain of neural decoding that uniquely allow the study and interpretation of spontaneous brain activity. Moreover, based on concomitant measures of neural reactivation and local SWA, this project seeks to offer an integrative view on these distinct mechanisms of neural plasticity. Finally, by clarifying how emotionally-significant events are selected for offline memory reprocessing, our experimental proposal may provide new insights into the role of sleep (and lack of thereof) in the development, maintenance but also management of some affective disorders. This work may have several important implications. At a theoretical level, by showing how distinct vigilance states contribute to the adaptive and ever-changing nature of memory representations. At a clinical level, by propounding that a healthy emotional balance involves a form of neural reverberation, which helps our brains learn from our daily failures and accomplishments.