Coury, S. | Search bioRxiv

bioRxiv2026

A Novel Cortico-Striatal NREM Sleep Rhythm in Mice and Non-Human Primates

With practice, rapid early gains in performance are followed by a slower phase marked by kinematic refinement, automaticity and enhanced cortical and striatal interactions. While sleep is known to support early learning, its causal role in the slow phase of learning is not known. Here we recorded neuronal activity in primary motor cortex (M1) and the dorsolateral striatum (DLS) during long-term skill acquisition and interleaved sleep. Surprisingly, the slow phase of learning was marked by the emergence of a previously unrecognized 5-10 Hz oscillatory activity during NREM sleep that was coherent across M1 and DLS. This oscillation resulted in repeated joint reactivation of task-specific information in cortex and striatum. Strikingly, during later stages of training, such joint reactivation of task activity increased over the course of NREM sleep, suggesting that sleep-dependent processing strengthens cortico-striatal interactions. The strength of M1-DLS coherence was predictive of next-day performance gains and increased cortico-striatal coupling during task performance. Targeted closed-loop disruption of this oscillation during NREM sleep abolished performance gains, whereas switching to a dose matched random stimulation paradigm enabled performance improvements in the same animals. Importantly, the same cortico-striatal 5-10 Hz rhythm was also found in sleeping non-human primates, where it was selectively enhanced following learning. Together, we identify, across species, a novel NREM sleep oscillation that is important for sleep-dependent performance gains which depend on cortico-striatal processing.

neuroscience↗

bioRxiv2026

Sleep to forget: active control of consolidation and forgetting by slow-wave sleep dynamics

Sleep supports both the consolidation of new memories and the forgetting of others, but how the cortex flexibly controls these outcomes remains poorly understood. Recent work has shown that two types of Up states may play distinct, competing roles during slow-wave sleep (SWS): slow waves actively consolidate memory traces, whereas delta waves promote their weakening. Here we use a biophysical thalamocortical network model equipped with spike-timing-dependent plasticity to investigate the synaptic mechanisms underlying this dissociation. By manipulating the intrinsic Ca2+ dynamics of cortical pyramidal cells, we generate both slow and delta wave Up states within a single network. Using a sequence-learning task paradigm we recapitulate the optogenetic dissociation: removing plasticity during slow waves degrades the memory, while removing it during delta waves enhances consolidation. Mechanistically, the model reveals the longer slow wave Up state affords a spontaneous reactivation phase, occurring after the interfering input, during which the trained memory is selectively reactivated and protected, a phase the truncated delta Up state cannot support. We further find that delta waves sparsen the synaptic representation more than slow waves and predict that the balance between consolidation and forgetting can be flexibly tuned by the ratio of slow to delta waves during SWS.

neuroscience↗