Biology subjects

Capurro, L.

Publications and source records attributed to Capurro, L..

3 recordsLinked to original sources

bioRxiv2026

Closed-loop acoustic stimulation promotes local slow oscillation train initiation and persistence in elderly adults

Slow oscillations (SOs) during non-rapid eye movement (NREM) sleep support memory consolidation and metabolic waste clearance. Aging is associated with reduced SO amplitude and density and disrupted temporal organization, characterized by more isolated events and shorter SO trains. We investigated whether closed-loop acoustic stimulation (CLAS) could enhance the initiation and persistence of rhythmic SO activity in elderly adults. Twenty-seven participants underwent a baseline night followed by an experimental night, during which online-detected SOs were either stimulated using CLAS (STIM; n = 16) or left unstimulated (SHAM; n = 11). We quantified the proportions of isolated and consecutive SOs, train-initiation probability, and SO train length. Analyses assessed local effects around online-detected SOs and global effects across NREM sleep using offline detection. Locally, CLAS reduced the proportion of isolated SOs and increased the proportion of consecutive SOs, train-initiation probability, and mean train length. Global overnight effects were weaker but directionally consistent, primarily reflecting a shift toward longer SO trains. These changes occurred without a significant between-group difference in the change in SO density, and local effects remained significant after adjustment for SO density. Thus, CLAS promoted sustained rhythmic activity beyond changes in SO occurrence. These findings suggest that CLAS can modify the temporal organization of SOs in elderly adults, supporting its potential to mitigate age-related disruptions in SO dynamics. Temporal organization measures may complement conventional amplitude and density measures when evaluating CLAS effects. Further studies should establish whether these changes translate into cognitive benefits or improvements in other aspects of brain health.

neuroscience↗

bioRxiv2026

TARGETED MEMORY REACTIVATION DURING NON-RAPID EYE MOVEMENT SLEEP STRENGTHENS CONSOLIDATED DECLARATIVE MEMORIES

Targeted memory reactivation (TMR) during sleep can benefit recently acquired memories, but whether it can also influence memories after an initial period of consolidation remains unclear. Here, we tested whether auditory reactivation during non-rapid eye movement (NREM) sleep could strengthen declarative memories learned 24 h earlier. Twenty-six healthy young adults learned 30 sound word associations and returned the following day for a 90 min nap. During NREM sleep, participants in the Reactivation group received incomplete reminders consisting of the learned sound followed by the first syllable of the associated word, whereas the No-Reactivation group slept under the same conditions without memory related cues. Participants who received reminders showed significantly less forgetting, despite comparable training performance and sleep macroarchitecture. Across NREM sleep, reactivation was associated with greater slow oscillation and delta power, more slow oscillations and fast spindles, and greater slow oscillation spindle cooccurrence. The memory benefit remained significant after adjusting for NREM physiological measures and in sensitivity analyses restricted to overlapping physiological ranges between groups. Cue locked analyses revealed significant responses in the slow oscillation, delta, theta, and fast-spindle ranges, but the magnitude of these responses was not associated with memory change. These findings show that TMR during NREM sleep can benefit declarative memories after a 24 h consolidation interval and suggest that its effects extend beyond the immediate post-learning sleep period.

neuroscience↗

bioRxiv2025

ELECTROPHYSIOLOGICAL CORRELATES OF CONSCIOUS EXPERIENCES DURING SLEEP: LUCID DREAMS, SLEEP PARALYSIS, OUT-OF-BODY EXPERIENCES, AND FALSE AWAKENINGS

Consciousness does not always fade during sleep. Instead, it can re-emerge, giving rise to lucid dreams (LDs), sleep paralysis (SP), out-of-body experiences (OBEs), and false awakenings (FAs). While some of these states have been studied phenomenologically, their neurophysiological underpinnings remain unclear. Here, we investigate their electrophysiological correlates and distinguish them from standard sleep stages. We conducted overnight polysomnography in frequent experiencers, capturing 10 episodes (3 LDs, 2 SP, 2 OBEs, 3 FAs). Eye movement markers identified periods of lucidity. Relative spectral power was analyzed using principal component analysis (PCA) and permutation-based multivariate analysis of variance (PERMANOVA). Our results indicate that these conscious sleep states are distinct from wakefulness, yet share features with both stage 1 (S1) and rapid eye movement (REM) sleep. Notably, we provide the first documented eye movement markers during FAs and OBEs.

neuroscience↗