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The claustrum has been linked to attention and sleep. We hypothesized that this reflects a shared function, determining responsiveness to stimuli, which spans the axis of engagement. To test this hypothesis, we recorded claustrum population dynamics from male mice during both sleep and an attentional task ('ENGAGE'). Heightened activity in claustrum neurons projecting to the anterior cingulate cortex (ACCp) corresponded to reduced sensory responsiveness during sleep. Similarly, in the ENGAGE task, heightened ACCp activity correlated with disengagement and behavioral lapses, while low ACCp activity correlated with hyper-engagement and impulsive errors. Chemogenetic elevation of ACCp activity reduced both awakenings during sleep and impulsive errors in the ENGAGE task. Furthermore, mice employing an exploration strategy in the task showed a stronger correlation between ACCp activity and performance compared to mice employing an exploitation strategy which reduced task complexity. Our results implicate ACCp claustrum neurons in restricting engagement during sleep and goal-directed behavior. Attention and sleep have been associated with the claustrum. Here authors pinpoint a cluster of neurons in the claustrum of male mice that dynamically determines engagement levels during both sleep and an attentional task. [ABSTRACT FROM AUTHOR]

Objective: To confirm and investigate why pathological high‐frequency oscillations (pHFOs), including ripples (80–200 Hz) and fast ripples (200–600 Hz), are generated during the UP‐DOWN transition of the slow wave and if information transmission mediated by ripple temporal coupling is disrupted in the seizure‐onset zone (SOZ). Methods: We isolated 217 total units from 175.95 intracranial electroencephalography (iEEG) contact‐hours of synchronized macro‐ and microelectrode recordings from 6 patients. Sleep slow oscillation (.1–2 Hz) epochs were identified in the iEEG recording. iEEG HFOs that occurred superimposed on the slow wave were transformed to phasors and adjusted by the phase of maximum firing in nearby units (i.e., maximum UP). We tested whether, in the SOZ, HFOs and associated action potentials (APs) occur more often at the UP‐DOWN transition. We also examined ripple temporal correlations using cross‐correlograms. Results: At the group level in the SOZ, HFO and HFO‐associated AP probability was highest during the UP‐DOWN transition of slow wave excitability (p < <.001). In the non‐SOZ, HFO and HFO‐associated AP was highest during the DOWN‐UP transition (p < <.001). At the unit level in the SOZ, 15.6% and 20% of units exhibited more robust firing during ripples (Cohen's d =.11–.83) and fast ripples (d =.36–.90) at the UP‐DOWN transition (p <.05 f.d.r. corrected), respectively. By comparison, also in the SOZ, 6.6% (d =.14–.30) and 8.5% (d =.33–.41) of units had significantly less firing during ripples and fast ripples at the UP‐DOWN transition, respectively. Additional data shows that ripple and fast ripple temporal correlations, involving global slow waves, between the hippocampus, entorhinal cortex, and parahippocampal gyrus were reduced by >50% in the SOZ compared to the non‐SOZ (N = 3). Significance: The UP‐DOWN transition of slow wave excitability facilitates the activation of pathological neurons to generate pHFOs. Ripple temporal correlations across brain regions may be important in memory consolidation and are disrupted in the SOZ, perhaps by pHFO generation. [ABSTRACT FROM AUTHOR]

Summary Sleep improves the consolidation and long‐term stability of newly formed memories and associations. Most research on human declarative memory and its consolidation during sleep uses word‐pair associations requiring exhaustive learning. In the present study, we present the visual paired association learning (vPAL) paradigm, in which participants learn new associations between images of celebrities and animals. The vPAL is based on a one‐shot exposure that resembles learning in natural conditions. We tested if vPAL can reveal a role for sleep in memory consolidation by assessing the specificity of memory recognition, and the cued recall performance, before and after sleep. We found that a daytime nap improved the stability of recognition memory and discrimination abilities compared to identical intervals of wakefulness. By contrast, cued recall of associations did not exhibit significant sleep‐dependent effects. High‐density electroencephalography during naps further revealed an association between sleep spindle density and stability of recognition memory. Thus, the vPAL paradigm opens new avenues for future research on sleep and memory consolidation across ages and heterogeneous populations in health and disease. [ABSTRACT FROM AUTHOR]

Background: Assessments of gaze direction (eye movements), pupil size, and the pupillary light reflex (PLR) are critical for neurological examination and neuroscience research and constitute a powerful tool in diverse clinical settings ranging from critical care through endocrinology and drug addiction to cardiology and psychiatry. However, current bedside pupillometry is typically intermittent, qualitative, manual, and limited to open-eye cases, restricting its use in sleep medicine, anesthesia, and intensive care., Methods: We combined short-wave infrared (SWIR, ~0.9-1.7μm) imaging with image processing algorithms to perform rapid (~30 ms) pupillometry and eye tracking behind closed eyelids. Forty-three healthy volunteers participated in two experiments with PLR evoked by visible light stimuli or directing eye movements towards screen targets. Imaging was performed simultaneously on one eye closed, and the other open eye serving as ground truth. Data analysis was performed with a custom approach quantifying changes in brightness around the pupil area or with a deep learning U-NET-based procedure., Results: Here we show that analysis of SWIR imaging data can successfully measure stimulus-evoked PLR in closed-eye conditions, revealing PLR events in single trials and significant PLRs in nearly all individual subjects, as well as estimating gaze direction. The neural net-based analysis could successfully use closed-eye SWIR data to recreate estimates of open-eye images and assess pupil size., Conclusions: Continuous touchless monitoring of rapid dynamics in pupil size and gaze direction through closed eyes paves the way for developing devices with wide-ranging applications, fulfilling long-standing goals in clinical and research fields., (© 2024. The Author(s).)