Skeletal Muscle-Derived Cell Implantation for the Treatment of Fecal Incontinence: A Randomized, Placebo-Controlled Study.

BACKGROUND AND AIMS: Fecal incontinence (FI) improvement following injection of autologous skeletal muscle-derived cells has been previously suggested. This study aimed to test the efficacy and safety of said cells through a multicenter, placebo-controlled study, to determine an appropriate cell dose, and to delineate the target patient population that can most benefit from cell therapy. METHODS: Patients experiencing FI for at least 6 months were randomized to receive a cell-free medium or low or high dose of cells. All patients received pelvic floor electrical stimulation before and after treatment. Incontinence episode frequency (IEF), FI quality of life, FI burden assessed on a visual analog scale, Wexner score, and parameters reflecting anorectal physiological function were all assessed for up to 12 months. RESULTS: Cell therapy improved IEF, FI quality of life, and FI burden, reaching a preset level of statistical significance in IEF change compared with the control treatment. Post hoc exploratory analyses indicated that patients with limited FI duration and high IEF at baseline are most responsive to cells. Effects prevailed or increased in the high cell count group from 6 to 12 months but plateaued or diminished in the low cell count and control groups. Most physiological parameters remained unaltered. No unexpected adverse events were observed. CONCLUSIONS: Injection of a high dose of autologous skeletal muscle-derived cells followed by electrical stimulation significantly improved FI, particularly in patients with limited FI duration and high IEF at baseline, and could become a valuable tool for treatment of FI, subject to confirmatory phase 3 trial(s). (ClinicalTrialRegister.eu; EudraCT Number: 2010-021463-32).

Optimal Time-Entropy Bounds and Speed Limits for Brownian Thermal Shortcuts.

By controlling the variance of the radiation pressure exerted on an optically trapped microsphere in real time, we engineer temperature protocols that shortcut thermal relaxation when transferring the microsphere from one thermal equilibrium state to another. We identify the entropic footprint of such accelerated transfers and derive optimal temperature protocols that either minimize the production of entropy for a given transfer duration or accelerate the transfer for a given entropic cost as much as possible. Optimizing the trade-off yields time-entropy bounds that put speed limits on thermalization schemes. We further show how optimization expands the possibilities for accelerating Brownian thermalization down to its fundamental limits. Our approach paves the way for the design of optimized, finite-time thermodynamics for Brownian engines. It also offers a platform for investigating fundamental connections between information geometry and finite-time processes.

Ten-year Evaluation of a Large Retrospective Cohort Treated by Sacral Nerve Modulation for Fecal Incontinence: Results of a French Multicenter Study.

OBJECTIVE: The aim of this study was to assess the effectiveness of sacral nerve modulation (SNM) in a large cohort of patients implanted for at least 10 years, quantify adverse event rates, and identify predictive factors of long-term success. SUMMARY BACKGROUND DATA: Few studies have evaluated the long-term success of SNM. METHODS: Data collected prospectively from patients implanted for fecal incontinence (FI) in 7 French centers between January 1998 and December 2008 were retrospectively analyzed. Patient FI severity scores were assessed before and 10 years after implantation. The main evaluation criterion was the success of SNM defined by the continuation of the treatment without additional therapies. The secondary evaluation criteria were the rate of device revisions and explantations. Preoperative predictors of success at 10 years were sought. RESULTS: Of the 360 patients (27 males, mean age: 59 ± 12 years) implanted for FI, 162 (45%) had a favorable outcome 10 years post-implantation, 115 (31.9%) failed, and 83 (23.1%) were lost to follow-up. The favorable outcome derived from the time-to-event Kaplan-Meier curve at 10 years was 0.64 (95% CI 0.58-0.69). FI severity scores were significantly better 10 years post-implantation compared to preimplantation (7.4 ± 4.3 vs 14.0 ± 3.2; P < 0.0001). During the 10-year follow-up, 233 patients (64.7%) had a surgical revision and 94 (26.1%) were explanted. A history of surgery for FI and sex (male) were associated with an increased risk of an unfavorable outcome. CONCLUSIONS: Long-term efficacy was maintained in approximately half of the FI patients treated by SNM at least 10 years post-implantation.

Indirect X-ray detectors with single-photon sensitivity.

The new generation of synchrotron light sources are pushing X-ray detectors to their limits. Very demanding conditions with unprecedented flux and higher operating energies now require high-performance X-ray detectors combining sensitivity, efficiency and scalability. Over the years, hybrid pixel detectors have supplemented indirect detectors based on scintillation, with undeniable advantages. Such detectors based on silicon are, however, rather expensive to produce and are no more satisfying in terms of X-ray stopping power when targeting energies above 20 keV. An indirect detector with single X-ray photon sensitivity therefore offers promising opportunities for applications operating over a wide range of energies and fluxes. In this work, the performances of such an approach are investigated with state-of-the-art elements: a commercial sCMOS camera with fiber-optics plate coupling and a Gd2O2S:Tb powder-based scintillator. A simple method is presented for evaluation of the single X-ray photon detection limit and single X-ray sensitivity is demonstrated with the studied detector above 20 keV. Geant4 simulations also provide insight to better define the limiting factors. Finally, guidelines are provided for future R&D in the design and assembly of an innovative detector combining advantages of direct and indirect detection schemes.

Compact and versatile neutron imaging detector with sub-4µm spatial resolution based on a single-crystal thin-film scintillator.

A large and increasing number of scientific domains pushes for high neutron imaging resolution achieved in reasonable times. Here we present the principle, design and performance of a detector based on infinity corrected optics combined with a crystalline Gd3Ga5O12 : Eu scintillator, which provides an isotropic sub-4 µm true resolution. The exposure times are only of a few minutes per image. This is made possible also by the uniquely intense cold neutron flux available at the imaging beamline NeXT-Grenoble. These comparatively rapid acquisitions are compatible with multiple high quality tomographic acquisitions, opening new venues for in-operando testing, as briefly exemplified here.

Coincidence study of core-ionized adamantane: site-sensitivity within a carbon cage?

We investigate the fragmentation dynamics of adamantane dications produced after core-ionization at the carbon edge followed by Auger decay. The combination of high-resolution electron spectroscopy, energy-resolved electron-ion multi-coincidence spectroscopy and different theoretical models allows us to give a complete characterization of the processes involved after ionization. We show that energy- and site-sensitivity is observed even for a highly-symmetric molecule that lacks any unique atomic site.

Working and Reference Memory Tasks Trigger Opposed Long-Term Synaptic Changes in the Rat Dentate Gyrus.

Long-term storage of information into memory is supposed to rely on long-term synaptic plasticity processes. The detection of such synaptic changes after training in long-term/reference memory (RM) tasks has yet been scarce, variable and only studied on a short time scale. Short-term or working memory (WM) is largely known to depend on persistent neuronal activity or short-term plasticity. However, processing information into WM could also involve long-term synaptic changes that could be responsible for the erasure/forgetting of items previously stored in WM and acting as proactive interference. In order to study long-term synaptic changes associated with RM or WM, we trained chronically implanted rats in 3 different radial maze tasks: a classical RM task and 2 WM tasks involving different levels of proactive interference. Synaptic responses in the dentate gyrus were recorded during 2 × 24 h in freely moving rats after training. We found that consolidation of long-term information leads first to a delayed synaptic potentiation, occurring 9 h after RM training that is replaced by a synaptic depression once the RM rule is fully acquired. In contrast, optimal information processing into WM triggers a synaptic depression immediately after training and lasting 3 h that could act as a mechanism for interference erasure/forgetting.

Slow Waves Promote Sleep-Dependent Plasticity and Functional Recovery after Stroke.

Functional recovery after stroke is associated with a remapping of neural circuits. This reorganization is often associated with low-frequency, high-amplitude oscillations in the peri-infarct zone in both rodents and humans. These oscillations are reminiscent of sleep slow waves (SW) and suggestive of a role for sleep in brain plasticity that occur during stroke recovery; however, direct evidence is missing. Using a stroke model in male mice, we showed that stroke was followed by a transient increase in NREM sleep accompanied by reduced amplitude and slope of ipsilateral NREM sleep SW. We next used 5 ms optical activation of Channelrhodopsin 2-expressing pyramidal neurons, or 200 ms silencing of Archeorhodopsin T-expressing pyramidal neurons, to generate local cortical UP, or DOWN, states, respectively, both sharing similarities with spontaneous NREM SW in freely moving mice. Importantly, we found that single optogenetically evoked SW (SWopto) in the peri-infarct zone, randomly distributed during sleep, significantly improved fine motor movements of the limb corresponding to the sensorimotor stroke lesion site compared with spontaneous recovery and control conditions, while motor strength remained unchanged. In contrast, SWopto during wakefulness had no effect. Furthermore, chronic SWopto during sleep were associated with local axonal sprouting as revealed by the increase of anatomic presynaptic and postsynaptic markers in the peri-infarct zone and corresponding contralesional areas to cortical circuit reorganization during stroke recovery. These results support a role for sleep SW in cortical circuit plasticity and sensorimotor recovery after stroke and provide a clinically relevant framework for rehabilitation strategies using neuromodulation during sleep.SIGNIFICANCE STATEMENT Brain stroke is one of the leading causes of death and major disabilities in the elderly worldwide. A better understanding of the pathophysiological mechanisms underlying spontaneous brain plasticity after stroke, together with an optimization of rehabilitative strategies, are essential to improve stroke treatments. Here, we investigate the role of optogenetically induced sleep slow waves in an animal model of ischemic stroke and identify sleep as a window for poststroke intervention that promotes neuroplasticity and facilitates sensorimotor recovery.

Partial homologies between sleep states in lizards, mammals, and birds suggest a complex evolution of sleep states in amniotes.

It is crucial to determine whether rapid eye movement (REM) sleep and slow-wave sleep (SWS) (or non-REM sleep), identified in most mammals and birds, also exist in lizards, as they share a common ancestor with these groups. Recently, a study in the bearded dragon (P. vitticeps) reported states analogous to REM and SWS alternating in a surprisingly regular 80-s period, suggesting a common origin of the two sleep states across amniotes. We first confirmed these results in the bearded dragon with deep brain recordings and electro-oculogram (EOG) recordings. Then, to confirm a common origin and more finely characterize sleep in lizards, we developed a multiparametric approach in the tegu lizard, a species never recorded to date. We recorded EOG, electromyogram (EMG), heart rate, and local field potentials (LFPs) and included data on arousal thresholds, sleep deprivation, and pharmacological treatments with fluoxetine, a serotonin reuptake blocker that suppresses REM sleep in mammals. As in the bearded dragon, we demonstrate the existence of two sleep states in tegu lizards. However, no clear periodicity is apparent. The first sleep state (S1 sleep) showed high-amplitude isolated sharp waves, and the second sleep state (S2 sleep) displayed 15-Hz oscillations, isolated ocular movements, and a decrease in heart rate variability and muscle tone compared to S1. Fluoxetine treatment induced a significant decrease in S2 quantities and in the number of sharp waves in S1. Because S2 sleep is characterized by the presence of ocular movements and is inhibited by a serotonin reuptake inhibitor, as is REM sleep in birds and mammals, it might be analogous to this state. However, S2 displays a type of oscillation never previously reported and does not display a desynchronized electroencephalogram (EEG) as is observed in the bearded dragons, mammals, and birds. This suggests that the phenotype of sleep states and possibly their role can differ even between closely related species. Finally, our results suggest a common origin of two sleep states in amniotes. Yet, they also highlight a diversity of sleep phenotypes across lizards, demonstrating that the evolution of sleep states is more complex than previously thought.

European Society of Coloproctology guidance on the use of mesh in the pelvis in colorectal surgery.

This is a comprehensive and rigorous review of currently available data on the use of mesh in the pelvis in colorectal surgery. This guideline outlines the limitations of available data and the challenges of interpretation, followed by best possible recommendations.

Enterovirus Persistence in Cardiac Cells of Patients With Idiopathic Dilated Cardiomyopathy Is Linked to 5' Terminal Genomic RNA-Deleted Viral Populations With Viral-Encoded Proteinase Activities.

BACKGROUND: Group B enteroviruses are common causes of acute myocarditis, which can be a precursor of chronic myocarditis and dilated cardiomyopathy, leading causes of heart transplantation. To date, the specific viral functions involved in the development of dilated cardiomyopathy remain unclear. METHODS: Total RNA from cardiac tissue of patients with dilated cardiomyopathy was extracted, and sequences corresponding to the 5' termini of enterovirus RNAs were identified. After next-generation RNA sequencing, viral cDNA clones mimicking the enterovirus RNA sequences found in patient tissues were generated in vitro, and their replication and impact on host cell functions were assessed on primary human cardiac cells in culture. RESULTS: Major enterovirus B populations characterized by 5' terminal genomic RNA deletions ranging from 17 to 50 nucleotides were identified either alone or associated with low proportions of intact 5' genomic termini. In situ hybridization and immunohistological assays detected these persistent genomes in clusters of cardiomyocytes. Transfection of viral RNA into primary human cardiomyocytes demonstrated that deleted forms of genomic RNAs displayed early replication activities in the absence of detectable viral plaque formation, whereas mixed deleted and complete forms generated particles capable of inducing cytopathic effects at levels distinct from those observed with full-length forms alone. Moreover, deleted or full-length and mixed forms of viral RNA were capable of directing translation and production of proteolytically active viral proteinase 2A in human cardiomyocytes. CONCLUSIONS: We demonstrate that persistent viral forms are composed of B-type enteroviruses harboring a 5' terminal deletion in their genomic RNAs and that these viruses alone or associated with full-length populations of helper RNAs could impair cardiomyocyte functions by the proteolytic activity of viral proteinase 2A in cases of unexplained dilated cardiomyopathy. These results provide a better understanding of the molecular mechanisms that underlie the persistence of EV forms in human cardiac tissues and should stimulate the development of new therapeutic strategies based on specific inhibitors of the coxsackievirus B proteinase 2A activity for acute and chronic cardiac infections.

FDXR Mutations Cause Sensorial Neuropathies and Expand the Spectrum of Mitochondrial Fe-S-Synthesis Diseases.

Hearing loss and visual impairment in childhood have mostly genetic origins, some of them being related to sensorial neuronal defects. Here, we report on eight subjects from four independent families affected by auditory neuropathy and optic atrophy. Whole-exome sequencing revealed biallelic mutations in FDXR in affected subjects of each family. FDXR encodes the mitochondrial ferredoxin reductase, the sole human ferredoxin reductase implicated in the biosynthesis of iron-sulfur clusters (ISCs) and in heme formation. ISC proteins are involved in enzymatic catalysis, gene expression, and DNA replication and repair. We observed deregulated iron homeostasis in FDXR mutant fibroblasts and indirect evidence of mitochondrial iron overload. Functional complementation in a yeast strain in which ARH1, the human FDXR ortholog, was deleted established the pathogenicity of these mutations. These data highlight the wide clinical heterogeneity of mitochondrial disorders related to ISC synthesis.

Mutations in TUBB4B Cause a Distinctive Sensorineural Disease.

Leber congenital amaurosis (LCA) is a neurodegenerative disease of photoreceptor cells that causes blindness within the first year of life. It occasionally occurs in syndromic metabolic diseases and plurisystemic ciliopathies. Using exome sequencing in a multiplex family and three simplex case subjects with an atypical association of LCA with early-onset hearing loss, we identified two heterozygous mutations affecting Arg391 in ß-tubulin 4B isotype-encoding (TUBB4B). Inspection of the atomic structure of the microtubule (MT) protofilament reveals that the ß-tubulin Arg391 residue contributes to a binding pocket that interacts with α-tubulin contained in the longitudinally adjacent αß-heterodimer, consistent with a role in maintaining MT stability. Functional analysis in cultured cells overexpressing FLAG-tagged wild-type or mutant TUBB4B as well as in primary skin-derived fibroblasts showed that the mutant TUBB4B is able to fold, form αß-heterodimers, and co-assemble into the endogenous MT lattice. However, the dynamics of growing MTs were consistently altered, showing that the mutations have a significant dampening impact on normal MT growth. Our findings provide a link between sensorineural disease and anomalies in MT behavior and describe a syndromic LCA unrelated to ciliary dysfunction.

Multiscale pink-beam microCT imaging at the ESRF-ID17 biomedical beamline.

Recent trends in hard X-ray micro-computed tomography (microCT) aim at increasing both spatial and temporal resolutions. These challenges require intense photon beams. Filtered synchrotron radiation beams, also referred to as `pink beams', which are emitted by wigglers or bending magnets, meet this need, owing to their broad energy range. In this work, the new microCT station installed at the biomedical beamline ID17 of the European Synchrotron is described and an overview of the preliminary results obtained for different biomedical-imaging applications is given. This new instrument expands the capabilities of the beamline towards sub-micrometre voxel size scale and simultaneous multi-resolution imaging. The current setup allows the acquisition of tomographic datasets more than one order of magnitude faster than with a monochromatic beam configuration.

Practical issues encountered while determining Minimal Clinically Important Difference in Patient-Reported Outcomes.

BACKGROUND: Using a real dataset, we highlighted several major methodological issues raised by the estimation of the Minimal Clinically Important Difference (MCID) of a Patient-Reported Outcomes instrument. We especially considered the management of missing data and the use of more than two times of measurement. While inappropriate missing data management and inappropriate use of multiple time points can lead to loss of precision and/or bias in MCID estimation, these issues are almost never dealt with and require cautious considerations in the context of MCID estimation. METHODS: We used the LIGALONGO study (French Randomized Controlled Trial). We estimated MCID on the SF-36 General Health score by comparing many methods (distribution or anchor-based). Different techniques for imputation of missing data were performed (simple and multiple imputations). We also consider all measurement occasions by longitudinal modeling, and the dependence of the score difference on baseline. RESULTS: Three hundred ninety-three patients were studied. With distribution-based methods, a great variability in MCID was observed (from 3 to 26 points for improvement). Only 0.2 SD and 1/3 SD distribution methods gave MCID values consistent with anchor-based methods (from 4 to 7 points for improvement). The choice of missing data imputation technique clearly had an impact on MCID estimates. Simple imputation by mean score seemed to lead to out-of-range estimate, but as missing not at random mechanism can be hypothesized, even multiple imputations techniques can have led to an slight underestimation of MCID. Using 3 measurement occasions for improvement led to an increase in precision but lowered estimates. CONCLUSION: This practical example illustrates the substantial impact of some methodological issues that are usually never dealt with for MCID estimation. Simulation studies are needed to investigate those issues. TRIAL REGISTRATION: NCT01240772 (ClinicalTrials.gov) registered on November 15, 2010.

Functional Results and Quality of Life Following Magnetic Anal Sphincter Augmentation in Severely Incontinent Patients.

OBJECTIVE: Magnetic anal sphincter augmentation is a novel surgical option in the treatment of severe fecal incontinence. This study aimed to analyze functional results, quality of life, and satisfaction after implantation in the mid-term, and to identify factors associated with success of this new treatment. METHODS: All patients, who underwent magnetic anal sphincter augmentation procedure at a single center between December 2008 and January 2016, were consecutively included. Symptom severity [Cleveland Clinic Incontinence Score (CCIS)], quality of life [Fecal-Incontinence Quality of Life Questionnaire (FIQL)], bowel diary data, and patients' satisfaction were assessed before and after implantation. RESULTS: Forty-five patients (43 female), mean (s.d.) age 66.82 (±10.07), were followed for a median of 36 months (range 6-84). Two patients were explanted and 1 lost to follow-up. On a 3-week diary, major leakage rate significantly improved as did CCIS and FIQL. No significant difference was seen for flatus and minor leaks. Postoperative decrease of CCIS by ≥5.5 points correlated best with satisfaction, expressed by 22 patients (48% in intention-to-treat analysis). An independent predictive factor for success after implantation was no previous fecal incontinence surgical treatment. CONCLUSIONS: Satisfaction, functional, and quality of life outcomes improve significantly following magnetic anal sphincter augmentation.

Long-term Outcome of Hirschsprung Disease: Impact on Quality of Life and Social Condition at Adult Age.

BACKGROUND: Hirschsprung disease is a rare congenital disease typically requiring surgical treatment during childhood. Quality of life and social condition at adult age can be impaired by disease-specific sequelae. OBJECTIVE: This study aimed to assess the quality of life and social outcome of adult patients operated on for Hirschsprung disease during childhood. DESIGN: Patients operated on for Hirschsprung disease during childhood were identified and specific questionnaires were sent to them. SETTINGS: Data from 2 referral centers were used. PATIENTS: Patients who completed the questionnaires regarding quality of life and social condition were included. MAIN OUTCOME MEASURES: The Hirschsprung's Disease and Anorectal Malformations Quality of Life disease-specific questionnaire (8 dimensions explored; each scored from 0 to 100 maximum score) and a sociodemographic questionnaire were sent to identified patients. Sociodemographic data were compared with those of the French general population. RESULTS: Thirty-four patients had Hirschsprung disease (men, 76%; mean age, 32 years) were included in the study. Mean total Hirschsprung's Disease and Anorectal Malformations Quality of Life score was 611 of 800 (maximum score 800). The 2 most impaired dimensions were "physical symptoms" and "diarrhea" (62.9/100 and 73.6/100). Fecal continence was only marginally affected (mean score, 89/100). Patients with Hirschsprung disease achieved better educational levels than the French general population. Parental and marital status did not differ between the 2 groups. LIMITATIONS: This study had the limitations inherent to a retrospective study. CONCLUSION: The quality of life of adult patients with Hirschsprung disease sequelae is marginally impaired in this study. Despite the consequences of this congenital abnormality, the condition eventually achieved can be considered as satisfactory. See Video Abstract at http://links.lww.com/DCR/A917.

From Biological Determination to Entangled Causation.

Biologists and philosophers often use the language of determination in order to describe the nature of developmental phenomena. Accounts in terms of determination have often been reductionist. One common idea is that DNA is supposed to play a special explanatory role in developmental explanations, namely, that DNA is a developmental determinant. In this article we try to make sense of determination claims in developmental biology. Adopting a manipulationist approach, we shall first argue that the notion of developmental determinant is causal. We suggest that two different theses concerning developmental determination can be articulated: determination of occurrence and structural determination. We shall argue that, while the first thesis is problematic, the second, opportunely qualified, is feasible. Finally, we shall argue that an analysis of biological causation in terms of determination cannot account for entangled dynamics. Characterising causal entanglement as a particular kind of interactive causation whereby difference-making causes ascribable to different levels of biological organisation influence a particular ontogenetic outcome, we shall, via two illustrative examples, diagnose some potential limits of a reductionist, molecular and intra-level understanding of biological causation.

Is Sacral Nerve Modulation a Good Option for Fecal Incontinence in Men?

OBJECTIVE: The objective was to assess the efficacy and the safety of sacral nerve modulation (SNM) in men with fecal incontinence (FI) compared with those of SNM in women. METHOD: Prospectively collected data from patients from seven tertiary colorectal units who underwent an implant procedure between January 2010 and December 2015 were reviewed retrospectively. Outcomes and surgical revision and definitive explantation rates were compared between men and women. RESULTS: A total of 469 patients (60 men [12.8%]; mean age = 61.4 ± 12.0 years) were included in the study, 352 (78.1%) (31 men [8.8%]) of whom received a permanent implant. The ratio of implanted/tested men was significantly lower than the ratio of implanted/tested women (p = 0.0004). After a mean follow-up of 3.4 ± 1.9 years, the cumulative successful treatment rates tended to be less favorable in men than in women (p = 0.0514): 88.6% (75.6-95.1), 75.9% (60.9-86.4), 63.9% (48.0-77.3), and 43.9% (26.7-62.7) at one, two, three, and five years, respectively, in men; 92.0% (89.1-94.2), 84.2% (80.3-87.4), 76.8% (72.3-80.7), and 63.6% (57.5-69.3) at one, two, three, and five years, respectively, in women. The revision rate for infection and the definitive explantation rate for infection were higher in men than in women (p = 0.0001 and p = 0.0024, respectively). CONCLUSION: Both short- and long-term success rates of SNM for FI were lower in men than in women. The revision and definitive explantation for long-term infection rates were significantly higher in men.

Electrophysiological Evidence That the Retrosplenial Cortex Displays a Strong and Specific Activation Phased with Hippocampal Theta during Paradoxical (REM) Sleep.

It is widely accepted that cortical neurons are similarly more activated during waking and paradoxical sleep (PS; aka REM) than during slow-wave sleep (SWS). However, we recently reported using Fos labeling that only a few limbic cortical structures including the retrosplenial cortex (RSC) and anterior cingulate cortex (ACA) contain a large number of neurons activated during PS hypersomnia. Our aim in the present study was to record local field potentials and unit activity from these two structures across all vigilance states in freely moving male rats to determine whether the RSC and the ACA are electrophysiologically specifically active during basal PS episodes. We found that theta power was significantly higher during PS than during active waking (aWK) similarly in the RSC and hippocampus (HPC) but not in ACA. Phase-amplitude coupling between HPC theta and gamma oscillations strongly and specifically increased in RSC during PS compared with aWK. It did not occur in ACA. Further, 68% and 43% of the units recorded in the RSC and ACA were significantly more active during PS than during aWK and SWS, respectively. In addition, neuronal discharge of RSC but not of ACA neurons increased just after the peak of hippocampal theta wave. Our results show for the first time that RSC neurons display enhanced spiking in synchrony with theta specifically during PS. We propose that activation of RSC neurons specifically during PS may play a role in the offline consolidation of spatial memories, and in the generation of vivid perceptual scenery during dreaming.SIGNIFICANCE STATEMENT Fifty years ago, Michel Jouvet used the term paradoxical to define REM sleep because of the simultaneous occurrence of a cortical activation similar to waking accompanied by muscle atonia. However, we recently demonstrated using functional neuroanatomy that only a few limbic structures including the retrosplenial cortex (RSC) and anterior cingulate cortex (ACA) are activated during PS. In the present study, we show for the first time that the RSC and ACA contain neurons firing more during PS than in any other state. Further, RSC neurons are firing in phase with the hippocampal theta rhythm. These data indicate that the RSC is very active during PS and could play a key role in memory consolidation taking place during this state.