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The effect of quantum radiation-pressure fluctuations on the collective motion of ultracold atoms is observed in a cavity-optomechanical system, and the back-action of this motion on the cavity light field is shown to produce sub-shot-noise optical squeezing. Radiation pressure's quantum signature Cavity optomechanics — the study of the phenomenon by which light exerts a force on massive objects in a cavity through a force known as radiation pressure — is a highly active research field. Until now it has not been possible to detect quantum aspects of this force because of the masking effect of technical and thermal noise. Here, Daniel Brooks et al . report a cavity optomechanical system consisting of ultracold atoms in which the collective atomic motion is dominantly driven by fluctuations in quantum radiation pressure. The back-action of this motion onto the cavity light field produces a quantum effect known as ponderomotive squeezing. The results could lead to various applications, including subquantum-limited measurements in optomechanical sensors, fundamental tests of quantum mechanics at macroscopic scales and mechanical links between quantum devices. Optomechanical systems 1 , in which light drives and is affected by the motion of a massive object, will comprise a new framework for nonlinear quantum optics, with applications ranging from the storage 2 , 3 , 4 and transduction 5 , 6 of quantum information to enhanced detection sensitivity in gravitational wave detectors 7 , 8 . However, quantum optical effects in optomechanical systems have remained obscure, because their detection requires the object’s motion to be dominated by vacuum fluctuations in the optical radiation pressure; so far, direct observations have been stymied by technical and thermal noise. Here we report an implementation of cavity optomechanics 9 , 10 using ultracold atoms in which the collective atomic motion is dominantly driven by quantum fluctuations in radiation pressure. The back-action of this motion onto the cavity light field produces ponderomotive squeezing 11 , 12 . We detect this quantum phenomenon by measuring sub-shot-noise optical squeezing. Furthermore, the system acts as a low-power, high-gain, nonlinear parametric amplifier for optical fluctuations, demonstrating a gain of 20 dB with a pump corresponding to an average of only seven intracavity photons. These findings may pave the way for low-power quantum optical devices, surpassing quantum limits on position and force sensing 13 , 14 , and the control and measurement of motion in quantum gases.

Law, like religion, provided one of the principal discourses through which early-modern English people conceptualised the world in which they lived. Transcending traditional boundaries between social, legal and political history, this innovative and authoritative study examines the development of legal thought and practice from the later middle ages through to the outbreak of the English civil war, and explores the ways in which law mediated and constituted social and economic relationships within the household, the community, and the state at all levels. By arguing that English common law was essentially the creation of the wider community, it challenges many current assumptions and opens new perspectives about how early-modern society should be understood. Its magisterial scope and lucid exposition will make it essential reading for those interested in subjects ranging from high politics and constitutional theory to the history of the family, as well as the history of law.

Cerebellar damage during posterior fossa surgery in children can lead to ataxia and risk of cerebellar mutism syndrome. Compartmentalisation of sensorimotor and cognitive functions within the cerebellum have been demonstrated in animal electrophysiology and human imaging studies. Electrophysiological monitoring was carried out under general anaesthesia to assess the limb sensorimotor representation within the human cerebellum for assessment of neurophysiological integrity to reduce the incidence of surgical morbidities. Thirteen adult and paediatric patients undergoing posterior fossa surgery were recruited. Sensory evoked field potentials were recorded in response to mapping (n = 8) to electrical stimulation of limb nerves or muscles. For motor mapping (n = 5), electrical stimulation was applied to the surface of the cerebellum and evoked EMG responses were sought in facial and limb muscles. Sensory evoked potentials were found in two patients (25%). Responses were located on the surface of the right inferior posterior cerebellum to stimulation of the right leg in one patient, and on the left inferior posterior lobe in another patient to stimulation of left forearm. No evoked EMG responses were found for the motor mapping. The present study identifies challenges with using neurophysiological methods to map functional organization within the human cerebellum and considers ways to improve success.

Pain sensitivity variations represent a critical frontier in pain neuroscience, where advanced neuroimaging has mapped cerebral correlates of nociception for decades, yet conventional brain-centric models persistently overlook the spinal cord’s hub role in pain gating and amplification. Here we show that a corticospinal pain sensitivity signature, a pattern of functional connectivity from simultaneous corticospinal magnetic resonance imaging, predicts individual pain sensitivity and clinical pain. Trained on resting-state data and validated across independent healthy (n = 723) and patient cohorts ( n  = 46), the model generalized to new datasets, distinguished pain from non-pain, and outperformed brain-centric models. Crucially, transcranial magnetic stimulation perturbation revealed a causal axis where enhanced motor cortex-spinal connectivity directly changes pain perception (r = 0.55). These results indicate a previously unknown corticospinal biomarker that bridges laboratory pain measures and patient symptoms, providing insights into translating pain mechanisms from healthy individuals to clinical populations and informing neuromodulation approaches. In this study, the authors present an fMRI‑based signature of corticospinal connections, which predicts individual pain sensitivity, generalizes to patient cohorts, and tracks changes after brain stimulation, suggesting a biomarker to guide personalized pain care.

Functional magnetic resonance imaging (fMRI) of the human spinal cord is a difficult endeavour due to the cord's small cross-sectional diameter, signal drop-out as well as image distortion due to magnetic field inhomogeneity, and the confounding influence of physiological noise from cardiac and respiratory sources. Nevertheless, there is great interest in spinal fMRI due to the spinal cord's role as the principal sensorimotor interface between the brain and the body and its involvement in a variety of sensory and motor pathologies. In this review, we give an overview of the various methods that have been used to address the technical challenges in spinal fMRI, with a focus on reducing the impact of physiological noise. We start out by describing acquisition methods that have been tailored to the special needs of spinal fMRI and aim to increase the signal-to-noise ratio and reduce distortion in obtained images. Following this, we concentrate on image processing and analysis approaches that address the detrimental effects of noise. While these include variations of standard pre-processing methods such as motion correction and spatial filtering, the main focus lies on denoising techniques that can be applied to task-based as well as resting-state data sets. We review both model-based approaches that rely on externally acquired respiratory and cardiac signals as well as data-driven approaches that estimate and correct for noise using the data themselves. We conclude with an outlook on techniques that have been successfully applied for noise reduction in brain imaging and whose use might be beneficial for fMRI of the human spinal cord. •We describe problems faced when acquiring functional data from the human spinal cord.•We discuss different model-based and data-driven approaches to correct these problems.•We provide an outlook on other correction techniques that might be useful in the cord.

Upon receiving a correction, initially presented misinformation often continues to influence people's judgment and reasoning. Whereas some researchers believe that this so-called continued influence effect of misinformation (CIEM) simply arises from the insufficient encoding and integration of corrective claims, others assume that it arises from a competition between the correct information and the initial misinformation in memory. To examine these possibilities, we conducted two functional magnetic resonance imaging (fMRI) studies. In each study, participants were asked to (a) read a series of brief news reports that contained confirmations or corrections of prior information and (b) evaluate whether subsequently presented memory probes matched the reports' correct facts rather than the initial misinformation. Both studies revealed that following correction-containing news reports, participants struggled to refute mismatching memory probes, especially when they referred to initial misinformation (as opposed to mismatching probes with novel information). We found little evidence, however, that the encoding of confirmations and corrections produced systematic neural processing differences indicative of distinct encoding strategies. Instead, we discovered that following corrections, participants exhibited increased activity in the left angular gyrus and the bilateral precuneus in response to mismatching memory probes that contained prior misinformation, compared to novel mismatch probes. These findings favour the notion that people's susceptibility to the CIEM arises from the concurrent retention of both correct and incorrect information in memory. •Investigated the neural mechanisms underlying the encoding and retrieval of confirmatory and corrective information.•No differences in neural activity were observed between the encoding of confirmations and corrections of prior information.•Bilateral parietal activity was unique to the presentation of misinformation-related cues following correction reports.•Results provide initial support for the concurrent-storage hypothesis of the CIEM.

•Reliability of spinal cord resting-state functional connectivity was investigated in 45 healthy participants using fMRI at 3T.•Reliability was in the fair-to-good range, though lower when looking at more focal aspects, i.e. segmental connectivity.•Different noise sources (physiological noise and thermal noise) impacted connectivity amplitude and reliability in distinct ways. The investigation of spontaneous fluctuations of the blood-oxygen-level-dependent (BOLD) signal has recently been extended from the brain to the spinal cord, where it has stimulated interest from a clinical perspective. A number of resting-state functional magnetic resonance imaging (fMRI) studies have demonstrated robust functional connectivity between the time series of BOLD fluctuations in bilateral dorsal horns and between those in bilateral ventral horns, in line with the functional neuroanatomy of the spinal cord. A necessary step prior to extension to clinical studies is assessing the reliability of such resting-state signals, which we aimed to do here in a group of 45 healthy young adults at the clinically prevalent field strength of 3T. When investigating connectivity in the entire cervical spinal cord, we observed fair to good reliability for dorsal-dorsal and ventral-ventral connectivity, whereas reliability was poor for within- and between-hemicord dorsal-ventral connectivity. Considering how prone spinal cord fMRI is to noise, we extensively investigated the impact of distinct noise sources and made two crucial observations: removal of physiological noise led to a reduction in functional connectivity strength and reliability – due to the removal of stable and participant-specific noise patterns – whereas removal of thermal noise considerably increased the detectability of functional connectivity without a clear influence on reliability. Finally, we also assessed connectivity within spinal cord segments and observed that while the pattern of connectivity was similar to that of whole cervical cord, reliability at the level of single segments was consistently poor. Taken together, our results demonstrate the presence of reliable resting-state functional connectivity in the human spinal cord even after thoroughly accounting for physiological and thermal noise, but at the same time urge caution if focal changes in connectivity (e.g. due to segmental lesions) are to be studied, especially in a longitudinal manner.

Establishing the reliability of spinal cord functional magnetic resonance imaging (fMRI) is critical before employing it to assess experimental or clinical interventions. Previous studies have mapped human motor activity primarily to the ipsilateral ventral horn, aligning with myotomal and dermatomal projections. Despite these insights, the test-retest reliability of spinal fMRI remains under-investigated. Here we assessed spinal cord activation during a sensorimotor paradigm involving right-hand grasping and grip force estimation in 30 healthy volunteers. Participants completed two identical scanning visits, each time performing the same task twice, enabling the investigation of test-retest reliability both within a single experimental visit and between visits performed on different days. Aggregating all task runs, motor-evoked activation was observed in ipsilateral ventro-dorsal regions of spinal segmental levels C5-T1, as well as in medial regions of levels C2-C3. Despite highly reliable task performance (grip force) and fMRI signal quality (temporal signal-to-noise ratio), the reliability of motor activation was predominantly poor-to-fair both within and between visits, with notable variability in spatial distribution observed across task runs. Increasing the number of task runs per individual improved the robustness of group-level activation, as indexed by higher activated voxel count, larger cluster spatial extent, and attenuated t-statistic distribution. Although we demonstrated that motor-evoked activation corresponds to the known neuroanatomical organisation of motor circuits, its low test-retest reliability presents a challenge for wider applications of spinal fMRI. Understanding the drivers of low reliability in functional imaging is warranted, but we suggest that looking beyond measurement error is required, including careful consideration of inherent within-individual variability underpinned by neurophysiological and psychological factors.

Systemic infection and inflammation impair mental function through a combination of altered attention and cognition. Here, we comprehensively review the relevant literature and report personal clinical observations to discuss the relationship between infection, peripheral inflammation, and cerebral and cognitive dysfunction in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Cognitive dysfunction in ME/CFS could result from low-grade persistent inflammation associated with raised pro-inflammatory cytokines. This may be caused by both infectious and non-infectious stimuli and lead to altered regional cerebral blood flow accompanied by disturbed neuronal function. Immune dysregulation that manifests as a subtle immunodeficiency or the autoimmunity targeting of one or more neuronal receptors may also be a contributing factor. Efforts to reduce low-grade systemic inflammation and viral reactivation and to improve mitochondrial energy generation in ME/CFS have the potential to improve cognitive dysfunction in this highly disabling condition.