Publications by authors named "John Downey"

. As brain-computer interface (BCI) research advances, many new applications are being developed. Tasks can be performed in different virtual environments, and whether a BCI user can switch environments seamlessly will influence the ultimate utility of a clinical device.

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Intracortical microstimulation (ICMS) of somatosensory cortex evokes tactile sensations whose properties can be systematically manipulated by varying stimulation parameters. However, ICMS currently provides an imperfect sense of touch, limiting manual dexterity and tactile experience. Leveraging our understanding of how tactile features are encoded in the primary somatosensory cortex (S1), we sought to inform individuals with paralysis about local geometry and apparent motion of objects on their skin.

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Intracortical microstimulation (ICMS) is a method for restoring sensation to people with paralysis as part of a bidirectional brain-computer interface (BCI) to restore upper limb function. Evoking tactile sensations of the hand through ICMS requires precise targeting of implanted electrodes. Here we describe the presurgical imaging procedures used to generate functional maps of the hand area of the somatosensory cortex and subsequent planning that guided the implantation of intracortical microelectrode arrays.

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Tactile feedback from brain-controlled bionic hands can be partially restored via intracortical microstimulation (ICMS) of the primary somatosensory cortex. In ICMS, the location of percepts depends on the electrode's location and the percept intensity depends on the stimulation frequency and amplitude. Sensors on a bionic hand can thus be linked to somatotopically appropriate electrodes, and the contact force of each sensor can be used to determine the amplitude of a stimulus.

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Precise anatomical implantation of a microelectrode array is fundamental for successful brain-computer interface (BCI) surgery, ensuring high-quality, robust signal communication between the brain and the computer interface. Robotic neurosurgery can contribute to this goal, but its application in BCI surgery has been underexplored. Here, the authors present a novel robot-assisted surgical technique to implant rigid intracortical microelectrode arrays for the BCI.

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Understanding how the body is represented in motor cortex is key to understanding how the brain controls movement. The precentral gyrus (PCG) has long been thought to contain largely distinct regions for the arm, leg and face (represented by the "motor homunculus"). However, mounting evidence has begun to reveal a more intermixed, interrelated and broadly tuned motor map.

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Populations of neurons produce activity with two central features. First, neuronal responses are very diverse - specific stimuli or behaviors prompt some neurons to emit many action potentials, while other neurons remain relatively silent. Second, the trial-to-trial fluctuations of neuronal response occupy a low dimensional space, owing to significant correlations between the activity of neurons.

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As brain-computer interface (BCI) research advances, many new applications are being developed. Tasks can be performed in different environments, and whether a BCI user can switch environments seamlessly will influence the ultimate utility of a clinical device. Here we investigate the importance of the immersiveness of the virtual environment used to train BCI decoders on the resulting decoder and its generalizability between environments.

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Intracortical microstimulation (ICMS) is a method for restoring sensation to people with paralysis as part of a bidirectional brain-computer interface to restore upper limb function. Evoking tactile sensations of the hand through ICMS requires precise targeting of implanted electrodes. Here we describe the presurgical imaging procedures used to generate functional maps of the hand area of the somatosensory cortex and subsequent planning that guided the implantation of intracortical microelectrode arrays.

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Background: Exercise Referral Schemes (ERS) are designed so health professionals can refer certain patients to a supervised programme of physical activity. However, evaluations have questioned the effectiveness of these schemes/programmes. The aim of this study was to systematically review the provision of ERS in England and analyse related promotional material.

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Volunteers are a popular unpaid support role in end of life care yet how accompaniment influences the dying is underdeveloped. This study examined how companionship works, for whom, in what circumstances and why. Initial realist ideas were developed through participant observation (14 months), document analysis, and realist interviews with companionship trainers ( = 6).

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The primary motor (M1) and somatosensory (S1) cortices play critical roles in motor control but the signaling between these structures is poorly understood. To fill this gap, we recorded - in three participants in an ongoing human clinical trial (NCT01894802) for people with paralyzed hands - the responses evoked in the hand and arm representations of M1 during intracortical microstimulation (ICMS) in the hand representation of S1. We found that ICMS of S1 activated some M1 neurons at short, fixed latencies consistent with monosynaptic activation.

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When we interact with objects, we rely on signals from the hand that convey information about the object and our interaction with it. A basic feature of these interactions, the locations of contacts between the hand and object, is often only available via the sense of touch. Information about locations of contact between a brain-controlled bionic hand and an object can be signaled via intracortical microstimulation (ICMS) of somatosensory cortex (S1), which evokes touch sensations that are localized to a specific patch of skin.

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Article Synopsis
  • Tactile signals from the hand are crucial for manual interactions, and they can be restored in bionic hands using a technique called intracortical microstimulation (ICMS) of the somatosensory cortex (S1).
  • In this study, researchers tested the effectiveness of ICMS-based tactile feedback in human participants by examining how well they could perceive different levels of sensation based on stimulation intensity and force sensors in the bionic hand.
  • The results demonstrated that using multi-channel biomimetic ICMS, which mimics natural touch patterns, provided stronger and more distinct sensations, leading to better performance in tasks that require force discrimination compared to traditional single-channel methods.
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Background: Palliative care requires innovative methods to understand what works, for whom, in what circumstances and why. Realist evaluation has become one prominent approach due to its preoccupation with building, and testing, causal theories to explain the influence of contextual factors on outcomes. Undertaking realist evaluation is not without challenges and may amplify issues of underrepresentation, disempower those working in palliative care, and produce results with poor ecological validity.

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Objective: To evaluate breast density notification legislation (BDNL) on breast imaging practice patterns, risk assessment, and supplemental screening.

Methods: A 20-question anonymous web-based survey was administered to practicing Society of Breast Imaging radiologists in the U.S.

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Microelectrode arrays are standard tools for conducting chronic electrophysiological experiments, allowing researchers to simultaneously record from large numbers of neurons. Specifically, Utah electrode arrays (UEAs) have been utilized by scientists in many species, including rodents, rhesus macaques, marmosets, and human participants. The field of clinical human brain-computer interfaces currently relies on the UEA as a number of research groups have clearance from the United States Federal Drug Administration (FDA) for this device through the investigational device exemption pathway.

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Article Synopsis
  • - The study aimed to assess the stability of intracortical microelectrodes implanted in the motor and somatosensory cortex of a person with a spinal cord injury, focusing on how recording quality changes over time and the ability to evoke sensations through stimulation.
  • - Findings showed that while both types of electrodes (platinum in the motor cortex and sputtered iridium oxide film (SIROF) in the somatosensory cortex) exhibited decreased signal quality over time, SIROF electrodes were better at continuously recording high-quality signals.
  • - The detection thresholds for sensations evoked by stimulation decreased significantly over the course of the study, suggesting that ICMS can effectively provide sensory feedback for an extended period without adversely affecting recording
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Objective: To determine the impact of the COVID-19 pandemic on breast imaging education.

Methods: A 22-item survey addressing four themes during the early pandemic (time on service, structured education, clinical training, future plans) was emailed to Society of Breast Imaging members and members-in-training in July 2020. Responses were compared using McNemar's and Mann-Whitney tests; a general linear model was used for multivariate analysis.

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Article Synopsis
  • Prosthetic arms can be controlled by brain-computer interfaces (BCIs), allowing people with tetraplegia to perform functional movements, but they often lack effective feedback during grasping.
  • To enhance feedback, researchers used a bidirectional BCI that records brain activity and provides tactile sensations through microstimulation of the somatosensory cortex, improving the user's experience.
  • With this technology, a participant significantly improved their performance with a robotic limb, cutting their task completion time in half from 20.9 seconds to 10.2 seconds by reducing time spent on grasping objects.
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Objective: To determine the early impact of the COVID-19 pandemic on breast imaging centers in California and Texas and compare regional differences.

Methods: An 11-item survey was emailed to American College of Radiology accredited breast imaging facilities in California and Texas in August 2020. A question subset addressed March-April government restrictions on elective services ("during the shutdown" and "after reopening").

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The utilization of person-centered care is highlighted as essential for health promotion, yet implementation has been inconsistent and multiple issues remain. There is a dearth of applied research exploring the facets of successful implementation. In this paper, a person-centered wellbeing program spanning various groups is discussed, outlining the central principles that have allowed for successful outcomes.

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Background: Exercise Referral Schemes have been delivered worldwide in developed countries to augment physical activity levels in sedentary patients with a range of health issues, despite their utility being questioned. Understanding the implementation mechanisms of behaviour change practices is important to avoid inappropriate decommissioning and support future service planning. The aim of this study was to develop initial theories to understand what influences the behaviour change practices of Exercise Referral practitioners within the United Kingdom.

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Article Synopsis
  • Motor commands for arm and hand movements usually come from the opposite side of the brain (contralateral motor cortex), but the same side (ipsilateral motor cortex) also shows some activity related to these movements, leading to confusion in previous research.
  • This study used implanted microelectrodes to record neural activity from two subjects while they performed arm and hand movements in a virtual setting, aiming to understand the strength and independence of these motor signals.
  • Results revealed that while ipsilateral arm movement is represented independently, it is weaker than contralateral movement; however, grasping movements were found to be similarly represented in both hands, raising new questions about how the motor cortex coordinates arm and hand functions differently.
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Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain.

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