Publications by authors named "Carter Lybbert"

Article Synopsis
  • A novel noninvasive method combines magnetic and focused ultrasonic fields to create electric fields deep in the brain for potential treatments of mental and neurological disorders.
  • This study tested this method on non-human primates' visual circuits, examining the effects of different ultrasonic pulse frequencies on neural activity.
  • Results showed that low-frequency stimulation (5 Hz) inhibited brain activity, while higher frequencies did not, indicating the importance of pulse frequency in neuromodulation without safety concerns.
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Rationale: The intravenous anesthetic propofol is known to induce positive mood effects during routine clinical use, suggesting it might be repurposed as an antidepressant, but also raising concerns about abuse potential. How propofol's acute effects vary by dose and with repeated infusions is unknown.

Objectives: This exploratory analysis aimed to (1) compare the immediate mood effects of propofol administered at two different doses, (2) describe how those mood effects change with repeated infusions, and (3) evaluate whether acute mood improvement predicts later antidepressant response.

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Objectives: Transcranial ultrasound neuromodulation (TUSN) is a noninvasive and spatially specific therapy that promises to deliver treatments tailored to the specific needs of individuals. To fulfill this promise, each treatment must be modified to adequately correct for variation across individual skulls and neural anatomy. This study examines the use of ultrasound-induced voltage potentials (measured with electroencephalography [EEG]) to guide TUSN therapies.

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The monitoring of vital signs in patients undergoing anesthesia began with the very first case of anesthesia and has evolved alongside the development of anesthesiology ever since. Patient monitoring started out as a manually performed, intermittent, and qualitative assessment of the patient's general well-being in the operating room. In its evolution, patient monitoring development has responded to the clinical need, for example, when critical incident studies in the 1980s found that many anesthesia adverse events could be prevented by improved monitoring, especially respiratory monitoring.

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Background: Anesthetic agents including ketamine and nitrous oxide have shown antidepressant properties when appropriately dosed. Our recent open-label trial of propofol, an intravenous anesthetic known to elicit transient positive mood effects, suggested that it may also produce robust and durable antidepressant effects when administered at a high dose that elicits an electroencephalographic (EEG) burst-suppression state. Here we report findings from a randomized controlled trial ( NCT03684447 ) that compared two doses of propofol.

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Article Synopsis
  • Burst suppression is a brain state characterized by alternating high and low electrical activity, which can occur due to illness or certain anesthetics, but its variations among individuals have been underexplored.
  • In a clinical trial assessing propofol's antidepressant effects, researchers analyzed EEG data from 21 subjects with treatment-resistant depression, identifying three distinct types of burst activity: broadband bursts, sleep spindle-like activity, and low-frequency bursts (LFBs), each with unique time and frequency traits.
  • The study highlights significant individual differences in the occurrence and spectral makeup of these EEG features, suggesting the need for personalized approaches to anesthetic dosing and revealing limitations in current clinical EEG monitoring systems.
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Foot placement can be selected to anticipate upcoming perturbations, but it is unclear how this anticipatory strategy is influenced by available response time or precise knowledge of the perturbation's characteristics. This study investigates anticipatory and reactive locomotor strategies for repeated underfoot perturbations with varying levels of temporal certainty, physical certainty, and available response time. Thirteen healthy adults walked with random underfoot perturbations from a mechanized shoe.

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Background: Acute kidney injury (AKI) is a common complication of cardiac surgery. An intraoperative monitor of kidney perfusion is needed to identify patients at risk for AKI. The authors created a noninvasive urinary oximeter that provides continuous measurements of urinary oxygen partial pressure and instantaneous urine flow.

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