The legalization of recreational cannabis use has expanded the availability of this psychoactive substance in the United States. Research has shown that chronic cannabis use is associated with altered working memory function, however, the brain areas and neural dynamics underlying these affects remain poorly understood. In this study, we leveraged magnetoencephalography (MEG) to investigate neurophysiological activity in 45 participants (22 heavy cannabis users) during a numerical WM task, whereby participants were asked to either maintain or manipulate (i.
View Article and Find Full Text PDFWorking memory (WM) enables the temporary storage of limited information and is a central component of higher order cognitive function. Irrelevant and/or distracting information can have a negative impact on WM processing and suppressing such incoming stimuli is critical to maintaining adequate performance. However, the neural mechanisms and dynamics underlying such distractor inhibition remain poorly understood.
View Article and Find Full Text PDFDespite effective antiretroviral therapy, cognitive impairment remains prevalent among people with HIV (PWH) and decrements in executive function are particularly prominent. One component of executive function is cognitive flexibility, which integrates a variety of executive functions to dynamically adapt one's behavior in response to changing contextual demands. Though substantial work has illuminated HIV-related aberrations in brain function, it remains unclear how the neural oscillatory dynamics serving cognitive flexibility are affected by HIV-related alterations in neural functioning.
View Article and Find Full Text PDFVerbal working memory (vWM) is an essential limited-capacity cognitive system that spans the fronto-parietal network and utilizes the subprocesses of encoding, maintenance, and retrieval. With the recent widespread use of noninvasive brain stimulation techniques, multiple recent studies have examined whether such stimulation may enhance cognitive abilities such as vWM, but the findings to date remain unclear in terms of both behavior and critical brain regions. In the current study, we applied high-definition direct current stimulation to the left and right parietal cortices of 39 healthy adults in three separate sessions (left anodal, right anodal, and sham).
View Article and Find Full Text PDFBackground: People who regularly use cannabis exhibit altered brain dynamics during cognitive control tasks, though the impact of regular cannabis use on the neural dynamics serving motor control remains less understood.
Aims: We sought to investigate how regular cannabis use modulates the neural dynamics serving motor control.
Methods: Thirty-four people who regularly use cannabis (cannabis+) and 33 nonusers (cannabis-) underwent structured interviews about their substance use history and performed the Eriksen flanker task to map the neural dynamics serving motor control during high-density magnetoencephalography (MEG).
Background: Cannabis is the most widely used psychoactive drug in the United States. While multiple studies have associated acute cannabis consumption with alterations in cognitive function (e.g.
View Article and Find Full Text PDFRegular cannabis use is associated with cortex-wide changes in spontaneous and oscillatory activity, although the functional significance of such changes remains unclear. We hypothesized that regular cannabis use would suppress spontaneous gamma activity in regions serving cognitive control and scale with task performance. Participants (34 cannabis users, 33 nonusers) underwent an interview regarding their substance use history and completed the Eriksen flanker task during magnetoencephalography (MEG).
View Article and Find Full Text PDFVisual entrainment is a powerful and widely used research tool to study visual information processing in the brain. While many entrainment studies have focused on frequencies around 14-16 Hz, there is renewed interest in understanding visual entrainment at higher frequencies (e.g.
View Article and Find Full Text PDFFluid intelligence (Gf) involves rational thinking skills and requires the integration of information from different cortical regions to resolve novel complex problems. The effects of non-invasive brain stimulation on Gf have been studied in attempts to improve Gf, but such studies are rare and the few existing have reached conflicting conclusions. The parieto-frontal integration theory of intelligence (P-FIT) postulates that the parietal and frontal lobes play a critical role in Gf.
View Article and Find Full Text PDFThe balance between energetic costs and acquisition in free-ranging species is essential for survival, and provides important insights regarding the physiological impact of anthropogenic disturbances on wild animals. For marine mammals such as beluga whales (Delphinapterus leucas), the first step in modeling this bioenergetic balance requires an examination of resting and active metabolic demands. Here, we used open-flow respirometry to measure oxygen consumption during surface rest and submerged swimming by trained beluga whales, and compared these measurements with those of a commonly studied odontocete, the Atlantic bottlenose dolphin (Tursiops truncatus).
View Article and Find Full Text PDFBackground: Regular cannabis is known to impact higher-order cognitive processes such as attention, but far less is known regarding cognitive flexibility, a component of executive function. Moreover, whether such changes are related to aberrations in the neural oscillatory dynamics serving flexibility remains poorly understood.
Aims: Quantify the neural oscillatory dynamics serving cognitive flexibility by having participants complete a task-switching paradigm during magnetoencephalography (MEG).
Objective: Hydration status and water intake are critical to physiological health. Despite a popular narrative that dehydration impairs cognitive performance, results are mixed in the literature. Therefore, we tested how hydration status was associated with cognitive performance in an ad libitum state over the course of 3 months.
View Article and Find Full Text PDFBackground: There are various published clinical practice guidelines (CPGs) for the management of pancreatic cystic lesions. However, the quality of these guidelines has not been systematically appraised. This study aimed to evaluate the quality of CPGs published in the last 5 years for the management of pancreatic cysts.
View Article and Find Full Text PDFCannabis is the most widely used recreational drug in the United States and regular use has been linked to deficits in attention and memory. However, the effects of regular use on motor control are less understood, with some studies showing deficits and others indicating normal performance. Eighteen users and 23 nonusers performed a motor sequencing task during high-density magnetoencephalography (MEG).
View Article and Find Full Text PDFIntroduction: Inflammatory processes help protect the body from potential threats such as bacterial or viral invasions. However, when such inflammatory processes become chronically engaged, synaptic impairments and neuronal cell death may occur. In particular, persistently high levels of C-reactive protein (CRP) and tumor necrosis factor-alpha (TNF-α) have been linked to deficits in cognition and several psychiatric disorders.
View Article and Find Full Text PDFUnlike the majority of marine mammal species, Hawaiian monk seals (Neomonachus schauinslandi) and West Indian manatees (Trichechus manatus latirostris) reside exclusively in tropical or subtropical waters. Although potentially providing an energetic benefit through reduced maintenance and thermal costs, little is known about the cascading effects that may alter energy expenditure during activity, dive responses and overall energy budgets for these warm-water species. To examine this, we used open-flow respirometry to measure the energy expended during resting and swimming in both species.
View Article and Find Full Text PDFPurpose: Water needs increase during pregnancy, and proper hydration is critical for maternal and fetal health. This study characterized weekly hydration status changes throughout pregnancy and examined change in response to a randomized, behavioral intervention. An exploratory analysis tested how underhydration during pregnancy was associated with birth outcomes.
View Article and Find Full Text PDFPorphyria cutanea tarda (PCT) is the most common porphyria and has a strong association with hepatitis C virus (HCV) infection and iron overload. Previous HCV treatment regimens, including interferon with or without ribavirin, may precipitate PCT relapse. Few case reports have shown that newer oral therapies, such as direct-acting antiviral agents, can successfully treat PCT parallel with HCV treatment.
View Article and Find Full Text PDFSome marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O store.
View Article and Find Full Text PDFBackground: Biotin is an essential cofactor for metabolic pathways in humans. It is frequently self-prescribed by consumers and often recommended by dermatologists and primary care physicians, despite limited evidence of its effect on skin, hair, and nail disorders. A recent Food and Drug Administration (FDA) warning stated that biotin can interfere with laboratory tests.
View Article and Find Full Text PDFNail conditions are routinely encountered in dermatology clinical practice. Nails have important aesthetic functions, and onychodystrophies may cause pain and difficulties with ambulation and performing activities of daily living. Ideally, accurate diagnosis and optimal treatment of nail disorders are taught as early as medical school and extend into dermatology residency.
View Article and Find Full Text PDFObjective: This study examined the distribution of spinal fusion usage among payer groups in the United States.
Methods: Using the National Inpatient Sample (NIS) database, total discharges, length of stay, and mean hospital charges of patients who underwent spinal fusion from 1997 to 2014 in the United States were determined and analyzed.
Results: 5,715,625 total discharges with spinal fusion were reported.