Analyzing the temporal trends of kidney transplantation surgeries and their impact on warm and cold ischemia time in a Canadian setting.

Background: The effect of weekend admission and surgery on patient morbidity and mortality has been studied in many settings and has been shown to lead to worse outcomes. Several studies have sought to determine whether there is a weekend effect in kidney transplantation specifically, but a clear effect on outcomes and graft survival has not been established.

Methods: We analyzed data from all deceased-donor organ procurements and cadaveric kidney transplants occurring during the 5-year period between Apr.

Distinct patterns of connectivity with the motor cortex reflect different components of sensorimotor learning.

Sensorimotor learning is supported by multiple competing processes that operate concurrently, making it a challenge to elucidate their neural underpinnings. Here, using human functional MRI, we identify 3 distinct axes of connectivity between the motor cortex and other brain regions during sensorimotor adaptation. These 3 axes uniquely correspond to subjects' degree of implicit learning, performance errors and explicit strategy use, and involve different brain networks situated at increasing levels of the cortical hierarchy.

Impact of travel distance on short-term outcomes in patients receiving treatment for urolithiasis: A population-based study.

Introduction: We aimed to assess the relationship between the distance traveled to receive treatment for urolithiasis and early outcomes.

Methods: This is a population-based study of patients who received interventions for urolithiasis in Ontario between 2003 and 2019 using administrative data. Patients were stratified into three groups according to the distance travelled.

Effects of cognitive behavioural therapy and exposure-response prevention on brain activation in obsessive-compulsive disorder patients: systematic review and meta-analysis.

Current psychotherapeutic treatments for OCD, while effective, have complex outcomes with mixed efficacy. Previous research has observed baseline brain activation patterns in OCD patients, elucidating some of the implications of this disorder. Observing the effects of evidence-based psychotherapeutics for OCD on brain activation (through MRI) may provide a more comprehensive outline of pathology.

Reconfigurations of cortical manifold structure during reward-based motor learning.

Adaptive motor behavior depends on the coordinated activity of multiple neural systems distributed across the brain. While the role of sensorimotor cortex in motor learning has been well established, how higher-order brain systems interact with sensorimotor cortex to guide learning is less well understood. Using functional MRI, we examined human brain activity during a reward-based motor task where subjects learned to shape their hand trajectories through reinforcement feedback.

A Novel Cooling Device for Kidney Transplant Surgery.

Prolonged warm ischemia time (WIT) in kidney transplantation is associated with numerous adverse outcomes including delayed graft function and decreased patient and graft survival. Circumventing WIT lies in maintaining renal hypothermia and efficiently performing the vascular anastomosis during this portion of the procedure. Although numerous methods of intra-operative renal cooling have been proposed, most suffer from practical limitations, and none have been widely adopted.

Virtual OSCE examinations during COVID-19 A 360 satisfaction assessment from examiners and candidates.

Introduction: We sought to determine the satisfaction rates of examiners and candidates in a virtual Objective Structured Clinical Exam (OSCE) of graduating Canadian urology residents.

Methods: An annual mock exam, aimed at simulating the licencing urology exam for Canadian graduates, was moved to an online format for the 2020 cohort. This exam consists of an OSCE, and a written multiple-choice exam.

Using electronically delivered therapy and brain imaging to understand OCD pathology: A pilot feasibility study.

Background: Obsessive-compulsive disorder (OCD) is a debilitating mental health disorder with current psychotherapeutic treatments, while somewhat effective, yielding low accessibility and scalability. A lack of knowledge regarding the neural pathology of OCD may be hindering the development of innovative treatments. Previous research has observed baseline brain activation patterns in OCD patients, elucidating some understanding of the implications.

Spontaneous Behavioural Recovery Following Stroke Relates to the Integrity of Parietal and Temporal Regions.

Stroke is a devastating disease that results in neurological deficits and represents a leading cause of death and disability worldwide. Following a stroke, there is a degree of spontaneous recovery of function, the neural basis of which is of great interest among clinicians in their efforts to reduce disability following stroke and enhance rehabilitation. Conventionally, work on spontaneous recovery has tended to focus on the neural reorganization of motor cortical regions, with comparably little attention being paid to changes in non-motor regions and how these relate to recovery.

Distinct patterns of cortical manifold expansion and contraction underlie human sensorimotor adaptation.

Sensorimotor learning is a dynamic, systems-level process that involves the combined action of multiple neural systems distributed across the brain. Although much is known about the specialized cortical systems that support specific components of action (such as reaching), we know less about how cortical systems function in a coordinated manner to facilitate adaptive behavior. To address this gap, our study measured human brain activity using functional MRI (fMRI) while participants performed a classic sensorimotor adaptation task and used a manifold learning approach to describe how behavioral changes during adaptation relate to changes in the landscape of cortical activity.

Neural excursions from manifold structure explain patterns of learning during human sensorimotor adaptation.

Humans vary greatly in their motor learning abilities, yet little is known about the neural mechanisms that underlie this variability. Recent neuroimaging and electrophysiological studies demonstrate that large-scale neural dynamics inhabit a low-dimensional subspace or manifold, and that learning is constrained by this intrinsic manifold architecture. Here, we asked, using functional MRI, whether subject-level differences in neural excursion from manifold structure can explain differences in learning across participants.

Using Electronically Delivered Therapy and Brain Imaging to Understand Obsessive-Compulsive Disorder Pathophysiology: Protocol for a Pilot Study.

Background: Obsessive-compulsive disorder (OCD) is a debilitating and prevalent anxiety disorder. Although the basal ganglia and frontal cortex are the brain regions that are most commonly hypothesized to be involved in OCD, the exact pathophysiology is unknown. By observing the effects of proven treatments on brain activation levels, the cause of OCD can be better understood.

Muting, not fragmentation, of functional brain networks under general anesthesia.

Changes in resting-state functional connectivity (rs-FC) under general anesthesia have been widely studied with the goal of identifying neural signatures of consciousness. This work has commonly revealed an apparent fragmentation of whole-brain network structure during unconsciousness, which has been interpreted as reflecting a break-down in connectivity and a disruption of the brain's ability to integrate information. Here we show, by studying rs-FC under varying depths of isoflurane-induced anesthesia in nonhuman primates, that this apparent fragmentation, rather than reflecting an actual change in network structure, can be simply explained as the result of a global reduction in FC.

Dynamic Reconfiguration, Fragmentation, and Integration of Whole-Brain Modular Structure across Depths of Unconsciousness.

General anesthetics are routinely used to induce unconsciousness, and much is known about their effects on receptor function and single neuron activity. Much less is known about how these local effects are manifest at the whole-brain level nor how they influence network dynamics, especially past the point of induced unconsciousness. Using resting-state functional magnetic resonance imaging (fMRI) with nonhuman primates, we investigated the dose-dependent effects of anesthesia on whole-brain temporal modular structure, following loss of consciousness.

Poly-Arginine Peptide-18 (R18) Reduces Brain Injury and Improves Functional Outcomes in a Nonhuman Primate Stroke Model.

Poly-arginine peptide-18 (R18) is neuroprotective in different rodent middle cerebral artery occlusion (MCAO) stroke models. In this study, we examined whether R18 treatment could reduce ischemic brain injury and improve functional outcome in a nonhuman primate (NHP) stroke model. A stroke was induced in male cynomolgus macaques by MCAO distal to the orbitofrontal branch of the MCA through a right pterional craniotomy, using a 5-mm titanium aneurysm clip for 90 min.

Resting CMRO fluctuations show persistent network hyper-connectivity following exposure to sub-concussive collisions.

Exposure to head impacts may alter brain connectivity within cortical hubs such as the default-mode network (DMN). However, studies have yet to consider the confounding effects of altered resting cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) on changes in connectivity following sub-concussive impacts. Here, 23 Canadian collegiate football players were followed during a season using calibrated resting-state MRI and helmet accelerometers to examine the interplay between the neural and vascular factors that determine functional connectivity (FC).

Stroke Longitudinal Volumetric Measures Correlate with the Behavioral Score in Non-Human Primates.

Stroke is the second leading cause of death worldwide. Brain imaging data from experimental rodent stroke models suggest that size and location of the ischemic lesion relate to behavioral outcome. However, such a relationship between these two variables has not been established in Non-Human Primate (NHP) models.

Grip force when reaching with target uncertainty provides evidence for motor optimization over averaging.

When presented with competing potential reach targets and required to launch a movement before knowing which one will be cued as the target, people initially reach in the average target direction. Although this spatial averaging could arise from executing a weighted average of motor plans for the potential targets, it could also arise from planning a single, optimal movement. To test between these alternatives we used a task in which participants were required to reach to either a single target or towards two potential targets while grasping an object.

Increased functional connectivity after stroke correlates with behavioral scores in non-human primate model.

Here we characterized the functional connectivity (FC) changes occurring after a controlled MCA stroke in a primate model. We hypothesize that if FC can inform about the neural changes after a stroke in the non-human primate (NHP) stroke model, then significant FC changes after the stroke would have to correlate with the remaining behavioral capacities. Eleven cynomolgus monkeys underwent an experimental middle cerebral artery occlusion while five monkeys remained as the control group.