Graph Analysis of the Visual Cortical Network during Naturalistic Movie Viewing Reveals Increased Integration and Decreased Segregation Following Mild TBI.

Traditional neuroimaging methods have identified alterations in brain activity patterns following mild traumatic brain injury (mTBI), particularly during rest, complex tasks, and normal vision. However, studies using graph theory to examine brain network changes in mTBI have produced varied results, influenced by the specific networks and task demands analyzed. In our study, we employed functional MRI to observe 17 mTBI patients and 54 healthy individuals as they viewed a simple, non-narrative underwater film, simulating everyday visual tasks.

Montreal Brain Injury Vision Screening Test for General Practitioners.

Visual disturbances are amongst the most commonly reported symptoms after a traumatic brain injury (TBI) despite vision testing being uncommon at initial clinical evaluation. TBI patients consistently present a wide range of visual complaints, including photophobia, double vision, blurred vision, and loss of vision which can detrimentally affect reading abilities, postural balance, and mobility. In most cases, especially in rural areas, visual disturbances of TBI would have to be diagnosed and assessed by primary care physicians, who lack the specialized training of optometry.

Blur Representation in the Amblyopic Visual System Using Natural and Synthetic Images.

Purpose: Amblyopia is diagnosed as a reduced acuity in an otherwise healthy eye, which indicates that the deficit is not happening in the eye, but in the brain. One suspected mechanism explaining these deficits is an elevated amount of intrinsic blur in the amblyopic visual system compared to healthy observers. This "internally produced blur" can be estimated by the "equivalent intrinsic blur method", which measures blur discrimination thresholds while systematically increasing the external blur in the physical stimulus.

Intersubject Spatial Pattern Correlations During Movie Viewing Are Stimulus-Driven and Nonuniform Across the Cortex.

A fundamental step to predicting brain activity in healthy and diseased populations is characterizing the common spatio-temporal response to a shared experience. Multivoxel pattern analysis allows us to investigate information encoding through these patterns; however, we have yet to explore local, stimulus-driven, patterns of cortical activity during naturalistic stimulation. We sought to examine these patterns with minimum interpolation-excluding functional alignment-to characterize the most basic degree of shared response between subjects.

Natural scene representations in the gamma band are prototypical across subjects.

Prototypical brain responses describe similarity in neural representations between subjects in response to a natural stimulus. During natural movie viewing, for example, inter-subject correlation (ISC) measured by fMRI is high in visual areas (Hasson et al., 2004).

Radio-Frequency Coil Array for Improved Concurrent Transcranial Magnetic Stimulation and Functional Magnetic Resonance Imaging.

Purpose: To perform concurrent TMS-fMRI on difficult targets, such as the occipital lobe.

Methods: a 3-channel flexible, thin RF coil was constructed that allows for whole head image coverage without impeding TMS placement. A custom MR-safe patient table which mates with typical 3T MR scanners was constructed for the purpose of face-down subject positioning to allow for access to posterior TMS targets.

Long-Range Interocular Suppression in Adults with Strabismic Amblyopia: A Pilot fMRI Study.

Interocular suppression plays an important role in the visual deficits experienced by individuals with amblyopia. Most neurophysiological and functional MRI studies of suppression in amblyopia have used dichoptic stimuli that overlap within the visual field. However, suppression of the amblyopic eye also occurs when the dichoptic stimuli do not overlap, a phenomenon we refer to as long-range suppression.

Increased Noise in Cortico-Cortical Integration After Mild TBI Measured With the Equivalent Noise Technique.

The bulk of deficits accompanying mild traumatic brain injury (mTBI) is understood in terms of cortical integration-mnemonic, attentional, and cognitive disturbances are believed to involve integrative action across brain regions. Independent of integrative disturbances, mTBI may increase cortical noise, and this has not been previously considered. High-level integrative deficits are exceedingly difficult to measure and model, motivating us to utilize a tightly-controlled task within an established quantitative model to separately estimate internal noise and integration efficiency.

Detection of distortions in images of natural scenes in mild traumatic brain injury patients.

Mild traumatic brain injuries (mTBI) frequently lead to the impairment of visual functions including blurred and/or distorted vision, due to the disruption of visual cortical mechanisms. Previous mTBI studies have focused on specific aspects of visual processing, e.g.

Magnetoencephalography adaptation reveals depth-cue-invariant object representations in the visual cortex.

Independent of edges and 2-D shape that can be highly informative of object identity, depth cues alone can also give rise to vivid and effective object percepts. The processing of different depth cues engages segregated cortical areas, and an efficient object representation would be one that is invariant to depth cues. Here, we investigated depth-cue invariance of object representations by measuring the category-specific response to faces-the M170 response measured with magnetoencephalography.

Mapping of neuron soma size as an effective approach to delineate differences between neural populations.

Background: A single histological marker applied to a slice of tissue often reveals myriad cytoarchitectonic characteristics that can obscure differences between neuron populations targeted for study. Isolation and measurement of a single feature from the tissue is possible through a variety of approaches, however, visualizing the data numerically or through graphs alone can preclude being able to identify important features and effects that are not obvious from direct observation of the tissue.

New Method: We demonstrate an efficient, effective, and robust approach to quantify and visualize cytoarchitectural features in histologically prepared brain sections.

Improved Outcomes With Integrated Intensivist Consultation for Cardiac Surgery Patients.

This study examined the impact of integrated intensivist consultation in the immediate postoperative period on outcomes for cardiac surgery patients. A retrospective cohort study was conducted in 1711 adult cardiac surgery patients from a single quaternary care center in Minnesota. Outcomes were compared across 2 consecutive 2-year time periods reflecting an elective intensivist model (n = 801) and an integrated intensivist model (n = 910).

Early Experience With New Transcatheter Mitral Valve Replacement.

Background: Transcatheter mitral valve replacement (TMVR) is a potential therapy for patients with symptomatic, severe mitral regurgitation (MR). The feasibility of this therapy remains to be defined.

Objectives: The authors report their early experience with TMVR using a new valve system.

The equivalent internal orientation and position noise for contour integration.

Contour integration is the joining-up of local responses to parts of a contour into a continuous percept. In typical studies observers detect contours formed of discrete wavelets, presented against a background of random wavelets. This measures performance for detecting contours in the limiting external noise that background provides.

Two cortical deficits underlie amblyopia: A multifocal fMRI analysis.

Amblyopia is a relatively common (incidence 3%) developmental disorder in which there is loss of vision as a consequence of a disruption to normal visual development. Although the deficit is monocular and known to be of cortical origin, the nature of the processing deficit is controversial. Human behavioral studies have identified two main deficits - a loss of contrast sensitivity and perceived spatial distortions.

Association of Guideline Adherence for Serial Evaluations With Survival and Adverse Clinical Events in Patients With Asymptomatic Severe Aortic Stenosis.

Importance: For patients with asymptomatic severe aortic stenosis and normal left ventricular function, current practice guidelines empirically recommend serial evaluations every 6 to 12 months. The benefit of this clinical monitoring is unknown.

Objective: To determine the association of guideline adherence with clinical outcomes in patients with asymptomatic severe aortic stenosis.

Aortic Root Reconstruction with a New Dacron Graft Featuring Prefabricated Coronary Side Branches: Lessons Learned from the Cabrol Procedure.

Background: Coronary button reimplantation can represent a technical challenge of aortic root reconstruction that can be associated with significant morbidity and mortality. With the goal of simplifying coronary reimplantation and reducing the incidence of related complications, we designed a new Dacron graft with prefabricated coronary branches to minimize coronary artery mobilization and prevent the potential mechanical complications of reattachment to the body of the graft.

Methods: Between June 2010 and May 2012, we implanted the graft in eight patients (six males, two females) ranging in age from 42-68 years (mean, 54 years).

Transcatheter Therapy for Mitral Regurgitation Clinical Challenges and Potential Solutions.

Severe mitral regurgitation is a common and complex disease that is associated with an adverse prognosis. For decades, surgical treatment has been the standard of care. Recently, multiple technologies for transcatheter mitral therapy have emerged, with the potential for both repair and replacement in patients with native mitral regurgitation.

Identifying Variability in Mental Models Within and Between Disciplines Caring for the Cardiac Surgical Patient.

Background: The cardiac operating room is a complex environment requiring efficient and effective communication between multiple disciplines. The objectives of this study were to identify and rank critical time points during the perioperative care of cardiac surgical patients, and to assess variability in responses, as a correlate of a shared mental model, regarding the importance of these time points between and within disciplines.

Methods: Using Delphi technique methodology, panelists from 3 institutions were tasked with developing a list of critical time points, which were subsequently assigned to pause point (PP) categories.

Sensitivity to Binocular Disparity is Reduced by Mild Traumatic Brain Injury.

Purpose: The impairment of visual functions is one of the most common complaints following mild traumatic brain injury (mTBI). Traumatic brain injury-associated visual deficits include blurred vision, reading problems, and eye strain. In addition, previous studies have found evidence that TBI can diminish early cortical visual processing, particularly for second-order stimuli.

Current Status of Catheter-Based Treatment of Mitral Valve Regurgitation.

Purpose Of Review: This review examines the current status of catheter-based repair and replacement for mitral valve disease, with a focus on native primary and secondary mitral valve regurgitation.

Recent Findings: Transcatheter mitral valve repair with the MitraClip®, with >40,000 performed procedures worldwide, has significantly advanced the field of transcatheter therapy for mitral valve regurgitation. Transcatheter mitral valve replacement remains in the early stages of development, mainly due to the complex anatomy and physiology of the mitral valve.

Gaze behavior during 3-D face identification is depth cue invariant.

Gaze behavior during scene and object recognition can highlight the relevant information for a task. For example, salience maps-highlighting regions that have heightened luminance, contrast, color, etc. in a scene-can be used to predict gaze targets.

Transcatheter Mitral Valve Replacement for Patients With Symptomatic Mitral Regurgitation: A Global Feasibility Trial.

Background: Symptomatic mitral regurgitation (MR) is associated with high morbidity and mortality that can be ameliorated by surgical valve repair or replacement. Despite this, many patients with MR do not undergo surgery. Transcatheter mitral valve replacement (TMVR) may be an option for selected patients with severe MR.