Brain topology underlying executive functions across the lifespan: focus on the default mode network.

Introduction: While traditional neuroimaging approaches to the study of executive functions (EFs) have typically employed task-evoked paradigms, resting state studies are gaining popularity as a tool for investigating inter-individual variability in the functional connectome and its relationship to cognitive performance outside of the scanner. Method: Using resting state functional magnetic resonance imaging data from the Human Connectome Project Lifespan database, the present study capitalized on graph theory to chart cross-sectional variations in the intrinsic functional organization of the frontoparietal (FPN) and the default mode (DMN) networks in 500 healthy individuals (from 10 to 100 years of age), to investigate the neural underpinnings of EFs across the lifespan. Results: Topological properties of both the FPN and DMN were associated with EF performance but not with a control task of picture naming, providing specificity in support for a tight link between neuro-functional and cognitive-behavioral efficiency within the EF domain. The topological organization of the DMN, however, appeared more sensitive to age-related changes relative to that of the FPN. Discussion: The DMN matures earlier in life than the FPN and it is more susceptible to neurodegenerative changes. Because its activity is stronger in conditions of resting state, the DMN might be easier to measure in noncompliant populations and in those at the extremes of the life-span curve, namely very young or elder participants. Here, we argue that the study of its functional architecture in relation to higher order cognition across the lifespan might, thus, be of greater interest compared with what has been traditionally thought.

Understanding the link between functional profiles and intelligence through dimensionality reduction and graph analysis.

There is a growing interest in neuroscience for how individual-specific structural and functional features of the cortex relate to cognitive traits. This work builds on previous research which, using classical high-dimensional approaches, has proven that the interindividual variability of functional connectivity profiles reflects differences in fluid intelligence. To provide an additional perspective into this relationship, the present study uses a recent framework for investigating cortical organization: functional gradients. This approach places local connectivity profiles within a common low-dimensional space whose axes are functionally interretable dimensions. Specifically, this study uses a data-driven approach focussing on areas where FC variability is highest across individuals to model different facets of intelligence. For one of these loci, in the right ventral-lateral prefrontal cortex (vlPFC), we describe an association between fluid intelligence and relative functional distance from sensory and high-cognition systems. Furthermore, the topological properties of this region indicate that with decreasing functional affinity with the latter, its functional connections are more evenly distributed across all networks. Participating in multiple functional networks may reflect a better ability to coordinate sensory and high-order cognitive systems.

Submitral left ventricular aneurysm. Case report and review of published Brazilian cases.

Submitral left ventricular aneurysm is a cardiac pathology widely recognized, but relatively unknown, occurred almost exclusively in African black patients. Although still this idea of racial prevalence exists, cases have been described in patients of all the races. Ten Brazilian cases were reported. One of them was presented inside an Italian paper that refers the surgical treatment of a Brazilian patient of black race. We reported one more submitral left ventricular aneurysm case in a brown female patient, with antecedents of peripheral thromboembolism initially not identified as consequence of the cardiac pathology.

[Postoperative atrial fibrillation in myocardial revascularization]. / Fibrilação atrial pós-operatória na revascularização do miocárdio.

Many studies have demonstrated fairly high incidence of supraventricular arrhythmias after coronary artery bypass surgery, and have tried to identify preoperative, operative and postoperative factors related to their appearance. The present paper analysed 186 patients submitted to coronary artery bypass and reported a incidence of atrial fibrillation of 6.04% (11 cases). The male sex was dominant (81.2%) with ages varying from 49 to 73 (mean 54.58) years. The preoperative incidence of diabetes, smoking and systemic hypertension were, respectively, 18.2%, 54.51% and 36.4%. The mean number of vessels bypassed was 2.42 +/- 1.19 and the left circumflex artery was involved in 81.20% of these cases. Cardiopulmonary bypass time was 100 +/- 39.6 min and ischemic arrest time of 79.6 +/- 37.7 min. Single double stage cannulae for venous drainage were used in 45.5% of the patients and ventricular fibrillation and cardiac overdistention occurred in 63.60% immediately after CPB. Atrial fibrillation presented around 1.66 +/- 2.17 days in the postoperative period and 45.5% of the patients had more than one distinct episode of the arrhythmia. Treatment constituted of cardioversion in 25%, atenolol oral in 18.75% and digitalis associated to quinidine in 56.25%. These numbers permit us to suggest that some of the above factors may contribute to the genesis of arrhythmias, such as single double stage cannulation for venous drainage, inadequate myocardial protection, overdistention and cardiac fibrillation and, mainly, the presence of proximal circumflex artery obstructions responsible for atrial ischemia before and during surgery.

Surgical excision of the vegetation as treatment of tricuspid valve endocarditis.

The usual surgical treatment of tricuspid endocarditis is valve replacement or valve excision alone without valve replacement. 'Vegetectomy', i.e. local excision of the vegetation and leaflet repair, has been previously described and can be applied to cases with well-circumscribed vegetations and little or no valve damage. A case of tricuspid valve endocarditis successfully managed by surgical excision of the vegetation is reported.