Frisk, M. | bioRxiv Science

bioRxiv2021

Gray Matter Differentiation Between Two Subordinate Personality Traits of Extraversion: Enthusiasm and Assertiveness

Enthusiasm and assertiveness are two subordinate personality traits of extraversion. These traits reflect different aspects of extroversion and have distinct implications on mental health. Whereas enthusiasm predicts satisfaction in life and positive relationships, assertiveness predicts psychological distress and reduced social support. The neural basis of these subordinate traits is not well understood. To investigate brain regions where enthusiasm and assertiveness have diverging relationship with morphology, enthusiasm and assertiveness were regressed to gray matter volume (GMV) across the whole brain in a sample of 301 healthy individuals. A significant interaction was found between enthusiasm and assertiveness in the left angular gyrus (t(296) = 4.18, family wise error corrected, FWE p = .001 (cluster-level); Cluster size = 880 voxels). Larger GMV in this area was associated with more enthusiasm and less assertiveness. Our study emphasizes the value of separating extraversion into its subordinate traits when investigating associations to neuroanatomy.

neuroscience↗

bioRxiv2018

Matched-filter based algorithm for sub- to multi-cellular classification of myocyte tubule-system

In mammalian ventricular cardiomyocytes, invaginations of the surface membrane form the transverse tubular system (T-system) which consists of transverse tubules (TTs) that align with sarcomeres and Z-lines as well as longitudinal tubules (LTs) that are present between Z-lines in some species. In many cardiac disease etiologies the T-system is perturbed, which is believed to promote spatially heterogeneous, dyssynchronous Ca2+ release and inefficient contraction. In general, T-system characterization approaches have been directed primarily at isolated cells and do not detect subcellular T-system heterogeneity. Here we present MatchedMyo, a matched-filter based algorithm for subcellular T-system characterization in isolated cardiomyocytes and millimeter-scale myocardial sections. The algorithm utilizes "filters" representative of TTs, LTs, and T-system absence. Application of the algorithm to cardiomyocytes isolated from rat disease models of myocardial infarction (MI), dilated cardiomyopathy induced via aortic banding (AB), and sham surgery confirmed and quantified heterogeneous T-system structure and remodeling. Cardiomyocytes from post-MI hearts exhibited increasing T-system disarray as proximity to the infarct increased. We found significant (p<0.05, Welchs t-test) increases in LT density within cardiomyocytes proximal to the infarct (12{+/-}3%, data reported as mean {+/-} SD, n=3) vs. sham (4{+/-}2%, n=5), but not distal to the infarct (7{+/-}1%, n=3). The algorithm also detected decreases in TTs within 5{degrees} of the myocyte minor axis for isolated AB (36{+/-}9%, n=3) and MI cardiomyocytes located intermediate (37{+/-}4%, n=3) and proximal (34{+/-}4%, n=3) to the infarct vs. sham (57{+/-}12%, n=5). Application of bootstrapping to rabbit MI tissue revealed distal sections comprised 18.9{+/-}1.0% TTs while proximal sections comprised 10.1{+/-}0.8% TTs (p<0.05), a 46.6% decrease. The matched filter approach therefore provides a robust and scalable technique for T-system characterization from isolated cells through millimeter-scale myocardial sections.

biophysics↗