Distortion of Visuo-Motor Temporal Integration in Apraxia: Evidence From Delayed Visual Feedback Detection Tasks and Voxel-Based Lesion-Symptom Mapping

Limb apraxia is a higher brain dysfunction that typically occurs after left hemispheric stroke and its cause cannot be explained by sensory disturbance or motor paralysis. The comparison of motor signals and visual feedback to generate errors, i.e., visuo-motor integration, is important in motor control and motor learning, which may be impaired in apraxia. However, in apraxia after stroke, it is unknown whether there is a specific deficit in visuo-motor temporal integration compared to visuo-tactile and visuo-proprioceptive temporal integration. We examined the precision of visuo-motor temporal integration and sensory-sensory (visuo-tactile and visuo-proprioception) temporal integration in apraxia after stroke by using a delayed visual feedback detection task with three different conditions (tactile, passive movement, and active movement). The delay detection threshold and the probability curve for delay detection obtained in this task were quantitative indicators of the respective temporal integration functions. In addition, we performed subtraction and voxel-based lesion-symptom mapping to identify the brain lesions responsible for apraxia and deficits in visuo-motor temporal integration. The behavioral experiments showed that the delay detection threshold was extended and that the probability curve for delay detection was less steep in apraxic patients compared to controls (pseudo-apraxic patients and unaffected patients), only for the active movement condition, and not for the tactile and passive movement conditions. Furthermore, the severity of apraxia was significantly correlated with the delay detection threshold and the steepness of the probability curve in the active movement condition. These results indicated that multisensory (i.e., visual, tactile, and proprioception) feedback was normally temporally integrated, but motor prediction and visual feedback were not correctly temporally integrated in apraxic patients. That is, apraxic patients had difficulties with visuo-motor temporal integration. Lesion analyses revealed that both apraxia and the distortion of visuo-motor temporal integration were associated with lesions in the fronto-parietal motor network, including the left inferior parietal lobule and left inferior frontal gyrus. We suppose that damage to the left inferior fronto-parietal network could cause deficits in motor prediction for visuo-motor temporal integration, but not for sensory-sensory (visuo-tactile and visuo-proprioception) temporal integration, leading to the distortion of visuo-motor temporal integration in patients with apraxia

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Proposed predictors of the need for retreatment after coil embolization of unruptured cerebral aneurysms with major or minor recanalization: Analysis of a single center’s experience

Objective: Various risk factors for recanalization after coil embolization have been reported, but the indications for retreatment of recanalized aneurysms have not been determined.The aim of this study was to identify risk factors indicating the need for retreating recanalization during long-term follow-up (approximately 1 year). Methods: A total of 172 unruptured saccular aneurysms in 155 patients treated by initial coil embolization between February 2012 and July 2019 were retrospectively analyzed. Intraluminal thrombosed aneurysms, aneurysms treated with stent assistance, and aneurysms followed without digital subtraction angiography (DSA) were excluded. Recanalization was identified in 31 aneurysms. Recanalized aneurysms (Meyer grade ≥2) were defined as major recanalization (MA); those that worsened to Meyer grade 1 were defined as minor recanalization (MI). Age, sex, aneurysm location, shape, five morphological variables (neck, height, width, dome-to-neck ratio, aspect ratio), aneurysm volume, endovascular technique, immediate Meyer grade, and volume embolization ratio (VER) were compared between MI (n = 18) and MA (n = 13). Predictors of MA were determined using logistic regression and receiver operating characteristic (ROC) curve analyses. Results: On multivariate logistic regression analysis, spherical shape (odds ratio (OR) 11.9; 95% confidence interval (CI) 1.28–111) and VER (OR 1.92; 95% CI 1.13–3.28) were independent predictors of MA. On ROC curve analysis, the optimal cut-off value for the VER was 20.8% (sensitivity, 76.9%; specificity, 77.8%). Conclusions: Lower VER and non-spherical shape appear to be independent risk factors for progression to MA in recanalized aneurysms, and packing with a VER >20.8% is expected to prevent progression to MA

Severe Pulmonary Arteriopathy Is Associated with Persistent Hypoxemia after Pulmonary Endarterectomy in Chronic Thromboembolic Pulmonary Hypertension

<div><p>Background</p><p>Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by occlusion of pulmonary arteries by organized chronic thrombi. Persistent hypoxemia and residual pulmonary hypertension (PH) following successful pulmonary endarterectomy (PEA) are clinically important problems; however, the underlying mechanisms remain unclear. We have previously reported that residual PH is closely related to severe pulmonary vascular remodeling and hypothesize that this arteriopathy might also be involved in impaired gas exchange. The purpose of this study was to evaluate the association between hypoxemia and pulmonary arteriopathy after PEA.</p><p>Methods and Results</p><p>Between December 2011 and November 2014, 23 CTEPH patients underwent PEA and lung biopsy. The extent of pulmonary arteriopathy was quantified pathologically in lung biopsy specimens. We then analyzed the relationship between the severity of pulmonary arteriopathy and gas exchange after PEA. We observed that the severity of pulmonary arteriopathy was negatively correlated with postoperative and follow-up PaO₂ (postoperative PaO₂: r = -0.73, p = 0.0004; follow-up PaO₂: r = -0.66, p = 0.001), but not with preoperative PaO₂ (r = -0.373, p = 0.08). Multivariate analysis revealed that the obstruction ratio and patient age were determinants of PaO₂ one month after PEA (R² = 0.651, p = 0.00009). Furthermore, the obstruction ratio and improvement of pulmonary vascular resistance were determinants of PaO₂ at follow-up (R² = 0.545, p = 0.0002). Severe pulmonary arteriopathy might increase the alveolar-arterial oxygen difference and impair diffusion capacity, resulting in hypoxemia following PEA.</p><p>Conclusion</p><p>The severity of pulmonary arteriopathy was closely associated with postoperative and follow-up hypoxemia.</p></div

Patient characteristics.

<p>Patient characteristics.</p

Relationship between the mean obstruction ratio and %DL_CO/V_A.

<p>The mean obstruction ratio was negatively correlated with postoperative (A) and follow-up %DL_CO/V_A (B). However, the mean obstruction ratio did not correlate with preoperative %DL_CO/V_A (C). The high obstruction group had lower %DL_CO/V_A values than the low-obstruction group (p = 0.002, analyzed by repeated measures ANOVA) (D). (*: p<0.05, vs preoperative data for each group; §: p<0.05, vs postoperative data for each group).</p

Univariate and multivariate analysis of variables associated with postoperative PaO₂.

<p>Univariate and multivariate analysis of variables associated with postoperative PaO₂.</p

Pulmonary arteriopathy in biopsied lung tissues.

<p>Severe pulmonary arteriopathy in the high-obstruction group (A). Pulmonary arteriopathy was composed of severe fibrous intimal thickening, moderate medial hypertrophy, and lumen stenosis. The low-obstruction group (B) demonstrated mild pulmonary intimal thickening and medial hypertrophy.</p