Neural basis of implicit motor sequence learning: Modulation of cortical power

Implicit sequence learning describes the acquisition of serially ordered movements and sequentially structured cognitive information, that occurs without awareness. Theta, alpha and beta cortical oscillations are present during implicit motor sequence learning, but their role in this process is unclear. The current study addressed this gap in the literature. A total of 50 healthy adults aged between 19 and 37 years participated in the study. Implicit motor sequence learning was examined using the Serial Reaction Time task where participants unknowingly repeat a sequence of finger movements in response to a visual stimulus. Sequence learning was examined by comparing reaction times and oscillatory power between sequence trials and a set of control trials comprising random stimulus presentations. Electroencephalography was recorded as participants completed the task. Analyses of the behavioral data revealed participants learnt the sequence. Analyses of oscillatory activity, using permutation testing, revealed sequence learning was associated with a decrease in theta band (4–7 Hz) power recorded over frontal and central electrode sites. Sequence learning effects were not observed in the alpha (7–12 Hz) or beta bands (12–20 Hz). Even though alpha and beta power modulations have long been associated with executing a motor response, it seems theta power is a correlate of sequence learning in the manual domain. Theta power modulations on the serial reaction time task may reflect disengagement of attentional resources, either promoting or occurring as a consequence of implicit motor sequence learning     

A Systematic Review of the Effect of Type,Pressure, and Temperature of the Distension Medium on Pain During Office Hysteroscopy

ObjectiveTo identify the optimal distension medium type, pressure, and temperature to minimize pain during office hysteroscopy.Data SourcesMEDLINE, EMBASE, CINAHL, and CENTRAL were searched from inception to January 29, 2020.Methods of Study SelectionWe included randomized controlled trials in which women undergoing office hysteroscopy were randomized to either a distension medium type, pressure, or temperature against a suitable control, where pain was an outcome. Data regarding feasibility, visualization, complications, and satisfaction were also collected.Tabulation, Integration, and ResultsThe literature search returned 847 studies, of which 18 were included for systematic review and 17 for meta-analysis. There was no significant difference in intraprocedural pain when comparing the use of normal saline against carbon dioxide (standardized mean difference [SMD], –0.12; 95% confidence interval [CI], –0.36 to 0.13). Subgroup analysis of high-quality studies revealed a statistically significant reduction in postprocedural pain with normal saline (SMD, –0.65; 95% CI, –1.14 to –0.16). Side effects were less frequent (Peto odds ratio, 0.29; 95% CI, 0.20–0.40) and patient satisfaction was higher (SMD, 1.39; 95% CI, 0.51–2.28) with normal saline compared with carbon dioxide. Pressures of ≤40 mm Hg reduced intraprocedural pain (SMD, –0.67; 95% CI, –1.09 to –0.26) at the expense of a higher proportion of unsatisfactory views (81%–89% at ≤40 mm Hg vs 95%–99% at ≥50 mm Hg). Postprocedural pain was reduced with lower filling pressures. Warming saline did not reduce intraprocedural pain (SMD, 0.59; 95% CI, –0.14 to 1.33).ConclusionNormal saline, instilled at the lowest pressure to acquire a satisfactory view, should be used for uterine distension during office hysteroscopy to minimize pain.     

Does Radical Hysterectomy for Clinically Apparent Stage II Endometrial Cancer Affect Risk of Local Recurrence?

ObjectiveCompare recurrence-free survival (RFS) and morbidity between radical hysterectomy (RH) and simple hysterectomy (SH) for clinically diagnosed stage II endometrial cancer.MethodsA multicentre, retrospective study, from 2000 to 2015, involving patients with endometrial cancer with cervical involvement preoperatively and stromal invasion on final pathology. Wilcoxon rank-sum test, Fisher exact test, Kaplan-Meier survival functions, and Cox proportional hazards models were used for analysis.ResultsNinety of 1613 patients had clinical stage II endometrial cancer; 57 underwent RH and 33 underwent SH, with no difference in adjuvant treatment or morbidity. About half of patients (51%) had pathologic stage III–IV disease. Mean follow-up was 3.3 and 3.8 years for SH and RH, respectively. Thirty-three percent of patients with RH and SH experienced a recurrence. Most recurrences were distant: 90% with SH and 79% with RH. There was no difference in RFS between groups (2-year: SH 65% vs. RH 75%; 5-year: SH 54% vs. RH 63%; P = 0.72). Controlling for stage, adjuvant treatment, and margin status, RH was not associated with RFS (HR 0.62; 95% CI 0.28–1.35). Among 44 patients with pathologic stage II disease, 7 had a recurrence (4 SH and 3 RH); 6 of 7 had distant recurrences.ConclusionsFifty-one percent of patients with clinical stage II endometrial cancer had advanced disease on final pathology, highlighting the importance of surgical staging. RH was not associated with RFS or reduced morbidity. Most recurrences were distant. Although RH could be performed to achieve negative surgical margins, SH may be sufficient for central, small tumours given the high risk of advanced disease and distant recurrence. Research efforts should further elucidate the ideal management of these patients.     

The limits of regulatory toxicology

The Acceptable Daily Intake (ADI) has been used by regulatory and public health organizations (e.g., the U.S. Food and Drug and Administration, and the World Health Organization) for chemicals for more than 50 years. The ADI concept was also initially employed at the U.S. Environmental Protection Agency at its inception in 1971, although with the adoption of newer terminology, it later became known as the Reference Dose (RfD). It is clear from the literature that both were first devised as instruments of regulatory policy. In the intervening years, it has become common to use language that implies that these standards are statements of scientific fact. Similarly, some of the discretionary or default values that are used to derive regulatory standards are represented as scientific assumptions when in fact they also represent regulatory policy. This confusion impedes both the best use of the available science and informed public participation in policy making. In addition, the misconception of the ADI or the RfD as statements of scientific fact may impede the consideration of alternative means to reduce exposure to chemicals that may be harmful, including regulatory measures that do not involve prescribing a regulatory concentration limit.     

Etiology of early age onset substance use disorder: a maturational perspective

The etiology of early age onset substance use disorder (SUD), an Axis I psychiatric illness, is examined from the perspective of the multifactorial model of complex disorders. Beginning at conception, genetic and environment interactions produce a sequence of biobehavioral phenotypes during development which bias the ontogenetic pathway toward SUD. One pathway to SUD is theorized to emanate from a deviation in somatic and neurological maturation, which, in the context of adverse environments, predisposes to affective and behavioral dysregulation as the cardinal SUD liability-contributing phenotype. Dysregulation progresses via epigenesis from difficult temperament in infancy to conduct problems in childhood to substance use by early adolescence and to severe SUD by young adulthood.     

Critical analysis of intravenous immunoglobulin therapy for recurrent miscarriage

Critical analysis of intravenous immunoglobulin therapy for recurrent miscarriage An alloimmune abnormality is believed to be the cause of recurrent miscarriage in couples in whom no other cause can be identified. Because of its immunosuppressive properties, intravenous immunoglobulin (IVIG) is used as a treatment for this disorder. The purpose of this study was to determine whether IVIG improves the chance of successful pregnancy in women with recurrent miscarriage by using individual patient data from efficacy trials. Detailed information on each patient enrolled in these trials was obtained to evaluate the efficacy of IVIG and investigate the effect of clinical variability on pregnancy outcome. Data from 125 patients in the IVIG group and 115 patients in the placebo group were available for analysis. Although the number of previous miscarriages and female age were both negative prognostic factors for successful outcome, there was no significant improvement in successful pregnancy or live birth rate with IVIG. Subgroup analyses indicated that timing of IVIG administration may be important. The results of the present study highlight the importance of stratification for known confounders, so that the role of IVIG can be evaluated in more detail. The collective evidence thus far indicates that IVIG does not have a therapeutic effect that is clinically meaningful.     

Remodeling of chick embryonic ventricular myoarchitecture under experimentally changed loading conditions

Adult myocardium adapts to changing functional demands by hyper‐ or hypotrophy while the developing heart reacts by hyper‐ or hypoplasia. How embryonic myocardial architecture adjusts to experimentally altered loading is not known. We subjected the chick embryonic hearts to mechanically altered loading to study its influence upon ventricular myoarchitecture. Chick embryonic hearts were subjected to conotruncal banding (increased afterload model), or left atrial ligation or clipping, creating a combined model of increased preload in right ventricle and decreased preload in left ventricle. Modifications of myocardial architecture were studied by scanning electron microscopy and histology with morphometry. In the conotruncal banded group, there was a mild to moderate ventricular dilatation, thickening of the compact myocardium and trabeculae, and spiraling of trabecular course in the left ventricle. Right atrioventricular valve morphology was altered from normal muscular flap towards a bicuspid structure. Left atrial ligation or clipping resulted in hypoplasia of the left heart structures with compensatory overdevelopment on the right side. Hypoplastic left ventricle had decreased myocardial volume and showed accelerated trabecular compaction. Increased volume load in the right ventricle was compensated primarily by chamber dilatation with altered trabecular pattern, and by trabecular proliferation and thickening of the compact myocardium at the later stages. A ventricular septal defect was noted in all conotruncal banded, and 25% of left atrial ligated hearts. Increasing pressure load is a main stimulus for embryonic myocardial growth, while increased volume load is compensated primarily by dilatation. Adequate loading is important for normal cardiac morphogenesis and the development of typical myocardial patterns. Anat Rec 254:238–252, 1999. © 1999 Wiley‐Liss, Inc.