Simulation of transcranial magnetic stimulation in head model with morphologically-realistic cortical neurons

BackgroundTranscranial magnetic stimulation (TMS) enables non-invasive modulation of brain activity with both clinical and research applications, but fundamental questions remain about the neural types and elements TMS activates and how stimulation parameters affect the neural response.ObjectiveTo develop a multi-scale computational model to quantify the effect of TMS parameters on the direct response of individual neurons.MethodsWe integrated morphologically-realistic neuronal models with TMS-induced electric fields computed in a finite element model of a human head to quantify the cortical response to TMS with several combinations of pulse waveforms and current directions.ResultsTMS activated with lowest intensity intracortical axonal terminations in the superficial gyral crown and lip regions. Layer 5 pyramidal cells had the lowest thresholds, but layer 2/3 pyramidal cells and inhibitory basket cells were also activated at most intensities. Direct activation of layers 1 and 6 was unlikely. Neural activation was largely driven by the field magnitude, rather than the field component normal to the cortical surface. Varying the induced current direction caused a waveform-dependent shift in the activation site and provided a potential mechanism for experimentally observed differences in thresholds and latencies of muscle responses.ConclusionsThis biophysically-based simulation provides a novel method to elucidate mechanisms and inform parameter selection of TMS and other cortical stimulation modalities. It also serves as a foundation for more detailed network models of the response to TMS, which may include endogenous activity, synaptic connectivity, inputs from intrinsic and extrinsic axonal projections, and corticofugal axons in white matter.     

Influence of COMT genotype and affective distractors on the processing of self-generated thought

The catechol-O-methyltransferase (COMT) enzyme is a major determinant of prefrontal dopamine levels. The Val¹⁵⁸Met polymorphism affects COMT enzymatic activity and has been associated with variation in executive function and affective processing. This study investigated the effect of COMT genotype on the flexible modulation of the balance between processing self-generated and processing stimulus-oriented information, in the presence or absence of affective distractors. Analyses included 124 healthy adult participants, who were also assessed on standard working memory (WM) tasks. Relative to Val carriers, Met homozygotes made fewer errors when selecting and manipulating self-generated thoughts. This effect was partly accounted for by an association between COMT genotype and visuospatial WM performance. We also observed a complex interaction between the influence of affective distractors, COMT genotype and sex on task accuracy: male, but not female, participants showed a sensitivity to the affective distractors that was dependent on COMT genotype. This was not accounted for by WM performance. This study provides novel evidence of the role of dopaminergic genetic variation on the ability to select and manipulate self-generated thoughts. The results also suggest sexually dimorphic effects of COMT genotype on the influence of affective distractors on executive function.     

桂枝汤加减治疗营卫不和型慢性瘾疹的临床疗效

目的:观察桂枝汤加减治疗营卫不和型慢性瘾疹的临床疗效。方法:将我院门诊2017年10月-2019年10月收治的48例营卫不和型慢性瘾疹患者,按随机数表法分成对照组(24例)与实验组(24例)。对照组实施常规西药治疗,实验组实施桂枝汤合地骨皮、白鲜皮加减治疗。对照两组治疗前后症状积分、临床疗效及并发症发生率。结果:两组治疗前症状积分相比无显著差异(P>0.05)。治疗后,两组症状积分均有所下降,实验组低于对照组;实验组临床总有效率为91.67%(22/24)高于对照组的66.67%(16/24);实验组并发症发生率0(0/24)低于对照组的16.67%(4/24),差异具有统计学意义(P<0.05)。结论:在营卫不和型慢性瘾疹治疗中,采取桂枝汤加减治疗,可明显降低症状积分,提高临床治疗效果,减少并发症,效果理想。     

Neural mechanisms regulating different forms of risk-related decision-making: Insights from animal models

Over the past 20 years there has been a growing interest in the neural underpinnings of cost/benefit decision-making. Recent studies with animal models have made considerable advances in our understanding of how different prefrontal, striatal, limbic and monoaminergic circuits interact to promote efficient risk/reward decision-making, and how dysfunction in these circuits underlies aberrant decision-making observed in numerous psychiatric disorders. This review will highlight recent findings from studies exploring these questions using a variety of behavioral assays, as well as molecular, pharmacological, neurophysiological, and translational approaches. We begin with a discussion of how neural systems related to decision subcomponents may interact to generate more complex decisions involving risk and uncertainty. This is followed by an overview of interactions between prefrontal-amygdala-dopamine and habenular circuits in regulating choice between certain and uncertain rewards and how different modes of dopamine transmission may contribute to these processes. These data will be compared with results from other studies investigating the contribution of some of these systems to guiding decision-making related to rewards vs. punishment. Lastly, we provide a brief summary of impairments in risk-related decision-making associated with psychiatric disorders, highlighting recent translational studies in laboratory animals.     

Anatomically contoured large femoral heads can reduce iliopsoas impingement: A cadaver verification study

While use of large heads in total hip arthroplasty (THA) continues to grow, concerns have been raised regarding anterior hip pain resulting from impingement of the prosthetic head against soft-tissues like the iliopsoas. To address these concerns, a new anatomically contoured head (ACH) was developed. In this study cadaver tests were utilized to show that iliopsoas impingement/tenting caused by conventional heads is significantly relieved with the more rounded and reduced distal profile of the ACH. Thus, the ACH implant may be able to decrease the risk of soft-tissue impingement with conventional heads, particularly in the smaller hip.     

Potentilla anserine L. polysaccharide protects against cadmium-induced neurotoxicity

Cadmium is a toxic metal that can damage the brain and other organs. This study aimed to explore the protective effects of Potentilla anserine L. polysaccharide (PAP) against CdCl₂-induced neurotoxicity in N2a and SH-SY5Y cells and in the cerebral cortex of BALB/c mice. In addition, we aimed to identify the potential mechanisms underlying these protective effects. Relative to CdCl₂ treatment alone, pretreatment with PAP prevented the reduction in cell viability evoked by CdCl₂, decreased rates of apoptosis, promoted calcium homeostasis, decreased ROS accumulation, increased mitochondrial membrane potential, inhibited cytochrome C and AIF release, and prevented the cleavage of caspase-3 and PARP. In addition, PAP significantly decreased the CdCl₂-induced phosphorylation of CaMKII, Akt, and mTOR. In conclusion, PAP represents a potential therapeutic agent for the treatment of Cd-induced neurotoxicity, functioning in part via attenuating the activation of the mitochondrial apoptosis pathway and the Ca²⁺-CaMKII-dependent Akt/mTOR pathway.     

髌周去神经化预防全膝关节置换术后膝前疼痛

目的　依据髌周解剖学特点，探讨全膝关节置换术（total knee arthroplasty，TKA）中应用髌周电灼去神经化的临床效果。 方法　纳入82名诊断为骨性关节炎的患者（91膝），予行双侧或单侧不置换髌骨的TKA，按随机对照原则将病人分为两组，共有41名实验组患者（45膝）在TKA中接受了髌周去神经化处理，41名对照组患者（46膝）未做该处理。手术主刀为同一骨科医师，均使用相同的膝关节假体系统。主要评价项目包括膝关节KSS评分、Western Ontario and McMaster Universities（WOMAC）、Feller髌骨评分及VAS评分。 结果　82名患者术后均获随访，平均随访时间为12个月，两组病人的膝关节KSS评分、WOMAC、Feller髌骨评分及VAS评分均无显著统计学差异（P>0.05）。 结论　在TKA中行髌周电灼去神经化，不能显著改善病人的预后。     

Oxyhemoglobin changes in the prefrontal cortex in response to cognitive tasks: a systematic review

Purpose of the study: the aim of this study was to synthesize PFC fNIRS outcomes on the effects of cognitive tasks compared to resting/baseline tasks in healthy adults from studies utilizing a pre/post design.

Material and methods: original research studies were searched from seven databases (MEDLINE, EMBASE, CENTRAL, CINAHL, SCOPUS, PEDro and PubMed). Subsequently, two independent reviewers screened the titles and abstracts followed by full-text reviews to assess the studies' eligibility.

Results: eleven studies met the inclusion criteria and had data abstracted and quality assessed. Methodology varied considerably and yet cognitive tasks resulted in the ΔO₂Hb increasing in 8 of the 11 and ΔHHb decreasing in 8 of 8 studies that reported this outcome. The cognitive tasks from 10 of the 11 studies were classified as “Working Memory” and “Verbal Fluency Tasks”.

Conclusions: although, the data comparison was challenging provided the heterogeneity in methodology, the results across studies were similar.     

Fetal anterior abdominal wall thickness between gestational diabetes and normal pregnant women

ObjectivesTo compare fetal anterior abdominal wall thickness (AAWT) between women with and without GDM during third trimester and to determine accuracy of AAWT to predict large for gestational age (LGA) infants.Materials and methodsA total of 250 pregnant women, including 125 women with GDM and 125 women without GDM, were enrolled. Tansabdominal ultrasonographic examinations were performed at 28–30, 32–34 and 36–38 weeks. In addition to standard fetal biometries, AAWT was measured. Patient characteristics and ultrasonographic measurements were compared between groups. Sensitivity and specificity of AAWT for identifying LGA were evaluated.ResultsWhile standard fetal biometries were comparable, mean fetal AAWT in GDM women were significantly higher than those without GDM at 28–30 weeks (2.8 ± 0.8 vs. 2.6 ± 0.6, p = 0.006) and 32–34 weeks (4.0 ± 0.9 vs. 3.5 ± 0.8, p = 0.042). LGA infants had significantly higher fetal AAWT at each time point only in GDM women. Using cut off values of AAWT of ≥2.0, 3.0, and 4.0 mm at 28–30, 32–34, and 36–38 weeks, sensitivity for LGA diagnosis in GDM women were 94.4%, 93.9%, and 89.3%, respectively. The use of abdominal circumference (AC) at >90th percentile showed lower sensitivity but higher specificity, regardless of GDM status. Combination of both measurements increased sensitivity to approximately 90% or higher in every time point, especially among GDM women.ConclusionSignificant increase in fetal AAWT was observed in GDM women at 28–30 and 32–34 weeks. Fetal AAWT significantly increased among LGA infants and had higher sensitivity than AC in identifying LGA during third trimester. In GDM women at 28–30 weeks, AAWT ≥2.0 mm and AC >90th percentile had 97.2% sensitivity for LGA diagnosis.