Dorsal bundle extinction effect: Motivation or attention?

Male albino Wistar rats were injected bilaterally with 4 micrograms of 6-hydroxydopamine into the dorsal noradrenergic bundle to deplete forebrain noradrenaline to less than 5% of control values. Acquisition learning of a fixed interval schedule or a continuously reinforced schedule was not altered but resistance to extinction was seen after food reinforced training on either schedule but not after water reinforced training. A possible increase in food motivation was tested by the use of preloading with free food prior to a fixed interval session but both control and lesioned rats reacted similarly to this manipulation thus appearing to exclude an increase in food motivation. An attentional explanation is proposed and tested by the demonstration that resistance to extinction does not occur after a partially (variable ratio 4), as opposed to a continuously, reinforced schedule. Further evidence in favour of an attentional mechanism comes from the finding that on both a fixed interval and a continuously reinforced schedule the lesion has to be present during the acquisition phase to result in subsequent resistance to extinction. Intact animals trained on either schedule and subsequently subjected to the lesion failed to show an increased resistance to extinction.     

Selective impairment of paired associate learning after administration of a centrally-acting adrenergic agonist (clonidine)

Eight normal volunteers had IV infusions of 200 g clonidine (a centrally-acting adrenergic agonist which reduces noradrenaline release), and saline in a double-blind cross-over design. Clonidine reduced subjective estimates of arousal but did not affect performance on the Digit Symbol Substitution Test. Clonidine impaired pairedassociate learning, but it did not affect performance on a number of measures of short and long term memory. The findings suggest either 1) that there is a specific (adrenergic) mechanism involved in the acquisition of novel associations, but not in other types of learning, or 2) that paired associate learning is more vulnerable than other learning tasks to disruption of adrenergic transmission.     

Rectal and brain temperatures in ethanol intoxicated mice

The organometal neurotoxin trimethyltin (TMT), induces impaired learning and memory for various tasks. However, administration is also associated with other non-specific behavioral changes which may be responsible for effects on conditioned behaviors. To determine if TMT treatment causes a specific learning impairment, three experiments were done using variations of a delay of reinforcement autoshaping task in which rats learn to associate the presentation and retraction of a lever with the delivery of a food pellet reinforcer. No significant effects of TMT treatment were found with a short (4 s) delay of reinforcement, indicating that rats were motivated and had the sensorimotor capacity for learning. When the delay was increased to 6 s, 3.0 or 6.0 mg TMT/kg produced dose-related reductions in behaviors directed towards the lever. Performance of a group given 7.5 mg TMT/kg, while still impaired relative to controls, appeared to be better than the performance of groups given lower doses. This paradoxical effect was investigated with a latent inhibition paradigm, in which rats were pre-exposed to the Skinner boxes for several sessions without delivery of food reinforcement. Control rats showed retardation of autoshaping when food reinforcement was subsequently introduced. Rats given 7.5 mg TMT/kg exhibited elevated levels of lever responding during pre-exposure and autoshaping sessions. The results indicate that 7.5 mg TMT/kg produces learning impairments which are confounded by hyperreactivity to the environment and an inability to suppress behavior toward irrelevant stimuli. In contrast, low doses of TMT cause learning impairments which are not confounded by hyperreactivity, and may prove to be useful models for studying specific associational dysfunctions.     

Attenuation of ethanol tolerance by a novel stimulus

A Pavlovian conditioning model of tolerance emphasizes that an association between predrug cues and the systemic effects of the drug contributes to tolerance. On the basis of this model, established tolerance should be attenuated by external inhibition, i.e., by presentation of a novel, extraneous stimulus. This prediction was evaluated in the present experiment. Rats that were so tolerant to the hypothermic effect of ethanol that they evidenced no drug-induced decrease in temperature were presented with a bright strobe light following ethanol administration. The light precipitated a large decrease in temperature in these rats. These results provide further evidence that tolerance to the hypothermic effect of ethanol is, in part, mediated by learning.     

Central mediation of the conditioned taste aversion induced in rats by harmaline

The assumption that drugs used as unconditioned stimuli in conditioned taste aversion (CTA) studies act centrally was tested by comparing the effects of systemic and intracerebral injections of harmaline hydrochloride (H) in 340 rats. Intraperitoneal injection of 5–20 mg/kg but not of 2.5 mg/kg H administered 5 min after 15-min saccharin (0.1%) drinking decreased saccharin-water preference in a two-choice retention test, performed 48 h later, from 55% to 20%. Since CTA was not diminished when H (10 mg/kg) was injected into rats anesthetised immediately after saccharin drinking by pentobarbital (40 mg/kg), H (1.7–50 g) was administered intracerebrally to anesthetised rats fixed in the stereotaxic apparatus. Injection of 3–6 g H into the inferior olive elicited CTA comparable to that of systemic injection of 10 mg/kg H. Injections of 6 and 50 g H into cerebellum and bulbar reticular formation elicited weaker CTA while neocortical, hypothalamic and mesencephalic applications were ineffective. CTA could also be elicited when 50 g but not 6 g H was injected into the inferior olive 1 or 2 h after saccharin drinking. This delay-dependent effect and failure of non-contingent H administration to change saccharin preference indicates that the H-induced CTA is not contaminated by a non-specific increase in neophobia. It is concluded that H probably elicits CTA by activation of caudal bulbar structures, including the nucleus of the solitary tract, area postrema and lateral reticular formation.     

Incremental repeated acquisition in the rat: acute effects of drugs

Rats lever pressed for food and learned new response sequences on three levers. At the beginning of each daily session, responses on only one of the levers produced food. After meeting criterion on one lever, the task was "incremented" so that sequential responses on two levers were required and so on up to five sequential responses. Each new required response was added in front of the previously performed sequence. Sequences of lever presses required to produce food changed each session. Following establishment of stable acquisition behavior, the acute effects of d-amphetamine (0.30-3.0 mg/kg), diazepam (0.125-4.0 mg/kg), morphine (0.30-10.0 mg/kg), pentobarbital (1.0-17.5 mg/kg), and chlorpromazine (0.10-3.0 mg/kg) were examined. All drugs decreased the number of response sequences completed in a dose-dependent fashion. Response rates generally decreased at or below those doses that caused an increase in errors. For d-amphetamine, the profound disruption of incremental repeated acquisition behavior was primarily due to drug-induced perserverative responding. Pentobarbital and chlorpromazine increased errors both when the sequence was incremented and within the sequence whereas diazepam only increased errors when the sequence was incremented. Morphine generally increased within sequence errors without affecting errors when the sequence was incremented.     

道路交通安全执法对医院质控的启示

道路交通安全执法对机动车的管理井然有序,而行人违规过马路现象却比比皆是。医院质控也常常出现类似的现象。文章比较了道路交通安全执法对机动车管理与行人管理的异同,认为道路交通安全执法与医院质控虽然属于不同的领域,但拥有相同或相似的功能和流程,可以作为跨行业功能性标杆来学习。道路交通安全执法对医院质控的启示为:（1）医院质控必须遵循结构质量—过程质量—结果质量（SPO）三维质量评价模型,且有机协同;（2）有效的质量控制必须符合热炉法则;（3）质控工作的重心应放在监控和改进上,即“有时去应急,常常去改进,总是去监控”;（4）遵循规章制度的自律文化的养成是良好质控的保证。     

完全腹腔镜根治性膀胱切除加体内改良回肠通道术的学习效果分析

目的分析术者对完全腹腔镜根治性膀胱切除(LRC)+改良回肠通道术(MIC)的学习效果。方法回顾性分析首都医科大学附属北京朝阳医院2014年4月至2019年10月42例接受完全LRC+MIC患者的临床资料。男34例,女8例;年龄(63.4±9.1)岁。其中术者1行34例手术,术者2行8例。将术者1的34例按时间顺序分为3组,第1~12例为A组,第13~23例为B组,第24~34例为C组;术者2实施的8例为D组。4组中有腹部手术史者分别为0、1、4、3例,差异有统计学意义(P<0.05);4组年龄、体质指数、美国麻醉医师协会评分等差异均无统计学意义(P>0.05)。改良术式的重要步骤包括光源透射下离断肠系膜、输出袢固定的条件下行输尿管-输出袢反流性对端吻合、缝合后腹膜缺口。比较各组患者手术时间、构建回肠通道时间、出血量、并发症发生比例、淋巴结清扫数量、切缘阳性比例等重要手术指标。结果各组手术均顺利完成,均无中转开放手术。A~C组手术时间分别为330.0(320.0,360.0)、300.0(250.0,308.0)、270.0(216.0,324.0)min,差异有统计学意义(P=0.010);3组构建回肠通道时间分别为136.5(131.3,147.5)、92.0(79.0,119.0)、79.0(72.0,115.0)min,差异有统计学意义(P<0.001)。手术时间和构建回肠通道时间组间两两比较,A、B组,A、C组差异均有统计学意义(P<0.05),B、C组差异无统计学意义(P>0.05)。3组出血量[200.0(125.0,300.0)、100.0(100.0,150.0)、200.0(100.0,400.0)ml]、并发症发生比例[4/12、4/11、3/11]、淋巴结清扫数量[(19.0±10.7)、(16.0±9.8)、(23.3±8.5)枚]、切缘阳性比例(1/12、1/11、2/11)的比较,差异均无统计学意义(P>0.05)。D组手术时间420.0(350.0,450.0)min,与A组比较差异有统计学意义(P<0.05)。D组出血量200.0(112.5,350.0)ml,并发症发生比例2/8,淋巴结清扫数量(13.8±7.1)个,切缘阳性比例1/8,与A组比较差异均无统计学意义(P>0.05)。结论完全LRC+MIC学习效果明显,随着手术例数的增加,手术时间及构建回肠通道时间显著下降;该术式具有较好的可重复性和安全性。     

Resecciones pulmonares anatómicas por vía robótica: análisis de la curva de aprendizaje

IntroductionRobotic surgery has become a safe and effective approach for the treatment of pulmonary surgical pathology. However, the adoption of new surgical techniques requires the evaluation of the learning curve. The objective of this study is to analyze the learning curve of robotic anatomical lung resections.MethodsRetrospective analysis of all robotic anatomical lung resections performed by the same surgeon between June 2018 and March 2020. The learning curve was evaluated using CUSUM charts to estimate trend changes in surgical time, surgical failure and the occurrence of post-operative cardiorespiratory complications throughout the sequence of cases.ResultsThe study included a total of 73 cases. The median duration of all complications was 120 min (interquartile range: 90-150 min), the prevalence of surgical failure was 23.29%, while 4/73 patients had any postoperative cardiorespiratory complication. Based on the CUSUM analysis, the learning curve was divided into 3 different phases: phase i (from the first to the 14th intervention), phase ii (between the 15th and 30th intervention) and phase iii (from the 31st intervention).ConclusionsThe learning curve for robotic anatomical lung resections can be divided into 3 phases. The technical competence that guarantees satisfactory perioperative outcomes was achived in phase iii from the 31st intervention.     

Analyzing the learning curves of a novice and an experienced urologist for transrectal magnetic resonance imaging-ultrasound fusion prostate biopsy

BackgroundThe aim of the current study was to evaluate and compare the learning curves of transrectal magnetic resonance imaging-ultrasound fusion biopsy for two urologists with different backgrounds (Operator 1: experienced, self-trained and Operator 2: novice, trained by a mentor/MRI reading courses).MethodsA cohort of 400 patients who underwent fusion prostate biopsy in our department was analyzed. The learning curves were assessed in terms of overall and clinically significant prostate cancer (PCa) detection rates, percentage of positive biopsy cores/targeted and the percentage of PCa tissue on positive targeted cores.ResultsIncreasing trends were observed for both urologists in terms of all biopsy outcomes during the study time. For the novice urologist, a significant increase was observed for overall PCa detection rate, but not for clinically significant disease (25.44%, P=0.04/15%, P=0.145). Operator 1 showed an increasing diagnosis yield of clinically significant disease up to 104 cases. Similar cancer detection rates were observed when comparing the first and last biopsies performed by both operators. Multivariate analysis adjusted for age, PSA, prostate volume, lesion diameter and PIRADS score showed an increase of PCa detection with 51% for every 52 biopsies performed (P=0.022).ConclusionsWhen starting with magnetic resonance imaging-ultrasound fusion prostate biopsy, mentoring and prostate magnetic resonance imaging reading training allow a novice urologist to demonstrate a good initial PCa detection rate. After about 52 cases, he reached a stable PCa and clinically significant PCa detection rate, that was similar to that of an experienced urologist.