意大利蜜蜂对两种油菜花朵气味的偏爱性

【目的】明确意大利蜜蜂Apis mellifera ligustica（简称“意蜂”）对两种油菜（甘蓝型胜利油菜 Brassica napus cv. Shengli和芥菜型马尾油菜 B. juncea cv. Mawei）的气味偏爱性及选择行为特征。【方法】本研究开展大田访花偏爱性试验、室外群体气味偏爱性试验以及室内“Y”型嗅觉仪行为反应和学习记忆试验,测定意蜂蜂群及青年采集蜂对甘蓝型胜利油菜和芥菜型马尾油菜两种油菜花朵的选择次数,并通过采集蜂训练时及训练后的喙伸反应率分析两种油菜花朵气味对采集蜂学习记忆能力的影响,最终评估意蜂蜂群及个体对这两种油茶花朵气味的选择性。【结果】大田试验12:00-13:00时间段,访问胜利油菜的意蜂数量显著高于访问马尾油菜的数量(P<0.05）。群体气味偏爱性试验14:00-15:00时间段意蜂访问胜利油菜的数量显著高于访问马尾油菜的数量（P<0.05）。行为反应试验结果显示意蜂选择胜利油菜的次数（3.86±2.83）显著高于访问马尾油菜的次数（2.28±1.87）（P<0.05）。在学习记忆试验中,随着训练次数的增加,意蜂对两种油菜花朵气味的喙伸反应率逐渐升高,相同的训练次数,意蜂对两种油菜气味的学习能力差异不显著（P>0.05）;训练结束后,随着时间的增加,意蜂对胜利油菜及马尾油菜的气味记忆逐渐下降,在24 h对胜利油菜的气味记忆明显高于对马尾油菜的气味记忆（P<0.05）。【结论】本研究证明意蜂较偏爱胜利油菜的花朵气味,花朵气味是影响其采集偏爱的重要因素,气味响应性试验可定量分析蜜蜂对花朵气味的嗅觉敏感性。     

长期肾移植受者外周血B淋巴细胞亚群分布特征

摘要 目的：观察移植肾功能稳定的长期受者（>10年）外周血B细胞亚群分布特征及其相关因素。方法：54名肾移植受者接受流式细胞仪检查,测算外周血总B细胞、未转化记忆B细胞、转化记忆B细胞、双阴性B细胞（CD19⁺CD27^-IgD^-）比例及数量（个/微升）。患者均服用包括环孢霉素的免疫抑制治疗。术后时间16.33±5.98年,GFR：91.63±11.28 mL/min/1.73 m²。结果：1长期肾移植患者外周血B细胞中幼稚B细胞最多（37.92% ± 22.06%）,未转化记忆B细胞最少(16.23% ± 11.10%)。B细胞亚群数量与白细胞总数、中性粒细胞比例等相关。2 以上述条件为控制因素行相关分析,转化记忆B细胞比例和GFR相关（r=-0.279,P=0.045）,双阴性B细胞数量和环孢霉素浓度相关（r=-0.300,P=0.029）。线性回归显示双阴性B细胞数目与环孢霉素浓度相关（R²=0.123,P=0.049）。3按GFR将患者分为肾功能减退组（GFR<90 mL/min/1.73 m²,n=19）和肾功能正常组（GFR≥90 mL/min/1.73 m²,n=35）。前者转化记忆B细胞比例显著升高（23.61% ± 10.96% vs.17.48%±8.91%,P=0.030）。按环孢霉素谷浓度将患者分为低浓度组（<64 mmol/L,n=28）和高浓度组（≥64 mmol/L,n=26）,前者双阴性B细胞数量显著升高（13.74±10.70 vs. 8.14±6.72/μL,P=0.027）。转化记忆B细胞比例与GFR分组相关（r=-0.326,P=0.018）,双阴性B细胞数量和环孢霉素浓度分组相关（r=-0.350,P=0.01）。结论：移植肾功能稳定的长期存活受者（>10年）外周血幼稚B细胞较多。转化记忆B细胞增多与移植肾功能减退相关,增多的双阴性B细胞和低孢霉素浓度治疗相关。     

桔小实蝇雄成虫联系性嗅觉学习

【目的】为了探究桔小实蝇 Bactrocera dorsalis (Hendel)雄成虫的嗅觉学习能力。【方法】本研究采用经典性嗅觉条件反射训练法（classical olfactory conditioning）在室内对固定的羽化后14-17日龄的桔小实蝇雄成虫进行气味与食物的联合学习训练, 即薄荷精油和10%蔗糖溶液联合的奖赏性训练（appetitive conditioning）以及甲基丁香酚(methyl eugenol, ME)和饱和盐溶液联合的惩罚性训练（aversive conditioning）,并以伸喙反射行为（proboscis extension reflex, PER）作为学习与否的判定标准。【结果】经过奖赏性训练后,桔小实蝇雄成虫对薄荷精油的伸喙反射率可从0%增加至68%;而经过惩罚性训练后,桔小实蝇对甲基丁香酚的伸喙反射率可从100%降低至36.54%,且这种伸喙反射率的变化是通过气味条件刺激（conditioned stimulus）和食物非条件刺激（unconditioned stimulus）的对称性联合而产生的。【结论】结果表明,桔小实蝇雄性成虫具有较强的联系性嗅觉学习能力,并且两种刺激的联合是形成学习记忆的必要条件。     

胸椎旁神经阻滞复合全麻对肝癌切除术患者术后镇痛效果、炎症应激反应和免疫功能的影响

摘要 目的：探讨胸椎旁神经阻滞（TPVB）复合全身麻醉在肝癌切除术的镇痛效果。方法：行肝癌切除术的患者120例根据麻醉方式不同分为对照组与TPVB组,每组60例。对照组实施单纯全身麻醉,TPVB组予以TPVB复合全身麻醉。记录两组术后4 h、术后12 h、术后24 h和术后48 h疼痛数字评价量表（NRS）评分;记录两组术中麻醉药物使用情况、术后镇痛相关指标;记录两组不良反应情况和首次排气时间、住院时间;分别于术前和术后24 h,检测患者血清白细胞介素-6（IL-6）和IL-8的测定并使用流式细胞仪对患者外周血T淋巴细胞亚群进行测定。结果：相比于对照组,TPVB组术后4 h、术后12 h和术后24 h的NRS评分均显著下降（P<0.05）。相比于对照组,TPVB组术中瑞芬太尼用量使用减少（P<0.05）,首次按压镇痛泵时间延迟（P<0.05）,术后24 h镇痛按压次数及用量减少（P<0.05）,且补救镇痛率显著降低（P<0.05）。TPVB组术后首次排气时间相比对照组提前（P<0.05）,住院时间相比对照组缩短（P<0.05）,术后恶心呕吐发生率显著低于对照组（P<0.05）。在术后24 h时,两组IL-6水平和IL-8水平均高于术前（P<0.05）,但TPVB组低于对照组（P<0.05）。在术后24 h时,两组CD3⁺、CD4⁺和CD4⁺/CD8⁺水平均低于术前（P<0.05）,但TPVB组高于对照组（P<0.05）。结论：TPVB复合全麻用于肝癌切除术能够提高术后镇痛效果,减少围术期阿片类药物消耗,减轻术后炎症反应,改善术后免疫功能,对术后恢复有积极作用。     

非小细胞肺癌组织PD-L1、TTF-1、SYN表达与临床病理特征及预后的关系研究

摘要 目的：探讨非小细胞肺癌（NSCLC）组织程序性细胞死亡蛋白1配体（PD-L1）、甲状腺转录因子-1（TTF-1）、突触素（SYN）表达与临床病理特征及预后的关系。方法：对2013年2月至2015年2月期间在我院治疗的97例NSCLC患者进行研究。检测NSCLC组织以及癌旁组织中PD-L1、TTF-1、SYN表达。分析PD-L1、TTF-1、SYN表达与临床病理特征的相关性。Kaplan-Meier生存曲线分析不同PD-L1、TTF-1、SYN表达患者总生存率的差异。Cox比例风险回归分析NSCLC患者预后的影响因素。结果：与癌旁组织相比,NSCLC组织中PD-L1、TTF-1阳性表达升高,SYN阴性表达升高（P<0.05）。PD-L1、TTF-1、SYN表达均与TNM分期和淋巴结转移相关（P<0.05）。PD-L1、TTF-1阴性患者的生存率分别高于PD-L1、TTF-1阳性患者,SYN阴性患者的生存率低于SYN阳性患者（P<0.05）。Cox比例风险回归分析结果显示,TNM分期、PD-L1阳性表达、TTF-1阳性表达、SYN阴性表达、淋巴结转移是NSCLC患者预后的影响因素（P<0.05）。结论：NSCLC组织中PD-L1、TTF-1阳性表达升高,SYN阴性表达升高,并且均与TNM分期、淋巴结转移和预后相关,其在NSCLC的诊断和预后评估中具有一定临床价值。     

Luminal B型乳腺癌不同亚型的临床病理特征及预后生存分析

摘要 目的：分析Luminal B型乳腺癌不同亚型患者的临床病理特征以及预后差异。方法：回顾性分析2006年1月至2016年1月期间上海市第六人民医院徐汇院区和临港院区收治的359例原发性Luminal B型乳腺癌患者的临床病理以及随访资料,根据Luminal B型乳腺癌分子亚型分为人表皮生长受体2（Her-2）阴性组（266例）和Her-2阳性组（93例）。比较两组患者的临床病理特征差异。绘制Kaplan-Meier生存曲线,分析两组患者5年无进展生存率和总生存率的差异,采用Cox风险比例回归分析Luminal B型乳腺癌患者预后的影响因素。结果：Her-2阳性组TNM分期Ⅲ～Ⅳ期、肿瘤组织学分级Ⅲ级、PR阴性、Ki-67高表达、淋巴结转移比例高于Her-2阴性组（P＜0.05）。Her-2阳性组5年DFS、OS生存率分别为12.90%、40.86%,分别低于Her-2阴性组的24.06%、59.77%（Log-Rankχ²=14.500、12.860,P=0.000、0.000）。TNM分期Ⅲ～Ⅳ期、淋巴结转移、Her-2阳性、PR阴性是Luminal B型乳腺癌患者不良预后的危险因素（P＜0.05）。结论：Luminal B 型乳腺癌患者不同分子亚型的TNM分期、肿瘤组织学分级、淋巴结转移、Ki-67和PR表达存在差异,同时,TNM分期、淋巴结转移、Her-2阳性、PR阴性是Luminal B 型乳腺癌患者预后不良的危险因素。     

记忆训练联合电针疗法对全脑放疗患者认知功能、健康相关生命质量和颅脑磁共振灌注成像参数的影响

摘要 目的：探讨记忆训练联合电针疗法对全脑放疗患者认知功能、健康相关生命质量和颅脑磁共振灌注成像参数的影响。方法：选择江南大学附属医院2020年3月～2022年1月期间收治的全脑放疗患者94例,根据随机数字表法分为研究组（常规干预、记忆训练联合电针疗法）和对照组（常规干预）,各为47例。对比两组认知功能、健康相关生命质量和颅脑磁共振灌注成像参数的变化。结果：治疗1周、2周、3周、4周后,两组蒙特利尔认知功能检查量表（MoCA）和简易精神状态量表（MMSE）评分均较治疗前逐渐下降,但研究组各时间点MoCA、MMSE评分高于对照组（P<0.05）。治疗4周后,两组健康相关生命质量量表（HRQoL）各维度评分及总分均较治疗前升高,且研究组上述评分均高于对照组（P<0.05）。治疗4周后,两组颅脑平均脑血容量（CBV）值和平均脑血流量（CBF）值均较治疗前下降,但研究组上述值高于对照组（P<0.05）。结论：记忆训练联合电针疗法可减缓全脑放疗后导致的认知功能损害,并提升患者的健康相关生命质量,可能与调节脑血容量、脑血流量有关。     

小剂量右美托咪定复合氯胺酮麻醉对先天性心脏病介入封堵术患儿心肌损伤和炎性因子的影响

摘要 目的：观察小剂量右美托咪定复合氯胺酮麻醉对先天性心脏病（CHD）介入封堵术患儿心肌损伤和炎性因子的影响。方法：纳入我院2020年6月-2021年6月期间收治的CHD行介入封堵术的患儿60例,根据随机数字表法将患儿分为K组（氯胺酮麻醉,n=30）和KD组（小剂量右美托咪定复合氯胺酮麻醉,n=30）。观察两组患儿血流动力学、心肌损伤和炎性因子指标的变化情况,记录两组患儿围术期间不良反应发生情况。结果：KD组患儿喉罩置入后（T1）~手术结束时（T4）时间点心率（HR）、平均动脉压（MAP）均低于K组患儿（P<0.05）。KD组患儿术后6 h、术后12 h血清心脏型脂肪酸结合蛋白（H-FABP）、肌酸激酶同工酶（CK-MB）、心肌肌钙蛋白I（cTnI）水平低于K组（P<0.05）。KD组患儿术后6 h、术后12 h血清C反应蛋白（CRP）、白介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）水平低于K组（P<0.05）。两组患儿不良反应发生率组间对比无统计学差异（P>0.05）。结论：小剂量右美托咪定复合氯胺酮麻醉用于行CHD介入封堵术患儿,可减轻其血流波动,减少心肌损伤,控制患儿炎症反应,安全可靠。     

慢性鼻窦炎患者嗅觉障碍的危险因素探讨及其对患者心理健康和生存质量的影响

摘要 目的：探讨慢性鼻窦炎患者嗅觉障碍的危险因素及其对患者心理健康和生存质量的影响。方法：选取2017年9月~2020年9月期间首都医科大学附属北京同仁医院收治的120例慢性鼻窦炎患者进行嗅觉功能测试。统计嗅觉功能障碍患者的发生率，并依据嗅觉功能测试情况将患者分为嗅觉障碍组（n=64）和嗅觉正常组（n=56）。对两组患者的基础资料、临床资料、心理健康状况和生存质量等进行比较分析，采用单因素分析慢性鼻窦炎患者嗅觉障碍发生的影响因素，多因素Logistic回归分析慢性鼻窦炎患者嗅觉障碍发生的危险因素。结果：经嗅觉功能测试结果统计，120例患者中有64例患者出现嗅觉功能障碍，嗅觉障碍患病率为53.33%，其中男性有36例（56.25%），女性有28例（43.75%）；嗅觉下降46例(38.33%)、失嗅18例(15.00%)。单因素分析显示：鼻内镜手术史、伴鼻息肉、哮喘病史、嗜酸粒细胞比例、鼻内镜Lund-Kennedy评分是慢性鼻窦炎嗅觉障碍发生的影响因素(均P<0.05)。多因素Logistic回归分析表明：鼻内镜手术史、伴鼻息肉、哮喘病史、嗜酸粒细胞比例>5%、鼻内镜Lund-Kennedy评分≥2分是慢性鼻窦炎嗅觉障碍发生的独立危险因素。嗅觉正常组的焦虑自评量表（SAS）、抑郁自评量表（SDS）评分均低于嗅觉障碍组（P<0.05）。嗅觉正常组生活质量简表（SF-36）各维度评分均高于嗅觉障碍组（P<0.05）。结论：慢性鼻窦炎患者的嗅觉障碍发生率较高，鼻内镜手术史、伴鼻息肉、哮喘病史、嗜酸粒细胞比例>5%、Lund-Kennedy评分≥2分是影响患者嗅觉障碍发生的危险因素。同时嗅觉障碍还会引起患者抑郁焦虑等不良情绪，降低患者的生活质量。     

东方蜜蜂和西方蜜蜂对红阳猕猴桃雌花挥发性气味响应的差异

【目的】植物的挥发性气味对传粉者的选择具有重要的影响,为探究红阳猕猴桃Actinidia chinensis ‘Hongyang’雌花的挥发性气味对东方蜜蜂Apis cerana和西方蜜蜂Apis mellifera行为反应的差异。【方法】利用顶空固相微萃取与气质联用技术（Headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS）鉴定红阳猕猴桃雌花挥发性物质成分及相对含量,并通过气相色谱-触角电位联用测量系统（GC-EAD）和Y型嗅觉仪测定东方蜜蜂和西方蜜蜂对红阳猕猴桃雌花气味的触角电位和行为反应。【结果】GC-MS结果表明,红阳猕猴桃雌花挥发性气味含有33种成分,包括醇类、酯类、酮类、烃类、萜烯类、醛类、胺类和盐类。GC-EAD结果表明,红阳猕猴桃雌花挥发性物质中7种化合物芳樟醇、壬醛、苯乙醇、2,6,6-三甲基-2-环己烯-1,4-二酮、苯甲酸乙酯、水杨酸甲酯和顺式-3-己烯醇2-甲基丁酸酯能够引起东方蜜蜂和西方蜜蜂的触角反应,而3种化合物乙酸叶醇酯、水杨酸乙酯和β-紫罗酮只引起东方蜜蜂的触角反应。嗅觉行为反应结果表明,红阳猕猴桃雌花的气味对东方蜜蜂具有引诱作用（P> 0.05）,引诱率为60%;对西方蜜蜂具有驱避作用（P <0.01）,驱避率是67.5%。【结论】东方蜜蜂和西方蜜蜂对红阳猕猴桃雌花挥发性气味的响应存在显著差异,东方蜜蜂对红阳猕猴桃雌花的气味无明显趋性,而西方蜜蜂对红阳猕猴桃雌花的气味具有明显驱避。因此,为红阳猕猴桃授粉时,东方蜜蜂相对于西方蜜蜂更理想。     

Odor information transfer in the stingless bee<Emphasis Type="Italic"> Melipona quadrifasciata</Emphasis>: effect of in-hive experiences on classical conditioning of proboscis extension

A recent study showed that the stingless bee Melipona quadrifasciata could learn to discriminate odors in a classical conditioning of proboscis extension response (PER). Here we used this protocol to investigate the ability of these bees to use olfactory information obtained within the colony in an experimental context: the PER paradigm. We compared their success in solving a classical differential conditioning depending on the previous olfactory experiences received inside the nest. We found that M. quadrifasciata bees are capable of transferring the food-odor information acquired in the colony to a differential conditioning in the PER paradigm. Bees attained higher discrimination levels when they had previously encountered the rewarded odor associated to food inside the hive. The increase in the discrimination levels, however, was in some cases unspecific to the odor used indicating a certain degree of generalization. The influence of the food scent offered at a field feeder 24 h before the classical conditioning could also be seen in the discrimination attained by the foragers in the PER setup, detecting the presence of long-term memory. Moreover, the improved performance of recruited bees in the PER paradigm suggests the occurrence of social learning of nectar scents inside the stingless bees’ hives.     

Hygienic behavior of the honey bee (Apis mellifera) is independent of sucrose responsiveness and foraging ontogeny

Hygienic behavior in honey bees is a behavioral mechanism of disease resistance. Bees bred for hygienic behavior exhibit an increased olfactory sensitivity to odors of diseased brood, which is most likely differentially enhanced in the hygienic line by the modulatory effects of octopamine (OA), a noradrenaline-like neuromodulator. Here, we addressed whether the hygienic behavioral state is linked to other behavioral activities known to be modulated by OA. We specifically asked if, during learning trials, bees from hygienic colonies discriminate better between odors of diseased and healthy brood because of differences in sucrose (reward) response thresholds. This determination had to be tested because sucrose response thresholds are susceptible to OA modulation and may have influenced the honey bee's association of the conditioned stimulus (odor) with the unconditioned stimulus (i.e., the sucrose reward). Because the onset of first foraging is also modulated by OA, we also examined whether bees from hygienic colonies differentially forage at an earlier age compared to bees from non-hygienic colonies. Our study revealed that 1-day- and 15- to 20-day-old bees from the hygienic line do not have lower sucrose response thresholds compared to bees from the non-hygienic lines. In addition, hygienic bees did not forage at an earlier age or forage preferentially for pollen as compared to non-hygienic bees. These results support the idea that OA does not function in honey bees simply to enhance the detection of all chemical cues non-selectively or control related behaviors regardless of their environmental milieu. Our results indicate that the behavioral profile of the hygienic bee is sculpted by multiple factors including genetic, neural, social and environmental systems.     

Innate attractiveness and associative learnability of odors can be dissociated in larval Drosophila

We investigate olfactory associative learning in larval Drosophila. A reciprocal training design is used, such that one group of animals receives a reward in the presence of odor X but not in the presence of odor Y (Train: X+ // Y), whereas another group is trained reciprocally (Train: X // Y+). After training, differences in odor preference between these reciprocally trained groups in a choice test (Test: X - Y) reflect associative learning. The current study, after showing which odor pairs can be used for such learning experiments, 1) introduces a one-odor version of such reciprocal paradigm that allows estimating the learnability of single odors. Regarding this reciprocal one-odor paradigm, we show that 2) paired presentations of an odor with a reward increase odor preference above baseline, whereas unpaired presentations of odor and reward decrease odor preference below baseline; this suggests that odors can become predictive either of reward or of reward absence. Furthermore, we show that 3) innate attractiveness and associative learnability can be dissociated. These data deepen our understanding of odor-reward learning in larval Drosophila on the behavioral level, and thus foster its neurogenetic analysis.     

Olfactory conditioning with single chemicals in the German Cockroach, Blattella germanica (Dictyoptera: Blattellidae)

Many insects find resources by means of the olfactory cues of general odors after learning. To evaluate behavioral responses to the odor of a particular chemical after learning with reward or punishment quantitatively, we developed a standardized odor-training method in the German cockroach, Blattella germanica (Linnaeus), an important urban pest species. A classical olfactory conditioning procedure for a preference test was modified to become applicable to a single odor, by which a (?)-menthol or vanillin odor was independently associated with sucrose (reward) or sodium chloride solution (punishment). The strength of the association with the odor was evaluated with the increase or decrease in visit frequencies to the odor source after olfactory conditioning. The frequency increased after (?)-menthol was presented with a reward, while it did not change with the rewarded vanillin odor. With both odors, the frequency decreased significantly after training with a punishment. These results indicate that cockroaches learn a single compound odor presented as a conditioned stimulus, although the association of the odor with a reward or punishment depends on the chemical. This olfactory conditioning method can not only facilitate the analysis of cockroach behavior elicited by a learned single chemical odor, but also quantify the potential attractiveness or repellency of the chemical after learning.     

Odor similarity does not influence the time needed for odor processing

The brain's link between perception and action involves several steps, which include stimulus transduction, neuronal coding of the stimulus, comparison to a memory template and choice of an appropriate behavioral response. All of these need time, and many studies report that the time needed to compare two stimuli correlates inversely with the perceived distance between them. We developed a behavioral assay in which we tested the time that a honeybee needs to discriminate between odors consisting of mixtures of two components, and included both very similar and very different stimuli spanning four log-concentration ranges. Bees learned to discriminate all odors, including very similar odors and the same odor at different concentrations. Even though discriminating two very similar odors appears to be a more difficult task than discriminating two very distinct substances, we found that the time needed to make a choice for or against an odor was independent of odor similarity. Our data suggest that, irrespective of the nature of the olfactory code, the bee olfactory system evaluates odor quality after a constant interval. This may ensure that odors are only assessed after the olfactory network has optimized its representation.     

Olfactory learning in the stingless bee Tetragonisca angustula (Hymenoptera, Apidae, Meliponini)

Tetragonisca angustula stingless bees are considered as solitary foragers that lack specific communication strategies. In their orientation towards a food source, these social bees use chemical cues left by co-specifics and the information obtained in previous foraging trips by the association of visual stimuli with the food reward. Here, we investigated their ability to learn the association between odors and reward (sugar solution) and the effect on learning of previous encounters with scented food either inside the hive or during foraging. During food choice experiments, when the odor associated with the food was encountered at the feeding site, the bees’ choice is biased to the same odor afterwards. The same was not the case when scented food was placed inside the nest. We also performed a differential olfactory conditioning of proboscis extension response with this species for the first time. Inexperienced bees did not show significant discrimination levels. However, when they had had already interacted with scented food inside the hive, they were able to learn the association with a specific odor. Possible olfactory information circulation inside the hive and its use in their foraging strategies is discussed.     

Olfactory interference during inhibitory backward pairing in honey bees

Background

Restrained worker honey bees are a valuable model for studying the behavioral and neural bases of olfactory plasticity. The proboscis extension response (PER; the proboscis is the mouthpart of honey bees) is released in response to sucrose stimulation. If sucrose stimulation is preceded one or a few times by an odor (forward pairing), the bee will form a memory for this association, and subsequent presentations of the odor alone are sufficient to elicit the PER. However, backward pairing between the two stimuli (sucrose, then odor) has not been studied to any great extent in bees, although the vertebrate literature indicates that it elicits a form of inhibitory plasticity.

Methodology/Principal Findings

If hungry bees are fed with sucrose, they will release a long lasting PER; however, this PER can be interrupted if an odor is presented 15 seconds (but not 7 or 30 seconds) after the sucrose (backward pairing). We refer to this previously unreported process as olfactory interference. Bees receiving this 15 second backward pairing show reduced performance after a subsequent single forward pairing (excitatory conditioning) trial. Analysis of the results supported a relationship between olfactory interference and a form of backward pairing-induced inhibitory learning/memory. Injecting the drug cimetidine into the deutocerebrum impaired olfactory interference.

Conclusions/Significance

Olfactory interference depends on the associative link between odor and PER, rather than between odor and sucrose. Furthermore, pairing an odor with sucrose can lead either to association of this odor to PER or to the inhibition of PER by this odor. Olfactory interference may provide insight into processes that gate how excitatory and inhibitory memories for odor-PER associations are formed.     

Brood Odor Discrimination Abilities in Hygienic Honey Bees (Apis mellifera L.) Using Proboscis Extension Reflex Conditioning

To understand the effect of abnormal brood odors on the initiation or control of hygienic behavior in honey bees, we employed the associative learning paradigm, proboscis extension reflex conditioning. Bees from two genetic lines(hygienic and non-hygienic) were able to discriminate between high concentrations of two floral odors equally well. Differential discrimination abilities were observed between the two lines when healthy and diseased brood odors were used, with the bees from the hygienic line discriminating between the pair of brood odors better than the non-hygienic bees. These results suggest that hygienic behavior in individual bees is associated with the bees' responses to olfactory stimuli emanating from diseased brood.     

Effects of acute sublethal exposure to coumaphos or diazinon on acquisition and discrimination of odor stimuli in the honey bee (Hymenoptera: Apidae)

Two organophosphate compounds, coumaphos and diazinon, were examined for effects of sublethal exposure on odor learning and generalization in honey bees, Apis mellifera L. Using proboscis extension response training as a measure of odor learning and discrimination, a series of two experiments tested whether these compounds would inhibit bees from learning a new odor or discriminating between different odors. Bees were exposed to coumaphos or diazinon in acetone applied to the thorax, or to coumaphos or diazinon in hexane injected intracranially. At no dose tested or exposure method used was coumaphos shown to inhibit acquisition of a novel odor stimulus, although it was shown to slightly reduce discriminatory ability when given by intracranial injection. Diazinon had effects on odor learning at several small doses, and a small injected dose was shown to significantly inhibit learning of an odor stimulus paired with a sucrose reward. When bee head acetylcholineasterase activity was measured after dermal applications of both pesticides, only the higher doses of diazinon showed reduced activity, indicating that externally-applied coumaphos shows no significant effect on bee brain acetylcholinesterase activity. These data suggest that acute application of coumaphos has only slight nonlethal effects upon the behavior of honey bees and should have little effect upon bee tasks that involve odor learning.     

Maturation of odor representation in the honeybee antennal lobe

The antennal lobe (AL) is the first center for processing odors in the insect brain, as is the olfactory bulb (OB) in vertebrates. Both the AL and the OB have a characteristic glomerular structure; odors sensed by olfactory receptor neurons are represented by patterns of glomerular activity. Little is known about when and how an odor begins to be perceived in a developing brain. We address this question by using calcium imaging to monitor odor-evoked neural activity in the ALs of bees of different ages. We find that odor-evoked neural activity already occurs in the ALs of bees as young as 1 or 2 days. In young bees, the responses to odors are relatively weak and restricted to a small number of glomeruli. However, different odors already evoke responses in different combinations of glomeruli. In mature bees, the responses are stronger and are evident in more glomeruli, but continue to have distinct odor-dependent signatures. Our findings indicate that the specific glomerular patterns for odors are conserved during the development, and that odor representations are fully developed in the AL during the first 2 weeks following emergence.