光肩星天牛的脑部结构

通过Mallory和HE染色,对光肩星天牛Anoplophora glabnpenn脑部显微结构进行了观察.结果表明,光肩星天牛的脑由前脑、中脑、后脑三部分组成.前脑叶髓层包括一对蕈形体、一个中央体、一个脑桥体和一对附叶,其中每个蕈形体仅有一个帽状的蕈体冠.中脑触角叶较大,由九簇放射状排列的触角神经束组成,中央的一束较粗,说明其嗅觉发达.后脑较小.     

昆虫嗅觉系统结构与功能研究进展

昆虫的脑由前脑、中脑和后脑组成,其中前脑含有高级感觉中枢,如蘑菇体和中央复合体,控制昆虫的学习、记忆和运动等高级神经活动;中脑包含触角叶,是嗅觉神经中心;而后脑则通常不发达,主要包括内分泌神经元和控制进食与消化的运动神经元。不同于其他物种,昆虫由于其特殊的生活习性,听觉和视觉系统相对退化,主要依赖嗅觉来捕食、交流和求偶,因此嗅觉系统尤其发达。本文综述了目前对昆虫的脑部主要神经结构和功能(中央复合体、蕈形体和触角叶结构)以及昆虫脑部结构遗传变异(性别异构,不同发育时期、不同昆虫以及昆虫与其他动物的脑部结构差异)的研究进展,并总结了目前昆虫脑对信号的加工处理和识别机制的研究结果。     

棉铃虫幼虫脑和咽下神经节的三维结构构建

【目的】解剖棉铃虫Helicoverpa armigera (Hübner) 5龄幼虫脑和咽下神经节及其内部神经髓形态结构,并分析和构建幼虫脑和咽下神经节以及各神经髓的三维结构模型。【方法】采用免疫组织化学方法解剖脑和咽下神经节的内部神经髓结构,利用激光共聚焦显微镜获取脑和咽下神经节扫描图像,然后利用AMIRA 三维图像分析软件进行图像分析,从而构建脑和咽下神经节的三维结构模型,并测量脑和咽下神经节以及内部各神经髓的体积,并分析了相对比例。【结果】 棉铃虫5龄幼虫脑和咽下神经节由围咽神经索连接在一起。脑主要由前脑、中脑和后脑3部分组成。前脑内包括视叶、蕈形体和中央体等形态结构较明显的神经髓。此外,前脑还包括其他位于脑的左右两侧以及背侧和腹侧大量神经髓区域,约占脑总神经髓的59.65%。这些神经髓区域边界不明显。中脑主要包括1对触角叶;后脑位于脑的腹侧和触角叶的下方,体积较小。咽下神经节由3个神经节融合构成,从前到后分别为上颚神经节、下颚神经节和下唇神经节,由于融合的紧密程度高,3个神经节间的边界不明显。【结论】阐明了棉铃虫5龄幼虫脑和咽下神经节的神经髓形态结构,构建了脑和咽下神经节以及内部神经髓的三维结构模型。三维模型可以任意旋转,能从任何角度观察脑、咽下神经节和内部不同神经髓的结构及其它们之间的空间关系。本研究结果对研究棉铃虫脑和咽下神经节信息接收、处理及调控行为的机制奠定了解剖学基础。     

茶尺蠖幼虫脑的解剖结构

【目的】明确茶尺蠖Ectropis obliqua Prout 5龄幼虫脑解剖结构,并分析和构建幼虫脑以及脑内部各神经髓结构的三维结构模型。【方法】采用免疫组织化学方法,利用突触蛋白抗体,染色标记脑内神经突触,定位突触联系密集分布的区域,获得脑内部神经髓的结构。利用激光共聚焦显微镜获取脑扫描图像,然后利用三维图像分析软件AMIRA进行图像分析,构建脑的三维结构模型,并计算脑以及脑内各神经髓结构的体积。【结果】突触蛋白抗体染色显示,茶尺蠖5龄幼虫脑内具有很多神经突触联系密集分布的区域,这些不同区域即为脑的不同神经髓结构。茶尺蠖幼虫脑主要包括前脑、中脑和后脑3个组成部分。其中前脑最大,包括成对的视叶、蕈形体、前脑桥和侧副叶以及不成对的中央体。视叶位于前脑的两侧后端。蕈形体位于脑半球正中间位置。侧副叶在中央体的下前方两侧。中央体在脑的正中心。前脑桥在中央体的上方后侧。除这些形态结构明显的神经髓区域外,前脑还包括大量内部边界不明显的神经髓区域,位于前脑左右两侧以及背侧和腹侧,这些区域被总称为中间脑,占整个脑神经髓的66%。触角叶为中脑的主要组成部分,在脑的下部最前端,为一对球状结构。后脑在脑的腹侧和触角叶下方,即围咽神经索进入脑的入口处。【结论】构建了茶尺蠖5龄幼虫脑以及各神经髓结构三维模型,分析了脑内各个神经髓之间的空间位置关系,明确了各神经髓的体积。茶尺蠖幼虫脑体积小而且结构简单的特征与其幼期视觉、嗅觉等感觉器官不发达、活动能力弱、行为简单的生物学习性相对应。     

烟青虫成虫脑结构解剖和三维模型构建

【目的】解剖分析烟青虫 Helicoverpa assulta 成虫脑的结构,并构建脑三维结构数字化模型。【方法】利用神经突触蛋白抗体,对烟青虫成虫脑进行免疫组织化学染色标记,利用共聚焦激光扫描显微镜获得脑扫描数码图像,并结合三维图像分析软件对烟青虫脑结构进行识别分析,构建三维模型。【结果】突触蛋白抗体免疫染色将烟青虫脑和颚神经节的神经髓区域清晰标记出来。烟青虫成虫脑与颚神经节愈合而成为一体,中间具有一个孔洞,为食道穿过的通道。脑主要包括前脑、中脑和后脑3部分。依据染色标记结果识别和构建了至少16个脑神经髓结构。这些神经髓包括边界清晰的视叶、前视结节、蕈形体、中央复合体和触角叶及其亚结构。除此之外,还包括围绕这些神经髓的其他前脑神经髓区域,但这部分前脑神经髓内部边界模糊,不容易细分,而将其与颚神经节区域作为一个整体标记为中间脑,占脑总神经髓的55.05%。【结论】识别出烟青虫脑的主要功能结构区域,并成功构建了三维模型。该研究结果为进一步研究烟青虫脑接收、处理和整合感觉信息及调控行为的机制奠定了解剖学基础,并为研究烟青虫或其他昆虫脑结构发育、变异和重塑提供结构形态和体积大小依据。     

中华蜜蜂蕈形体的发育

中华蜜蜂(Apis cerana cerana)的脑由前脑、中脑和后脑三部分构成,蕈形体位于前脑的背侧,是其重要的学习及其他复杂行为的整合中心。通过对中华蜜蜂工蜂的幼虫、蛹及成虫的蕈形体形态发育的观察研究,发现中华蜜蜂的蕈形体包含约1000个成神经细胞,它们最终形成了蕈形体的所有Kenyon细胞。这些成神经细胞来自于在新孵化的幼虫脑中已存在的四丛成神经细胞,每一丛细胞的数量不多于45个。蕈形体柄区的出现约在3龄幼虫,而α叶和β叶在5龄幼虫已可明显辨认。冠区出现较晚,大约在蛹期的第二天以后。由于社会性昆虫复杂的学习、记忆和认知需求,其蕈形体的体积和复杂程度都优于其他昆虫。     

中华蜜蜂雄蜂脑部组织结构观察

通过组织化学方法,对中华蜜蜂Apis cerana cerana Fabricius雄蜂的脑部的形态结构进行观察。结果表明,雄蜂的脑由前脑、中脑和后脑三部分构成,前脑视叶两侧具有大而显著的复眼,而其他结构相对较小。蕈形体在脑中所占的比例小于工蜂和蜂王;中心体的比例小于工蜂,与蜂王接近;中脑的嗅叶相对较为发达,这使它们在同蜂王的交配过程中,能够更灵敏地接收来自于蜂王性外激素的刺激。中华蜜蜂雄蜂的嗅叶具有性二态现象,但是与意大利蜜蜂Apis mellifera L.雄蜂发达的巨大纤维球复合体相比,中华蜜蜂并不明显;除此之外,它们在脑部结构上没有显著差异。     

蓖麻蚕变态期神经系统的变化及脑的胆碱酯酶活性研究

蓖麻蚕在变态期间,脑及腹神经索产生了一系列的变化。脑外部形态的显著变化是体积的增大,视叶的出现及脑与食管下神经节的愈合。由幼虫上簇开始至成虫羽化,共约19天。在此期间,脑的宽度由0.93毫米增至2.48毫米。视叶出现于幼虫上簇后第四天,即化蛹前一天;发育至化蛹后第七天,食管下神经节完全与脑愈合成环状。幼虫脑组织比较简单,视叶尚未显明分化,只是在脑的两侧前方有成团的神经细胞聚合而成的“原基”,成虫视叶组织即由这些原基分化而来。蕈体尚不完整,仅蕈体柄显明。化蛹后,视觉中枢的三个纤维区——神经节层,外髓和内髓——都已出现,中心体也清楚可见。化蛹后第九天,视叶的三个纤维区之间的交叉纤维显明地出现,其它各部分如中心体、脑桥体、腹体及嗅觉中枢都完全分化出来。脑构造的复杂化也明显表现在内部组织的分化上。 腹神经索的变化主要是缩短和神经节的合并。最显著的缩短阶段是在预蛹期,整条神经索由原来的43毫来缩短为29毫米。食管下神经节与脑愈合,腹部第一二神经节并入后胸神经节,第六、七、八神经节合并成一大型的复合神经节,这样便由原来的八个腹神经节减少了一半。胸部三个神经节则因菱形区的消失而互相靠拢。 从化蛹后第九天起至成虫羽化,除了脑的体积稍有增大以外,整个中枢神经系统基本上没有多大变化。 在整个变态期间,脑ChE的活性渐进增高,酶的水解率(微克分子Ach毫克脑/30分钟)开始时为0.078微米,最后至第十八天竟增至0.485微米,总共约增长六倍左右。     

三疣梭子蟹胚胎期中枢神经系统的发生和发育

应用组织学方法研究三疣梭子蟹胚胎期中枢神经系统的发生和发育,光学显微镜下镜检切片,在第二期卵内无节幼体阶段开始观察到脑;第二期卵内状幼体阶段,前脑由视神经层、侧原脑和中央原脑组成,与位于食道两侧的中脑和后脑形成完整的脑。三疣梭子蟹胚胎期腹神经链由1对大颚、2对小颚和2对颚足所对应的神经节以及腹部神经链组成。光镜下大颚神经节可于第二期卵内无节幼体阶段观察到,2对小颚和2对颚足神经节则在第二期卵内状幼体阶段观察到;腹部神经链则在第三期卵内状幼体阶段观察到。三疣梭子蟹胚胎期中枢神经系统由脑和腹神经链组成,脑由前脑、中脑和后脑组成,脑位于背部,通过2条围食道神经与腹神经链相连。中枢神经系统的不同部分的形成在胚胎发育过程中具有阶段性差异。     

蟋蟀视觉系统的解剖结构与生理机能

蟋蟀视觉系统由单眼、复眼、视叶三部分组成。蟋蟀的单眼为背单眼,由角膜、角膜生成细胞、视网膜等组成,是提高昆虫复眼所感知的视觉刺激的兴奋水平部位;复眼是最主要的视觉器官,由角膜、晶锥、感杆束和网膜细胞、基膜组成,是光电转导和视觉级联反应的中心;视叶由神经节层、外髓和内髓组成,是视觉神经系统的中心。     

Physiology and morphology of olfactory neurons associating with the protocerebral lobe of the honeybee brain

Physiology and morphology of olfactory neurons associated with the protocerebral lobe around the alpha-lobe of the mushroom body were studied in the brain of the honeybee Apis mellifera using intracellular recording and staining techniques. The responses of neurons to behaviorally relevant odorants (a blend, and components of the Nasonov pheromone, and some other non-pheromonal odors) were recorded. Different response patterns were observed within different neurons, and often within the same neuron, in response to different stimuli. All the neurons stained had innervations in the protocerebral lobe. The cell profiles varied from cells connecting the antennal lobe with both the protocerebral and lateral protocerebral lobes (projection neurons), cells linking the pedunculus of the mushroom body with both the protocerebral and lateral protocerebral lobes (PE1 neurons), cells linking the alpha-lobe and protocerebral lobe with the calyces of the mushroom body (feedback neurons), and cells linking the alpha-lobe and protocerebral lobe with the antennal lobe (recurrent neurons), to cells connecting the protocerebral lobe with the contralateral protocerebrum (bilateral neurons). These findings suggest that the protocerebral lobe acts as an olfactory center associating with other centers, and provides multi-layered recurrent networks within the protocerebrum and between the deutocerebrum and the protocerebrum in honeybee olfactory pathways.     

Anatomical and physiological characteristics of individual neurones in the central antennal pathway of insects

Signals of tens up to hundreds of thousands of (mostly olfactory) receptor cells on an insect antenna are switched to a comparatively low number of neurones in the antennal lobe of the deutocerebrum in circumscribed units of neuropile, the glomeruli. Each glomerulus is connected via its output neurone to two separate neuropiles (calyces of mushroom body, and lateral lobe) of the protocerebrum. Local interneurones interconnect between the glomeruli. Certain modes of convergence between receptors and central neurones provide for a very high sensitivity of the latter to certain odours and their sensitivity for complex odour stimuli, and in many cases for a marked multimodality. Anatomical and physiological data are given especially for pheromone sensitive neurones and their projections.     

Multimodal interneurons in the cricket brain: properties of identified extrinsic mushroom body cells

Summary 322 neurons were recorded intracellularly within the central part of the insect brain and 150 of them were stained with Lucifer Yellow or cobaltous sulphide. Responses to mechanical, olfactory, visual and acoustical stimulation were determined and compared between morphologically different cell types in different regions of the central brain. Almost all neurons responded to multimodal stimulation and showed complex responses. It was not possible to divide the cells into different groups using physiological criteria alone.Extrinsic neurons with projections to the calyces connect the mushroom bodies with the deutocerebrum and also with parts of the diffuse protocerebrum. These cells probably give input to the mushroom body system. The majority are multimodal and they often show olfactory responses. Among those cells that extend from the antennal neuropil are neurons that respond to non-antennal stimulation (Figs. 1, 2).Extrinsic neurons with projections in the lobes of the mushroom bodies often project to the lateral protocerebrum. Anatomical and physiological evidence suggest that they form an output system of the mushroom bodies. They are also multimodal and often exhibit long lasting after discharges and changes in sensitivity and activity level, which can be related to specific stimuli or stimulus combinations (Figs. 3, 4).Extrinsic neurons, especially those projecting to the region where both lobes bifurcate, exhibit stronger responses to multimodal stimuli than other local brain neurons. Intensity coding for antennal stimulation is not different from other areas of the central protocerebrum, but the signal-tonoise ratio is increased (Fig. 5).Abbreviation AGT antenno-glomerular tract     

The developmental expression of serotonin-immunoreactivity in the brain of the pupal honeybee

The biogenic amine serotonin is a neurotransmitter and modulator in both vertebrates and invertebrates. In the CNS of insects, serotonin is expressed by identifiable subsets of neurons. In this paper, we characterize the onset of expression in the brain and suboesophageal ganglion of the honeybee during pupal development. Several identified serotonin-immunoreactive neurons are present in the three neuromeres of the suboesophageal ganglion the dorsal protocerebrum, and the deutocerebrum at pupal ecdysis. Further immunoreactive neurons are incorporated into the developing pupal brain in two characteristic developmental phases. During the first phase, 5 days after pupal ecdysis, serotonin immunoreactivity is formed in the protocerebral central body, the lamina and lobula, and the deutocerebral antennal lobe. During the second phase, 2 days later, immunoreactivity appears in neurons of the protocerebral noduli of the central complex, the medulla, and the pedunculi and lobes of the mushroom bodies. Three novel serotonin-immunoreactive neurons that innervate the central complex and the mushroom bodies can be individually identified.     

A neuroanatomical study on the organization of the central antennal pathways in insects

1. Single unimodal (olfactory) or multimodal (olfactory and mechanosensory) neurons in the antennal lobe of the deutocerebrum of the American cockroach were characterized functionally by microelectrode recording, and their morphological types and positions in the brain were established by dye injection. Thus individual, physiologically identified neurons of known shape could be mapped in reference to the areas of soma groups, glomeruli, tracts and their projection regions in the brain. 2. All of these neurons send processes to deutocerebral glomeruli, i.e., the regions in which the axons of antennal sensory cells terminate. Output neurons have axons that leave the deutocerebrum whereas local interneurons are anaxonic. 3. An output neuron innervates only one glomerulus, sending its axon into the calyces of the corpora pedunculata (CP) in the protocerebrum, where by multiple branching they reach many CP neurons. The same axons send collaterals into the lateral lobe of the protocerebrum. Because of this arrangement, each deutocerebral glomerulus is represented individually and separately in the two projection regions. The fine structure of the endings of the deutocerebral axons in the protocerebrum is described. In the CP calyces they form microglomeruli with typical divergent connectivity. 4. A local interneuron innervates many glomeruli without sending processes to other parts of the brain. 5. Unimodal olfactory and multimodal neurons can be either output neurons or local interneurons; multimodal information is sent to the protocerebrum directly, in parallel with the unimodal information. 6. At least one glomerulus--the macroglomerulus of the male deutocerebrum--is specialized so as to provide an exclusive topographic representation of certain olfactory stimuli not represented elsewhere (female sexual pheromone).     

An electrophysiological study of olfactory interneurones in the brain of the honey-bee

Discharges of the olfactory units in the brain of the honey-bee were recorded extracellularly. Discharges were excitatory and inhibitory and showed on and on-off responses. In the on responses, phasic, phasic-tonic, and tonic patterns were found. No relation between discharge pattern and the region in the brain was found. The dominant pattern was phasic-tonic in the excitatory and tonic in the inhibitory units. Rebound or long-lasting phenomena seemed to be one of the characteristics of the neurones in the central nervous system.The latency of the response showed that olfactory information entering the deutocerebrum from the antenna was carried to the calyx of the ipsilateral brain via the antenno-cerebral tracts reported by Kenyon (1896), and then to the protocerebral lobe through the stalk of the mushroom body. The information was also carried to the contralateral brain after passing through the calyx of the ipsilateral brain or the central commissure.