The subtlety of simple eyes: the tuning of visual fields to perceptual challenges in birds

Birds show interspecific variation both in the size of the fields of individual eyes and in the ways that these fields are brought together to produce the total visual field. Variation is found in the dimensions of all main parameters: binocular region, cyclopean field and blind areas. There is a phylogenetic signal with respect to maximum width of the binocular field in that passerine species have significantly broader field widths than non-passerines; broadest fields are found among crows (Corvidae). Among non-passerines, visual fields show considerable variation within families and even within some genera. It is argued that (i) the main drivers of differences in visual fields are associated with perceptual challenges that arise through different modes of foraging, and (ii) the primary function of binocularity in birds lies in the control of bill position rather than in the control of locomotion. The informational function of binocular vision does not lie in binocularity per se (two eyes receiving slightly different information simultaneously about the same objects from which higher-order depth information is extracted), but in the contralateral projection of the visual field of each eye. Contralateral projection ensures that each eye receives information from a symmetrically expanding optic flow-field from which direction of travel and time to contact targets can be extracted, particularly with respect to the control of bill position.     

大鼠脊神经节感觉神经特异蛋白35kD(SSP-35)的纯化及鉴定(英文)

 以大鼠脊髓背根神经节及背根纤维组织为材料 ,通过离子交换层析 ,FPLC凝胶过滤等技术分离纯化了脊感觉神经特异蛋白 35kD(SSP 35) .经SDS PAGE分析 ,该蛋白特异地存在于脊感觉神经而不存在于脊运动神经 .非还原电泳结果表明 ,该蛋白分子内含有巯基 ,有二聚体存在 .根据HPLC测定 ,蛋白纯度达 90 %以上 .将此蛋白给予培养的PC 1 2细胞 ,观察到它具有神经营养作用 .     

产后抑郁症患者听感觉门控 P50 的研究

摘要 目的： 探讨产后抑郁症患者感觉门控 P50 的变化特征,为产后抑郁患者的早期预防提供参考依据。方法： 采用配对听觉条件 (S1)、测试(S2)刺激范式, 对本院 2011 年 1 月至 2012 年 6 月收治的 26 例产后抑郁症患者(实验组)进行听觉诱发电位 P50 检测, 测量 P50 的潜伏期、 波幅, 并与 25 例健康被试者(对照组)的结果进行比较。 结果： (1) 与对照组相比, 实验组 S1-P50 潜伏期[(56.62 ± 17.42) ms vs. (49.86 ± 15.21) ms], S2-P50 潜伏期[(57.36 ± 15.42) ms vs. (50.04 ± 16.27) ms]的差异均无统计学意义(P>0.05); (2) 与对照组相比, 实验组 S1-P50 波幅[(3.58 ± 1.72) μV vs. (1.13 ± 0.91) μV]显著降低, 差异有统计学意义(P<0.05); S2-P50 波幅[ (1.32 ± 1.16) μV vs. (1.48 ± 1.05) μV]差异无统计学意义(P>0.05); (3) 与对照组相比, 实验组 S2/S1 波幅比值[(1.17 ± 0.26) vs. (0.41 ± 0.13)]显著升高, 差异有统计学意义(P<0.05)。结论： 产后抑郁症患者感觉门控抑制能力有缺陷, P50 受损指标可能为评估 产后抑郁症患者的潜在生物学指标。     

Preterm EEG: A Multimodal Neurophysiological Protocol

Since its introduction in early 1950s, electroencephalography (EEG) has been widely used in the neonatal intensive care units (NICU) for assessment and monitoring of brain function in preterm and term babies. Most common indications are the diagnosis of epileptic seizures, assessment of brain maturity, and recovery from hypoxic-ischemic events. EEG recording techniques and the understanding of neonatal EEG signals have dramatically improved, but these advances have been slow to penetrate through the clinical traditions. The aim of this presentation is to bring theory and practice of advanced EEG recording available for neonatal units. In the theoretical part, we will present animations to illustrate how a preterm brain gives rise to spontaneous and evoked EEG activities, both of which are unique to this developmental phase, as well as crucial for a proper brain maturation. Recent animal work has shown that the structural brain development is clearly reflected in early EEG activity. Most important structures in this regard are the growing long range connections and the transient cortical structure, subplate. Sensory stimuli in a preterm baby will generate responses that are seen at a single trial level, and they have underpinnings in the subplate-cortex interaction. This brings neonatal EEG readily into a multimodal study, where EEG is not only recording cortical function, but it also tests subplate function via different sensory modalities. Finally, introduction of clinically suitable dense array EEG caps, as well as amplifiers capable of recording low frequencies, have disclosed multitude of brain activities that have as yet been overlooked.In the practical part of this video, we show how a multimodal, dense array EEG study is performed in neonatal intensive care unit from a preterm baby in the incubator. The video demonstrates preparation of the baby and incubator, application of the EEG cap, and performance of the sensory stimulations.     

The cephalic sensory organ in veliger larvae of pulmonates (Gastropoda: Mollusca).

The apical area of larvae of four primitive pulmonate species was investigated by means of serial ultrathin and light microscope sections. Cephalic sensory organs (CSOs) were found in the larvae of Onchidium cf. branchiferum (Onchidiidae) and Laemodonta octanfracta (Ellobiidae), while no trace of the organ was present in the larvae of Ovatella myosotis (Ellobiidae) or Williamia radiata (Siphonariidae). TEM investigation revealed very similar CSOs in O. cf. branchiferum and L. octanfracta, with characteristic putative sensory cell types: ampullary cells with an internal ampulla containing densely packed cilia, para-ampullary cells with external cilia parallel to the surface, and ciliary tuft cells, bearing short ciliary tufts. The epithelium covering the organ has a thick microvillar border with microvilli laterally bearing a pair of electron-dense accumulations and a glycocalyx with interspersed flat plaque-like elements. While homologues of all major elements of the CSO can be found in other gastropod taxa, for example caenogastropods and opisthobranchs, the homology of the ampullary cell with similar cells in nongastropods appears unlikely. The CSO of L. octanfracta is associated with an additional structure, an epithelial external protrusion, lying ventral to the CSO. The absence of the organ in W. radiata weakens hypotheses on the organ's function of examining settlement conditions and velar control.     

Drosophila neural progenitor polarity and asymmetric division

In the Drosophila embryonic central nervous system, the neural precursor cells called neuroblasts undergo a number of asymmetric divisions along the apical-basal axis to give rise to different daughter cells of distinct fates. This review summarizes recent progress in understanding the mechanisms of these asymmetric cell divisions. We discuss proteins that are localized at distinct domains of cortex in the neuroblasts and their role in generating asymmetry. We also review uniformly cortical localized factors and actin cytoskeleton-associated motor proteins with regard to their potential role to serve as a link between distinct cortical domains in the neuroblasts. In this review, asymmetric divisions of sensory organ precursor and larval neuroblasts are also briefly discussed.     

An Approach for Adaptive Limbless Locomotion Using a CPG-Based Reflex Mechanism

Animals＇ free movement in natural environments has attracted many researchers to explore control methods for bio-inspired robots. This paper presents a novel reflex mechanism based on a Central Pattern Generator （CPG） for adaptive locomotion of limbless robots. First, inspired by the concept of reflex arc, the reflex mechanism is designed on a connectionist CPG model. Since the CPG model inspired by the spinal cord of lampreys is developed at the neuron level, it provides a possible natural solution for sensory reflex integration. Therefore, sensory neurons that bridge the external stimuli and the CPG model, together with the concept of reflex arc, are utilized for designing the sensory reflex mechanism. Then, a border reflex and a body reflex are further developed and applied on the ends and the middle part of a limbless robot, respectively. Finally, a ball hitting scenario and a corridor passing scenario are designed to verify the proposed method. Results of simulations and on-site experiments show the feasibility and effectiveness of the reflex mechanism in realizing fast response and adaptive limbless locomotion.     

Abrogation of peripheral cholecystokinin-satiety in the capsaicin treated rat

Cholecystokinin (CCK) is a peripheral and central mediator of short-term satiety. When given i.p., CCK decreases food intake in previously fasted rats for a period of 30 min. The effect has been previously shown to be abolished by vagotomy and more specifically by severing of vagal sensory rootlets. These studies were designed to determine the effects on rat feeding behavior, and in particular CCK-satiety, of the sensory neurotoxin capsaicin. In neonates, capsaicin selectively and permanently destroys unmyelinated sensory fibers including those in the vagus nerve. Rat neonates were treated with capsaicin, 50 mg/kg or vehicle, and surviving females studied at 8-10 weeks of age. The weights, 24-h food intake, and feeding responses to insulin were the same in adult capsaicin treated (Cap Rx) and vehicle treated (Veh Rx) rats. CCK (8 micrograms/kg i.p.) reduced 30 min food intake 61 +/- 18% in Veh Rx animals (mean +/- S.D., P less than 0.01). In capsaicin denervated animals, CCK also significantly reduced 30 min food intake from 5.09 +/- 1.10 to 3.92 +/- 0.84 g (P less than 0.01), but the mean reduction, 23 +/- 6%, was significantly less than in Veh Rx rats (P less than 10(-4]. A separate group of females, similarly treated as neonates with capsaicin or vehicle, were subjected to bilateral lesioning of the ventromedial hypothalamus. Both Cap Rx and Veh Rx animals gained significantly and equally more than non-lesioned controls. 24 h vagal transport of substance P was reduced 70% in age matched capsaicin treated animals compared to controls. These studies demonstrate that peripheral CCK-satiety is partly mediated by capsaicin sensitive fibers, presumably in the vagus nerve. Substance P is one possible transmitter mediating this reflex. Further conclusions are that active inhibition of an intact peripheral CCK-stimulated reflex arc is not necessary for full expression of central inducers of feeding, e.g., insulin or lesioning of the ventromedial hypothalamus, and that destruction of these fibers does not alter long-term weight regulation in rats receiving a normal diet.     

Light- and electron-microscopic analysis of a complex sensory organ: The tegula of Locusta migratoria

Summary Structure and organization of the tegula, a cupola-shaped structure located at the anterior base of the wings of locusts, is described using various morphological methods. Based on histological and cytological criteria, two different sensory systems are distinguished: (1) a field of mechanoreceptive hairs, and (2) a chordotonal organ. The total number of sensory cells corresponds to the number of axons within the nerve supporting the tegula. The hairs are situated at the posterior region of the tegula, and each hair is innervated by only one sensory cell. The complex architecture of the chordotonal organ is analyzed and the attachment of the scolopidia to the cuticle is described. A single scolopidium makes contact with several epidermal cells. The attachment cells run in parallel and are oriented longitudinally within the tegula, being connected to each other and to the epidermal cells by desmosomes. A function in relation to wing movements during flight is suggested for the two sensory systems within the mixed sense organ, tegula.     

中华蜜蜂感觉神经元膜蛋白基因克隆、组织表达分析及原核表达

为明确中华蜜蜂Apis cerana cerana嗅觉形成中重要功能因子的信号转导通路, 本研究利用RT-PCR方法, 克隆了中华蜜蜂感觉神经元膜蛋白 (sensory neuron membrane protein, SNMP) 基因编码区, GenBank登录号为KC012595, 命名为AccSNMP1。序列分析表明, 该编码区开放阅读框长1 563 bp, 编码520个氨基酸, 推测的编码蛋白的相对分子量和等电点分别为58.02 kD和5.83。同源性比较发现, 中华蜜蜂AccSNMP1与其他昆虫感觉神经元膜蛋白基因同源性差异很大, 在氨基酸水平上与西方蜜蜂Apis mellifera SNMP基因一致性达99.2%, 与熊蜂Bombus impatiens SNMP基因一致性达90.9%, 而与赤拟谷盗Tribolium castaneum SNMP基因一致性仅为22.7%。系统发育树显示中华蜜蜂与西方蜜蜂遗传距离最近。实时荧光定量PCR结果分析表明, AccSNMP1在触角中表达量最高, 在足中表达量较高, 与胸、 腹、 头（去除触角和喙）、 喙中表达量相比差异显著（P<0.05）。构建原核表达载体pEASY-E1-AccSNMP1, 经IPTG诱导, 中华蜜蜂感觉神经元膜蛋白在大肠杆菌Escherichia coli BL21 （DE3）中高效表达。结果为进一步研究AccSNMP1在中华蜜蜂体内的作用机理奠定了基础。