生物嗅觉神经系统模型的模拟与分析

研究生物嗅觉神经系统模型,有助于更好地了解嗅觉机理和嗅神经的放电模式.本研究分析了K系列嗅觉神经系统模型的拓扑结构、数学基础的发展和应用,对该系列模型中的KⅢ模型进行了数值模拟及时域,频域和时频域分析;概述了K系列模型的发展和应用.由结果看出,KⅢ网络模型可以很好地模拟嗅觉神经系统的电活动.     

僧帽细胞电位发放的模型分析

本文构造从感觉神经元、僧帽细胞到大脑皮层神经元,并反馈到颗粒细胞的嗅觉神经系统模型.数值分析模型结构中各个神经元的电位发放,特别是嗅小球内的细胞电位变化,结果显示僧帽细胞的发放对感觉神经元的刺激变化较大,僧帽细胞对皮层细胞的相图出现各种模式,从而模型刻画了嗅觉系统中僧帽细胞的信息传递特性.     

兔嗅觉系统的动力学研究——混沌状态

本文是参考文献（１）的继续。参考文献（１）根据人类的识别原理，介绍了Ｆｒｅｅｍａｎ兔嗅觉系统的动力学研究。文章的发表引起了学者们的注意，提出许多建立新识别原理需要解决的理论问题，本文只包括几个问题的部分结果：（１）由Ｆｒｅｅｍａｎ建立的兔嗅觉模型的离散数学解是真实的。（２）兔嗅觉模型在什么情况下处在混沌状态中，它们为什么与初值无关。（３）兔嗅觉识别的过程，作者最后提出一些有待进一步解决的问题。     

嗅觉模型研究的进展

本文对嗅觉机理及模型的研究进展进行了综述，重点介绍了嗅觉的生理结构和辨识机理，以及近年来研究嗅觉机理的层析模型，回归模型，知识模型和网络模型，并对嗅觉模型的研究进行了展望。     

仿生嗅觉与味觉传感技术及其应用的研究进展

动物的化学感受系统具有惊人的能力,能够在极低的浓度下识别数千种分子结构各异的化学物质,其灵敏性、选择性和响应速度都远高于当前的人工识别系统.近年来,研究者致力于利用完善的天然分子识别机制,开发出一种与传统嗅觉/味觉传感器相比更具仿生意义的新型化学探测系统,即仿生嗅觉/味觉传感器.仿生嗅觉/味觉传感器通常将动物嗅觉味觉的受体、细胞和组织作为敏感材料,然后使用多种人工检测方法,如光学、电化学和声波检测器件等,实现对化学物质的检测和识别.文中概述了动物嗅觉/味觉感受系统对化学物质的信息处理机制,并结合本实验室的工作,综述了目前仿生嗅觉/味觉传感器的常用技术及其未来发展趋势,并展望了其在医疗、工业和军事等领域的应用前景.     

嗅觉模型研究的进展

本文对嗅觉机理及模型的研究进展进行了综述。重点介绍了嗅觉的生理结构和辨识机理，以及近年来研究嗅觉机理的层析模型、回归模型、知识模型和网络模型，并对嗅觉模型的研究进行了展望。     

中国简短嗅觉识别测试在早期阿尔茨海默病筛查中的应用

目的:用中国人群嗅觉识别测验(CSIT)作为工具，探讨早期阿尔茨海默病(AD)患者嗅觉障碍特征，并筛选出与AD疾病特异性相关的嗅觉识别测试。方法:从社区招募正常对照组(NC)135例，河北医科大学第一医院门诊入组轻度认知功能障碍组(MCI)85例和可疑AD组20例。所有受试者使用CSIT测定嗅觉识别功能，并完成成套的神经心理评估。本研究在CSIT基础上删减较少识别错误的气味构建简短嗅觉识别测试1(B-CSIT 1),在B-CSIT1基础上删减与年龄相关的气味构建简短嗅觉识别测试2(B-CSIT 2)。结果:MCI组和可疑AD组的CSIT平均正确选择数低于NC组(P<0.001)。CSIT评分与受教育程度、MMSE及MoCA评分呈正相关(r=0.22、0.54、0.57,均P<0.05),而与年龄存在负相关(r=-0.32,P<0.05)。通过不同受试者工作特征(ROC)曲线分析显示：CSIT和B-CSIT 1敏感度及特异度差异相当(敏感度、特异度均为68.6%、78.8%),但B-CSIT 2较CSIT和B-CSIT 1的特异度增加10%。结论:早期阿尔茨海默病患者存...     

不定常溴觉模型及其解

本文把嗅觉反尖描述为发下四个连续的过程：（１）空气中的气味分子，通过鼻腔内对流与扩散作用，到达嗅区；（２）气味分子被嗅觉表面的粘液所吸附；（３）气味分子在嗅觉粘膜层中扩散，（４）气味子与嗅细胞相互作用，产生嗅觉，本文建立了包含上述主要机理的不定常的嗅觉模型，并得到了该模型的解析解，数值模拟表明这一结果与实验结果是一致的，解析解加深了对嗅觉机理的了解，同时也揭示了各生理参数之间的相互关系，为进一步实     

基于声表面波器件的仿生嗅觉受体传感器的研究

嗅觉受体可以与气味分子发生特异性的相互作用,这一机理不仅在生物嗅觉系统分辨和识别气味的过程中发挥着重要作用,而且也为解决传统嗅觉传感器特异性低的问题提供新的途径。从仿生设计角度,利用嗅觉受体对其配体特异性识别的机理,提高嗅觉传感器的特异性。以嗅觉受体作为敏感元件,声表面波器件作为二级传感器,构建一种可用于特异性气味检测的新型嗅觉受体传感器。选择秀丽线虫嗅觉受体ODR-10作为生物识别元件,通过基因工程的方法,将其表达在人乳腺癌细胞MCF-7细胞质膜上,提取含有ODR-10的细胞质膜组分,将其涂覆在声表面波器件的敏感区域。结果表明,ODR-10可以有效地表达于MCF-7的细胞质膜上,用这种异源表达的ODR-10构建的仿生嗅觉传感器对ODR-10的配体丁二酮具有很高的灵敏度,并具有很好的特异性。实验结果证实,这种基于嗅觉受体的仿生嗅觉传感器不仅适用于特异性气味检测,也适用于筛选特异性的嗅觉受体-配体对,将进一步推动嗅觉传导机理研究的进展。     

细胞因子在神经系统相关疾病发病中的作用

免疫系统与神经系统间的相互作用机制一直是研究的热点之一,其中主要由免疫系统产生的细胞因子在免疫与神经两大系统的联系中起到了重大作用,同时在神经系统相关疾病的发病机制中起到了重要作用.本文针对细胞因子在神经系统相关疾病的发病机制中的作用进行了综述.     

Morphological and electrophysiological examination of olfactory sensory neurons during the early developmental prolarval stage of the sea lamprey Petromyzon marinus L

This study examined olfactory sensory neuron morphology and physiological responsiveness in newly hatched sea lamprey, Petromyzon marinus L. These prolarvae hatch shortly after neural tube formation, and stay within nests for approximately 18 days, before moving downstream to silty areas where they burrow, feed and pass to the larval stage. To explore the possibility that the olfactory system is functioning during this prolarval stage, morphological and physiological development of olfactory sensory neurons was examined. The nasal cavity contained an olfactory epithelium with ciliated olfactory sensory neurons. Axons formed aggregates in the basal portion of the olfactory epithelium and spanned the narrow distance between the olfactory epithelium and the brain. The presence of asymmetric synapses with agranular vesicles within fibers in the brain, adjacent to the olfactory epithelium suggests that there was synaptic connectivity between olfactory sensory axons and the brain. Neural recordings from the surface of the olfactory epithelium showed responses following the application of L-arginine, taurocholic acid, petromyzonol sulfate (a lamprey migratory pheromone), and water conditioned by conspecifics. These results suggest that lampreys may respond to olfactory sensory input during the prolarval stage. In gratitude to Dr. A.I. Farbman (AI), who offered words of encouragement when I cautiously presented my first studies on the lamprey olfactory system. B.Z.     

The importance of olfactory bulb noradrenalin for maternal recognition in sheep

Herds of grazing mammals characteristically produce precocial offspring in synchrony, and it is therefore important for the mother to form a rapid recognition of her own offspring to distinguish them from others. In sheep, the ewe forms such a selective bond with her lamb within 2-4 hours of parturition, a bond which is primarily dependent on olfactory sensory recognition. Here we report that the neuronal mechanism whereby the olfactory "imprint" is made is dependent on the centrifugal noradrenergic projections to the olfactory bulbs. Lesioning of this neural pathway prevents the ewe from forming a selective bond with her own lamb, enabling her to adopt alien lambs.     

Studying the effects of smell and taste experience in the pediatric population using functional near infrared spectroscopy: A hypothesis

There are different postnatal sensitive periods throughout the development course of sensory functions. During sensitive periods, there is a biological display of an extreme neural sensitivity to the storage of experience-driven sensory information that is not present outside these developmental stages. This neural property is reflected in subjects’ reported preferences for sensory stimuli, such as odors and tastes. The human brain mapping approach (HBA) has demonstrated that disease-free human postnatal and later development of any sensory function parallels morphological and functional development of the CNS and that this development correlates with signal changes that have been acquired by means of neuroimaging techniques. Whether experience with tastes and/or odors has a stronger effect on the perception of gustatory and/or olfactory stimuli the earlier subjects are exposed to certain odors and tastes is still unknown. It is also unknown, whether as well as how this effect is reflected in brain activation patterns and whether we are currently able to identify sensitive periods of gustatory and olfactory development from the imaging signals. To answer these research questions, repeated exposure to tastes and/or odors should be applied in children of different age ranges in order to induce different age-related degrees of olfactory/gustatory preferences as well as different aged-related patterns of oxyhemoglobin (OH) and deoxyhemoglobin (DOH) changes that should be measured by means of the functional near-infrared spectroscopy (fNIRS) technique.     

NMDA-Antagonist MK-801-induced neuronal degeneration in Wistar rat brain detected by the Amino-Cupric-Silver method

The neurotoxic effect following a single intraperitoneal injection of MK-801 (10 mg/kg) in adult female Wistar rats at different survival times was studied with the 1994 version of de Olmos' Amino-Cupric-Silver (A-Cu-Ag) technique for detection of neural degeneration. In addition to the well documented somatodendritic degeneration observable in cortical olfactory structures, dentate gyrus, retrosplenial and sensory cortices, we detected this type of neuronal degeneration also in the main olfactory bulb, motor and anterior cingulate cortices, thalamus and cerebellum. Terminal degeneration, not reported by previous authors, was detected in cortical olfactory structures, hippocampal formation, sensory, infralimbic, prelimbic, agranular insular, ectorhinal, perirhinal and lateral orbital cortices. These results demonstrate that the A-Cu-Ag procedure is more efficient than other silver methods for detecting the degeneration induced by MK-801. In fact, the use of the A-Cu-Ag method has made it possible to infer the connectional relations between the damaged cell bodies and corresponding terminal degeneration. Our results also indicate that the A-Cu-Ag technique may be a suitable method for the staining of neurons undergoing apoptotic-like degeneration. The probable degenerative mechanism of MK-801 in the main olfactory system is discussed.     

Optical mapping of spatiotemporal emergence of functional synaptic connections in the embryonic chick olfactory pathway

In order to understand the functional maturation of the CNS, it is essential to first describe the functional maturation of sensory processing. We have approached this topic by following the ontogenetic patterning of neural circuit formation related to cranial and spinal sensory input using voltage-sensitive dye imaging. In previous studies, we have described the functional maturation of synapses in brainstem/midbrain neural circuits. Here, we elucidate the functional maturation of forebrain circuits by investigating neural networks related to the olfactory nerve (N. I) of chicken embryo. In the isolated N. I-olfactory bulb-forebrain preparation, application of electrical stimulation to N. I elicited excitatory postsynaptic potential (EPSP)-related slow optical signals in the olfactory bulb. The slow signal was mainly mediated by glutamate, and was easily fatigued with repetitive stimuli because of the immaturity of synapses in the embryonic CNS. Ontogenetically, the slow signal was detected from the 6-day embryonic stage, suggesting that functional synaptic connections between N. I and olfactory bulb emerge around this stage. In addition, from the 8-day embryonic stage, another response area was discriminated within the forebrain, which corresponded to the higher-ordered nucleus of the olfactory pathway. In comparison with our previous studies concerning the functional development of other cranial nerve-related sensory nuclei in the embryonic brainstem and midbrain, these results suggest that the olfactory pathway is functionally generated in the early stages of development when neural networks related to other visceral and somatic sensory inputs are also in the process of developing.     

The E3 ubiquitin ligase Mycbp2 genetically interacts with Robo2 to modulate axon guidance in the mouse olfactory system

The E3 ubiquitin ligase Mycbp2 and it homologues play an important role in axon guidance and synaptogenesis in Drosophila, Caenorhabditis elegans, zebrafish and mouse. Despite this conserved function, the molecular and cellular basis of Mycbp2-dependent axon guidance remains largely unclear. We have examined here the effect of the loss-of-MYCBP2 function on the topography of the olfactory sensory neuron projection from the nasal cavity to the olfactory bulb in mice. A subpopulation of olfactory sensory axons failed to project to the dorsal surface of the olfactory bulb causing abnormal topography in this neural pathway. These defects were similar to the olfactory bulb phenotype in loss-of-ROBO2 function mice. While mice heterozygous for either Mycbp2 or Robo2 were normal, mice double heterozygous for these two genes produced severe defects in the olfactory system. Therefore, Mycbp2 and Robo2 were found to cooperate within a genetic network that has profound effects on axon guidance. The Mycbp2 phenotype could be partly explained by aberrant patterning of olfactory sensory neurons residing in the dorsal compartment of the nasal cavity. Some of these neurons fail to appropriately express Robo2 which is consistent with their aberrant projection to the ventral olfactory bulb. These results provide the first evidence linking an ubiquitin ligase to an axon guidance receptor during pathfinding in the developing mammalian nervous system.     

仿生光学人工鼻及其呼吸气体检测的实验研究

针对呼吸气体诊断的需要，介绍了一种新型的具有仿生特点的光学人工鼻实验系统，用于探索通过呼吸气味诊断疾病的可行性。该系统由气敏光纤传感器阵列和信号处理系统组成，利用光纤传感器易与多种聚合物敏感材料相结合和其对气味的响应快、精度高以及易获得嗅觉动态信息的特点，通过计算化学方法，实现了多种聚合物敏感材料与荧光试剂的定量配制，研究了具有不同选择性的气味光纤传感器阵列。此外，将生物嗅觉机理模型用于人工鼻系统的设计过程，采用模拟生物嗅觉的感受器-嗅球-线性延迟神经网络算法，实现了从光纤传感器阵列的响应数据中同时分离出混合气味的成分和浓度信息。实现结果表明，该光学人工鼻传感器实验系统具有一定的仿生特性和应用前景。