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1.
应用HRP进行追踪法在光镜水平研究了猫丘脑中央外侧核向前乙状回、前上薛氏回和中上薛氏回前端投射的神经元的形态与分布。结果表明:中央外侧核向大脑皮质的投射为同侧投射;中央外侧核向前乙状回投射的神经元集中于核的尾段,少部分位于中段,偏内侧分布,大、中、小型投射神经元均有,以中、小型为主;中央外侧核向前上薛氏回和中上薛氏回前端投射的神经元集中干中段,略向前后延伸,分布于嘴段和部分尾段。整个投射细胞群偏外侧分布,以中小型为主,少部分大型投射神经元位于最外侧。大型标记的投射神经元主要为圆形,卵圆形和多边型,中、小型标记的投射神经元呈各种形态。 相似文献
2.
本文应用HRP逆行追踪法在电镜水平上对猫丘脑中央外侧核内皮质投射神经元的超微结构及其突触联系首次进行了研究,该核内皮质投射神经元以中型多见,胞核较大,核仁清晰,偏位,核膜有凹陷,常染色质较多,胞质内含丰富的线粒体、游离核糖体和粗面内质网,标记树突直径变化较大,从0.68μm到4.4μm,含较多的线粒体、微管及滑面内质网,未见突触小泡,标记的皮质投射神经元胞体和树突做为突触后成份,与非标记的突触前成份形成下列突触:①轴-树突触,突触前轴突终末以SR型和F型居多;②轴-体突触,突触前终末中有F型和RF型;③树-树突触;④轴-轴-树突触;⑤突触复合体,许多标记树突做为中央树突参与形成汇聚型突触复合体。 相似文献
3.
本文应用顺行溃变的方法,首次在电镜水平对猫丘脑中央外侧内脊丘系终末的超微结构和突触联系进行了研究。在横断第四脊髓颈节一侧的外侧索和部分前索4-5天后,电镜下发现在损毁同侧的丘脑中央外侧核的中段和尾段,均有少量的溃变终末。脊丘系溃变的轴突终末有两种形式:电子致密型和电子透明型,以电子致密型多见。溃变的脊丘系终末大小形态各异,主要含大量密集的圆形突触小泡。根据小泡形状和终末大小的差异,溃变终末可分以下两型:SR型占82.5％;LR型占17.5％。溃变轴突终末主要与树突形成不对称型轴——树突触,个别的突触后树突含突触小泡。溃变轴突终末多参与形成以树突为中心的汇聚型突触复合体。在由溃变轴突终末与树突所形成的轴——树突触中,有42.5％的数量位于突触复合体内。偶尔见到溃变轴突终末参与形成的轴-轴-树突触。 相似文献
4.
为确立后索核内初级传入终末与丘脑投射神经元间的突触联系,本文采用顺行溃变与 HRP 逆行追踪相结合的方法,在电镜水平对后索核内初级传入终末与丘脑投射神经元间的突触联系组合形式进行了研究。结果表明,后索核内有6种突触联系形式:(1)溃变轴突终末与 HRP 标记树突形成轴—树突触;(2)溃变轴突终末与 HRP 标记胞体形成轴—体突触;(3)溃变轴突终末及正常轴突终末与标记的中央树突形成汇聚型突触复合体;(4)轴—轴—树连续性突触;(5)溃变轴突终末与非标记树突形成轴—树突触;(6)非溃变的含扁平小泡或多形态小泡轴突终末与 HRP 标记的神经元胞体形成轴—体突触.本研究首次报道了猫后根初级传入终末与后索核丘脑投射神经元间的直接突触联系。突触形式计有轴—树和轴—体突触及以树突为中心的突触复合体.本研究结果为阐明后索核内非伤害性信息传递与整合的作用方式提供了直接的突触学基础。 相似文献
5.
本文应用辣根过氧化物酶(HRP)逆行追踪技术与电镜相结合的方法,对猫后索核丘脑投射神经元的分市及超微结构进行了研究。结果表明,后索核丘脑投射神经元主要分布于后索核中段,尾侧段次之,嘴侧段最少。标记神经元均出现于HRP注射部位的对侧后索核内,主要为中等园形细胞。电镜下,神经元胞核较大,核膜光滑或有凹陷,常染色质较多,异染包质1较少,胞浆丰富,含有大量的游离核糖体,粗面内质网及线粒体。标记的丘脑投射神经元胞体和树突可以作为突触后成分与轴突形成轴一体突触和轴一树突触;标记神经元胞体还可以和突触前树突形成树一体突触;标记的树突做为中央成分与多个轴突形成汇聚型突触复合体。此外,还发现标记的胞体和树突与非标记的树突之间的非突触的粘着斑连接。 相似文献
6.
目的:介绍了神经元的间室模型和底丘脑核投射神经元的动作电位的仿真方法。方法:将神经元分成一个个间室,每个间室分列微分方程。具体实验中利用"Neuron"这个神经元仿真计算平台对底丘脑核投射神经元的动作电位进行仿真。结果:当神经元结构比较复杂,膜的特性具有电压依从性,膜上有突触后电流的时候,间室模型能很好地反映了复杂神经元的电学特性。底丘脑核投射神经元的动作电位仿真结果和真正的动作电位结果非常相似。结论:间室模型很好地反映了复杂神经元的电学特性。底丘脑核投射神经元的动作电位仿真结果和真正的动作电位结果非常吻合。 相似文献
7.
1.关于兴奋传导方向的判断(l)兴奋在单个神经元以及神经元之间传导方向的判断兴奋在单个神经元内的传导方向是双向的,但在神经元之间的传导方向只能是:前—神经元的轴突→突触→后 相似文献
8.
用顺行溃变方法对猫后索核内后根初级传入纤维终末的超微结构和突触联系进行了研究。在切断C_4-T_1和L_4-S_1脊神经后根3～4天后,电镜下发现后索核内有三种溃变终末,出现最多的是电子致密型溃变,此外,也观察到了少量的神经微丝型溃变和电子透明型溃变。溃变的初级传入终末多数较大,含有圆形突触小泡。溃变初级传入终末作为突触前成分主要与后索核内的树突形成轴-树突触,而轴-体突触和轴-轴突较少。此外,还观察到溃变轴突终末参与形成突触复合体。 相似文献
9.
采用微电极胞内穿刺技术探查鲫鱼Mauthner细胞(M-细胞)对迷叶刺激的电反应特征。电刺激鲫鱼迷叶背面中央外侧区,可在双侧M-细胞胞体,腹侧树突和外侧树突近端记录到一种复合性兴奋性突触后电位(迷叶诱发性EPSP)。迷叶诱发性EPSP表现较短潜伏期(0.584±0.16 ms),较长持续时间(6.20±2.13 ms),幅度分级和刺激频率依从等特征,并可引起M-细胞顺向激活。多点胞内连续穿刺实验显示迷叶诱发性EPSP起源于腹侧树突远端。实验结果提示,迷叶—M-细胞通路可能包含一组长短不等的神经元链,它们依链的短或长,由近及远依次投射在腹侧树突的限定节段。 相似文献
10.
和其它神经递质一样,去甲肾上腺素(norepine phrine,NE)在突触前神经元中合成之后贮存在突触小泡中,当神经冲动达到突触前膜时,NE随突触小泡内其它物质一起被排放到突触间隙.本文讨论的只是NE到达突触后膜后如何识别其受体并与之结合;又通过怎样的中间环节使下一个神经元或效应细胞产生一系列生物学效应的. 相似文献
11.
本文用 H-600型透射电子显微镜观察了6例眙儿大脑皮层枕极245个突触的超微结构,结果表明在4.5个月胎儿枕极大脑皮层未见到突触,在5个月胎儿仅观察到少量突触,以后随胎龄的增加,突触数逐渐增多。在六个月以后胎儿大脑皮层,突触数明显增多,在新观察到的245个突触中,次轴树突触占绝大多数,占胎儿突触观察总数的77.6%。其次为轴棘突触,占胎儿突触观察总数的4.5%,从五个月胎脑开始观察到轴极突触,且这些轴棘突出的后成分中均不含有棘器。另外在胎儿枕极皮层,还观察到较多的轴-体突触,占胎儿突触观察总数的3.7%。此外,尚见到少量轴-轴,树-树,树-棘突触和串,并联突触。 相似文献
12.
Jorge Cuartas David G. Weissman Margaret A. Sheridan Liliana Lengua Katie A. McLaughlin 《Child development》2021,92(3):821-832
Spanking remains common around the world, despite evidence linking corporal punishment to detrimental child outcomes. This study tested whether children (Mage = 11.60) who were spanked (N = 40) exhibited altered neural function in response to stimuli that suggest the presence of an environmental threat compared to children who were not spanked (N = 107). Children who were spanked exhibited greater activation in multiple regions of the medial and lateral prefrontal cortex (PFC), including dorsal anterior cingulate cortex, dorsomedial PFC, bilateral frontal pole, and left middle frontal gyrus in response to fearful relative to neutral faces compared to children who were not spanked. These findings suggest that spanking may alter neural responses to environmental threats in a manner similar to more severe forms of maltreatment. 相似文献
13.
Jujuboside A (JuA) is a main component of Jujubogenin extracted from the seeds of Ziziphus. The authors have not seen any
report on JuA's direct effect on the neurons of the central nervous system. This study aimed to assess the effect of JuA on
paired-pulse responses of dentate gyrus granule cells in urethane-anaestherized rats, used intracerebroventricular (i. c.
v.) JuA to mimic in vitro bath conditions in vivo. Paired-pulse stimuli with 80ms interpulse interval were used to stimulate
the perforant pathway. Evoked responses were recorded in the dentate gyrus cell layer after i. c. v. administration of 0.9%
normal saline or JuA. In the first responses, the slopes of excitatory postsynaptic potential (EPSP1) and the amplitudes of
population spike (PS1) decreased significantly after administration of JuA while the PS1 latencies increased significantly.
In the second responses, the EPSP2 slopes and PS2 latencies were changed similarly to those of the first ones, but PS2 amplitudes
increased. The results showed that JuA may have some inhibitory effect on the granule cell excitability mediated by presynaptic
mechanism but may have little effect on the excitability mediated by postsynaptic mechanism since the second evoked N-methyl-D-aspartic
mediating paired-pulse facilitation is a postsynaptic mechanism.
Project supported by the National Key Scientific and Technological Planning Fund of China (Grant 99-929-04-03), and by the
Visiting Scholar Fund of Key Laboratory from the Education Ministry of China 相似文献
14.
Feng ZY Zheng XJ Tian C Wang Y Xing HY 《Journal of Zhejiang University. Science. B》2011,12(9):704-711
Dysfunction of inhibitory synaptic transmission can destroy the balance between excitatory and inhibitory synaptic inputs
in neurons, thereby inducing epileptic activity. The aim of the paper is to investigate the effects of successive excitatory
inputs on the epileptic activity induced in the absence of inhibitions. Paired-pulse orthodromic and antidromic stimulations
were used to test the changes in the evoked responses in the hippocampus. Picrotoxin (PTX), γ-aminobutyric acid (GABA) type
A (GABAA) receptor antagonist, was added to block the inhibitory synaptic transmission and to establish the epileptic model. Extracellular
evoked population spike (PS) was recorded in the CA1 region of the hippocampus. The results showed that the application of
PTX induced a biphasic change in the paired-pulse ratio of PS amplitude. A short latency increase of the second PS (PS2) was
later followed by a reappearance of PS2 depression. This type of depression was observed in both orthodromic and antidromic
paired-pulse responses, whereas the GABAergic PS2 depression [called paired-pulse depression (PPD)] during baseline recordings
only appeared in orthodromic-evoked responses. In addition, the depression duration at approximately 100 ms was consistent
with a relative silent period observed within spontaneous burst discharges induced by prolonged application of PTX. In conclusion,
the neurons may ignore the excitatory inputs and intrinsically generate bursts during epileptic activity. The depolarization
block could be the mechanisms underlying the PPD in the absence of GABAA inhibitions. The distinct neuronal responses to stimulations during different epileptic stages may implicate the different
antiepileptic effects of electrical stimulation. 相似文献