共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
研究表明γ-氨基丁酸受体及其抑制性神经回路在视觉发育和可塑性中起着至关重要的作用,近年来相关研究主要集中在GABA能抑制性回路在视觉发育关键期的开始、终止及其在成年视觉发育可塑性中的作用.本文主要回顾近年国内外在视觉发育和可塑性变化方面对γ-氨基丁酸受体及其抑制性神经回路研究的最新进展和成就,探讨影响视觉发育的机制及其与视皮层其他神经回路或结构的关系,并展望在弱视治疗中的应用前景. 相似文献
3.
神经营养素在视觉发育可塑性中的作用 总被引:1,自引:1,他引:0
越来越多的证据表明神经营养家族参与神经发育的可塑性,并对视觉发育起着至关重要的作用。本文主要回顾近年来,国内外在视觉发育和可塑性变化方面对神经营养素家族研究的最新进展和成就,探讨其影响视觉发育的机制,及与其他神经递质之间的相互作用关系,并对其在弱视治疗中的应用前景加以展望。 相似文献
4.
可能与弱视发病密切相关的部分基因有抗凋亡基因(Bcl-2、Bax)、即刻早期基因(c-jun、c-fos)、视觉可塑性神经递质相关基因(N-甲基-D-天冬氨酸受体1亚单位基因)、视觉可塑性神经营养因子相关基因(Neuritin mRNA、GDNF mRNA、BDNF mRNA、GAP-43 mRNA)、PTPσ mRNA、β-catenin mRNA等。Bcl-2、Bax可能通过调节视觉系统相关神经细胞的存活来参与弱视的发病;c-jun、c-fos进入细胞核后能够改变靶基因的转录活性从而调节视皮质神经元的功能状态;N-甲基-D-天冬氨酸受体1亚单位基因位于突触后膜,可以通过调节不同亚单位的表达水平来调节视皮层突触的可塑性;视觉可塑性神经营养因子相关基因中的Neuritin mRNA编码一种活性分子,这种活性分子可以促进树突的生长,从而调节视觉系统发育过程中神经元的活动;GDNF mRNA存在于视皮层和外侧膝状体,对各种损伤后的神经元具有保护和修复作用,能通过影响视觉系统正常发育过程中的转录来参与对视觉发育的调控,BDNF mRNA具有调节神经系统突触发育可塑性的效应,参与视觉发育关键期突触的可塑性变化;PTPσ mRNA、β-catenin mRNA参与了成年大鼠视皮层可塑性关键期的终止及可塑性再激活的过程。(国际眼科纵览, 2018, 42: 163-168) 相似文献
5.
李少敏 《中国斜视与小儿眼科杂志》2014,(2):41-45,40
弱视是一种儿童早期由于异常的视觉经历如斜视,屈光参差,视觉剥夺等导致的皮层性视觉损害,因而,只有理解了其发病的神经机制,才可能提出有效的治疗。一般观念认为弱视只有在儿童期治疗才有效,而成人的弱视基本无法治愈,但是近年来随着对弱视发病机制的分子生物学及神经电生理的研究,尤其是对视觉皮层发育可塑性的细胞间交流及细胞内分子信号通路的认识,拓展了人们对弱视病理的知识,因而也成功地通过恢复成年期的可塑性改善了成年弱视的视力。本文介绍了视觉发育可塑性的进展,就近年在增强成年可塑性途径如改变神经兴奋性与抑制性的平衡、细胞外基质、丰富环境及表观遗传学修饰等作了介绍,以其对弱视的病理机制,尤其对成人弱视的治疗有更深入的认识。 相似文献
6.
7.
8.
视觉障碍人群往往伴随着行为代偿,如听觉和触觉能力的提高.脑成像技术研究结果表明,视觉障碍人群行为代偿的机制之一是皮层可塑性.笔者从五个方面对视觉障碍人群皮层可塑性的研究进展进行综述:(1)视觉剥夺的行为代偿;(2)早晚期视觉剥夺对交叉模式重组的影响;(3)任务需求的复杂性与交叉模式重组的关系;(4)视觉系统发育敏感期与交叉模式重组出现时间之间的关系;(5)交叉模式重组的神经机制.这些研究为视觉障碍人群的康复训练及促进神经康复医学的发展提供了强有力的理论基础. 相似文献
9.
哺乳动物的视皮层在生后发育过程中具有经验依赖性可塑性,正常视觉环境对视皮层特化、精化和维持神经元之间的功能联系至关重要。视觉系统受视觉经验影响最敏感的时期称为视觉发育可塑性的关键期。同时,关键期前与关键期结束后视觉经验对视觉系统也有不同程度的影响。眼优势柱可塑性一直是研究视觉系统可塑性的有效模型。本文对视觉发育不同阶段中视觉经验对眼优势柱可塑性的影响及其作用机制作一综述。 相似文献
10.
目的 探讨人重组睫状神经营养因子 (recombinanthumanciliaryneurotrophicfactor,rhCNTF)对大鼠视神经不全损伤后功能恢复的作用。方法 采用无创血管夹在成年鼠造成视神经不全损伤 ,治疗组玻璃体腔内注射rhCNTF ,对照组注射等量双蒸水。在损伤前、损伤后即刻及伤后 1、2、4、8和 12周检测伤眼闪光视觉诱发电位。结果 视神经损伤后即刻 ,闪光视觉诱发电位波形几近熄灭。伤后 1周 ,潜伏期 (LP1) 2组基本恢复至损伤前水平 ,与损伤前比较无显著性差异 (P >0 .0 5 ) ,组间比较无显著性差异 (P >0 .0 5 )。振幅 (AP1 N2 )恢复缓慢 ,伤后 1~ 2周治疗组与对照组比较无显著差异 (P >0 .0 5 ) ;4周以后 2组间差异非常显著 (P <0 .0 1)。 8周时对照组恢复至损伤前的30 .84 % ,而治疗组恢复至 5 0 .35 % .结论 rhCNTF对大鼠视神经不全损伤后神经传导功能的恢复有明显的促进作用 相似文献
11.
12.
13.
R. Pigassou Albouy G. Pujol Prunes 《Documenta ophthalmologica. Advances in ophthalmology》1981,51(1-2):145-159
The author defines motor and sensory alternation: the term alternation should not be used in isolation, it should always be accompanied by the name of the parameter concerned. Sensory alternation is always found together with motor alternation but the reverse is not true.The examining criteria for a diagnosis of sensory alternation are given, sensory alternation must not be confused with alternating inhibition. Working from clinical observations of cases of motor alternating strabismus, the author selects 2 types of binocular sensory relations which allow one to differentiate between:- cases of primary alternating strabismus- cases of secondary alternating strabismusThese forms will develop in different ways; in both cases a cure is possible providing that the right treatment is prescribed and once prescribed carefully followed, etc. It is always a case of serious forms of strabismus whose developmental period is spread over several years.According to the authors, the frequency of cases of true primary strabismus is from 1–3%, the frequency of cases of secondary alternating strabismus varies according to the type of therapy practised on cases of monocular strabismus with amblyopia. These latter will become cases of alternating strabismus under the influence of certain types of therapy carried out over several years (penalization, rocking, alternated occlusion, etc...).Experimental data on kittens confirm clinical data; kittens placed in abnormal environments during the sensitive period will show modification in the distribution of cortical cells and the absence of binocular cells (either because the excitation of the two eyes was not simultaneous, or not identical: artificial strabismus, occlusion, opaque glasses). This disturbances become irreversible after a certain period of exposure (a function of age, length of exposure, etc...).It is thus necessary to bear in mind: 1) the iatrogenic risks of certain orthoptic treatments, 2) the necessity for a binocular form of treatment as soon as possible, as once a certain stage is passed, cortical plasticity diminishes and the elaboration of normal binocular relations becomes impossible.
相似文献
相似文献
14.
15.
16.
17.
BAOHE TIAN B'ANN T GABELT CRAIG E CROSSON PAUL L KAUFMAN 《Experimental eye research》1997,64(6):979-989
The effects of single or multiple topical doses of the relatively selective A1adenosine receptor agonists (R)-phenylisopropyladenosine (R-PIA) and N6-cyclohexyladenosine (CHA) on intraocular pressure (IOP), aqueous humor flow (AHF) and outflow facility were investigated in ocular normotensive cynomolgus monkeys. IOP and AHF were determined, under ketamine anesthesia, by Goldmann applanation tonometry and fluorophotometry, respectively. Total outflow facility was determined by anterior chamber perfusion under pentobarbital anesthesia. A single unilateral topical application of R-PIA (20–250 μg) or CHA (20–500 μg) produced ocular hypertension (maximum rise=4.9 or 3.5 mmHg) within 30 min, followed by ocular hypotension (maximum fall=2.1 or 3.6 mmHg) from 2–6 hr. The relatively selective adenosine A2antagonist 3,7-dimethyl-1-propargylxanthine (DMPX, 320 μg) inhibited the early hypertension, without influencing the hypotension. Neither 100 μg R-PIA nor 500 μg CHA clearly altered AHF. Total outflow facility was increased by 71% 3 hr after 100 μg R-PIA. In conclusion, the early ocular hypertension produced by topical adenosine agonists in cynomolgus monkeys is associated with the activation of adenosine A2receptors, while the subsequent hypotension appears to be mediated by adenosine A1receptors and results primarily from increased outflow facility. 相似文献
18.
19.