五山湖杯数学建模大赛官方网站
设为首页
 
首 页 | 五山湖 | 数学建模 | 自然现象 | 思想源泉 | 木棉芒果 | 礼品收藏 | 珊瑚礁 | 百步梯 | 联系咨询
  当前位置:首页 > 思想涌现 

前庭眼动反射 -Vestibulo-ocular reflex
发布日期:2013/10/13 8:34:00
 点击:6030
点击图片查看原图
The VOR is ultimately driven by signals from the vestibular apparatus in the inner ear. The semicircular canals detect head rotation and drive the rotational VOR, whereas the otoliths detect head translation and drive the translational VOR. The main direct path neural circuit for the horizontal rotational VOR is fairly simple. It starts in the vestibular system, where semicircular canals get activated by head rotation and send their impulses via the vestibular nerve (cranial nerve VIII) through Scarpas ganglion and end in the vestibular nuclei in the brainstem. From these nuclei, fibers cross to the contralateral cranial nerve VI nucleus (abducens nucleus). There they synapse with 2 additional pathways. One pathway projects directly to the lateral rectus of eye via the abducens nerve. Another nerve tract projects from the abducens nucleus by the medial longitudinal fasciculus to the contralateral oculomotor nucleus, which contains motorneurons that drive eye muscle activity, specifically activating the medial rectus muscle of the eye through the oculomotor nerve. Another pathway (not in picture) directly projects from the vestibular nucleus through the ascending tract of Dieters to the ipsilateral medial rectus motoneuron. In addition there are inhibitory vestibular pathways to the ipsilateral abducens nucleus. However no direct vestibular neuron to medial rectus motoneuron pathway exists.[4] Similar pathways exist for the vertical and torsional components of the VOR. In addition to these direct pathways, which drive the velocity of eye rotation, there is an indirect pathway that builds up the position signal needed to prevent the eye from rolling back to center when the head stops moving. This pathway is particularly important when the head is moving slowly, because here position signals dominate over velocity signals. David A. Robinson discovered that the eye muscles require this dual velocity-position drive, and also proposed that it must arise in the brain by mathematically integrating the velocity signal and then sending the resulting position signal to the motoneurons. Robinson was correct: the neural integrator for horizontal eye position was found in the nucleus prepositus hypoglossi[5] in the medulla, and the neural integrator for vertical and torsional eye positions was found in the interstitial nucleus of Cajal[6] in the midbrain. The same neural integrators also generate eye position for other conjugate eye movements such as saccades and smooth pursuit.
 
收 藏 推 荐 打 印 关 闭


最新录入  
 · 2019年广东省工业与应用数...
 · 第一届“百农杯”数学建模竞赛...
 · A Microcircuit...
 · Burst firing t...
 · 第二届全国神经动力学会议回执
 · 第二届全国神经动力学会议论文...
 · 第二届全国神经动力学会议征文通知
 · 第二届全国神经动力学会议学术...
 · 第二届全国神经动力学会议(第...
 · 第二届全国神经动力学会议
相关内容   更多>>
 · A Microcircuit...
 · 感觉传入和传递过程
 · Recruitment an...
 · FitzHugh–Nagum...
 · 前庭眼动反射 -Vestib...
 · 疼痛原理-pathway c...
 · 工蜂采蜜和蚂蚁觅食
 · 灵长类动物的奖励回路
 · 海马Schaffer侧枝
 · 情感神经科学-人和动物的感情基础
 
声明 | 报名须知 | 联系方式 | 五山湖 技术支持:郑州建网站 Copyright (c) 2011 All Rights Reserved.