Three Critical Vertical Pathways: Neuroanatomy Video Lab - Brain Dissections

翻译者：高杰 Translator：Gao Jie 为了进行除了颅神经之外的神经定位 In order to do neurological localization and figure 并找出患者的病灶所在 out where in your patient the difficulty is,in addition to the cranial nerves, 了解三个束或通路也很重要 it's important to know three tracts or pathways.

束是来自相似位置并到达相似位置的 A tract is a collection of axons coming from a similar place 轴突的集合 and going to a similar location.

现在这条束有交叉点或连接点 Now this tract has junctions or connections 或者我们称它们为中间的突触 or we call them synapses in between, 但是这两个感觉束来自感觉背根 but the two sensory tracts come from the sensory dorsal roots, 现在我给你看看马尾 here I'm showing you the cauda equina 因为它们在这里被撕开 because they've been torn off up here 并上升到脊髓或延髓 and ascend either connecting in the cord or in the medulla, 在被称为丘脑的深层结构中传递 relay in deep structures called the thalamus and eventually come

并最终在大脑皮层中感知 to perception in the cerebral cortex.

因此 一条感觉通路是 So one pathway, one sensory pathway is the spinal, 从脊髓到丘脑 脊髓丘脑束 from the cord, to the thalamus, the spinothalamic tract 它携带痛温觉和一些触觉 and that carries pain and temperature and some touch.

第二个重要的通路是 The second important pathway is the pathway that's called the 被称为背柱的通路 因为一些信息 dorsal column because some of the information is travelling 在这些背柱中传导 这个钳子之间的白质区域 in these dorsal columns, this area of white matter 位于背侧面 between the forceps here on the dorsal aspect 或脊髓后柱 or the posterior columns of the spinal cord, 在延髓接力传导 再到丘脑 relaying up in the medulla and again onto the thalamus

最后到大脑皮层 and finally the cerebral cortex.

该通路称为背柱-内侧丘系通路 That pathway is called the dorsal column-medial lemniscus 它携带本体感觉 振动 pathway and that carries proprioception, vibration, 关节位置 清楚身体和肌肉 joint position, knowing where your body and muscles are 在空间中的位置以及精细和离散的触摸 in space as well as fine and discrete touch.

所以我们有两条来自身体的感觉 躯体感觉通路 So we have two sensory, somatic sensory pathways coming 也有类似的通路 from the body and there are comparable pathways just 就像来自三叉神经的通路一样 like it coming in from the trigeminal nerve 但我们今天只讨论 but we're just going to talk 脊髓相关的通路 about the spinal cord contribution today.

脊髓丘脑 The spinal thalamic 或前外侧通路有三种神经元 or anterolateral pathway has three neurons.

它总是二级神经元向对侧交叉 It is always the second neuron that decussates or crosses 或交叉上行至丘脑 to the opposite side to ascend to the thalamus.

一级神经元的细胞体在背根神经节中 The first neuron has its cell body in the dorsal root ganglion 几乎是进入之后马上形成突触 and synapses almost immediately in the spinal cord.

二级神经元交叉到对侧 The second neuron crosses to the opposite side and ascends 并上行至脑干 到达丘脑腹后外侧核 to the brain stem to the ventral posterior lateral nucleus of the thalamus.

位于丘脑核中的三级神经元 The third neuron located in that nucleus of the thalamus ascends 通过内囊上行 through the internal capsule to terminate 止于中央后回 这是初级躯体感觉皮层 in the postcentral gyrus, which is primary somatosensory cortex.

来自身体的第二条感觉通路 The second pathway for sensation from the body, 背柱内侧丘系通路 the dorsal column medial lemniscus pathway has a very 具有非常相似的模式和轨迹 similar pattern and trajectory except 除了一个非常重要的区别 for one very important difference, 一级神经元的细胞体 the first neuron the one with cell body 在背根神经节中 不会立即交叉 in the dorsal root ganglion does not cross immediately

而是上行到脊髓的同一侧 but ascends on the same side of the spinal cord 再至延髓的后部 to the posterior part of the medulla.

在那里它与二级神经元相遇并交叉上行 There it meets neuron number 2 and crosses to ascend 到对侧丘脑 to the thalamus on the opposite side.

然后在延髓尾段中 它也上行 The decussation then is in the caudal medulla, it too ascends 到同一个丘脑核 腹后外侧核 to the same thalamic nucleus, ventral posterior lateral, 然后该核中的不同神经元发出它们的轴突 and different neurons in that nucleus then send their axons, 这些是三级神经元 通过内囊 these are the third neurons, through the internal capsule

到达中央后回 初级躯体感觉皮层 to the post central gyrus, primary somatosensory cortex.

第三条通路是运动通路 The third pathway is a motor pathway that comes 来自皮层 通过脊髓下行 from the cortex and descends through the spinal cord or down 至脑干颅神经 终止于 as far as the brainstem cranial nerves to end in the cord 脊髓或脑干运动神经元 并延伸至肌肉 or brainstem on motor neurons that go out to muscles.

这些肌肉 横纹肌 Those muscles, striated muscles, 控制我的小指的随意运动 voluntary willed movement controlling my little finger 或大拇指的随意意志运动或收拢 都是随意运动 而不是反射 or my big thumb or pinching all that are willed, not reflexes, 这些是意志反应 these are willed responses.

这是皮质脊髓束或运动通路 This is the corticospinal tract or the motor pathway.

自主控制横纹肌的 The important motor pathway for voluntary control 重要运动通路称为 over your striated muscles is called the 皮质脊髓通路 corticospinal pathway.

有轴突通过这条通路 There are axons traveling with this pathway coming 从皮质中央前回的面部区域传导 from the face area of the cortex precentral gyrus, 终止于脑神经运动核上的脑干 also terminating in the brain stem on cranial nerve motor nuclei.

但是这张图只显示了一个到达脊髓 But this diagram shows you only one going to the spinal cord, 通过内囊 穿过脑干 descending through the internal capsule, through the brainstem 在髓质和脊髓之间重要的交点或连接点 and crossing, important crossing or decussation at the junction between the medulla and the spinal cord.

此时左脑控制右侧身体 At this point left brain controls right body.

这个神经元 这个运动控制单位被称为上运动神经元 This neuron, this motor control unit is called the upper motor 因为它来自皮层之上 neuron because it comes from upstairs in the cortex, 下行并终止于脊髓 因此我们称 it descends and terminates in the cord therefore we call next 次级或二级神经元为下运动神经元 or second neuron the lower motor neuron.

下运动神经元无非是 The lower motor neuron is nothing more 前角细胞 than the anterior horn cell, 也称为腹角细胞或普通的运动神经元 also called the ventral horn cell or just plain motor neuron.

该神经元通过腹根发送其轴突 This neuron sends its axon through the ventral root 终止于横纹肌上的运动终板 to terminate as the motor end plate on striated muscle.

因此 我们将研究皮质脊髓 运动 So three pathways we're going to look at corticospinal, motor, 脊髓丘脑 疼痛和温度 spinothalamic, pain and temperature, 背柱-内侧丘系 dorsal column-medial lemniscus, 精细触觉振动和本体感觉的三个途径 fine touch vibration and proprioception.

关键是能够可视化 The critical thing is to be able to visualize 它们靠近脑神经的位置 where they are close to cranial nerves 以及远离其的位置 and where they are far apart from them 需在脑干的不同水平上来看 at different levels of the brainstem.

所以我们要回来 必须看看我们 So we're going to come back and have to look at our levels 脑干的水平 我们要看看髓质 of the brainstem, we're going to look at medulla, 我们要看看脑桥 we're going to look at pons and we're going to look 我们要向上看看中脑 at the midbrain as we ascend.

我们还必须将这些信息 And we're also going to have to ring this information 传递给大脑皮层 up to the cerebral cortex.

我这里有一个萎缩的大脑 这使得脑回 I have a atrophied brain here which makes the gyri stand 显着突出 因为脑组织损失太多 out remarkably, because there's been so much loss 脑沟很深 of brain tissue that the sulci are deep 这些脑回很窄 and these gyri are narrow and remember 记住要明确中央沟的位置 你会发现两个平行的脑回 to define the central sulcus you find two parallel gyri that come 来自内部半球裂 from the inner hemispheric fissure all the way the way

一直向下到侧裂 所以这是中央沟 down to the lateral fissure so this is the central sulcus 记住中央沟后面 and keep in mind that behind the central sulcus is the post 是中央后回 这是感觉皮层 central gyrus and this is sensory cortex and in front 中央沟前面是中央前回 of the central sulcus is the precentral gyrus 那就是我们所说的运动皮层 and that is what we call motor cortex.

因此 有意识的随意运动将从中央前回的神经元开始 So the willed voluntary movement is going to start with neurons 而躯体感觉的感知 in the precentral gyrus and the perception 将在中央后回 of somatic sensation is going to end in the postcentral gyrus 即躯体感觉皮层结束 which is somatosensory cortex.