This tightness results from a lesion in an upper motor neuron.

这种僵硬由上运动神经元损伤引起。

If the underlying problem is in the brain or brainstem before the upper motor neurons cross the midline, it's called an upper motor neuron lesion.

如果潜在病因在于脑或脑干，即在上运动神经元穿过脑干前，叫做上运动神经元损害。

In other words, there are two upper motor neurons, one from each side of the brain, giving input to one lower motor neuron.

换言之，这里有两种上运动神经元，分别来自大脑两侧，向下运动神经元传导信息。

The first is the upper motor neuron, whose cell body is located in the precentral gyrus of the brain.

第一级神经元是胞体位于大脑中央前回的上运动神经元。

In a healthy body, the upper motor neurons, which sit in the brain's cortex, transmit messages from the brain to the lower motor neurons, situated in the spinal cord.

在健康的身体中，上部运动神经元位于大脑皮层，将信息从大脑传递到位于脊髓的下运动神经元。

The upper motor neuron releases acetylcholine from its axon terminal knobs and these are received by nicotinic receptors on the alpha motor neuron.

上运动神经元从轴突末端释放乙酰胆碱，作用于α运动神经元上的烟碱受体。

In a healthy body, the upper motor neurons, which sit in the brain’s cortex, transmit messages from the brain to the lower motor neurons, situated in the spinal cord.

在健康的身体中，位于大脑皮层的上运动神经元将信息从大脑传递到位于脊髓的下运动神经元。

Once your brain receives sensory information, it sends a motor signal down the upper motor neurons through the corticospinal tract in the midbrain, and cross to the opposite side at the medulla before continuing down the spinal cord.

当大脑接收到感觉信息时，它通过中脑的皮质脊髓束向上运动神经元发送运动信号，先交叉至对侧延髓，然后继续下行。

If it's overactive, meaning it's too jumpy, it can signal a problem with an upper motor neuron, something in the spinal cord above the level of the knee jerk reflex, which is L3, L4, or something in the brain.

如果它过度活跃，意味着它太紧张，它可能表明上运动神经元有问题，脊髓中高于膝跳反射水平的东西，也就是 L3、L4 或大脑中的东西。

The one huge difference is that there's another upper motor neuron that extends down from a region in the right motor cortex, and stays on the ipsilateral or same side to meet with same the lower motor neuron.

有一点很不同，即面部右上部分，还有右侧运动皮质发出的上运动神经元，在同侧走行，并与下运动神经元交汇。

An upper motor neuron extends down from the left motor cortex, goes across the midline in the brainstem to the right side, and then meets with a right lower motor neuron which hitches a ride on the right facial nerve.

从左侧运动皮质发出的上运动神经元，在脑干穿过中线到达右侧，然后连接右侧下运动神经元并传导至右侧面神经。