Fill in the blanks: The tracts of the posterior columns decussate in the_____, whereas the tracts of the anterolateral system decussate in the _____.

Video transcript

Hey, everyone. Let's take a look at this question together in the medulla, the fibers of the posterior columns cross over to the opposite side and form a bundle called, what is it? Answer choice. A the Fasciculus cuneatus. Answer choice B the nucleus Gryllus, answer choice C the medial lemniscus or answer choice. D the gower fasciculus. Let's work this problem out together to try to figure out which of the following answer choices is the name for the bundle that is formed by the fibers of the posterior columns crossing over to the opposite side. So in order to solve this question, we have to recall what we have learned about the medulla, specifically the fibers of the posterior columns crossing over to the opposite side, which is that contralateral side and forming a bundle. And we know that when we are talking about the fibers of the posterior columns, we are talking about the Fasciculus Gryllus and the fasciculus cuneatus specifically of which those fibers ascend and synapse with the second order neurons in the nucleus Gryllus and nucleus cuneatus. And after those fibers ascend and synapse, they cross over to the opposite side. And when those fibers cross over they form a bundle that is called the medial lemniscus. So answer choice C medial lemniscus is the correct answer. Since answer choice C is the name for that bundle that is formed when the fibers of the posterior columns cross over to the opposite side. So answer choice C is the only correct answer choice. I hope you found this video to be helpful. Thank you and goodbye.