biology and Medicine videos please make sure to subscribe join the Forman group for the latest videos please visit Facebook Armand hudan in this video we're going to look at the motor pathways if you have not watched the video on the introduction to the descending and ascending tracts please watch that beforehand there's also a sensory motor pathway video if you're interested so in the brain there are two important cortexes one in front of the uh the the central gyrus known as the motor cortex and the other at the back which is um the somato sensory cortex now these two cortexes are important One controls motor movement and the other sensation we will be focusing on the motor cortex so let us take a crosssection of the motor cortex um here so here is the motor uh the cortex of the brain it is made of the Outer Gray matter where synapses are and then there's the inner white matter which contains melinated axons on each side of the cortex right and left there are areas that represent a particular region in our body so here I am drawing uh on the left side and we can see um here we have repres uh represented particular areas of the body such as the hands the face the legs um and these areas these regions make up the motor cortex and essentially signals will arise from one of these areas which will then uh travel to that particular area of the body to perform that movement or action so I hope that made sense and if it doesn't we'll look at some examples soon enough and of course in the in the cortex itself there's a region called a which is the relay station and this is quite important to know so the motor pathways can be divided into two main Pathways the the lateral pathway and the anterior medial pathway we will first focus on the lateral pathway which is responsible for voluntary movements so we control these movements and there are three main tracks involved in uh the lateral pathway and these are the lateral corticos spinal tract which control distal muscles such as our forearm there is also the anterior corticos spinal tract which control the proximal muscles so it would be the arm for example the anterior cortical spinal tract I highlighted here because it is voluntary but not part of the lateral pathway itself um regardless the lateral and anterior corticos spinal tracts are very important in voluntary muscle control the third tract that we will talk about is the rubos spinal tract before looking at these tracks let us learn some other important structures involved so here I am drawing the midbrain below the midbrain is the ponds which I have not drawn then we have the medala here and here is a section of a spinal cord let us just say it's a cervical uh segment of the spinal cord and here is a skeletal muscle for uh for movement of the arm or forearm for for example now within within sections of the spinal cord like within the spinal cord there are uh designated tracts for example there are designated tracts for uh the ones I mentioned earlier so here we have a tract for the lateral corticospinal uh pathway the anterior cortical spinal pathway and then the rubos spinal tract is here and there are many other tract which we will look at later in this video let us first focus on the corticos spinal tract so let us say we want to move our hands so distal muscle so a neuron will arise from the motor cortex which control hand movements here it will pass through the thalamus pass through this uh cus cerebri of the midbrain and the pyramids of the medala where it will then cross over and land on the lateral corticospinal tract before synapsing with a second neuron on the vental Horn of the spinal cord the first neuron coming down is therefore part of the lateral corticos spinal pathway the second neuron coming from the ventral Horn of the spinal cord will then Target the skeletal muscle which has to be the distal muscle so for example muscles of the hands the second neuron is known as the lower motor neuron and the first neuron arising from the cortex is the upper motor neuron of course if this neuron was part of the anterior corticospinal tract I would uh it would pass through the anterior cortical spinal tract here uh before sin aping with the lower motor neuron okay so we know about the lateral and anterior corticos spinal tract now let us learn about the rubos spinal tract the rubos spinal tract is for voluntary control of big muscles um it's basically it's it is important there is an area in the midbrain uh known as the red nucleus where the rub R spinal pathway begins it essentially descends down and Crosses over passing the ponds the medala before landing on the rubos spinal tract on this of the spinal cord and then synapsing with the lower motor neuron with a corticospinal lesion there can be Paralysis on the contralateral side the opposite side the function of the muscle can be recovered by the rubos spinal tract if the rubos spinal tract is intact now it is important to understand that the left side of the brain controls movements of the right side of the body and vice versa so if we damage the the left side of the brain corticospinal pathway there will be Paralysis on the right side on the opposite side and this is known as the contralateral side so I hope you understood the the lateral Pathways which are made up of the lateral cortical spinal tract and the uh rubos spinal tract but we also added onto this U section the anterior cortical spinal tract because it is voluntary control but now let's just recap the descending motor tracts that we we've learned where where where it's located and some of the new ones so here is a spinal cord section and here I'm drawing uh I'm coloring in yellow the descending motor tract which we have learned so far are the lateral motor pathways which are part of our voluntary control uh these are the lateral corticos spinal tract and here is the rubos spinal tract and here in the front the anterior uh the ventral side is the anterior cortical spinal tract some new tracts which we will now invest at um are the tectospinal vestibular spinal and reticular spinal tract let us look at these tract and briefly look at their functions we won't however go into too much detail all these tracks are part of the anterior medial pathway these Pathways control axial muscles such as you know the the spine muscles and the rib muscles and these are which are responsible for posture and balance and the coarse control of axial and proximal muscles note the proximal muscles so the anterior medial pathway include the vestibular spinal tract which uh which are which also include the medial and lateral vestibular spinal tracts there is also the reticul spinal tracts which include the pontine and mol tracts and there's also the tech spinal tract and part of this uh category is the anterior cortical spinal tract which we already talked about and which is voluntary and controls proximal muscles and so I highlighted it so basically the anterior uh the anterior medial Pathways um mainly controls the axial muscles for posture and balance it except for the anterior corticos spinal tract which is voluntary control of proximal muscles remember again here we are drawing some important structures the brain the cortex the thalamus the motor cortex here we have the midbrain ponds which I've not drawn the medala and there is the cerebellum here which is important and it actually connect interconnect with all these motor pathways and is responsible for coordination and essentially as well as posture and balance then of course we have the spinal cord and here are some skeletal muscles which we will Target on the spinal cord level we can find the tract here is the tectospinal tract and the medullary reticular spinal tract we will first focus on the vestibulo spinal pathway which originates from the medullas vestibular nucleus it descends down and synapses with a second neuron in the spinal cord but we won't look at that just know that the vestibular spinal tract is responsible for head maintaining head balance and turning now the reticular spinal tract can either originate from the medola or the pawns so it can be mullery or pony here I am drawing the r particular spinal tract which originates from the medulla an area known as the medullary the medary reticular formation it travels down this neuron that arises from here and lands on the medol reticular spinal tract before it synapses with a second order neuron on the ventral horn and then targets an axial muscle uh responsible for posture imbalance if the reticular spinal tract is damaged harmless stimulus can elicit a flexor reflex um the last track we will look at is the tectospinal tract which originates from the midbrain here the area known as the uh Superior culus the tecto spinal pathway descends down and then crosses over descends again and lands on the tector spinal tract before synapsing with a second neuron which will Target an axial muscle now the tectospinal tract is responsible in the orientation uh response so orientating yourself in the world essentially so I hope that made sense um so the motor pathways again can be divided into the lateral Pathways or the anterior medial pathway the cortico spinal tract is probably the most important because it's voluntary control anyway so anyway I hope you enjoy this video thanks for watch watching bye