[Music] okay so now for everyone who's sitting there at home and alone you can do the following demo which is to make a fist so i'm making a fist right or left hand doesn't matter uh the brain is basically like a boxing glove like your fist and your thumb it's going to be your temporal lobe your knuckles are going to be your frontal lobe back of your hand is going to be your parietal lobe and your your wrist arm is connecting to your wrist is where your occipital lobe is going to be located and then as we go to the mesial surface the boundary here is going to form uh the limbus or the boundary where the cortex ends ends up there in that corpus callosum and that is just generally referred to as limbic cortex limbus meaning edge there's multiple things going on in there but that's sort of the big gross level divvying up of the brain now you can computationally unfold inflate and view cortex so here's a three-dimensional rendering of a human brain and i've color-coded in tan the frontal cortices green the parietal in salmon pink the occipital and the temporal lobe here in blue as you can see you can computationally just increase and reveal the deeper lying sulci and these are going to be common in all humans and and in many primates for that matter so for instance we talked earlier the earlier talk about the central sulcus located here nice centrally in the brain and the sylvian fissure deep fissure in here segmenting the thumb out where we have our temporal lobe and you can just uh take that extreme and flatten it what have you so the flow of information the general organization for the brain is going to be from this luria model where we have sensation coming in from the eyes skin the ears what have you going up through relay nuclei in the thalamus and then thalamus up into primary visual cortices primary somatosensory primary auditory core disease and then from there up into secondary or association cortices and ultimately all this information is coming together in associations which give you a unified perception of a single object so for instance if you were to click your finger i can hear the clicking of my finger i can see the clicking finger i have a sense of touch to it this is a single unified event and i perceive it as such even though from the sensory perspective all of that is being conveyed through different sensory channels now the major thing to remember about organization's brain is that it's a nice division from the sensory systems mostly in posterior portions and then we have the motor systems mostly anterior to the central sulcus and this is going to be similar to what we saw about the um in the brain stem the lr plate opens and you have that sulcus limit hands you have uh motor more medially and sensory more laterally and here in cortex we also have a rough division of motor more anteriorly and sensory more on the posterior surface so for instance we have at the posterior lobe primary visual cortex we have laterally just inside deep in that sylvian sulcus auditory cortex and along that post central lobule uh the primato uh sensory cortex for sense of touch okay so in the next series of slides we're going to hit one through seven motor somatosensory vestibular vision hearing taste and smell as primary cortical systems before we go to associational areas any questions to this point okay so learn in first uh first couple blocks of the neuroscience court course that there's all these horrific tracks and pathways coming up the brain stem to get to the cortex which we're going to bypass other than to say the peripheral nervous system touch pain temperature coming up here for example into the thalamus thalamus is then going to project that information of i'm feeling sensation on my toe to primary somatosensory cortex and also to some other sensory association cortices and put together i have the sensation and there's a crossing here and then similarly with motor cortexes coming back down you have your primary motor cortex pre-motor and supplementary motor areas working together kind of as a trifecta of regions that are then going to send information to say i'm going to wiggle my toe and you have these cortical bulbar and cortical spinal tracts that then cross at the pyramids and deca state cross so this sets up the point here this slide is that you have these crossing so that when you hear about the left side of the brain controls the right side of the body well this is where we're talking about various levels of crossing or occurring and that's important to keep track of from this from a neurosurgeon's perspective so for instance here are the pyramids and the pyramidal decussation from motor input will be coming down here 90 of the fibers are crossing over from the right to the left or vice versa and that's where that decision occurs and similarly here are those pyramids again and here's that inferior olive some some neural anatomy to give you some flashbacks to when you had learned this stuff or when you're going to be learning this stuff in upcoming years [Music] hey everyone ryan rad here from neurosurgerytraining.org if you like that video subscribe and donate to keep our content available for medical students across the world