guys get an advantage at least you heard some of this stuff I will back up to the brain and start talking there at the end of today's session we'll review what I didn't record so that you can at least make a note of that so when we talk about the brain we're going to divide the brain into sections that are separating their functions as well as to some degree their structures so we start with a pair of cerebral hemispheres a single one is called a cerebrum and we're going to label those regions by the loes uh that are most closely associated with these bones of the skull then we get to the diyon areas in the diyon that we're going to talk about include the thalamus and the hypothalamus then when we move to the brain stem midbrain pawns and medulla oblong Gata and then finally the last segment that we're going to talk about that's associated with the brain specifically is the cerebellum and that literally means little cerebrum so it's going to have some things that are similar in appearance but a group of neurons with a completely different set of responsibilities okay so what we're going to do then is we're going to start by looking at the cerebral hemispheres and when we look at the brain and we talk about those regions that we've just been discussing we can think of it a little bit like a mushroom so sitting over top of the entire structure is the cerebral hemisphere in this picture this is anterior and this is posterior so are we looking at the left cerebrum or are we looking at the right the left correct yay everybody's got their orientation good so the mushroom cap would be made up of the right and left cerebrum and then the post that the mushroom sits on top of the cap of the mushroom sits on top of is basically the brain stem so the pawns midbrain pawns and Mulla and then sitting on the top of that is the thalamus and just below the thalamus is the hypothalamus so those are the regions that we were that we listed on the previous slide and then sitting back in here would be the cerebellum so we're going to start by looking at the cerebral hemispheres so we're going to draw out our cerebral hemisphere so it looks something like that okay so this is our left cerebral Hemisphere and we can see that it's got raised and indented regions that we talked about when we talked about the layers if we talked the P matter would be right against and then we had our arachnoid matter I can't remember what colors we used oh I think we used green didn't we then we had our arachnoid matter with the extensions that separated from the Pia so that we could have cereal spinal fluid in here and then we had our Dura matter that was a tough whoops that's not the color we used outermost layer that had a dural sinus that showed up period ically which was where our cerebral spinal fluid could Escape back to the circulatory system to be replenished so the Duram matter in the brain has some connections to bones of the skull as well as connections to the underlying arachnoid matter it's really a two-layered structure in the brain area and just a single layer of dura in the spinal cord a little bit different in the spinal cord than in the brain but but otherwise that's the protective layers and then we had the skull sitting outside that we knew was made of plat bone which is Compact and spongy and then compact bone protecting the outside of the skull when we look at this left cerebral hemisphere so let's keep our orientation we the raised areas is called the gyus and the indented are called a sulcus and deep indents are called fishes so this area right in here is a very deep indentation goes deep into the center of the cerebrum so that's called a transverse fissure if we looked at the top of this skull what the top of the brain I should say it would look a little bit I made it a little bit too skinny but you get the idea and we'll keep the anterior there and the posterior here uh convenience but there's a longitudinal Fisher a very deep indentation that actually separates the right and left hemispheres from each other except in the very center part this region that I kept solid is a region of fibers that cross from right to left and back again so that the right side of the brain knows what the left side of the brain is doing that's a connection between the two cerebral hemisphere hemispheres that's called the Corpus colossum otherwise those two SE those hemispheres remain separate from one another the two sides the right and left cerebral hemispheres so then we have this what's called a Sal here that's kind of right smack in the middle so it's simply called the central sulcus so it becomes a reference point for us and we can generally not perfectly but we can generally indic indicate that on the behind behind this Central sulcus we're going to see a lot of nuclei that are associated with sensory function and in front of that Central nucleus or sulcus we're going to see a lot of nuclei that have motor responsibilities so even up in the brain even in the cerebral cortex we've got sensory and motor responsibilities and this is a major site this cerebral hemisphere major site for conscious decision making so a lot of the neurons are going to be involved with conscious uh functions in the body so the motor neurons from up here will signal skeletal muscles to contract and when we perceive pain it'll be when the signal reaches this cerebral cortex so these cortical functions are often that word cortical is often in reference to conscious but not always conscious um integration voluntary integration and a lot of our unconscious or subconscious integration is going to come from other neurons deeper in the central nervous system those ones we mentioned like the brain stem and the dianon so we use our Central sulcus as a reference point and the group of neurons that are found immediately behind the central sulcus okay there's posterior so we know behind is going to be this area and I'm going to color code it because this was a sulcus the the gyrus immediately behind would be called the post Central gyrus and more importantly than remembering that the post Central gyrus is the location for neurons that are responsible for somatic sense so this area is called the primary somato sensory area primary somato sensory area remember earlier today I said if it has that word Soma in it it's body so this is body sense this is sensation that's coming from the body in other words external receptors pain touch temperature from the external environment receptors that are typically going to be found in the skin between the epidermis and the dermis so we've got areas in the primary somat sensory area that are dedicated to the baby finger on the right hand remember we're looking at the left cerebral cortex so we've got groups of neurons that are going to be specific to Sensation from the baby finger on the right hand and then another group of neurons for the fourth digit on the right hand third digit on the right hand palm of the right hand forearm arm shoulder you follow me on this yes sir yes okay so when we talk about the primary somato sensory area we we describe it as being spatially organized so what we're saying is these neurons here are receiving sensation for somatic stimula like touch temperature and pain from specific locations so there's a group of neurons that are going to be dedicated to the baby finger to the fourth digit to the third digit to the hand to the arm to the trunk to the leg and you can reproduce the body in this primary somat sensory area based on the neurons that have spatial organization so remember we said earlier today said you could the brain doesn't have pain receptors so you can open up the skull and you can you can put electrodes on the brain and monitor electrical activity so literally what we're saying here is if I squeeze the baby finger on the right hand then we would see electrical activity in that part of the primary somato sensory area if I went and I squeezed the knee then we would see a different area light up in response to that group of neurons that are dedicated to that part of the body so when I say that it's spatially organized that's what I mean groups of neurons reproduce the sensation from specific parts of the body that's predictable and you can map it so that took that takes care of a group of neurons that are responsible for somatic sensation and we know somatic sensation is pain and temperature and touch from the skin receptors in the skin right so now we have special sense so for example in the occipital lobe area we have the primary visual area so if you had to take a wild guess what sensation is the primary visual area going to be receiving site yeah Sight Vision light dark color okay and in this region right in kind of the junction between this lateral fissure and this Central sulcus we've got a group of neurons that are known as the primary auditory area what do you think the sensation is that these neurons receive hearing yeah hearing okay now it gets a little tricky but all the senses are represented so it gets tricky because they just get deeper sort of deeper in behind this area would be the primary old factory what do you think the old factory area receives well think of the special senses which ones haven't we talked about so far sense yeah so yes in this case it's smell okay and then deeper again we would have the gustatory area gustatory area is for Taste and the vestibular area for balance so they're all kind of clustered in that Central Area deeper down we can't see them in our picture that we're drawing right here because the other ones overlap them a little bit now in the case of sensation all of these primaries you notice that primary is part of the description in each of these Sensations so when it has Primary in front of it it means that this sensory information is raw data so most of the time with raw data we have to be able to process that and put some context to it so nearby all of these primary areas there are going to be what are called association areas so for example a group of neurons and I'm going to I'll just put cross-hatch on these ones so we know it's a different area is just going to be called the somato and I'm going to get rid of this for now we don't need it so it's called the somal sensory Association so Association neurons are important neurons because they're going to receive the raw data for their responsibility somatic sense in this case and also receive data from other parts of the brid brain such as our emotional brain and our memories and our you know past experiences and our our centers for higher sort of what they call Executive functioning in order to put some context so we our neurons here are going to integrate somatic sense raw data and memory to give us context so in sometimes with with sematic sense it's hard to appreciate context what we mean by that but the one example that I use um that helps I think a little bit is if you're in the hallways at senica college and you're in a crowded hallway and somebody comes up behind you and they they grab your shoulder okay so that's touch right they grab your shoulder and you were expecting your friend to come up behind you because you saw them earlier in the hallway or whatever the circumstance was so when that shoulder gets grabbed you put context to the touch oh that's got to be my friend because they said they were going to meet me in the hallway and it's a friend so I'm happy to meet them and I'm glad for the touch okay or you're going down the hallway and you're on your own and you're thinking about your next class and you're you weren't expecting to meet a friend and somebody grabs your shoulder and you're shocked you're surprised and you turn around with an angry look on your face that's context in both cases the touch could be exactly the same but your context was different does that make sense do you understand what I'm trying to say there yes okay now with visual I can show you a visual that I think helps with this as well so we have our primary visual area and the group of neurons that are nearest it would be called what what would we call those group of neurons visual Association yeah visual Association area so we know that the visual Association area is responsible for context it's going to put memory and emotion and learning against the Raw so here's here's a good illustration or at least I think it's a good illustration um you may disagree with me we'll see so here we have a hill on the horizon and on that Horizon there's a tree okay hopefully we can all agree that looks like a tree but it's on the horizon it's all out in the distance so I'm telling you there's a tree out in the distance and then I have two people in the classroom take a look at that tree and the one person lives up in the Arctic Circle and up in the Arctic Circle trees don't grow any taller than about three or 4 feet in height but out on the west coast those trees can grow 200 feet tall so two people are looking at this tree one person makes a statement that says that tree is probably 150 feet tall and the second person the person from the Arctic Circle says are you kidding me trees don't grow that tall that's going to be a 4 foot tall tree at the most we're both looking at the same raw data we can see a tree on a horizon but there's no other points of reference so that's why two different people that draw on two different sets of experiences will come up with a different height you follow me so far yeah okay so how do we fix that problem let's put in a point of reference let's put in a ladder so now I tell you that this ladder is 10t tall so if I tell you the ladder's 10 ft tall and we look at this tree the tree is a bit taller than that let's say we agree that it's a bit taller than a 10ft tree it's maybe about 12 feet tall right we can both agree on it being taller than 10t because we can see that it's taller than the 10 foot ladder now we both have a point of reference that we both can relate to that allows us to agree on the size of that tree that's the role for the association area of any of these primary Sensations that we're talking about right now if two people were sitting in a room and one was a bad guy and one was a good guy and they heard a siren the prime auditory area here's the raw data for a siren the bad guy says uhoh I got to get out of here I'm going to be in trouble if I get caught the good guy says well thank goodness the people running that siren are coming because they're going to save the day you know what I'm trying to say there if it's the police or if it's a fire Department we think about good things if we don't have anything to worry about but if we're bad we may think about bad things but we're hearing the same raw data does that make sense yes okay so it means our response is different right yeah and our response will be different based on our own personal experiences and our own emotions right so what it really means is that you know deeper down in the in the brain tissue we've got memories and emotions and those will be being sent to this Association area along with the information o of raw data and we're going to integrate that we're going to compare the raw data to our past experiences and our current emotions and we're going to come up with an appropriate response does that make sense yes so uh a group whoops a group of neurons that are around the auditory area would be the auditory so we're going to have association areas for all of our primary Sensations so when we look at association areas they receive input to get our response so our primary areas might be somato sensory visual auditory old Factory uh gustatory which is taste you can imagine what happens with taste and emotion and memory and so on you know sometimes you got a a bad memory with a food you won't never you never want to eat that food again and vestibular so remember vestibular was a fancy word for balance so those are all your senses accounted for so there's a primary for all of these Sensations and there's going to be an association area associated with each specific to each with a similar responsibility integration of emotion memory and learning that's going to give each of us our unique response to sometimes the same primary data now if we go to in front of our Central sulcus we've got a pre PR Central gyrus and our precentral gyrus is this area right here now I can get rid of some of this just to make some space and our pre Central J is a group of neurons that are called the pre I'm sorry primary motor cortex so the primary C sensory area was the last place in the sensory pathway before we get to integration and starting to starting to form a response the primary motor cortex is the first place that we're going to generate a motor response from in the brain in other words it's so the primary stat sensory was the last place to receive a signal of sensation and the primary motor cortex is going to initiate our descending pathway the primary motor cortex is spatially arranged just like our primary somato sensory area was in other words there's a group of neurons in this area for example that are responsible for the muscles of the fifth digit in the right hand and another group of neurons responsible for muscles to the thumb and another group of neurons responsible to muscles of the forearm different ones for the extensors than for the flexors and so on and so on and so on so the primary motor cortex is also spatially organized the primary motor Cor Vex so what we're saying there is it's not dedicated neurons whoops to specific parts of the body is that what that really means specific muscles in parts of the body so we've got the word motor in there so no longer sensory and we don't need association areas here because this is part of our planning for a response we're not receiving and trying to react we're now planning a motor response but we do need to plan so we have a group of neurons near the primary motor cortex and I'll show you where in just a minute but we'll list them first premotor cortex and the premotor cortex is responsible for the planning and will signal the primary motor cortex for the final pathway so in our picture here we've got a group of neurons uh let's uh we'll change the color just a little bit kind of in this area right here that would be the premotor cortex and then right up in the front here right up in the front here uh let's uh give it a different color that's called the prefrontal so remember we said that the loes of the cerebral hemisphere are named for the bones that they're closely associated with the visual areas occipital every everything in here would be parietal down in here would be temporal up front here would be frontal because of the bones that are located that's where those names come from it's pretty simple as far as that part goes but we're talking about the very very front part of the cerebral cortex is called the prefrontal so even in theory it's even before or in front of the frontal prefrontal cortex but the prefrontal cortex is what we call is is dedicated to what we call intellectual or higher intellect functions so that's where their initial planning you know guys that were famous for inventions probably had a really really well-developed prefrontal cortex animals don't have much of a prefrontal cortex CU animals mostly Survive by reacting to their environment if they're cold they're going to go try to get warm somewhere if they're warm they're going to go find some shade and slow down and and cool off if they're hungry they're going to go find food you know if they're mad they're going to growl and attack uh and and um you know there's not much higher intellect functioning that goes on but human beings can create initial ideas and and uh come up with with new and novel sort of thinking right that's how we discovered fire and made a round wheel and um that sort of thing so when we talk about the the prefrontal cortex what happened there so we all of these things that we're listing here are are higher or or uh the term that you'll sometimes see with respect to the prefontal cortex is executive functioning so in other words uh more complex thoughts and and recognizing consequence for actions that's a big one and you women you you women out there are going to know this for a fact and Boys in particular do not develop their prefrontal cortex sometimes until they're as old as 25 or 26 years of age and you girls develop your prefrontal cortex much earlier than that maybe 18 or 19 years of age and really what that boils down to is you recognize that there's consequence for your actions much earlier than boys do and if you don't believe me look at the insurance companies and who they will rent a car to they won't rent a a car to a boy till he's 25 or older in many many cases and girls can often Rent A Car at a younger age so if you don't believe the the anatomy and physiology of it you can believe the insurance companies because they don't want to pay for car accidents boys will drive a car at 100 kilm an hour around a corner that's supposed to be driven at 50 because they don't recognize and I'm exaggerating here they don't recognize that there's going to be a consequence for trying to take the corner at that kind of speed right so that's what we're talking about there but with respect to motor we can sort of look at these three components to planning a motor response as already set go so when we're planning a motor response we've got to get ready then we've got to get set and then we've got to get go so in the brain in the cerebral cortex the prefrontal is where we get ready this where we're going to decide that we're going to reach out and pick up that pen that's on that table about three foet three feet in front of us and the planning the sequencing of the events is going to be premotor and then go is primary motor so when we're looking here let's get a color that's going to show up ready that didn't come out Ready Set Go go and all we're saying there is from go we're going to descend out of the cerebral cortex into the spinal cord and onto skeletal muscle that's the goal do you follow me on that yes sir could you repeat that please okay so we're on the motor side right now right so if we've received sensory information that says you know that that tack is in our thumb and we want to remove it we've got to set up a motor plan maybe we're going to take our left hand and reach out and grab that tack and pull it out of our hand more than just withdraw which would be more or less a reflex so if it required a more complex response the prefrontal cortex is going to tell us that we got to get rid of that attack it hurts and we've got to act quick Ready Set is sending these signals over so we're going to relay over from the ready group of nuclei to the premotor group and the premotor group is going to sequence the events we don't want to squeeze our our thumb and forefinger before we grab the tack so we have to coordinate and that's the premotor cortex's responsibility and then from there we're going to send over to the primary motor cortex to the specific groups of neurons that finish on the specific muscles of the body part that we want to move Ready set go Ready set go prefrontal premotor primary motor so if we wanted to follow that up we would go synapse synapse synapse then would leave to the spinal cord and out to the skeletal muscles that's our motor response that would be from integration descending two effectors Ready set go descending to skeletal muscle does that make sense yes yeah yeah do you need yeah yeah okay I just I hear some hesitation I don't know if that's just because we've covered a lot of stuff today it's it's more like the last part where we were talking about the motor and then the um a lot of information but still kind of like hard to process it yeah so you're going to need to you're going to want to review it you're going to read through your Powerpoints and your textbook to support the stuff we're talking about here but again like always don't go into crazy detail in the textbook if we haven't gone into crazy detail here I'm only going to ask you questions like give me a responsibility for the premotor cortex right I'm not going to ask you to give me all kinds of crazy details so you just want to be able to discuss some of these areas that we've been drawing if we don't draw them I'm probably not going to ask you any questions about them right if we if we haven't talked about them there's not likely to be any questions on it but I mean we've got quite a bit drawn in here as it is it's we don't need to to bog you down with more okay now we got I I just want to finish up with two more areas in the left hand osphere and then we'll be done okay and these are areas associated with speech so and they're typically found in the left hemisphere only the one we're looking at here so we have an area right be right behind the primary auditory area and another area that's right in front of it and you can appreciate that it's or or you want to be consistent here and consider that if it's in front it's in the motor area and if it's behind it's in the sensory area and this will stay consistent for us so in this case this is called Wares unfortunately it's a guy's name stick sticks with it is called W's area for speech and this segment in front there is broka area for speech so War's area for speech is responsible for putting context to speech so that makes sense if it's on the sensory side we're going to hear the speech and the wori neurons will determine for example that that person is speaking English or that person is speaking Mandarin or Spanish whatever the case may be but the wores area is the area that puts context to the sounds coming out of that other person's mouth so it's like the sensation of speech right so you're going to be able so that's the wores area the area that was behind and close to the auditory area it also makes sense it would be close to auditory because you have to hear the sounds in order to put some context to the language so it's putting context to the language it might take some um uh inputs from the emotion so you can tell that the person's angry or excited or that sort of thing as well right whereas broka [Music] area for speech is motor so the neurons in this area are the neurons that are going to finish on muscles that help us pronounce and say things with emphasis or with Clarity broker's area is motor for um so the primary motor area typically finishes on skeletal muscles in the in the trunk or in the Upper Limb or the lower limb Broca's area is like the primary motor except it's going to finish on the muscles that we use for talking so those two purple are worni area for speech context for the sounds that people are making and we can deter detect language difference or maybe an emotional difference to the way they're speaking and broka area is motor for speech so those neurons will finish on muscles that are going to help us with speaking clearly and uh properly we okay with that yeah that's that's [Music] okay okay so I think that's enough for today