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大脑皮质

Matthew Barry Jensen 创建

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in this video I'm gonna talk about the cerebral cortex cerebral cortex and that's the layer of gray matter on the outside of the cerebrum so here we're looking at a brain from the left side and there's been some colors drawn in here but this was all gray matter cortex on the outside of the cerebrum and down here is a cerebellum and here's the brainstem and the cerebral cortex has these ridges and these grooves on its surface it's kind of all wrinkled up and folded up and these ridges like let me just pick this one right here these ridges are called gyri gyri that's the plural a single a single one is called a gyrus multiple is called gyri and then these small grooves that are on either side of a gyrus like this are called sulci sol sign that's multiple can be sulcus for just one so this would be one sulcus right here and so that's a small groove but there's also some really large grooves like this one right here those large grooves we usually call fissures fissures like this one right here that goes back like that and we divide the cerebral cortex into lobes and we name them the same as the bones of the skull that are right over those areas of cerebral cortex so that this big lobe right in the front here under the frontal bone is called the frontal lobe frontal lobe that's this one right here this one behind the frontal lobe is right next to the parietal bone of the skull so we call that the parietal lobe this one right here on the other side of this big fissure from the frontal lobe is by the temporal bones we call that the temporal lobe temple roll lobe and this one way in the back is by the occipital bone of the skull occipital so we call it the occipital lobe of the brain there are some other areas of cerebral cortex so we can't see you at this illustration like if we pull apart this fissure right here there's some in there and on the other side on the side in between the two cerebral hemispheres or some other areas but when people talk about cerebral lo usually referring to one of these for the frontal parietal temporal or occipital lobes of the brain and there's a lot going on in the cerebral cortex it's really the most complex part of the entire nervous system and the most complex types of information processing and functions of the nervous system occur in the cerebral cortex so I'm just briefly gonna touch on a couple of the functions of the cerebral cortex because there's so much going on but I'll save lots of the other details for later videos I want to mention a couple things about some of the senses and motor functions of the cerebral cortex and that's that a couple of the senses and the motor functions of the cerebral cortex on one side of the brain tend to be involved with the other side of the body and the environment for example visual information coming in onto one side of the body so let's say visual information over here on the right side of this person coming in this way is gonna end up being processed and part of the cerebral cortex on the other side of the brain let me just draw a little little bit of color over here to represent that that visual information from the right side of this person it's gonna end up in the left side of the brain and vice versa and actually it ends up tending to be back here in the occipital lobe where most of the visual processing the areas of the cerebral cortex doing visual stuff handles that information the same is true for somatosensory information some Manto's sensory information coming in to one side of the body because of the way this information travels in the nervous system is primarily gonna get processed in areas of cerebral cortex in the other side of the brain so for example if something hot or cold some kind of temperature stimulus is applied to the skin over here on the right side of this person bad information will actually end up over here on the left side of the brain in the cerebral cortex somewhere around here to get processed and brought to consciousness so that it can be perceived almost all of the other senses besides vision and somatosensory End to get processed in areas of cerebral cortex on both sides so stimuli involving these other senses are coming in to this person from the right side usually there's going to be areas of cerebral cortex on both sides of the brain they're going to do some processing of that and formation but for visual information and somatosensory information that predominantly makes it over to the other side of the brain similarly motor information information about movement and control of skeletal muscles which involves areas of cerebral cortex around here this area of cerebral cortex will be controlling muscles in general on the other side of the body so if I can address um draw some red in over here on the left side of this person's cerebrum that information will get carried by upper motor neurons down to lower motor neurons on the other side of the spinal cord and that's going to affect movement of the other side of the body so for instance I'll just shade in this leg read here that muscles of the right leg would primarily be controlled by areas of cerebral cortex on the left side of this person's cerebrum now if we take a big step back and look at the cerebral cortex as a whole we can divide up the cerebral cortex into a couple of types based on what kind of function that that area of cerebral cortex is performing the first type we call primary so a primary cortex is one that's performing basic motor or sensory functions and that's in contrast to other areas of cerebral cortex we call Association cortex Association and the idea with this word is that they're associating different types of information to do more complex processing and functions so for example for the areas of motor cortex there's a primary motor cortex that's kind of doing the basic motor functions and then there are Association motor cortices they're doing more complex motor functions like planning of movements and then their areas of Association cortex that are taking in different types of information like maybe somatosensory information and visual information and they're integrating that information and doing higher-level processing to perform complex motor or sensory functions and to produce the higher functions of the nervous system like cognition emotion and consciousness one aspect of cognition is language which could be described as the ability to turn thoughts into words and vice versa and in most people that's poor by certain areas of cerebral cortex in the left hemisphere there are some people that have language functions in the cerebral cortex on both sides or even all on the right side but most people have language functions occurring in cerebral cortex just in the left cerebral hemisphere or predominantly on the left cerebral hemisphere one last thing I want to mention is attention which is another important function of the cerebral cortex and there are lots of areas of cerebral cortex on both sides that play a big role in attention but in particular in most people the right cerebral hemisphere areas of cortex over there in the right cerebral hemisphere play a role in paying attention to both sides of the body and the environment whereas in a lot of people the left hemisphere seems to predominantly just pay attention to the right side of the body in the environment so there are some additional attention functions being carried out by the right hemisphere that are not carried out in most people in the left hemisphere so I'll stop there there's a lot more to talk about in terms of the structure and the function of the cerebral cortex and how these areas of cerebral cortex connect to and work with other areas of the nervous system for example these motor cortices work with the basal ganglia some of those deep subcortical cerebral structures and the cerebellum to perform a lot of different motor functions and for almost all these parts of the cerebral cortex and the functions they perform there are lots of connections between areas of cerebral cortex and between areas of cerebral cortex and other parts of the nervous system that are important but I'll stop there just to give a little bit of an overview of the structure and some of the functions of the cerebral cortex