Source: Video and Images Created by Amanda Soderlind
Welcome to this lesson today on the cerebrum. Today, we will be discussing the structure and function of the cerebrum and the roles that it plays in emotion, consciousness, and memory.
So the cerebrum is a part of the brain located in the forebrain. The brain is composed of three sections, the midbrain, forebrain, and hindbrain. Our cerebrum is found in our forebrain. And it's composed of two cerebral hemispheres.
So if you take a look at this diagram right here, we can see our two hemispheres of the cerebrum. And these two hemispheres are connected by a band of nerves, called the corpus callosum. The two sides of the brain can communicate with each other via that corpus callosum.
An interesting fact is that any sensory information detected by the left side of your body will be interpreted by the right side of your cerebrum and vice versa. So basically, if you were to touch a hot stove with you right hand, the left side of your cerebrum would be the side of your cerebrum that would interpret that information. So they're opposite in that way.
The cerebrum is responsible largely for processing information. And it's composed of an outer layer of gray matter, called the cerebral cortex. This outer layer of gray matter-- referred to as the cerebral cortex-- is divided into three areas, motor areas, sensory areas, and association areas.
The motor areas of the cerebral cortex control our voluntary movements. The sensory area of our cerebral cortex interpret the meaning of different sensations that we experience. And association areas of the cerebral cortex process information to produce some sort of action.
So we're going to take a look at this diagram of the cerebrum right here and identify the different divisions of the cerebrum-- the different lobes. Here, we have the frontal lobe. And the frontal lobe of our cerebrum is responsible for movements, memory, and behaviors. The parietal lobe is our green lobe right here. And the parietal lobe is responsible for receiving and processing sensations from our internal organs.
The occipital lobe, in purple-- the occipital lobe is responsible for vision. And the temporal lobe plays a large role in hearing and visual processing. So these are the four lobes of the cerebrum.
We're going to take a look at another diagram here, another page, and discuss emotions, consciousness, and memory. The cerebrum does play a role in each of these. We're going to start by discussing consciousness here.
Stages of consciousness depend on our reticular formation. So stages of consciousness can range from being fully alert, wide awake, to being on the extreme other end, in a coma. Our stages of consciousness are determined by our reticular formation. And our reticular formation is basically a network of neurons that runs through our brain.
What it does is it receives and processes sensory information and then sends those signals, that it receives, to the central nervous system. The reticular activating system, or the RAS, is a part of the reticular formation. And what this RAS does is, it sends signals to the thalamus of your brain, which then arouses the cerebral cortex.
And remember, that cerebral cortex that we talked about is that outer layer of gray matter of the cerebrum. So it'll arouse the cerebral cortex. And the amount of the cerebral cortex that it arouses, or that it stimulates, determines our level of consciousness. So the more of it that it arouses, the more conscious we are.
Another part of the reticular formation also helps us to maintain our posture, balance, and it filters incoming signals. Certain signals that come in that are unimportant, it allows us to not even have to worry about them or to be aware of them. So it filters what signals are important, what we need to be aware of, what we need to pay attention to, and what is unimportant.
The limbic system is a system that controls our emotions. And the limbic system is located in our upper brainstem. It includes parts of the thalamus, the amygdala, the hypothalamus, and the hippocampus. This part of the brain basically controls our feelings and our emotions and some are behaviors associated with those emotions.
Memory also plays a role with the cerebrum. Memory is a way in which our brain stores and retrieves information. So you'll remember, I had mentioned that the frontal lobe plays a large role in memory when we looked at that diagram earlier.
There are two types of memory, short term memory and long term memory. As the name suggests, long term memory is a more permanent type of memory. And when memories are stored, generally only relevant information is stored. Information that is irrelevant is then forgotten. It's not necessary to be stored.
Two types of memory that can be stored are declarative and skill memory. Declarative memory are basically facts that are stored. You're able to store fact recall, such as dates, names, faces, odors, words-- anything along those lines.
Whereas skill memory is a type of memory that's gained by practice. It's something that involves a motor skill. So if you're an ice skater, for example, the tricks that you can do while you're ice skating-- if you practice them over and over and over again-- your body and your mind remembers how to do those different skills. So it's basically a type of memory that's gained by practice and that involves a motor skill. Whereas, again, declarative memory is more of a fact recall.
There are links between memory storage and the different parts of your brain, like the cerebral cortex, the limbic system, the thalamus, and the hypothalamus. For example, a connection between memory in the limbic system would be, if there's a certain smell that reminds you of a certain memory. Every time you smell the specific smell, it makes you think of something else.
So, for example, maybe every time you smell blueberry muffins, it reminds you of being at your grandma's house when you were little. Basically, it's just associating memory with some sort of emotional connection with the limbic system.
So this lesson has been an overview on the structure and function of the cerebrum, as well as an overview on emotions consciousness and memory.
Areas of the cerebral cortex that control voluntary movements.
A part of the brain located in the forebrain that processes incoming sensory input.
The outer layer of the cerebrum that deals with conscious behaviors.
Areas of the cerebral cortex that interpret the meaning of sensations.
Areas of the cerebral cortex that processes information and works to produce an action.
An area of the brain that controls emotions.
The level of alertness of the brain.
A network of neurons that runs through the brain.
A part of the reticular formation that plays a role in determining our level of consciousness.
The way in which the brain is able to store and retrieve information.
Information that is stored for a short period of time.
Information that is stored more permanently.
A band of nerve tracts that connects the hemispheres of the cerebrum.