Introduction to the Cerebrum

Cerebral Cortex Hills and Valleys

We will be considering the cerebrumThe largest part of the brain, responsible for thought, memory, and voluntary movements.. It is also known as the big brain hat. We will consider its Gray matter and its white matterThe outer portion of the spinal cord made of myelinated nerve fibers that transmit signals.. As you can see here, the Gray matter is the cortex of the brain. Cortex means bark, like bark on a tree. One of the first things you might notice about a brain is the longitudinal fissureA deep groove separating the left and right hemispheres of the brain.. This fissureA deep groove in the brain’s surface. divides the brain into left and right hemispheres. Very few structures can move from the left side to the right side of the brain. We talked about connoisseurs in the spinal cordThe central nervous system structure that relays signals between the brain and body. and we have commissars here in the brain but only very few. A sulcus is a valley or an indentation of the brain kind of like these that you see here. A sulcus is not as deepAway from the surface of the body. as the longitudinal fissure. In between sulky are gyri which are basically hills. Each gyrus as we are coming to find out has very specific functions. No gyrus works alone. This Gray matter can connect to other parts of the brain. It does so by using myelinated axons of white matter.

Cerebral Cortex Landmarks

The most important landmark of the cerebrum is the central sulcusA groove separating the frontal and parietal lobes.. This structure is a sulcus or a valley. It is significant because it generally divides the brain into front and back, or rostral and caudal. It also divides the brain by function. Most structures rostral or anteriorThe front of the body or toward the front when standing in the anatomical position. to the central sulcus are motor structures. Most structures caudal or posterior to the central sulcus are sensory. For example this gyrus immediately adjacent to the central sulcus and anterior to it is called the precent gyrus. The gyrus immediately posterior to the central sulcus is called the post central gyrus. This should come as no surprise.

Cerebral Cortex

The cerebral cortexThe outermost layer of the brain, responsible for higher-order thinking and processing. or just that Gray matter outer covering is actually a layer of six different cellsThe basic structural and functional units of life.. The neuronsThe functional cells of the nervous system that transmit signals. that make up these six different layers are neurons of many different shapes. Most of them that you can see here are bipolar neurons however there are an axonic neurons as well.

Cerebral Cells

Most of the cells in your cerebral cortex are referred to as stellate cells which are technically the neuroglia astrocytesStar-shaped glial cells in the CNS that support neurons and maintain the blood-brain barrier.. Astrocytes are the most important neuroglia. They obtain things from blood vessels. Then, they feed these to neurons. The most common neuron type in the cerebral cortex are pyramidal neurons. They have a funky long Axon and a whole bunch of dendritesBranch-like extensions from a neuron that receive signals from other neurons.. Previously pyramidal neurons were classified as bipolar neurons because they fit the definition.

Areas in the Cerebrum

When we cover the cerebrum, we will take care to cover three types of areas in the cerebrum. There are sensory areas which are mostly posterior to the central sulcus. So we’ll see some sensory areas like the occipitalPosterior and base of the skull; curves under to form the back of the head. sensory area the auditory sensory area etcetera. We will also explore motor areas which are mostly anterior to the central sulcus. The third type of area that we will look at are called association areasBrain regions that integrate sensory input and coordinate responses.. These are very complex areas. They might be taking sensory information from various sources. They consolidate it into a memoryThe ability to store and recall information., a pattern of instructions for output, or an emotion. Ohh for example there is an occipital sensory area that perceives information by way of your optic nerve. However this occipital sensory area cannot assign meaning to anything that it sees. There is an occipital association area that is nearby. This area can assign meaning to the incoming sensory information received through the optic nerve. The same type of association areas exist for almost all of the senses. We’re also going to see very specialized association areas like those associated with language period