What Is the Paleocortex?

Cortex:

Cortex:

The cortex is also known as the cerebral cortex. The cerebral cortex covers the gray matter in the two hemispheres of the brain. It is the material basis for advanced neural activity and consists of neurons, nerve fibers, and glial matter. There are a large number of wrinkles on the human cerebral cortex, called the gyrus, the shallow gap between the gyrus is called the groove, and the deep and wide groove is called the fissure. The area of the sulcus gyrus increases the area of the cortex. The surface of the cerebral cortex is divided into five lobes-frontal, parietal, temporal, occipital, and limbic. The frontal lobe, parietal lobe, temporal lobe, and occipital lobe appear later in the phylogeny, called the neocortex, and the marginal lobe occurs earlier, called the old cortex. The cerebral cortex is divided into six layers from the outside to the inside: the molecular layer, the outer granular layer, the pyramidal cell layer, the inner granular layer, the ganglion layer, and the multi-type cell layer. They are composed of different types of nerve cells, and the granular cells receive the sense Signals, pyramidal cells transmit movement information.

Chinese name

Cortex

Foreign name

cerebral cortex

Attributes

Collagen fiber protein

Cortical Anatomy:

1. Neocortex:

The neocortex is a higher-grade cortex. It is the most part of the mammalian cerebral cortex. It is about 2 to 4 mm thick in the top layer of the cerebral hemisphere and is divided into six layers. It is related to some higher functions such as perception, generation of motion instructions, spatial reasoning, consciousness, and human language.

The gray matter covered by the surface of the telencephalon is called the cerebral cortex, also known as the neocortex. According to evolution, the cerebral cortex is divided into archeocortex, paleocortex and neocortex. The ancient cortex and the old cortex are related to the sense of smell, collectively known as the olfactory brain. In mammals, the higher the grade, the more developed the neocortex. The ancient and old cortex are three layers, while the neocortex develops into six layers. Due to the highly developed human neocortex, it accounts for approximately 96% of the entire cortex. The thickness of each area of the cerebral cortex varies, such as the central anterior gyrus is 4.5 mm, and the visual area of the occipital lobe is only 1.5 mm. The size, shape, and density of the nerve cells that make up each layer of the cortex are also different. From 7 to 9 months of human embryos, all parts of the cortex are six layers. Therefore, the six-layer cortex can be regarded as the basic type, and most of the adult cortex maintains this type.

2. The cerebral cortex:

The cerebral cortex is a layer of gray matter, which forms the surface of the grooves and gyrus of the cerebral hemisphere. It is the most important part of the brain and the material basis for advanced neural activity. The volume of the human cerebral cortex is about 300 cubic centimeters and the total area is about 2200 square centimeters. Among them, 1/3 is exposed on the surface, and 2/3 is located on the trench wall and trench bottom. The average thickness of the cortex is 2.5 mm, the central anterior gyrus is the thickest, about 4.5 mm, and the cortex at the occipital pole is the thinnest, about 1.5 mm. There are two main components in the cerebral cortex, one is a cell, which includes the cell body and neuroglia of a neuron; the other is a nerve fiber.

3. Ancient Cortex:

The paleocortex is the oldest cortex that has evolved. Includes the cortex that forms the hippocampus and dentate gyrus. [1]

Paleocortex belongs to allocor-tex, which is only found in the hippocampus, and is basically composed of three layers of cells. The hippocampal structure is the part of the medial border of the cerebral hemisphere cortex. Due to the extreme development of the neocortex, this cortex is pushed to the inner side of the cerebral hemisphere. Between hippocampus and choroid, it bends down as the temporal lobe develops, and then turns to the front, from the foramen to the tip of the inferior corner of the lateral ventricle. , Hippocampus, lower leg, and part of the hippocampal hook.

4. Old Cortex:

The old cortex is an older cortex. It is the cortex that makes up the olfactory brain. Together with the ancient cortex, it is called the limbic cortex, and the tonsil nucleus, septum nucleus and lower thalamus, which are closely related to it, are collectively called the limbic system of the brain.

The old cortex includes the anterior piriform region and the entorhinal region. It also belongs to allocortex and basically consists of three layers of cells. However, sub-layers appear in many areas, forming six layers similar to isocortex, and there are fewer cell types in the cortex. For example, Golgi type II cells are much different than neocortex.