What forms the forebrain and what functions does it perform?

The forebrain is the most rostral part of the nervous system. It consists of large hemispheres (cortex) and basal ganglia. The latter, located in the cortex, are located between the frontal parts of the brain and the intermediate brain. The structure of these nuclear structures includes the caudate nucleus, the shell, which together constitute the striped body. Its name is due to the alternation of gray matter, consisting of nerve cells, and white. These elements of the brain, together with the pallid sphere, which is called the pallidum, form a striopallidal system. This system in mammals, including humans, is the main nuclear apparatus and participates in the processes of motor behavior and other important functions.

The basal ganglia include subcortical nuclei, which have a very diverse cellular composition. In a pale ball there are large and small neurons. The striatum has a similar cellular organization. The neurons of the striopallidal system are pulses from the cortex of the hemispheres, the thalamus, and the stem nuclei.

What are the functions of the subcortical nucleus?

The nuclei of the striopallidal system participate in the coordination of movements and motor activity. Irritation of the caudate nucleus, causes head turns of a stereotypical nature and trembling movements of the hands or forelimbs in animals. In the process of studying the striatum, it is clarified that it has significance in the processes of remembering movements. The irritating effect on this structure disrupts the processes of memory and learning. Stryopallidarnaya system has a retarding effect on motor activity and its emotional components, for example, on aggressive reactions.

Bark of the cerebral hemispheres

The forebrain includes an education called bark. It is considered the youngest formation of the brain. Morphologically, the crust consists of a gray matter that covers the entire brain and has a large area due to numerous folds and convolutions. The gray matter consists of a huge number of nerve cells. Due to this the number of synoptic connections is very high, this ensures the processes of storage and processing of the information received. Based on the appearance and evolution, the ancient, old and new bark are distinguished. During the evolution of mammals, the new crust developed particularly rapidly. Ancient bark in its composition has olfactory bulbs and tracts, olfactory tubercles. The composition of the old includes the gyrus gyrus, amygdala and convolutions of the hypocampus. The remaining areas belong to the new bark.

Nerve cells of the cortex of the hemispheres are layered and ordered, forming six layers in their composition:

The 1 st - is called molecular, it is formed by the intertwining of nerve fibers and contains the minimal amount of nerve cells.

The second is called the outer granular. It consists of small neurons of different shapes, similar to grains.

The third one consists of pyramidal neurons.

4th - inner granular, like the outer layer, consists of small neurons.

The 5th contains Betz cells (giant pyramidal cells). The processes of these cells (axons) form a pyramidal tract that reaches the caudal areas and passes into the anterior roots of the spinal cord.

6th - multiform, consists of neurons of triangular and fusiform form.

Although the neural organization of the cortex has much in common, a more detailed study of the cortex showed the differences that appear during the fibers, the size and number of cells, and the branching of their detritus. Studying the human brain, a map of the cortex was compiled, which includes 11 regions and 52 fields.

What does the forebrain answer ?

Very often, the ancient and old cortex are united. They form the olfactory brain. The forebrain is also responsible for alerting and attention, and participates in vegetative reactions. The system takes part in instinctive behavior and the formation of emotions. In experiments on animals, with an irritating effect on the old cortex, there are effects associated with the digestive system: chewing, swallowing, peristalsis. Also, the irritating effect on the tonsils causes a change in the function of internal organs (kidneys, uterus, bladder). Some areas of the cortex participate in the memorization processes.

Together, the hypothalamus, the limbic region and the forebrain (the ancient and old cortex) form a limbic system that preserves homeostasis and ensures the preservation of the species.