BRAIN ANATOMY 101 - THE BRAIN

The brain in general.

The brain consists for 80 percent of water and for 20 percent of physical and biochemical structures. The brain only takes up about two percent of the total body weight. Yet it uses up to 25 percent of the oxygen and glucose that circulate in the body for nutrition. The size of the brain is hereditary and it says nothing about a person's intelligence level .The brain is also part of the central nervous system.

Skull (cranium)

The brain is made up of soft tissue surrounded by a skull. At birth the brain still consists of separate parts so that the head fits better through the birth canal during birth. After birth, the parts grow together and ossify.

Brain hemispheres

The brain consists of both a left half and a right half. We call these 2 hemispheres:

The left hemisphere controls specific matters such as: language, speaking, writing, reading and arithmetic.

The right half mainly regulates: spatial insight, music, intuition, feelings, ability to make connections

The anatomy

The brain is the most complicated organ in the body. While scientific researchers have already discovered a lot about the brain in recent years, much of it still remains a mystery. Globally, the brain can be divided into various parts, each of which is responsible for certain functions

Many brain functions take place in the outer layer of the brain, also called the cerebrum. This is the place of the humans thought-life. The cerebrum covers most of the brain. The cerebrum can be divided into four parts: the frontal lobes, the parietal lobes, the occipital lobes and the temporal lobes. (You can find these lobes on both sides of the hemispheres.) In this blog story, we will mainly focus on these structures.

Frontal lobe(s)

The frontal lobes are the anterior (front) part of the cerebral cortex. They are involved in planning, organizing, memory, impulse control, problem solving, selective attention, decision making and controlling behavior and emotions. The left frontal lobe also plays a role in speech and language.

Processes that are responsible for executive functioning also take place in the frontal lobe. This includes recognizing the consequences of certain actions, choosing between two different actions, suppressing socially undesirable responses and identifying differences and similarities between different situations.

The primary motor cortex is also located in the frontal lobes. The primary motor cortex controls movements. Different neurons respond to specific movements.The frontal lobes are the last part of the brain to be fully developed. This brain region continues to grow during the age of 20.

Parietal lobe(s)

The parietal lobes are located between the occipital and frontal lobes, and above the temporal lobes. The parietal lobes are separated from the frontal lobes by the central sulcus, and from the temporal lobes by the sylvian fissure.

The main role of this brain part is to integrate sensory information, for example: to think spatially. This part of the brain contains the primary and secondary somatosensory cortex. There are also areas of the dorsal path of visual information processing here. By combining somatosensory and visual information, the area can help visualize body position.

Posterior section of the parietal lobes

The posterior portion of the parietal lobes (PPC's) are important for controlling movements of the arm, hand and eyes. In this way, the area is involved in picking up an object that you see lying on the table. You need visual information to perform these actions, otherwise you may grab next to or in front of the object.

The PPC’s can also be divided into four parts: lateral, ventral, medial and anterior.

The lateral part of the PPC’s contain a map of all areas of the visual field. This information is used to control eye movements. When you see a relevant stimulus, you move your eyes here to study it better.

• The ventral part of the PPC’s receive information from the various senses (visual, auditory, somatosensory and of the organ of balance).
  

• The medial part of the PPC’s have neurons that encode the location of a movement. In order to perform a movement properly and to grab an object from the table, you need to know exactly where on the table the object is, and therefore where the movement must go.
  

• The anterior section of the PPC’s processes information about the shape, size and orientation of objects. This information is then used to control the fine movements of the hand. This makes the distance between your fingers just enough to pick up the object.

Temporal lobe(s)

The temporal lobes are below the parietal lobes, and in front of the occipital lobes. When you should point to this area from the outside, you should look at the brain area directly behind the ears. The lobes contains, among other things, the hippocampus (memory) and amygdala (emotions).

Because of the different areas that can be found in the temporal lobes, this part of the brain also has many different functions. You can think of simply processing auditory information, but this is not the only thing. For example, the area is also involved in recognizing and naming people, animals and objects. In addition, temporary memories are stored in the hippocampus. This area is therefore part of the declarative memory.

Furthermore, the lobes also contain the parahippocampal gyrus (production and retrieval of memories), fusiform gyrus, the Brodmann areas 20, 21 and 22. The area of ​​Wernicke ( meaningful speech) is therefore also located here. And in the lateral part you will also find the primary and secondary cortex.

Occipital lobe(s)

The occipital lobes are the posterior portion of the cerebral cortex. Visual information is processed in this brain area. The lobes can be further divided into different parts. The posterior part is known as the primary visual cortex, or striate cortex. This brain region receives information from the eyes and forwards this information for further processing.

Other visual areas are also located in the occipital cortex. You can think of V2, V3, V4, and V5, which together with V1 form the dorsal and ventral path of visual processes.

Cerebellum

The cerebellum is a ball of nerve tissue on the underside of the skull. The cerebellum accounts for about one-eighth of the brain mass. They also contain more than half of all nerve cells and are highly pleated.

The cerebellum is responsible for the coordination of the muscles, reflexes and balance. It is the switching center for controlling the muscles. This part of the brain is mainly for fine muscle movements, and the cerebellum is also involved in performing highly automated actions. (Implicit learning). The cerebellum also plays a role in language and in tasks that have something to do with the working memory, such as redialing a phone number to remember it.

The brainstem

The brainstem connects the cerebrum and the midbrain to the cerebellum and spinal cord. This part of the brain controls vital life functions such as: regulation of body temperature, heart rate, blood pressure, breathing and digestion. The brainstem is also important for maintaining a sleep rhythm, crying, urinating, chewing and changing the pupil size.

The brain stem consists of three parts; the medulla, the pons and the midbrain. The medulla is the part of the brain stem that is connected to the spinal cord. From here, the signals from the brain are sent to the body, for example to the muscles to make a certain movement. In this way, the medulla is also involved in heart rate, blood pressure, digestion and body temperature.

The pons is the connection between the cerebellum and the cerebrum. The anterior portion of the pons is important for sending sensory information to the cerebrum. This mainly concerns information about movements. The back part of the pons helps with breathing, taste and sleep.

The midbrain is involved in sensory and motor functions, visual and auditory reflexes, the pupillary reflex and in hearing. The midbrain consists of the tectum and tegmentum. The tectum contains the superior and inferior colliculi, which control the eye movements.

Brain bar (corpus callosum)

The brain bar forms a connection between the left and right hemispheres of the brain. It contains as many as 200 million axons. The brain bar is somewhat larger in women than in men. It ensures that if you see something with your left hemisphere, the right hemisphere recognizes this.