How is the brain organized

Fascinating facts about our brain

Our brain is a complex marvel that controls perceptions, memories, dreams, thoughts and feelings and thus our entire behavior. Brain research has not yet unlocked all the secrets of our thinking organ.

The human brain is a huge network of billions of nerve cells that are linked together. A wealth of information is processed there.

The Ten Most Interesting Facts About Our Brain

Here are ten fascinating facts neuroscientists have discovered about our “control center”1:

  1. The brain weighs an average of 1.4 kilograms. But even though it makes up only about two percent of body weight, it needs it 20 to 25 percent of the total energy. It consumes it regardless of whether we are thinking hard, letting our thoughts drift or sleeping.
  2. Our brain is that most fatty organ in our body. Over half of its mass is made up of fat.
  3. Unlike a muscle, the brain cannot use fatty acids for energy production; it's on the Intake of glucose reliant. The brain needs around 130 grams of this sugar per day as fuel.
  4. According to current estimates, our brain contains 86 billion nerve cells (Neurons). That is ten times more than people live on earth. Each nerve cell is connected to other nerve cells via an average of 1,000 contact points (synapses).
  5. At the synapses, most nerve cells release signal molecules, so-called "Neurotransmitters". These messenger substances are recognized by receptors (signal receivers) on the opposite synapse and cause an electrical signal there. In this way, impulses are passed on from one cell to the other.
  6. The electrochemical impulses reach speeds of up to 200 meters per second in the nervous system - this corresponds to 720 kilometers per hour - the cruising speed of a Boeing.
  7. Four fifths of our nerve cells (neurons) are not located in our cerebrum, but are in the Cerebellum settled. There they are responsible for coordination, fine-tuning, unconscious planning and learning how to move.
  8. Another important cell type in the brain are those Glial cells. These form what are known as myelin sheaths around the neurons, similar to the insulating layer on an electrical cable. Glial cells are also involved in the blood-brain barrier, which is responsible for ensuring that only certain substances get into the brain. In this way you protect the brain from unwanted substances.
  9. The human brain feels no painbecause it has no pain receptors. Operations on the brain can therefore be performed painlessly without anesthesia. On the other hand, the headaches we feel arise in the blood vessels of the meninges.
  10. New nerve cells and synapses are formed in the brain throughout its life. Therefore, our brain is able to get into old age to learn new things.

Structure and functioning of our brain

There is probably no other organ in the human body that is as complex as the brain. Researchers are trying to find out how sensory stimuli are encoded in the brain and how the 86 billion nerve cells interact with one another. But so far they know little about how the network of neurons processes information and organizes itself independently. For important questions, for example after Seat of our personality or how the brain copes with certain tasks, for example making a decision, there are no answers yet. The anatomical brain structures, which include the cerebrum, cerebellum, brain stem and diencephalon, have been well studied:

Seen from the outside, the brain, with its folds and depressions, resembles a walnut - only much larger. About 80 percent take this Cerebrum one that consists of two nearly symmetrical halves of the brain (hemispheres). A bundle of nerve fibers (corpus callosum or bars) connects the two halves. The Cerebral cortex (Cortex cerebri) is a gray layer a few millimeters thick in which complex processes such as learning, thinking and speaking are controlled. In addition, our memories are stored here for a long time. The cortex surrounds the internal white matter (substantia alba) of the cerebrum. Based on the furrows and folds of the cortex, anatomists divide the cerebrum into several areas, including the frontal or frontal lobes, the parietal or parietal lobes, the occipital or occipital lobes, the temple or temporal lobes. Certain functions can be assigned to each of these areas.

That's how it is Frontal lobe involved in the planning and execution of movements and actions. It also plays an important role in character and personality. in the Parietal lobes is where the somatosensory system is located, a kind of body information center. One of its tasks is to teach us about the movements and sensations in our body. in the Occipital lobe the processing of our sense of sight takes place. The most famous functions in the Temporal lobe what counts is hearing. Sound signals from the ear are transmitted here and "translated" into tones and noises for us. There are also so-called “lexical” centers that deal with the recognition of written and spoken words.

The cerebellum is located below the occipital lobe. It is the second largest part of our brain after the cerebrum. The cerebellum is essentially responsible for our motor skills, i.e. for balance, movements and their coordination.

The Brain stem is quite small, but essential for survival: Here is the control center for heart rate, blood pressure and breathing. Sleep is also regulated from here. The brain stem is also responsible for various reflexes such as the blinking, swallowing and coughing reflexes. This part of the brain is evolutionarily the oldest: there are hardly any differences between the brainstem of humans and animals.

This lies deep inside the brain, between the cerebrum and the brain stem Diencephalon. Here is that Limbic systemwhich functions, among other things, as an information filter that decides which sensory impressions penetrate into consciousness. The relevance of information evaluates a structure that Almond kernel or Amygdala is called. The amygdala receives signals from all sensory systems and is responsible for the emotional coloring of the information.

An important part of the diencephalon is that Hypothalamus. This is in direct contact with the pituitary gland (pituitary gland) and connects the hormonal system with the nervous system. The hypothalamus is the most important control center of the autonomic nervous system (also autonomous nervous system; it regulates automatically running processes). Among other things, it regulates body temperature and the water and salt balance. But also sex drive, pain and temperature sensation are controlled here.

Networks - the principle of organization in the brain

Brain researchers have mapped the individual regions of the brain and been able to assign some functions. But how the brain areas are interconnected and interact is largely unclear. There is agreement that networks - comparable to the Internet - represent an important organizational principle of our brain. The dimensions are impressive: since each nerve cell is connected to around 1,000 others, a signal can reach a million neurons in just two steps. In purely mathematical terms, therefore, no neuron is more than four steps away from any other nerve cell. The Signal forwarding takes place electrically and biochemically. Experts also call the signal molecules involved in transmission neurotransmitters, or “transmitters” for short.

Our thoughts, feelings and actions take place within the gigantic network. The secret lies in the interaction of different neural networks in the individual brain regions. Some of these networks are genetically determined and develop permanently. Others only exist for a short time. Groups of networks can overlap and their extent can vary. A single neuron can also be part of different networks. This explains why a place in the brain is involved in multiple functions. If, for example, speech is lost due to a stroke, this ability can partly be taken over by other regions.

Brain disorders

In many textbooks, diseases of the brain are differentiated according to whether they are neurological or psychiatric diseases. This classification originally has to do with the idea that the structure and function of the brain are changed in neurological disorders, while there is a "mental" problem in psychiatric diseases. According to this, the neurological diseases include stroke, multiple sclerosis, Parkinson's disease and epilepsy, while depression and schizophrenia belong to the psychiatric diseases.

Today this Separation between neurological and psychiatric illnesses is no longer maintained. For example, depression can be an early symptom of Parkinson's disease. Conversely, functional and structural changes in the brain can also be demonstrated in the case of depression2. Therefore, experts now speak of mental disorders instead of psychiatric illnesses.

How common are mental disorders?

The Robert Koch Institute (RKI) has determined that about a third of the population has one or more clinically significant mental disorders calculated over the year. Surprisingly, it affects young people most often3Many people suffer from several mental illnesses, for example anxiety disorders and depression. The consequences can be very stressful for those affected. So are mental disorders too most common reason for sick leave. On average, employees in Germany are unable to work 25 days a year due to a mental disorder - longer than with any other illness4.

This guide is primarily dedicated to cognitive disorders such as dementia and schizophrenia as well as mood disorders, which include bipolar disorder and depression.

2Bonhoeffer T, Gruss P (Ed.). Future brain. Verlag CH Beck; Munich, 2011.
3Robert Koch Institute: Study on Adult Health in Germany (DEGS1) 2012. Available here.
42015 absenteeism report from the AOK Scientific Institute. Available here.