The brain (brain, Latin cerebrum, grch. Ενκεφαλον Encephalon) refer to the head part of the central nervous system (CNS) of vertebrates. It is protected in the cranial cavity and is surrounded by the meninges.

Function

The vertebrate brain highly processed sensory information and coordinate complex behaviors. It is therefore the Hauptintegrationsort survive for all-important information in one organism can be processed.

However, not getting any information to the cortex and thus consciousness. Peripheral nerves are Plaits (Plexus) and notably in the brainstem center serve the unconscious pre-processing of signals. Reflex arcs take over tasks, with high speed and without conscious processing and delaying influence must run. Also in humans there is such an autonomic nervous system. It serves to coordinate vegetative functions such as breathing, circulation (heart function), food intake, digestion and release, fluid intake and excretion, and procreation. The regulation of these processes would be those structures of the brain associated with conscious awareness are employed, and thus completely overwhelm block.

The function of the brain is mainly based on the interaction of highly interconnected neurons through electrical impulses (see Neural Network). One way to analyze brain activity, therefore, the measurement of brain waves using an EEG dar. Another method of measuring the MEG.

In the course of evolution, the brain of higher animals a considerable degree of differentiation and organization of inner reaches (Zerebration). The structure and – to a lesser degree – the size of the brain may be clue to the learning ability and intelligence of an animal may be used. Again, the brain is not alone capable of learning; neural plasticity can be found on virtually all levels of the nervous system.

In addition to vertebrates also have squid highly complex brains, which they dedicated to empowering activities. In a broader Sense, therefore, also called the central nervous system of different invertebrates, such as the ringed worms or insects, as the brain. Depending on the brain-type talk about Cerebralganglion, Oberschlundganglion etc.

Structure of the vertebrate brain

* Prosencephalon (fore brain)
* telencephalon (Endhirn)
+ Cortex
+ Basal ganglia
+ Limbic system
* Diencephalon (mid brain)
+ Thalamus
+ Epithalamus
+ Subthalamus
+ Hypothalamus (with the hypothalamus is the pituitary gland)
+ Metathalamus

* Mesencephalon (midbrain)
* Tectum
* Tegmentum
* Crura cerebri
* Rhombencephalon (hash Brain)
* Metencephalon (hind brain)
+ Cerebellum (cerebellum)
+ Pons
* Myelencephalon
+ Medulla oblongata (by Brain)
* (Spinal cord)

The division of the brain varies according to the textbook and institution different. The Rhombencephalon Mesencephalon and are often combined truncus cerebri.

The human brain in addition is simple to nervous systems of some worms, and the brains of mice, rats, cats and primates, the best-studied brain in the animal kingdom.

Summary of the structure of the human brain

There are simplified four main areas:

a) The big brain is in the middle by an incision in two hemispheres (= hemispheres) divided. They are strongly folded or gefurcht. There is a broad connection between the hemispheres, which are also called bars – it is a thick nerve strand. Furthermore, there are other smaller compounds.

The 2-4mm thick surface is called cerebral cortex. It contains about 14 billion Somata of nerve cells. It appears gray and is therefore also called gray matter.

On her, the so-called cortical fields localized. We distinguish between primary and association areas of fields. The former processes solely a quality information. These are either information about perceptions (perception, such as seeing, smelling, touching, etc.) or movements (simple movements). The latter agree with each other from different functions. Important to note is that a single cortical field is not alone responsible for a function, but that the correct combination on a network from different nerves, which originate from different fields, only a full function allows.

Among the primary fields is expected, for example, the visual cortex, on which the projections of Sehbahn lead. It lies at the posterior pole of the brain. Another example is the auditory cortex, the processing of acoustic stimuli and used laterally in the temporal lobe is located.

Associative fields can be found for example in the front part of the brain. These are tasks such as memory and higher thinking too.

The position of the cortical fields by failures (eg after stroke), studies with electrical stimulation, microscopic and other techniques intended.

Inside the big brain is the white substance. In these axons course that the individual parts of the large brain with other parts of the nervous system connects.

b) On the cerebellum, can also distinguish between two hemispheres. In addition, we limited further parts. It is for example for balance, movement and coordination. In animals, the cerebellum is often large relative to the brain more pronounced than in humans, particularly in animals with flight capital, or at fast predators.

In addition to the automated movements of the cerebellum is also an option when unconscious learning ascribed. Recent research (2005) suggests that it is also a share in the language and social learning is.

c) Intermediate brain expects to 4 parts:

1. Thalamus (upper part)
2. Hypothalamus, the pituitary (pituitary gland) is connected.
3. Subthalamus
4. Epithalamus

The thalamus is the mediator of sensitive and motor signals to and from the Big Brain. With him running all the information from the sensory organs together, and will be taught next. Mainly consists of gray matter from the thalamus. The hypothalamus controls many physical and mental life processes and is itself partly Nerval on the vegetative nervous system and partly hormonally controlled via the bloodstream. Hypothalamus and pituitary (important endocrine gland in the body, through the Hypophysenstiel with the hypothalamus is connected) are the central link between the endocrine system and the nervous system. The intermediate brain is inter alia responsible for the sleep-wake control, pain sensation and temperature regulation.

d) The brainstem is the phylogenetic oldest area of the brain. It is the lowest brain section and consists of ascending and descending nerve fibers (white matter) and from clusters of neurons or Somata (gray matter). It consists of the midbrain, the bridge (pons) and the post-cranial (also extended Mark = medulla oblongata, since it is between the bridge (pons) and spinal cord is located). The brainstem and interconnected processes incoming sensory information and outgoing motor information and is also responsible for elementary and reflex-like mechanisms responsible.

In the brain after crossing the nerves of the two body halves. In addition, many self-running processes such as heartbeat, respiration, or metabolic is controlled. Equally important here are reflex centers, so that Lidschluss, swallowing, cough and other reflexes are triggered. The lower end of the after-brain to the spinal cord closes at.

Brains of men and women

On average, the brain weighs an adult woman and the 1245 g of an adult male 1375 g. It is assumed that this weight difference with a higher number of windings and grooves in the brains of women is balanced, thus increasing the total surface area of the brain increased. Moreover, the neurons in the brain in women closer together. In terms of intelligence there is no significant differences between men and women.

Basically, there are many differences in the structure and functioning of the brain between men and women. Sex hormones such as estrogen and testosterone affect not only the gonads, but in many ways on the nervous system as a whole and nerve cells, synapses, etc. in individual gene expression both during embryonic development, both during childhood and adolescence and in adulthood. Examples are as compared to women with young men praeoptica larger regions in the hypothalamus. Recently, with modern imaging methods, that the proposed three-dimensional objects rotating in men a brain region shows increased activity in women two.

Performance of the brain

The brain is a very active organ and has an enormous energy and oxygen. It makes about 2% of body mass, but still have about 20% of the blood (cardiac output) from the heart to be pumped into the brain. Because the brain is only very small storage capacity for oxygen and energy has already carries a brief loss of blood supply to brain damage.

The historical misconception ingenuity needed on (after death removed) to read his brain is as old as the brain research and is even now still occasionally continued. The non-fiction author Michael Hagner and others provided the basis of the brain specificity of many personalities, such as Immanuel Kant, Vladimir Ilich Lenin, or Albert Einstein alongside a history of brain research, and thematic insights into the cultural and social history of the past three centuries. Not a few brain researchers also ran into the fairway nationalist and nationalist-racist thinking.

Often, comparisons between the performance of a computer and the human brain employed. Since the brain as the seat of cognitive performance was detected, it was always in the literature with the most complex technical apparatus available compared (steam engine, telegraph). So we also tried, from the operation of computers on the functioning of the brain to close. Today, however one tries in the neuro-computer science, the functioning of the brain in part on computers or to replicate through these new ideas for “intelligent” information to come. As a structure for thinking and knowledge production in the brain provides an architecture, which is recommended for imitation. Artificial neural networks are already in the organization of artificial intelligence processes established.

Connectivity

The human brain is estimated to follow about 100 billion (1011) neurons, which by about 100 trillion (1014) synapses are closely linked. This means that on average each neuron with 1000 is connected to other neurons and thus, in principle, any neuron by neuron from each start in a maximum of 4 steps is reached. However, there are locally significant deviations from this mean. A basic principle of organization of the brain is the topological map (eg Retinotopie), ie side by side on what the body is made in the brain in the relevant areas and processed side by side.

The 12 pairs of main nerves of the brain

1. Nervus olfactorius – allows you to smell
2. Optic nerve – directs optical pulses
3. Oculomotorius nerve – will send 4 of 6 muscles that move the eye, including Features
4. Trochlearis nerve – supplies the upper oblique eye muscle
5. Trigeminal nerve – including forward Information about touching the facial area
6. Abducens nerve – supplies the lateral eye muscle
7. Nervus facialis – including possible mimic movements and taste perception
8. Vestibulocochlearis nerve (N. statoacusticus) – passes information from the hearing and the organ of balance
9. Glossopharyngeal nerve – including he information (including taste) from the pharyngeal area and allows movement in this area
10. Vagus nerve – perception and movement-including glandular activity and hormone release-from one part of the viscera
11. Nervus accessorius – allows movement in two large muscles of the neck and head
12. Hypoglossal nerve – allows movement of the tongue

Videos and DVDs

* Manfred Spitzer: Half a brain. Real Video from the BR-alpha-series mind and brain. (approx. 15 minutes)

* Interesting DVD on the subject brain (E-brain, P-brain), and Savant autism
Arte and Radio Bremen (ARD): A journey into the mysterious world of the super gifted in three parts,
1 – memory giants, 2 – The Einstein Effect, 3 – The big difference, TR-Union Verlag, 2006, ISBN 3-8058-3772-0