Neuroscience

The plural of the term neuroscience research areas of medicine, psychology and biology are meant sweeping and summarized, in which the German language area - are examined structure and function of nervous systems - usually in cooperation with adjoining science areas such as information technology and computer science to robotics.

History of brain research

Research field

The research field of neuroscience is the role of the nervous systems of all types during the entire execution of the life processes of biological organisms.

It covers in detail in neuroscience to the analysis of the structure and functioning of the central nervous systems of all units, the neurons and other cell types such as glial cells in particular. It examines the characteristics and the effects of cross-linking of these cells to neural networks in complex nervous systems. Examples of this are the diffuse nervous system of coelenterates, the rope ladder nervous system of arthropods and the central nervous system of vertebrates.

Directions of research in neuroscience, which mainly deals with the investigation of the structure and performance of the brain of primates (ie humans and apes ) deal, are often summarized in the vernacular under the name brain or brain research.

Besides the experimental basic research is research from the medical point also for causes and cures of neurological diseases such as Parkinson's, Alzheimer's or dementia. Furthermore, we studied in neuroscience, cognitive information processing ( neural processes involved in perception, formerly traditionally referred to as " mental " phenomena ) as well as formation and flow of emotional reactions or broad phenomena such as consciousness and memory.

In recent decades, so numerous, partly institutionally embedded collaborations between neuroscientists and researchers have shown from other departments, with the closest relations with representatives of cognitive science, psychology and philosophy of mind exist.

Disciplines

The neurosciences beyond the trial, they sharply divided according to various criteria into sub-areas. Although it would be the first of disciplines according to the considered microscopic and macroscopic levels of the hierarchy (molecules, cells, cell structure, network behavior) order, however, tend to neuroscience to a more functional approach. That is, most of the functional role of a member for a microscope ( macroscopic ) system is examined, one or more levels above.

Roughly speaking, the neurosciences, according to the levels, divided into four disciplines:

• Neurobiology
• Neurophysiology
• Cognitive Neuroscience
• Clinical and medical subjects

Neurobiology mainly with the molecular and cell biological foundations of neuroscience. Other disciplines who work at this level, the neuroscientific branches of biochemistry, molecular biology, genetics and epigenetics, as well as cell biology, histology and anatomy, and developmental biology. With the expansion of neuroscientific insights from zoology to cover plants is concerned that - controversial - Plant Biology euros.

At the core of neuroscience is neurophysiology. Although the physiology is usually a sub-discipline of biology, it takes so far in neuroscience a special role, as neuronal activity and thus falls the "language of nerves" in the field of neurophysiology. The neurophysiology can be divided into the electrophysiology and the physiology of the senses but is also closely related to the neuropharmacology, neuroendocrinology and toxicology.

A central place at a higher level occupies the Cognitive Neuroscience. It is concerned with the neural mechanisms that underlie cognitive and mental functions. So you interested in especially for higher powers of the brain as well as for its deficits neuro- pedagogy.

The clinical medical subjects dealing with pathogenesis, diagnosis and treatment of diseases of the brain and include neurology, neuropathology, neuroradiology and neurosurgery as well as the Biological Psychiatry and Clinical Neuropsychology.

Methods

The methods of neuroscience initially differ in their applicability in humans. Non-invasive methods can be used for study of the human nervous system. The following list shows the available non-invasive methods of neuroscience, ie methods that do not harm the system. Exception here are the lesion studies that try to get through systematic comparison of damaged brains information on the localization of functions. However, the damage is not done deliberately, but patients with brain injuries or strokes are the basis for the study dar.

Psychophysics is totally dedicated to the measurement of ability of the brain as a whole complex within the organism. It gives an indication of the range of options that has a living being. Psychophysics is often brought together with the anatomy, if lesion studies to be performed. Patients with brain injury, for example after a stroke, compared with healthy individuals. The comparison of the ( psycho-physical ) possibilities of two neural systems with intact or damaged brain allows to assess the role of the damaged brain area for the skills and assets. However, lesion studies have the disadvantage that the location of the damage could be detected only after the death of the patient. They were really slow, but presented a long time the basis of all neuroscientific studies is limited and the speed of the neuroscience knowledge acquisition. In its methodology, the activity of nerve cells plays no direct role in this respect, as not the nerve cell, but the entire system of the living being is the focus of the study.

With the development of devices that allow direct or indirect conclusions about the activity of the brain, also the type of study changed. The development of the electroencephalogram ( EEG ) allows you to watch the brain at work indirectly. The activity of nerve cells, producing an electrical field that can be measured outside of the skull. Since the electrical field orthogonal to each propagating a magnetic field, even this can be measured by this method is referred to as magnetoencephalography (MEG). Both methods have in common is that they make it possible to measure the activity of large cell clusters with high temporal resolution and thus to obtain information about the sequence of processing steps. The spatial resolution is moderate, but it is allowed researchers to gain insight into the time and place of neuronal process steps on living people.

Using computed tomography (CT ), it becomes possible, place and extent of a lesion in a living patient and to determine. Lesion studies were therefore faster and more accurate because the brain can be scanned immediately after damage already and the anatomy of the damage already indications of possible (cognitive ) can give failures, which can then be studied specifically. Another side effect is the fact that the brain is deformed by an injury to the patient's death, making it difficult to determine the precise anatomical damage. This deformation extent plays the CT does not matter, as the time between injury and imaging is usually short. This applies in equal measure for magnetic resonance imaging ( MRI / MRI, also called nuclear magnetic resonance imaging ). Both methods have a good to very good spatial resolution, but do not allow any conclusions about the activity of nerve cells. Make the continuation of the lesion studies dar.

Functional studies, ie studies examining the function of certain brain areas that were only possible, have been developed as imaging procedures, the measured signal strength varies depending on the activity of brain areas. These methods include positron emission tomography ( PET), Single Photon Emission Computed Tomography (SPECT ) and functional magnetic resonance imaging (fMRI / fMRI). They all produce a signal of moderate to good spatial resolution, but have the disadvantage of being virtually blind to the temporal sequence of neural processes ( in the millisecond range ). A relatively new method is non-invasive near-infrared spectroscopy, which indeed has a good temporal resolution, but can represent only small areas of the brain. Unlike other methods, they can also be functional, such as an EEG mobile and used in natural environments.

And invasive procedures are used, which specifically alter the properties of the nervous system or cause damage or injury through the measurement come in animal models or in clinical trials. At the global level, especially pharmacological agents alter the properties of neurons or other for neuronal activity, plasticity or development of relevant mechanisms. When pharmacological intervention may be influenced or completely destroyed or merely influences of a particular channel or receptor type of neuronal cell membranes throughout the brain depending on the substance, a brain area. The pharmacological intervention thus making it equally a global as a specific functional method. To measure the effects of the intervention, it takes usually to the psychophysics, electrophysiology or (post mortem ) histology back.

Transcranial magnetic stimulation ( TMS ) allows short off areas of the brain. It is, though invasive, also used in humans, since you do not run out of permanent damage. By means of a strong magnetic current is painless induced in all brain areas whose activity has thus nothing to do with the normal task of the areas. One sometimes speaks therefore of a temporary lesion. The duration of the lesion is usually in the millisecond range and therefore provides insight into the sequence of neuronal processes. When repetitive transcranial magnetic stimulation (rTMS ), however, are areas of the brain turned off by repeated stimulation for minutes, by taking advantage of a protective mechanism of the brain advantage. The repeated simultaneous stimulation of whole areas of the brain tricks the brain before an impending epileptic seizure. In response, the activity of the stimulated brain area is suppressed to prevent spread of excitation. The temporary lesion thus produced remains only persist for a few minutes. The spatial resolution is moderate, the temporal resolution very well for TMS and bad for rTMS.

By means of electrical stimulation of cortical areas can, as in the TMS, momentarily affect the processing of nerve impulses in certain brain areas or eliminate. In contrast to TMS, however, the skull is to be opened ( as must be applied from the outside of the skull much stronger, painful currents) and an electrode implanted into a brain area of interest. This allows a much more accurate spatial determination of the affected areas. The electrical stimulation is applied primarily in neurosurgery to determine the language centers that can not be damaged during surgery, but also in animal models to short-term influence of neural activity.

The opposite works electrophysiology, which, instead of inducing currents into the brain, the brain waves of single cells or cell aggregates measures. There is a difference between in vivo and in vitro experiments. In in vivo experiments, electrodes are placed in the brain of a living animal, namely either by being permanently implanted (chronic implant) or temporarily inserted into brain areas of interest (acute experiment). Chronic implants make it possible to study the brain activity in an animal that behaves normally. In vitro experiments to study the electrical activity of cells and are not carried out on live animals, but only on the brain tissue. The activity of the tissue does not correspond here to the normal behavior of the animal, but techniques such as the patch -clamp technique allows much more accurate conclusions about the properties of neurons in a brain area, as these can be studied systematically.

For the study of the morphological structure of brain tissue microscopy has always been important. Newer techniques, especially multi-photon microscopy and confocal microscopy allow a hitherto unsuspected spatial resolution. Individual neurons can be studied in detail in 3D measured and morphological changes. When using ion-sensitive or voltage- sensitive dyes and functional studies can be performed.

Other fields of neuroscience at the cellular level, the techniques of genetics. With the help of very specific genes can be deleted (eg knockout mouse ), modified or be implemented ( see, for example Gal4/UAS-System ) to observe their significance for the nervous system in experimental animals. Virtually all methods mentioned above are applicable to such mutants or transformants.