RxPG News Feed for RxPG News

Medical Research Health Special Topics World
  Home
 
   Health
 Aging
 Asian Health
 Events
 Fitness
 Food & Nutrition
 Happiness
 Men's Health
 Mental Health
 Occupational Health
 Parenting
 Public Health
 Sleep Hygiene
 Women's Health
 
   Healthcare
 Africa
 Australia
 Canada Healthcare
 China Healthcare
 India Healthcare
 New Zealand
 South Africa
 UK
 USA
 World Healthcare
 
 Latest Research
 Aging
 Alternative Medicine
 Anaethesia
 Biochemistry
 Biotechnology
 Cancer
 Cardiology
 Clinical Trials
 Cytology
 Dental
 Dermatology
 Embryology
 Endocrinology
 ENT
 Environment
 Epidemiology
 Gastroenterology
 Genetics
 Gynaecology
 Haematology
 Immunology
 Infectious Diseases
 Medicine
 Metabolism
 Microbiology
 Musculoskeletal
 Nephrology
 Neurosciences
 Obstetrics
 Ophthalmology
 Orthopedics
 Paediatrics
 Pathology
 Pharmacology
 Physiology
 Physiotherapy
 Psychiatry
 Radiology
 Rheumatology
 Sports Medicine
 Surgery
 Toxicology
 Urology
 
   Medical News
 Awards & Prizes
 Epidemics
 Launch
 Opinion
 Professionals
 
   Special Topics
 Ethics
 Euthanasia
 Evolution
 Feature
 Odd Medical News
 Climate

Last Updated: Oct 11, 2012 - 10:22:56 PM
Research Article
Latest Research Channel

subscribe to Latest Research newsletter
Latest Research

   EMAIL   |   PRINT
Learn more quickly by transcranial magnetic brain stimulation

Jan 28, 2011 - 5:00:00 AM
Further information

 
[RxPG] What sounds like science fiction is actually possible: thanks to magnetic stimulation, the activity of certain brain nerve cells can be deliberately influenced. What happens in the brain in this context has been unclear up to now. Medical experts from Bochum under the leadership of Prof. Dr. Klaus Funke (Department of Neurophysiology) have now shown that various stimulus patterns changed the activity of distinct neuronal cell types. In addition, certain stimulus patterns led to rats learning more easily. The knowledge obtained could contribute to cerebral stimulation being used more purposefully in future to treat functional disorders of the brain. The researchers have published their studies in the Journal of Neuroscience and in the European Journal of Neuroscience.

Magnetic pulses stimulate the brain

Transcranial magnetic stimulation (TMS) is a relatively new method of pain-free stimulation of cerebral nerve cells. The method, which was presented by Anthony Barker for the first time in 1985, is based on the fact that the cortex, the rind of the brain located directly underneath the skull bone, can be stimulated by means of a magnetic field. TMS is applied in diagnostics, in fundamental research and also as a potential therapeutic instrument. Used in diagnostics, one single magnetic pulse serves to test the activability of nerve cells in an area of the cortex, in order to assess changes in diseases or after consumption of medications or also following a prior artificial stimulation of the brain. One single magnetic pulse can also serve to test the involvement of a certain area of the cortex in a sensorial, motoric or cognitive task, as it disturbs its natural activity for a short period, i.e. switches off the area on a temporary basis.

Repeated stimuli change cerebral activity

Since the mid-1990's, repetitive TMS has been used to make purposeful changes to the activability of nerve cells in the human cortex: In general, the activity of the cells drops as a result of a low-frequency stimulation, i.e. with one magnetic pulse per second. At higher frequencies from five to 50 pulses per second, the activity of the cells increases, explained Prof. Funke. Above all, the researchers are specifically addressing with the effects of specific stimulus patterns like the so-called theta burst stimulation (TBS), in which 50 Hz bursts are repeated with 5 Hz. This rhythm is based on the natural theta rhythm of four to seven Hertz which can be observed in an EEG, says Funke. The effect is above all dependent on whether such stimulus patterns are provided continuously (cTBS, attenuating effect) or with interruptions (intermittent, iTBS, strengthening effect).

Contact points between cells are strengthened or weakened

It is unknown to a great extent how precisely the activity of nerve cells is changed by repeated stimulation. It is assumed that the contact points (synapses) between the cells are strengthened (synaptic potentation) or weakened (synaptic depression) as a result of the repeated stimulation, a process which also plays an important role in learning. Some time ago, it was also shown that the effects of TMS and learning interact in humans.

Inhibitory cortical cells react particularly sensitive to stimulation

The researchers in Bochum have now shown for the first time that an artificial cortex stimulation specifically changes the activity of certain inhibitory nerve cells as a function of the stimulus protocol used. The balanced interaction of excitatory and inhibitory nerve cells is the absolute prerequisite for healthy functioning of the brain. Nerve cells specialised in inhibition of other nerve cells show a much greater variety in terms of cell shape and activity structure than their excitatory counterparts. Amongst other things, they produce various functional proteins in their cell body. In his studies, Prof. Funke has concentrated on the examination of the proteins Parvalbumin (PV), Calbindin-D28k (CB) and Calretinin (CR). They are formed by various inhibitory cells as a function of activity, with the result that their quantity gives information about the activity of the nerve cells in question.

Stimulus patterns act specifically on certain cells

For example, the examinations showed that activating stimulation protocol (iTBS) almost only reduces the PV content of the cells, whereas continuous stimulation attenuating activity (cTBS protocol), or a likewise attenuating 1 Hz stimulation, mainly reduces the CB production. CR formation was not changed by any of the tested stimulus protocols. Registration of the electrical activity of nerve cells confirmed a change in inhibition of the cortical activity.

Learning more quickly after stimulation

In a second study, recently published in the European Journal of Neuroscience, Prof. Funke's group was able to show that rats also learned more quickly if they were treated with the activating stimulus protocol (iTBS) before each training, but not if the inhibiting cTBS protocol has been used. It was seen that the initially reduced formation of the protein Parvalbumin (PV) was increased again by the learning procedure, but only in the areas of the brain involved in the learning process. For animals not involved in the specific learning task, production of PV remained reduced following iTBS. The iTBS treatment therefore initially reduces the activity of certain inhibiting nerve cells more generally, with the result that the following learning activities can be stored more easily, concludes Prof. Funke. This process is termed gating. In a second step, the learning activity restores the normal inhibition and PV production.

More purposeful treatment in future

Repetitive TMS is already being used in clinical trials with limited success for therapy of functional disorders of the brain, above all in severe depressions. In addition, it was shown that especially disorders of the inhibitory nerve cells play an important role in neuropsychiatric diseases such as schizophrenia. It is doubtless too early to derive new forms of treatment of functional disorders of the brain from the results of our study, but the knowledge obtained provides an important contribution for a possibly more specific application of TMS in future, is Prof. Funke's hope.

Literature

Benali, A., Trippe, J., Weiler, E., Mix, A., Petrasch-Parwez, E., Girzalsky, W., Eysel, U.T., Erdmann, R. and Funke, K. (2011) Theta-burst transcranial magnetic stimulation alters cortical inhibition. J. Neurosci., in press.

Mix, A., Benali, A., Eysel, U.T., Funke, K. (2010) Continuous and intermittent transcranial magnetic theta burst stimulation modify tactile learning performance and cortical protein expression in the rat differently. In: Eur. J. Neurosci. 32(9):1575-86. doi: 10.1111/j.1460-9568.2010.07425.x. Epub 2010 Oct 18.

Further information

Prof. Dr. Klaus Funke, Dept. of Neurophysiology, Faculty of Medicine of the Ruhr University, 44780 Bochum, Tel. 0234/32-23944, E-Mail: [email protected]




Publication: Journal of Neuroscience

Advertise in this space for $10 per month. Contact us today.


Related Latest Research News
Drug activates virus against cancer
Bone loss associated with increased production of ROS
Sound preconditioning prevents ototoxic drug-induced hearing loss in mice
Crystal methamphetamine use by street youth increases risk of injecting drugs
Johns Hopkins-led study shows increased life expectancy among family caregivers
Moderate to severe psoriasis linked to chronic kidney disease, say experts
Licensing deal marks coming of age for University of Washington, University of Alabama-Birmingham
Simple blood or urine test to identify blinding disease
Physician job satisfaction driven by quality of patient care
Book explores undiscovered economics of everyday life

Subscribe to Latest Research Newsletter

Enter your email address:


 Feedback
For any corrections of factual information, to contact the editors or to send any medical news or health news press releases, use feedback form

Top of Page

 
Contact us

RxPG Online

Nerve

 

    Full Text RSS

© All rights reserved by RxPG Medical Solutions Private Limited (India)