Monday, June 6, 2016

Brain stimulation, potentials and limitations

Human brain By NIDA
Measuring the brain electric activity by electrodes placed on the cortical surface is more than a hundred years old technique. Recently it has been noted that environmental electric and magnetic fields can influence brain activity. For example, cell radio-frequency waves emitted by cell phones can modulate brain frequencies within neurons that are in close proximity to the phone. In animal experiments it has been shown that similar radio frequencies even cause brain cancer. However, the study used extreme exposures and extreme treatment conditions. Probably you should not worry. Yet, outside electric and magnetic fields can noticeably influence brain activity in some cases for extended amount of time.

In disease:
EEG or electroencephalogram picks up voltage fluctuations resulting from ionic current of the cortical neurons, which are arranged close to the brain's surface. Brain stimulation reverses the process. it uses electrical, magnetic, radiowave, or focally targeted sources to modulate the electric activity inside the brain. The number of brain areas that can be manipulated with electric impulses toward physiological, physical changes is growing. In a special case electrodes can be implanted deep in the brain to influence activity there, called deep brain stimulation. Deep brain stimulation can be effective treatment for Parkinson's disease, depression, chronic pain and other movement disorders. Although deep brain stimulation has immense potential in the treatments of many diseases, some caution  is warranted. The results have been inconsistent so far. For example individual differences in the position of brain structures can influence the effectiveness of the procedure. Potential side affects of deep brain stimulation, due to the incision of the procedure can also be dangerous. New technique, which might produce deep brain stimulation without the need for incision is in the works.

In healthy subjects:
In healthy subjects brain stimulation can enhance creativity, applied during slow wave sleep it enhances memorization, and a new study has shown a dramatic improvement of piloting skills of novice pilots. If confirmed, this study really opens the possibility for mental enhancements with this technique. Studies in rodents have shown motivation and behavior modification by manipulating the VTA  (small area at the base of the brain, marked on the human brain image), with potential treatment for addiction and other mental problems. Stimulation of the frontal part of the brain has been shown to increase performance and endurance in tasks requiring sustained attention and focus. Transcranial direct current stimulation with slow oscillations during slow wave sleep almost doubles overnight memory retention. Magnetic stimulation improved spatial-precision memory via improved brain network function. However, the treatments are currently based exclusively on empirical studies, because the theoretical background for brain stimulation has been missing so far.

A new, physics based hypothesis of consciousness is urgently needed to give brain stimulation a strong predictive power. The book, 'The Science of Consciousness' considers brain frequencies and emotions as energy states of the brain. This way some mental diseases have distorted or faulty brain activity, which can be modulated and improved by brain stimulation. For example enhanced brain frequencies play important role in focused activities, and during physical or emotional pain. In contrast, decreasing frequencies correspond to joy, and creative states. However, in the brain's complex operation the relative change of the frequencies and their rhythm is important, not their absolute value. Changing the energy balance of the mind through manipulating brain frequencies has a powerful physiological influence, making it an efficient modulator of thinking, emotional states and behavior. Long term stimulation can modify the strength, or even induce the formation of new synaptic paths, leading to learning and some possible long term operational consequences. However the effect on the mental energy balance, therefore emotional, intellectual behavior need to be followed by behavioral modifications to maintain the effects. In addition, a better understanding of the mechanism and long-term effectiveness, side-effects of brain stimulation is essential. For this reason, it would be highly irresponsible to practice self-help brain stimulation at home just yet. 

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