Search This Blog

Brain Waves


Electrical recordings from the surface of the brain or even from the outer surface of the head demonstrate that there is continuous electrical activity in the brain.
Both the intensity and the patterns of this electrical activity are determined by the level of excitation of different parts of the brain resulting from sleep, wakefulness, or brain diseases such as epilepsy or even psychoses. The undulations in the recorded electrical potentials, are called brain waves, and the entire record is called an EEG (electroencephalogram).

The intensities of brain waves recorded from the surface of the scalp range from 0 to 200 microvolts, and their frequencies range from once every few seconds to 50 or more per second. The character of the waves is dependent on the degree of activity in respective parts of the cerebral cortex, and the waves change markedly between the states of wakefulness and sleep and coma. Much of the time, the brain waves are irregular, and no specific pattern can be discerned in the EEG. At other times, distinct patterns do appear, some of which are characteristic of specific abnormalities of the brain such as epilepsy,

In normal healthy people, most waves in the EEG can be classified as alpha, beta, theta, and delta waves, which are

Alpha waves are rhythmical waves that occur at frequencies between 8 and 13 cycles per second and are found in the EEGs of almost all normal adult people when they are awake and in a quiet, resting state of cerebration.These waves occur most intensely in the occipital
region but can also be recorded from the parietal and frontal regions of the scalp. Their voltage usually is about 50 microvolts. During deep sleep, the alpha waves disappear. When the awake person’s attention is directed to some specific type of mental activity, the alpha waves
are replaced by asynchronous, higher-frequency but lower-voltage beta waves.visual sensations


Beta waves occur at frequencies greater than 14 cycles per second and as high as 80 cycles per second.They are recorded mainly from the parietal and frontal regions during specific activation of these parts of the brain.

Theta waves have frequencies between 4 and 7 cycles per second. They occur normally in the parietal and temporal regions in children, but they also occur during emotional stress in some adults, particularly during disappointment and frustration. Theta waves also occur in
many brain disorders, often in degenerative brain states.

Delta waves include all the waves of the EEG with frequencies less than 3.5 cycles per second, and they often have voltages two to four times greater than most other types of brain waves. They occur in very deep sleep, in infancy, and in serious organic brain disease. They also occur in the cortex of animals that have had subcortical transections separating the cerebral cortex
from the thalamus. Therefore, delta waves can occur strictly in the cortex independent of activities in lower regions of the brain.

9 comments:

  1. Straight out of Guyton and Hall 11th Ed. Word-for word.

    ReplyDelete
  2. Wisdom Overseasis authorized India's Exclusive Partner of Southwestern University PHINMA, the Philippines established its strong trust in the minds of all the Indian medical aspirants and their parents. Under the excellent leadership of the founder Director Mr. Thummala Ravikanth, Wisdom meritoriously won the hearts of thousands of future doctors and was praised as the “Top Medical Career Growth Specialists" among Overseas Medical Education Consultants in India.

    Southwestern University PHINMAglobally recognized university in Cebu City, the Philippines facilitating educational service from 1946. With the sole aim of serving the world by providing an accessible, affordable, and high-quality education to all the local and foreign students. SWU PHINMA is undergoing continuous changes and shaping itself as the best leader with major improvements in academics, technology, and infrastructure also in improving the quality of student life.

    ReplyDelete
  3. this is pretty common with the brain waves and thus it is very important to include in the assignment help providers which is too common and among the people who needed the immediate and comfort support of existing policies.

    ReplyDelete
  4. Study MBBS abroad is a lifetime Achievement for a Medical Student. Studying in a place where students and faculty from different backgrounds help students to build their overall personality. They learn new languages, exchange their ideas and gain more confidence. These soft skills are essential to make for sophisticated professionals like doctors. Students who have exposure to the outer world have a broader perspective towards the world, and they learn to be responsible and independent. A few years spent abroad helps them emerge as a confident individual. Foreign medical colleges have a world-class infrastructure with all modern facilities. It has the latest medical equipment, medical laboratories and enough resources for research and experiments. The infrastructure of these medical institutes is better than that of most medical colleges in India.

    ReplyDelete
  5. Great post, very informative. I wonder why the other experts of this sector do not realize this. You should continue your writing. I am sure, you have a huge readers’ base already!
    토토사이트
    메이저사이트

    ReplyDelete
  6. These are in fact wonderful ideas in concerning blogging.
    You have touched some good factors here. Any way keep up writing.
    온라인경마
    온라인경마

    ReplyDelete
  7. My brother suggested I might like this website.
    He was totally right. This post actually made my day.
    You can not imagine simply how much time I had spent for this info!
    Thanks!
    바카라사이트
    바카라

    ReplyDelete
  8. Hello! I just would like to offer you a huge thumbs up for
    the excellent info you have right here on this post. I am coming back to
    your website for more soon.
    사설토토
    토토

    ReplyDelete