Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What exactly is brainwave?

  1. Dec 28, 2004 #1
    According to some researcher, brain wave can be divided to thita,gama,beta and alpha wave. But what forms the wave? What affects it? Or it doesn't exist at all?
  2. jcsd
  3. Dec 28, 2004 #2
    Brain waves or electrical activity in the brain is measured and displayed by lines drawn on paper or on a computer screen. Brain waves are used to diagnose nervous-system diseases and to learn more about how the brain works, especially with regard to wakefulness, sleep, and dreaming. Brain waves do not indicate what a person is thinking.

    That's all I know.
  4. Dec 28, 2004 #3


    User Avatar
    Staff Emeritus
    Gold Member

    I think the term "brain wave" is a little misleading. The wave is just the output of an oscilloscope and does vary according to the state a person's brain is in, but the output is the result of so many individual waves being added up that the "brain wave" tells us relatively little. The individual waves that make up the "brain waves" are action potentials formed in the axons of individual neurons. They are caused by ion channels opening in the axon membranes, which are in turn caused by other ion channels opening and changing the membrane voltage in the vicinity of the channels. The fluctuation in membrane voltage is what the oscilloscope measures. Even this, though, is due to the addition of many smaller forces that are at work. There is a certain threshold voltage that must be attained for an action potential to be generated and a signal to be sent and this threshold voltage can be attained in a number of ways, each resulting from a unique combination of signal transduction cascades within the neuron that are caused by neurotransmitters bonding to the active sites in the dendrites. Put simply, each individual neuron makes a computation based on the inputs it receives from all of its input sites (dendrites). If the input (however it may be added up) equals a certain value, then a signal will be sent down that neuron's axon that in turn will become the input for another neuron, which will perform its own computation. The signal sent down the axon is an electrical signal, different from the electrical signals we send in man-made circuits because the current is carried by ions rather than bare electrons. The current flow propagates a change in the local membrane voltage down the axon to its terminal. The currents from every neuron in the brain can be measured as a wave pattern on an oscilloscope. If every wave from each neuron is added together, we end up with the measured "brain wave."

    God, I stated that terribly. I probably just confused the heck out of anybody reading this. Let's hope I'm never a teacher.
  5. Dec 28, 2004 #4

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Last edited: Dec 29, 2004
  6. Dec 29, 2004 #5
    The electrical potential difference between two electrodes that are placed on the scalp of a person will change over time. A plot of this potential difference against time is somtimes called a brain wave. the shape of this wave is caused by the motion of charged particles (ions) in the neighbourhood of the electrodes, which is the electrical activity in the brain.

    In the picture on this site some "brain waves" are shown.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook