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Medical Brain Waves (frequency)

  1. Dec 22, 2008 #1
    how can brain waves have a frequency. frequency is the amount of cycles per second. I'm guessing that this is the time it takes for brain waves to "refresh" I don't understand what it exactly means. The reason I'm asking is that when awake brainwaves are at a higher frequency than when sleeping.
     
  2. jcsd
  3. Dec 23, 2008 #2

    jim mcnamara

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    I think this link will help you understand an eeg and brainwaves:
    http://www.crossroadsinstitute.org/eeg.html

    There are several types of brainwave patterns with distinctive fequencies that have names like 'delta'... and so on.
     
  4. Dec 23, 2008 #3
    EEG signals aren't the only place where we talk about power spectra. You can perform similar analyses on other (analog) neural signals such as local field potentials (LFP) or single unit activity binned spike count. Recently there's been a lot of interest in analyzing data this way. A lot of this stems from work done in Nikos Logothetis' lab showing LFP power in certain frequency bands correlating better with the fMRI BOLD response than the single unit activity does...

    There's also been various hypotheses (some that have been around for a while) postulating that attentional effects are best characterized in the frequency domain (buzzword: neural synchrony). Also there's been a lot of interest in LFP oscillations in schizophrenia research...

    Analysis of neural data in the frequency domain seems to be an exploding field.
     
  5. Jan 5, 2009 #4
    I'm wondering about the time the brain needs to understand a sound.i know sounds are been transformed into electrical signals which brain understands.But what time is needed for the whole process(from the creation of the sound till we finally hear it)?And what time brain needs to decode 2 same sounds in row?
     
  6. Jan 10, 2009 #5
    I googled and found a paper about LFP research on monkeys.

    http://www.jneurosci.org/cgi/content/full/28/22/5696

    To perform the research they implanted depth electrodes, and had to dope the monkeys up considerably. Is there a non-invasive method of collecting this data as well?

    As far as I know they only do depth electrodes on people who are being prepared for brain surgery, since a much more invasive procedure is going to follow anyway. I'm not aware it's ever done for research only. Heard anything about this?
     
  7. Jan 11, 2009 #6
    Zoobyshoe is correct that we do only record directly from the brains of (consenting) brain surgery patients. So far this only happens during an intervening step in the middle of a long procedure that certain intractable epilepsy patients must go through...

    The fact is that the only human electrophysiology data we have (or will ever have) is from epilepsy patients. This is a confounding variable that cannot easily be overcome.
     
  8. Jan 13, 2009 #7
    Thanks. I am concerned about your mention of interest in LFP with respect to schizophrenia research, which raises the question of how they could collect any data non-invasively.
     
  9. Jan 13, 2009 #8
    They can't.

    This is why animal models are necessary.
     
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