frontal locations; large delta amplitude associated with sleep (Davis et al)
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Theta (4-8) location/features
widespread locations; linked to maximal altertness and mental activity (Mizurhara et al), found during light drowsiness (Tekahashi et al), liked to alter state of consciousness, e.g. as a meditative state
2 of 20
Alpha (8-13Hz) location/features
posterior region e.g. across parietal and occipital cortices; increased amplitudes are attenuated during visual/mental effort. an eyes-closed condition causes increase in amplitude vs. eyes open condition. increased alpha-state of relaxation
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Beta (13-30 Hz) location/features
most evidently present in frontal locations; beta is attenuated bu motor movement; associated with walking states, alterness and anxious thinking (Gola et al, Kropotov)
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Gamma (30-100+Hz)
found across somato sensory cortex, linked to cognition, this rhythm thought to represent connecting neutrons into a network to aid cognitive and motor function (Niedermeyer)
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Pros of EEG (direct method)
it is very fast, effectively recording electrical activity as it occurs within the brain-it has excellent temporal resolution. very cheap by comparison with some of the other methods and from a practical perspective isn't not too unpleasant+ portable
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Cons of EEG 1
necessary to solve, inverse problem, to locate the source of the electrical signals-number of constraints that mean this problem can be solved reasonably well but it’s not an exact science.
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Cons of EEG 2
poor spatial resolution. This means that it is not possible to locate smaller spatial regions of change
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Pros of MEG (direct method)
good temporal resolution, quite good spatial resolution,
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Pros of MEG 2
quite good spatial unlike electrical signals which can only seep through the sutures in the skull, the magnetic signals can pass directly through. thus path isn’t distorted and possible to tell with reasonable accuracy where the signal derives from
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Cons of MEG 1
spatial resolution is only good in cortical areas, below these areas the signal diminishes
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Cons of MEG 2
extremely expensive,
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Cons of MEG 3
issue with signals derived at 90°from the sensors- electrical+magnetic fields set up perpendicular to one another (90°). So electrical signal occurs at 90°to the brain surface the respective magnetic field will be parallel to the surface+not detected
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Cons of fMRI 1 (indirect method)
signal relies on metabolic changes accompanying changes in the neural activity so is very slow
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Cons of fMRI 2
expensive technique + being in the scanners can be quite unpleasant because they are noisy and claustrophobic
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Pros of fMRI
excellent spatial resolution throughout the brain.
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Cons of PET (indirect method)
low temporal resolution, requires the participant to have a radioactive substance which raises some safety concerns
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Pros/cons of PET
Its spatial resolution is consistent throughout the brain so better than MEG, but it is not as good as fMRI because the gamma ray is emitted from the point of annihilation (destruction) rather than the point of the radioactive material.
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Pros of DTI
It is relatively fast and is only technique capable of mapping out tracts in this way
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cons of DTI
expensive, noisy and claustrophobic because it is carried out in the same scanner as fMRI.
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Other cards in this set
Card 2
Front
Theta (4-8) location/features
Back
widespread locations; linked to maximal altertness and mental activity (Mizurhara et al), found during light drowsiness (Tekahashi et al), liked to alter state of consciousness, e.g. as a meditative state
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