Evoked potentials (EP) (a.k.a. Event related potentials, ERP)

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Evoked potentials (EP)(a.k.a. Event related
potentials, ERP)

• Raw signal is noisy so we reduce noise by
  repeating stimulus and averaging potentials
• A time domain analysis

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Time-locked presentations, repeated with EEG
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EPs to test sensory pathway integrity
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Letter Positive or negative deflectionNumber
milliseconds (or 100s ms)

• Examples
• P300 can occur between 300-800 ms
• N400 may occur prior to it.

task deviant stimuli
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Presentations and Responses

• Oddball

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Oddball paradigm

• We habituate to regular stimulation
• Any sound, image, pattern
• Oddball is the rare event
• A A A A C A A oddC
• C C C A C C C oddA

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• Positive deflections
• P300
• Negative deflections
• N100
• N400

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Atypical housing of language functions in autism
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ERP reveals age, diagnoses
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Kayser et al, in press
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ERD Event related desynchronization(frequencies
may tell us more about mental operations)
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CSA compressed spectral array
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Time domain (ERP)vs Frequency domain (ERD)
task deviant stimuli
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• Fewer trials needed than ERP

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Assess extent of info processing
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Diagnosing with ERD
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Effect of sleep deprivation
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Different neurophysiological operations reflected
in different rhythms (thalamocortical,
intracortical)
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Topography reveals specific de/activation patterns
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Leveraging functional laterality
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ERD PRS
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Lie detection
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Neuroimaging of Lie detection