1. A Darren Parker Presentation
ERP Waveforms
A Darren Parker Presentation

2. Presentation of ERP Data
Single channel waveforms
Topographies (or Topos)
ERP data can be used to infer sources (source analysis, beyond this presentation)

3. A Typical Waveform

4. Waveform Properties X-Axis: Time Y-Axis: Voltage in microvolts (uV)
Channel Labels (Ours vs. standard 10-20)
Legend describing conditions
Component labels
Oriented positive up (sometimes negative up)
Zero point usually stimulus on-set, but may be response-locked.

5. All Channels

6. Scalp Topographies (Topos)
Red = Positive
Blue = Negative
Time Points

7. Advantages/Disadvantages
Waveforms
Topographies
Advantages
High temporal information.
Pretty.
Shows scalp voltage distribution.
Disadvantages
Specific to a single electrode (or area).
Each topo only shows one point in time.

8. Component Examples Response related potentials:
Error Related Negativity (ERN)
Lateralized Readiness Potential (LRP)
Contingent Negative Variation (CNV)
Early Attention related potentials:
P1, N1, P2, N2 and variations on these.
Later Cognitive related potentials:
P3, N400 (language)

9. ERN Response related potential.
Results from when an individual produces an error.
Location shown in diagram below, top of scalp at Cz.
Error
Correct

10. N170 Early stimulus related potential.
Response to facial stimuli that gets attenuated to repeated facial stimuli.
Location in diagram shown O9, at rear of head (occipital cortex) on the left side.

11. N400 Late stimulus related potential. Negative-up.
Sensitive to semantic incongruities in language.
Location not indicated in diagram, but from paper, Pz. Parietal cortex, central.
Kutas &Van Petten. (1988) “Event-related brain potential studies of language,” Advances in Psychophysiology. 3:

12. Questions?

13. Thank you for your attention.
Tips always welcome!

14. Electrode Map