Brief summary of classical components of ERP 事件相关成分（ERP）经典成分小结

Source: Wikipedia: Event-related potential

C1 and P1 / P100

• C1
  First negative-going component (when using a mastoid reference point) or a positive going component.
  Latency: (peak normally observed in the) from 50–100ms (post-stimulus onset).
  Polarity: negative polarity if the stimuli presented in the upper half of the visual field (when using a mastoid reference); positive polarity if the stimuli presented in the lower half of the visual field.
  Location: fairly broad distributed with the greatest polarity typically along the occipitoparietal sites; primary visual cortex (striate cortex).
  Indication: typically found to be invariable to different levels of attention.

• P1
  First positive-going component (when also using a mastoid reference point).
  Latency: around 70–90 ms with a peak around 80-130 ms.
  Location: amplitude maximum is over the lateral occipital scalp; other visual areas (Extrastriate cortex).
  Indication: modulated by attention.

N100

Latency: peaks in adults between 80 and 120 ms.
Polarity: negative polarity if the stimuli presented in the upper half of the visual field (when using a mastoid reference); positive polarity if the stimuli presented in the lower half of the visual field.
Location: mostly over the frontocentral region.
Indication: elicited by any unpredictable stimulus in the absence of task demands. It is often referred to with the following P200 evoked potential as the "N100-P200" or "N1-P2" complex. While most research focuses on auditory stimuli, the N100 also occurs for visual (visual N1, see below), olfactory, heat, pain, balance, respiration blocking, and somatosensory stimuli.

• Visual N1
  Latency: 150 to 200 ms.
  Location: widely distributed over the entire scalp, it peaks earlier over frontal than posterior regions of the scalp.
  Indication: elicited by visual stimuli; its amplitude is influenced by selective attention.
  Shaped by: color & motion of visual information, objects & location, emotional stimuli.

N170

Latency: 130-200 ms.
Location: maximal over occipito-temporal electrode sites. Right-hemisphere lateralization.
Indication: reflects the neural processing of faces. Has been linked with the structural encoding of faces.

P200 / P2

Latency: varying between about 150 and 275 ms (peaks at about 200 milliseconds).
Location: around the centrofrontal and the parietooccipital areas (maximal around the vertex (frontal region)).
Indication: evoked as part of the normal response to visual stimuli, but the amplitude and latency may be affected by exogenous factors, such as repeated visual stimuli. This component has been linked with higher-order perceptual and attentional processes, including feature analysis of geometric figures and visually presented words. May reflect general neural processes that occur when a visual (or other sensory) input is compared with an internal representation or expectation in memory or language context.

N200 / N2

Latency: peaks 200-350ms.

P300

• P3a
  Latency: a peak in the range of 250–280 ms.
  Location: maximal over frontal/central sites on the scalp, such as FCz/Cz in the international 10-20 system.
  Indication: associated with brain activity related to the engagement of attention (especially the orienting, involuntary shifts to changes in the environment), and the processing of novelty.

• P3b
  Latency: peaks at around 300 ms, and the peak will vary in latency from 250–500 ms or more depending upon the task.
  Location: highest on the scalp over parietal brain areas.
  Indication: plays a key role in cognitive psychology research on information processing. Generally speaking, improbable events will elicit a P3b, and the less probable the event, the larger the P3b. The P3b can also be used to measure how demanding a task is on cognitive workload.