The stability of error-related brain activity with increasing trials

Psychophysiology. 2009 Sep;46(5):957-61. doi: 10.1111/j.1469-8986.2009.00848.x. Epub 2009 Jun 23.


The error-related negativity (ERN) and error positivity (Pe) are increasingly being examined as neural correlates of response monitoring. The minimum number of error trials included in grand averages varies across studies; indeed, there has not been a systematic investigation on the number of trials required to obtain a stable ERN and Pe. In the current study, the ERN and Pe were quantified as two random trials were added to participants' (N=53) ERP averages. Adding trials increased the correlation with the grand average ERN and Pe; however, high correlations (rs>.80) were obtained with only 6 trials. Internal reliability of the ERN and Pe reached moderate levels after 6 and 2 trials and the signal-to-noise ratio of the ERN and Pe did not change after 8 and 4 trials, respectively. Combined, these data suggest that the ERN and Pe can be quantified using a minimum of between 6 and 8 error trials.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Brain / physiology*
  • Electroencephalography
  • Evoked Potentials / physiology*
  • Female
  • Humans
  • Individuality
  • Male
  • Psychomotor Performance / physiology*
  • Self Concept
  • Young Adult