Prestimulus EEG alpha activity reflects temporal expectancy

Byoung Kyong Min, Jin Young Park, Eun Joo Kim, Joong Il Kim, Jae Jin Kim, Hae Jeong Park

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Since prestimulus EEG alpha activity has recently been considered to convey prestimulus top-down processing, we investigated whether prestimulus alpha activity reflects temporal expectancy of upcoming stimulation even under the non-classical contingent negative variation (CNV) paradigm. EEG was recorded from 16 subjects performing a color and a shape discrimination task manipulated with constant and variable inter-stimulus interval (ISI) conditions. The power of oscillatory activity was investigated by convolving the EEG signals with Morlet wavelets. The constant ISI condition yielded significantly shorter reaction times than the variable ISI condition, indicating more efficient preparation for upcoming stimuli during the constant ISI. We found significantly higher prestimulus alpha activity in the constant ISI condition than in the variable ISI condition, but no significant CNV even in the constant ISI condition. Such a reflection of temporal expectancy in the prestimulus alpha activity corroborates that the prestimulus top-down mental state for preparing upcoming task-performance is considerably reflected in the prestimulus ongoing alpha activity.

Original languageEnglish
Pages (from-to)270-274
Number of pages5
JournalNeuroscience Letters
Issue number3
Publication statusPublished - 2008 Jun 27
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MOST) (No. R0120050001052202006).


  • CNV
  • Expectancy
  • Prestimulus alpha activity
  • Top-down processing

ASJC Scopus subject areas

  • Neuroscience(all)


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