noun (n)

• (neurophysiology) rapid fluctuations of voltage between parts of the cerebral cortex that are detectable with an electroencephalograph(noun.phenomenon)

  Synonym:
  brain wave, cortical potential
  

  source: wordnet30
• the clear (and often sudden) understanding of a complex situation(noun.cognition)

  Synonym:
  brainstorm, insight
  

  source: wordnet30