Lack of cortical contrast gain control in human photosensitive epilepsy

Vittorio Porciatti, Paolo Bonanni, Adriana Fiorentini, Renzo Guerrini

Research output: Contribution to journalArticlepeer-review


Television and video games may be powerful triggers for visually induced epileptic seizures. To better understand the triggering elements of visual stimuli and cortical mechanisms of hyperexcitability, we examined eleven patients with idiopathic photosensitive epilepsy by recording visually evoked potentials (VEPs) in response to temporally modulated patterns of different contrast. For stimuli of low-medium, but not high, temporal frequency, the contrast dependence of VEP amplitude and latency is remarkably abnormal for luminance contrast (black-white), but not so for chromatic contrast (equiluminant red-green) stimuli. We conclude that cortical mechanisms of contrast gain control for pattern stimuli of relatively low temporal frequency and high luminance contrast are lacking or severely impaired in photosensitive subjects.

Original languageEnglish
Pages (from-to)259-263
Number of pages5
JournalNature Neuroscience
Issue number3
Publication statusPublished - Mar 2000

ASJC Scopus subject areas

  • Neuroscience(all)


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