title: Reflex seizures, traits, and epilepsies: from physiology to pathology.
abstract: Epileptic seizures are generally unpredictable and arise spontaneously. Patients often report non-specific triggers such as stress or sleep deprivation, but only rarely do seizures occur as a reflex event, in which they are objectively and consistently modulated, precipitated, or inhibited by external sensory stimuli or specific cognitive processes. The seizures triggered by such stimuli and processes in susceptible individuals can have different latencies. Once seizure-suppressing mechanisms fail and a critical mass (the so-called tipping point) of cortical activation is reached, reflex seizures stereotypically manifest with common motor features independent of the physiological network involved. The complexity of stimuli increases from simple sensory to complex cognitive-emotional with increasing age of onset. The topography of physiological networks involved follows the posterior-to-anterior trajectory of brain development, reflecting age-related changes in brain excitability. Reflex seizures and traits probably represent the extremes of a continuum, and understanding of their underlying mechanisms might help to elucidate the transition of normal physiological function to paroxysmal epileptic activity.
authors.affiliation: Department of Clinical and Experimental Epilepsy, University College London (UCL) Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, UK. Electronic address: m.koepp@ucl.ac.uk.
authors.forename: Matthias J
authors.initials: MJ
authors.lastname: Koepp
authors.affiliation: Department of Clinical and Experimental Epilepsy, University College London (UCL) Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, UK.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Caciagli
authors.affiliation: Department of Clinical Neurophysiology, Great Ormond Street Hospital, London, UK; Clinical Neuroscience, UCL Institute of Child Health, London, UK.
authors.forename: Ronit M
authors.initials: RM
authors.lastname: Pressler
authors.affiliation: Department of Epileptology, University Hospital of Bonn, Bonn, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Lehnertz
authors.affiliation: Department of Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark; Department of Clinical Neurophysiology, Aarhus University, Aarhus, Denmark.
authors.forename: Sándor
authors.initials: S
authors.lastname: Beniczky
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology* / Q000502:physiology*; D004569:Electroencephalography / Q000639:trends; D020195:Epilepsy, Reflex / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D012018:Reflex / Q000502:physiology; D012640:Seizures / Q000175:diagnosis* / Q000503:physiopathology