Some observations on the mechanism of photic and photo-metrazol activation

Increasing the Yield of EEG

“…The photoparoxysmal response (PPR), initially termed a photoconvulsive response (Bickford et al, 1952), corresponds to the Type IV pattern described by Waltz et al (1992). This is an abnormal response to IPS characterized by generalized spike-and-slow wave and polyspike-and-slow wave complexes.…”

Generalized Paroxysmal Discharges Induced by Visual Stimuli and Eye Movements

“…On the other hand, it has been reported that clinical seizures and/or paroxysmal discharges are induced by closing the eyes (Robinson 1939;Green 1968;Lewis 1972;Tieber 1972;Takahashi 1973a) and eye deviation (Shanzer et al 1965;Takahashi 1974b; Takahashi and Tsukahara 1974b) as well. Takahashi and Tsukahara (1974b) elucidated that paroxysmal discharges are often induced by eye closing and eye deviation in patients with photosensitive epilepsy associated with photoconvulsive response (Bickford et al 1952). Based on such experiences, they proposed a new conception named ophthalmic epilepsy in which paroxysmal discharges and/or clinical seizures are induced by either visual stimuli or eye movements, or by both in epileptics.…”

Nonepileptogenic epileptiform electroencephalographic activity

“…Photic stimulation can trigger epileptic (most frequently absence) seizures, or subclinical abnormal paroxysms of diffuse spike-and-slow-wave complexes known as photoparoxysmal (previously called photoconvulsive) responses (61. The photomyogenic or photomyological (previously called photomyoclonic) response occurs less frequently, but it is considered to be nonepileptogenic 13,4,42,441. The photomyogenic response consists of muscle spikes of very short duration that are usually most prominent over the frontal regions of the head, related in frequency to the flashes, and not self-pefpetuating after cessation of the photic stimulus.…”