Characteristics and origin of frontal paroxysmal responses induced by light stimulation in the Papio papio under allylglycine.
In the Papio papio, curarized and rendered photosensitive by injection of a subconvulsant dose of DL-allylglycine, single flashes induce frontal paroxysmal evoked responses on condition that they be preceded by trains of intermittent light stimulation (ILS). The characteristics of these responses have been compared to those of non-paroxysmal responses induced in the same cortical area by isolated flashes (not preceded by trains of ILS). The paroxysmal responses resemble spikes and waves and consist of one or two positive spikes followed by a slow negative wave. The intracortical distribution of these responses has been studied in the motor cortex. The non-paroxysmal responses are probably not generated at this level. On the other hand, observations made during paroxysmal responses show the existence of two cortical responses; this demonstration follows from the existence of an inversion in some response components, linked to a negativity and a local cellular activation. A generator, situated in the pyramidal cell layer, is active during the positive surface spikes; the other generator, situated in the more superficial cortical layers, is active at the beginning of the slow negative surface wave. The cortical and subcortical afferents likely to bring these generators into play are discussed.
D000344:Afferent Pathways / Q000502:physiology; D000501:Allylglycine / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects*; D005625:Frontal Lobe / Q000502:physiology*; D005998:Glycine / Q000031:analogs & derivatives*; D009044:Motor Cortex / Q000502:physiology; D010215:Papio; D010775:Photic Stimulation
D000501:Allylglycine; D005998:Glycine