Novel method of monitoring electroencephalography at the site of microdialysis during chemically evoked seizures in a freely moving animal

This paper covers the design, development and operation of a novel piece of equipment, based around the CMA/12 guide probe (Carnegie Medicin, Sweden), which offers a low cost alternative for monitoring EEG at the site of microdialysis in a freely moving animal. This equipment is entirely based on commercially available parts, and thus call be easily replicated. Moreover, it is less intrusive than earlier models, offering advantages for experiments in which behavioural testing or chronic monitoring is required. We illustrate its use in a study of changes in electrical seizure activity, in both cortex and basal nuclei, evoked by the administration of the chemoconvulsant soman. The inference from the many experimental paradigms looking at the mechanisms of chemoconvulsants is that paroxysmal discharges are a better correlate of seizure activity than behavioural signs. The correlation of the EEG with extracellular neurotransmitter data, over a period of hours post-injection of chemoconvulsant, allows the determination of whether extracellular neurotransmitter changes are a cause or consequence of the evoked electrical activity. (C) 2000 Elsevier Science B.V. All rights reserved.