TRANSITORY AND SHORT-DURATION CHANGES OF SLEEP ORGANIZATION PROVOKED BY AMYGDALOID KINDLING IN THE CAT - A DAILY 23-HOUR SLEEP RECORDING STUDY

The effect of amygdaloid kindling on sleep organization was tested in chronically implanted cats on a 12:12 light-dark cycle. Electrical kin dling stimuli were delivered to the amygdala every 2 h during the ligh t period. Total sleep time and percentage, mean duration, and mean num ber, as well as the hourly accumulation of waking (W) and sleep (slow wave sleep I and II, and paradoxical sleep) episodes were assessed fro m daily 23-h sleep recordings, consisting of baseline control recordin gs, control recordings where cats were briefly alerted at 2-h interval s to mimic the kindling trials manipulation, and recordings on each ki ndling day. The kindling process was completed within six days achievi ng three to five consecutive fully kindled seizures. Analysis of total recording time showed that the kindling process enhanced W stage and diminished total sleep time only on the second kindling day. Analysis of light and dark periods demonstrated compensatory W and sleep change s during the dark periods. Hourly sleep stage time accumulation was sl owed during kindling trials, but compensated while stimuli were suspen ded. All of these changes returned to baseline values at the end of ki ndling. No significant differences between changes induced by kindling and those produced by alerting trials were found. We conclude that sl eep alterations can not be exclusively attributed to kindling developm ent, and that sleep is able to become adapted to the focal and general ized seizures effect.