Pulse jitter retards kindling without affecting brain-stimulation reward.
Convulsions in rats bar-pressing for electrical stimulation of the brain can interfere with the behavioural evaluation of the properties of the reward substrate. If seizure activity involves the synchronous activation of populations of neurons, then the regular timing of pulses may be important in epileptogenesis produced by electrical stimulation. In the first experiment we found that behaviourally derived, charge-duration functions collected from three self-stimulating rats with lateral hypothalamic electrodes were not affected by introducing a controlled, 50% jitter to the interpulse interval of self-stimulation trains. In the second experiment, we kindled two groups of 6 rats with once-daily, 1.0 s bursts of either regularly timed or jittered pulses to the amygdala until full motor seizures developed. Although both groups eventually attained Class 5 convulsions, the time to first seizure was about two days longer with jittered pulses. Thus, while the circuitry that accumulates input from self-stimulation is not affected by the irregularity of asynchronous pulses, the jitter does seem to retard the development of seizures.
Rick
J T
JT
School of Psychology, University of Ottawa, Ont. Canada.
Fouriezos
G
G
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D005260:Female; D007696:Kindling, Neurologic; D008297:Male; D051381:Rats; D012055:Reinforcement Schedule; D012201:Reward; D012653:Self Stimulation