Fear conditioning, pre-pulse inhibition and drug modulation of a short latency startle response measured electromyographically from neck muscles in the rat.
The present study evaluated if startle measured electromyographically in the neck muscles (having a 5 msec latency) would exhibit behavioral and pharmacological plasticity known to alter startle measured in a stabilimeter device. A total of 15 rats were implanted with bilateral EMG electrodes in the dorsal neck muscles and subsequently exposed to a variety of manipulations known to affect the whole-body startle response. The peak-to-peak EMG response that occurred within 10 msec of startle stimulus onset displayed pre-pulse inhibition, enhancement by prior fear conditioning, inhibition by clonidine, and enhancement by strychnine. The data are discussed in terms of modulation of neural transmission along a primary startle-mediating pathway.
D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D004576:Electromyography; D005239:Fear / Q000502:physiology*; D008297:Male; D009132:Muscles / Q000502:physiology*; D009334:Neck Muscles / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000502:physiology; D013216:Reflex, Startle / Q000187:drug effects / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology*
D013331:Strychnine; D003000:Clonidine