A primary acoustic startle circuit: lesion and stimulation studies

摘要: The latency of the acoustic startle reflex in rat is 8 msec, measured from tone onset to beginning electromyographic response hindleg. This extremely short indicates that only a few synapses could be involved some primary circuit. Acoustic being used as model system for studying habituation, sensitization, prepulse inhibition, classical conditioning, fear or anxiety, and drug effects on behavior. present study attempted delineate circuit, since this would provide critical information further all these areas. Bilateral lesions ventral cochlear nucleus, which receives auditory input, abolish startle. Electrical, single pulse stimulation nucleus elicits startle-like responses with about 7 msec. dorsal nuclei lateral lemniscus, receive direct input nuclei, Electrical 6 regions reticularis pontis caudalis, contain cell bodies give rise reticulospinal tract, points 5 Reaction product horseradish peroxidase iontophoresed into area found lemniscus. In contrast, vestibular oralis, gigantocellularis, caudalis fail Also, “startle” cannot elicited electrically data suggest circuit consists nerve, spinal interneuron, lower motor neuron, muscles. Hence, five synapses, plus neuromuscular junction, are probably involved.