Modification of the rat's startle reaction by termination of antecedent acoustic signals.

Reflex inhibition and reflex elicitation by acoustic stimuli differing in abruptness of onset and peak intensity

“…The initial stimulus can be effective if it is at the detection threshold (Reiter & Ison, 1977);it may be auditory (Hoffman & Searle, 1965), visual (lson & Hammond, 1971, or tactile (Pinckney, 1976); and it may be an offset as well as an onset of a stimulus (Stitt, Hoffman, & Marsh, 1973). Thus it is clear that the occurrence of inhibition does not require that the initial stimulus actually elicit an acoustic startle reaction.…”

“…The OR (Sokolov, 1963) or "investigatory reflex" (Pavlov, 1927) is observed to occur to stimulus changes in any modality and may be assumed to be a weaker version of the startle, located at one pole of a reflex intensity dimension that includes startle, with defensive reactions at the other more vigorous pole. For these reasons, Stitt, Hoffman, and Marsh (1973) hypothesized that the initial stimulus may be effective because of its OR elicitation, inasmuch as, presumably, the OR component of the startle reflex to S2 would be occluded by a prior occurrence of S1. This occlusion hypothesis implies that inhibition is produced by reflex elicitation and thus it may be inferred that stimulus characteristics, including rise time, which are important for one phenomenon are equally important for the other.…”

The Effect of Signalling Upon Control of an Aversive Stimulus

“…According to this notion, S1 in Session P, where information about S2 presentation was the least, would evoke the largest OR, and Si in Session WTP, where the information was the most, the smallest. So if this is the case, the hypothesis by Stitt et al (1973) would predict that the inhibitory lead-stimulation effect would be much greater in Session P than in Session WTP. However, the results were completely inconsistent with this prediction.…”

“…As for skeletal muscle responses like the eyeblink reflex, numerous studies on this kind of phenomenon have been presented under the name of " lead-stimulation effects " (e.g., Graham, 1975). Although in fact various ideas have been presented there, we will concern ourselves only with Graham's (1975) and Stitt, Hoffman, and Marsh's (1973) notions in the present study. Each of these studies used the orienting response (OR) as a concept for explanation.…”

“…Each of these studies used the orienting response (OR) as a concept for explanation. Stitt et al (1973) presented the following notion to explain the inhibitory leadstimulation effect. They hypothesized that the OR which was evoked to Si interfered with the responses to S2 so that the inhibitory effect occurred because " the orienting and startle reflexes share essential neural components "(p.215).…”