Acoustic startle reactions, activity, and background noise intensity, before and after lesions of medial cortex in the rat

Ison, James R.; Silverstein, Laura

doi:10.3758/bf03326721

Cited by 10 publications

(7 citation statements)

References 15 publications

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“…The performance ofthe acoustic startle group was typical of the results of comparable experiments reported in the literature, showing an inverted-U-shaped relationship between response amplitudes and the level of broadspectrum background noise. The ascending portion ofthe curve was not as evident as is shown in some prior reports, but this might be expected because here the lowest noise value was 60 dB, whereas in other research, noise levels as low as 30 dB have been used (e.g., Ison & Silverstein, 1978). The empirical goal ofExperiment 1 was to determine whether this prototypic biphasic curve was unique to the case of reflex elicitation by an acoustic stimulus, or whether it also could be obtained with stimuli in another modality.…”

Section: Resultsmentioning

confidence: 58%

Enhancement and depression of tactile and acoustic startle reflexes with variation in background noise level

Ison

Russo

1990

Psychobiology

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The amplitude ofthe acoustic startle reflex in the rat is related to the level ofbroadband background noise by an inverted-U-shaped function. We tested the hypotheses that (1) the initial increment, (2) the subsequent decrement, or (3) the entire function results from a nonspecific noise effect on reflex expression, as would be indicated by a common effect across reflexes elicited by acoustic and nonacoustic stimuli. Responses to electrotactile, airpuff, and acoustic startle stimuli were measured, each in aseparate group of rats, in noise levels varying from 60 to 100 dB. A biphasic effect of noise on the acoustic startle reflex was observed, with a modest increase from 60 to 70 or 80 dB, and a decline thereafter. In contrast, electrotactile startle provided a monotonie increase in amplitude to a maximum at 90 or 100 dB, whereas airpuff startle showed a progressive decline in amplitude, with an increase in background level beyond the optimal value at 60 to 70 dB. The latter effects demonstrated an unexpected division between facilitation versus reflex depression within the tactile modality, but subsequent data demonstrated that the effective component of the airpuff was acoustic, rather than tactile, in nature. The overall empirical conclusion is that facilitation by noise is nonspecific, whereas reflex depression that appears at noise levels beyond 70 to 80 dB is specific to acoustic stimuli. These findings suggest that reflex facilitation results from motor excitation and that reflex depression results from a partial masking of the eliciting stimulus.

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Section: Resultsmentioning

confidence: 58%

Enhancement and depression of tactile and acoustic startle reflexes with variation in background noise level

Ison

Russo

1990

Psychobiology

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“…For example, Putnam (1976) reported a progressive increment in probe blink reflex amplitude (elicited either acoustically or tactically) for human subjects as background noise increased in intensity—except at the highest level tested (e.g., 90 dB for the acoustic probe). These data were replicated in the rat by Ison and Silverstein (1978), who also found progressive reflex augmentation with increasing background noise until a level of 90 dB was reached.…”

Section: Discussionmentioning

confidence: 67%

Emotion, novelty, and the startle reflex: Habituation in humans.

Bradley¹,

Lang²,

Cuthbert³

1993

Behavioral Neuroscience

340

249

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Previous research with both animal and human subjects has shown that startle reflex magnitude is potentiated in an aversive stimulus context, relative to responses elicited in a neutral or appetitive context. In the present experiment, the same pleasant, unpleasant, and neutral picture stimuli were repeatedly presented to human subjects. Startle reflex habituation was assessed in each stimulus context and was compared with the habituation patterns of heart rate, electrodermal, and facial corrugator muscle responses. All systems showed initial differentiation among affective picture contents and general habituation over trials. The startle reflex alone, however, continued to differentiate among pleasant, neutral, and unpleasant pictures throughout the presentation series. These results suggest that (a) the startle probe reflex is relatively uninfluenced by stimulus novelty, (b) the startle modulatory circuit (identified with amygdala-reticular connections in animals) varies systematically with affective valence, and (c) the modulatory influence is less subject to habituation than is the obligatory startle pathway or responses in other somatic and autonomic systems.

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“…The motor units are activated before the eliciting stimulus is presented. We have reported that variation in background noise level does produce a systematic and correlated variation in general activity with levels of noise characteristic of reflex experiments (Ison & Silverstein, 1978). This observation suggests that overarousal does occur, if we assume that the neural elements responsible for general activity in response to background noise are those involved in the acoustic startle reflex.…”

Section: Discussionmentioning

confidence: 81%

“…The interaction is not restricted to variation produced by differences in signal strength. Habituation (Cory & Ison, 1979;Davis, 1974) and cortical ablation (Ison & Silverstein, 1978), as well as variation in the intensity of the eliciting stimulus (Davis, 1974), all affect reflex vigor and all similarly influence the facilitatory effect of background noise level. The sensory masking hypothesis is seemingly appropriate for the effects of variation in the intensity of the eliciting stimulus (at least when stimulus and mask are of similar intensities), but there is little reason to suppose that a similar process underlies the effects of habituation and cortical ablation.…”

Section: Discussionmentioning

confidence: 99%

Reflex inhibition and reflex strength

Ison

Reiter

1980

Psychobiology

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In Experiment 1. the amplitude of the acoustic startle reflex in rats was shown to increase linearly with increases in the intensity of the eliciting stimulus (Se). A preliminary stimulus (Si), a light flash, inhibited the reflex. The amplitude of the reflex was reduced by an equal amount regardless of Se intensity. In Experiment 2. the amplitude of the same reflex was shown to have a biphasic relation to the intensity of a white noise background (Sn) and reflex amplitudes peaked at the intermediate noise levels. Although the vigor of the reflex elicited in the presence of the most intense noise approximated that elicited by the weak Se in Experiment 1, in this condition the reflex was unaffected by the occurrence of the otherwise inhibitory light flash. It has been previously hypothesized that the decrement in reflex vigor obtained at high Sn results because sensory masking of Se by Sn reduces the effective intensity of Se. The different effect of Si in these two conditions suggests that this hypothesis is incorrect. A hypothetical neural model was devised to account for the difference between the two reflexes in their susceptibility to a preliminary stimulus. and the model was extended to other effects of stimulus strength and background noise on reflexive behavior.The strength of the acoustic startle reflex in the rat is substantially affected by the intensity of the eliciting stimulus (Se), by the level of the background noise present at the time of reflex elicitation (Sn), and by the occurrence of irrelevant stimuli just prior to that time (Si simple assumptions produce an invariant decrement in reflex amplitudes regardless of reflex strength, unless the amount of inhibition produced by Si is large relative to the strength of the reflex (i.e., a "floor effect" may deform the relationship). The present experiment assessed the generality of this invariance by examining the effectiveness of Si on the variously sized reflexes that occur in different noise backgrounds. The descending upper limb of the biphasic curve relating response amplitude to Sn intensity has been ascribed to a process akin to that responsible for the relationship between Se intensity and reflex strength. It has been proposed that, at noise levels higher than the optimum, the background noise increasingly masks Se and reduces its effective intensity (Davis, 1974; Ison & Hammond, 1971): an increment in Sn is formally identified with a decrement in Se. If this hypothesis is correct, then, in this range of relatively high noise levels past the optimal value, the preliminary stimulus should subtract a constant amount from reflex amplitude. METHOD SubjectsThe subjects were albino male rats of the Holtzman strain weighing 350-500 g at the time of testing. They were maintained on an ad-lib food and water schedule. ApparatusThe rats were restrained during testing in a small perforated Plexiglas stabilimeter cage (8 x 6 x 9 cm high) that was mounted on compression springs in an aluminum frame. An accelerator mounted on the back of the stabilimeter de...

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Acoustic startle reactions, activity, and background noise intensity, before and after lesions of medial cortex in the rat

Cited by 10 publications

References 15 publications

Enhancement and depression of tactile and acoustic startle reflexes with variation in background noise level

Enhancement and depression of tactile and acoustic startle reflexes with variation in background noise level

Emotion, novelty, and the startle reflex: Habituation in humans.

Reflex inhibition and reflex strength

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