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Biomedical subjects

D A Siddle

Publications and source records attributed to D A Siddle.

At least 55 records · Page 3Linked to original sources
PubMed1985

Effects of stimulus omission and stimulus change on dishabituation of the skin conductance response.

Three experiments examined the effects of stimulus omission and stimulus change on dishabituation of the skin conductance response. In all experiments, subjects received 17 tone-light or light-tone (S1-S2) pairings, and the primary manipulations were omission of and change in S2 on Trial 16. Responses to S1 and S2 on Trial 17 constituted the data of primary interest. Experiment 1 (N = 72) demonstrated that omission of an expected stimulus was more effective in producing dishabituation than was presentation of an unexpected but not experimentally novel stimulus. Experiment 2 (N = 60) indicated that both omission of an expected stimulus and presentation of an unexpected and experimentally novel stimulus produced dishabituation. Experiment 3 (N = 72) revealed that both the omission and the miscuing of 52 produced reliable dishabituation. The results are interpreted as indicating the importance of a comparison between current input and the stored representation of previous stimulation in the development of habituation.

Acoustic Stimulation↗
PubMed1984

Effects of stimulus change on the electrodermal orienting response.

This experiment (N = 48) examined recovery of the skin conductance response, following habituation training, to change in type of visual stimulus. Maher and Furedy (1979) have argued that the majority of such studies have not controlled for time, trial, or stimulus-specific effects. These variables were controlled in the present study by using no-change control groups and by counterbalancing training and test stimuli. Experimental groups received either shapes during training and a letter on the test trial (trial 41) or letters during draining and a shape on the test trial; control groups received either shapes or letters for 41 trials. Test trial response magnitude was larger in experimental than control groups, and the effect was independent of the nature of the test stimulus. In addition, responsiveness increased from the last block of training trials to the test trial for experimental groups, but not for control groups. These results demonstrate recovery of the skin conductance response to change per se.

Adolescent↗
PubMed1979

The orienting response and stimulus significance: some comments.

Bernstein (1969, 1979) has argued that Skolov's (1963) model is not sufficient to account for the data concerning orienting response (OR) elicitation to stimulus change. He has argued that following the registration of stimulus mismatch, an additional stage of stimulus evaluation occurs and that only stimuli which represent change and are judged as 'significant' elicit ORs. The present paper takes issue with this assertion. It is argued that the data on which the 'significance hypothesis' was originally based are not replicable and that the argument, as it was formulated originally, is tautological. It is also argued that individual differences in OR responsiveness are more parsimoniously explained in terms of individual response stereotypy and that differential responsiveness to different sorts of stimulus change poses problems for the significance hypothesis. Evidence is also reviewed which suggests that the relationship between stimulus change and stimulus significance is additive rather than multiplicative as suggested by Bernstein, i.e., stimulus change and stimulus significance are each sufficient for OR elicitation. Finally, it is concluded that the concept of 'significance', introduced operationally, may be of value in terms of examining the role of the OR in information processing.

Auditory Perception↗
PubMed1979

Effects of frontalis EMG feedback and reinforcement on frontalis EMG level.

This experiment employed a between-subjects design (N = 40) to investigate the effects of feedback and reinforcement on the lowering of frontalis electromyographic (EMG) activity. The feedback and reinforcement manipulations were combined in a 2 x 2 factorial design and each subject underwent one baseline and two training sessions on three consecutive days. The analogue feedback signal was a 55 dB tone whose pitch varied as a function of EMG activity, while the reinforcement consisted of points which were exchangeable for money. The training sessions were each divided into 10 2-min baseline periods and 10 2-min trial periods. The results indicated that although analogue feedback did not result in lowered EMG levels, trial period EMG level was significantly lower than baseline level under conditions of reinforcement. These results pose problems for Budzynski and Stoyva's (1972) views concerning the therapeutic usefulness of frontalis EMG feedback training.

Adolescent↗
PubMed1978

Cardiac and forearm plethysmographic responses to high intensity auditory stimulation.

This paper reports an investigation of forearm blood flow and cardiac responses to high intensity auditory stimulation. Blood was assessed in terms of forearm girth (FG) using a strain gauge, and since this technique had not been used previously, a preliminary study was conducted to validate the measure. In Experiment 1 (N = 24), subjects performed either a fast- or slow-paced mental arithmetic task. The data indicated that the strain gauge technique differentiated periods of rest from arithmetic stress and produced results comparable with those obtained using limb volume plethysmography. In Experiment 2 (N = 24), subjects received eight presentations of either a 60 dB or a 110 dB white noise stimulus at randomly ordered intervals of 35, 40, 45 and 50 sec; stimulus rise time was 50 msec and the duration 1 sec. Both groups displayed short-latency (i.e. within 10 beats poststimulus) cardiac accelerative responses which habituated over trials. In addition, the 110dB group displayed a long-latency (19.9 sec) accelerative response of approximately 25 beats per min and this was accompanied by an increase in FG. These responses occurred only following the first stimulus presentation, and analysis of the EKG T-wave amplitude suggested that the cardiac response was mediated sympathetically. These results are discussed in terms of conceptions of the startle and defence responses in man and the fight/flight reaction in animals.

Acoustic Stimulation↗
PubMed1978

Measurement of the evoked cardiac response: the problem of prestimulus variability.

This paper discusses the problem of prestimulus variability in cardiac activity and its implications for the measurement of evoked cardiac responses (ECRs). Two methods which have been proposed to reduce error arising from respiratory sinus arrhythmis (SA) were reviewed critically. The first approach attempts to control only for the error associated with the sampling of the prestimulus level. This is considered inappropriate since it does not take into account the continuation of SA into the poststimulus period. The second approach reviewed was time series analysis which provides an elegant statistical solution of the problem. Unfortunately, the application of time series analysis has not yet been evaluated for adult cardiac data. A third approach which utilizes an adjustment for SA by employing the actual prestimulus values of an SA cycle was proposed. The application of this technique in the case of a pseudostimulus demonstrated that correction for SA results in significantly smaller 'responses' with less variance than does a conventional procedure which does not take prestimulus variability into account.

Adult↗
PubMed1976

Dishabituation of the electrodermal orienting response following decay of sensitization.

This study tested one of the basic propositions of dual-process theory (Groves and Thompson, 1970) that 'dishabituation' results from an independent, superimposed process of excitation and not from disruption of the habituation process as proposed by Sokolov (1963). Skin conductance level (SCL) was employed as a measure of sensitization. On the basis of dual-process theory, it was hypothesized that if sensitization produced by the 'dishabituating' stimulus has decayed prior to re-presentation of the habituating stimulus, skin conductance response (SCR) amplitude to the habituating stimulus will not differ from that displayed by a control group which did not receive presentation of the 'dishabituating' stimulus. In experiment 1 (N = 10), subjects received 13 presentations of a 1000 Hz, 70 dB tone of 3 sec duration with interstimulus intervals of 40, 50 and 60 sec. Between trials 11 and 12, there was one presentation of a dishabituating (light) stimulus. Analysis of SCL indicated that an interval of 50 sec between trials 12 and 13 was sufficient to allow sensitization to decline to the pre-light level. The experimental conditions in experiment 2 (N = 32) were the same as in experiment 1 except that only half the subjects received presentation of the dishabituating stimulus. The results indicated that although there were no group differences in SCR amplitude on trials 1-11, experimental subjects displayed significantly larger responses on trial 13 than did control subjects. These results suggest that interpolation of a different stimulus in an habituation series does, in fact, disrupt the habituation process.

Acoustic Stimulation↗