Thesis--University of Houston, 1965. / eContent provider-neutral record in process. Description based on print version record.

Thesis--University of Houston, 1965.

Mathematical models have been used to study the effects of various electrical stimuli on nerve. The applicability of the findings to electrocutaneous stimulation in man has been investigated experimentally. With the model of a nerve membrane the influence of variations in the stimulus parameters have been investigated. This was done for multiple bipolar pulses by considering selected cases and for single bipolar pulses with a systematic investigation. The main findings were i) that the threshold charge for a single bipolar pulses changes only slightly for different pulsewidths; ii) that the threshold charge monotonically decreases with pulsewidth and threshold charge also decreases monotonically with increasing delay of the symmetric negative pulse; iii) that threshold amplitude for multiple bipolar pulses was only slightly lower than the amplitude for a single bipolar pulse. The influence of different components involved in cutaneous stimulation, such as skin, electrode, and neuroanatomy, have been examined. Corresponding models for the passive components involved were selected. From these models the following limiting conditions for the stimulus were derived: i) the stimulus has to be current regulated; ii) it must be bipolar (no net charge transfer); and iii) the electrode voltage must remain below the skin break-down voltage. The aspect of the conversion of stimulus' energy into heat in the skin has been examined in detail. A review of mathematical models of the active nerve membrane is presented and the applicability of a nerve model to the stimulation of peripheral nerve fibres in man is discussed. Numerical methods were used to solve the model's differential equations. The effects on the solution of different integration methods and of different integration step sizes has been assessed. Experiments with electrocutaneous stimulation have been performed using single bipolar current stimuli. The duration of a pulse was less than 100 microseconds. For the experiments, an electrically isolated stimulator has been designed and built. It operated under the control of a PDP-12 computer. The sensations produced were slightly suprathreshold and painless. The thenar region of the hand was stimulated using a concentric electrode. The results of the experiments supported the theoretical predictions and indicated the possibility of using models to investigate the optimization of stimulus parameters within the range tested. The close correspondence between the experimental results and the nerve model calculations seems to provide some evidence for the hypothesis that in electrocutaneous stimulation the nerve fibres are stimulated directly. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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Left hemisphere brain-damaged, right hemisphere brain-damaged and non-brain-damaged controls viewed four videotaped vignettes portraying four different emotions (e.g. neutral, inappropriate happiness, inappropriate anger and sadness). Each of the vignettes was followed by a questionnaire which tested the subjects recall of the emotional, and some non-emotional, content. Additionally all subjects had continuous galvanic skin response recordings taken from the hand ipsilateral to injury during the entire testing session. Left hemisphere brain-damaged subjects and right hemisphere brain-damaged subjects displayed impaired performance on the postvignette questionnaires. Control subjects performance was the highest. Left hemisphere brain-damaged subjects had the greatest increase in GSR from baseline levels for all scenes. The right hemisphere brain-damaged and control subjects remained stable at or around baseline levels.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1957. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 189-196).

The skin conductance response is involved in the preparation for and response to stimuli with emotional significance. The neural mechanisms responsible for the generation of the skin conductance response are not well understood despite the common use of this signal as an index of emotional response. Data from anatomical, lesion, and neuroimaging studies in humans suggest that the amygdala, a component of the brain circuit for emotion, plays a critical role in the generation of the skin conductance response. Here we employ a novel combination of existing techniques to understand the stimuli that elicit skin conductance responses in the monkey and the neural mechanisms in the amygdala that participate in its generation. We recorded skin conductance responses in monkeys trained to perform a passive image viewing task. This paradigm is a staple of human emotion research but to date has not been adapted to the monkey. In addition, skin conductance responses to these stimuli were recorded in conjunction with single unit responses from the amygdala. This study addresses the relationship between the activity of single neurons recorded from identified nuclei of the monkey amygdala and autonomic responses. Neurons in multiple nuclei of the amygdala showed reliable changes in neuronal discharge prior to the skin conductance response. These neurons were primarily in the dorsal nuclei of the amygdala, which confirms predictions made from anatomical and neuroimaging data. It is suggested that these changes in neuronal discharge may correspond to the generation of this autonomic component of the expression of emotion.

The sensitivity of pupillary responses (PR) to emotional states brought on by psychological state of deception was explored. Utilizing a combination of guilty person and guilty knowledge techniques, 16 male and 14 female Ss were presented with neutral and relevant names, with relevant names involving deception. Half of the Ss were presented with one relevant name and the other half were presented with two. The lists of five names were presented on three trials during which PR and GSR were monitored. Pupiliary responses and GSRs to relevant names were significantly different than PRs and GSRs to neutral names. There were no significant effects with respect to the number of relevant names and trials. In terms of detection rates, GSR yielded higher rates than PR. The correlational tests indicated no significant relationship between PR and GSR under the experimental conditions employed.

Thesis (M.D.)--University of Adelaide, Dept. of Psychiatry, 1987. / Includes bibliographical references (leaves 350-389).