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With the technique of biofeedback it has become possible for humans to enter into a direct and objective dialogue with their body functions. By this method one can, for example, try to reduce muscle tension, increase peripheral blood flow or influence cortical activity. It has been clinically applied in neuromuscular rehabilitation, as an adjunct therapy of cardiovascular disorders such as cardiac arrhythmias and hypertension, in the treatment of headache and epileptic seizures as well as for bodily relaxation.
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The investigation of afferent cardiovascular influences upon central nervous processes needs a methodology which allows for independent and systematic manipulation of circulatory processes. By mechanical manipulation of posture (tilt table, orthostasis) and compression of lower body parts (by anti-G-suit) reliable changes in heart rate and blood pressure can be induced. In fourty subjects (study 1) it could be shown that sustained (30 min.) changes in heart rate (e.g. orthostatic tachycardia, decrease of heart rate during compression) and mean arterial blood pressure (increase during orthostasis with and without compression) occur. Although changes in heart rate could be achieved irregardless of whether the venous "pooling" was suppressed by an air- or water-filled pressure suit, the pressor effect did differ quite considerably. In fourty-four subjects (study 2) it could be demonstrated that only by means of an water-filled suit further increases in mean arterial blood pressure could be evoked during orthostasis. Changes in hemodynamic also lead to changes in sympatho-vagal control of cardiac activity. In study 3 (ten subjects) it could be shown, that orthostasis mainly evokes alterations in sympathetic activity whereas lower body compression leads to additional increases of vagal activity and respiratory sinus arrhythmia during orthostasis.
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Nonaversive unconditional stimuli (USs) are seldom used in human classic conditioning of autonomic responses. One major objection to their use is that they produce deficits in electrodermal (ED) second- and third-interval response conditioning. However, a nonaversive reaction time (RT) task that includes feedback of success has been shown to be an effective US while avoiding this disadvantage (Lipp and Vaitl 1988). The present study compared this new RT task (RT-new) with a traditional RT task (RT-old) and with a standard aversive US (shock) in differential classic conditioning of ED, heart rate (HR), and digital pulse volume (DPV) responses. Eight-second-delay differential conditioning was applied in three groups of 12 subjects each. Simple geometric features (square, cross) displayed on a television screen served as conditional stimuli (CS+ and CS-). In acquisition, there were no statistically significant differences among the groups; differential conditioning did occur in HR, first- and second-interval ED responses, and first-interval DPV responses. Separate analyses within each group, however, revealed that there was no second-interval ED conditioning in the RT-old group. During extinction, neither DPV nor second-interval ED conditioning could be obtained, whereas HR and first-interval ED conditioning occurred in each group. In third-interval omission ED responses, RT-old and shock groups exhibited extinction, while response differentiation was maintained in the RT-new group throughout extinction. The RT task including feedback proved to be as reliable a US as a standard aversive US, whereas application of a traditional RT task again yielded some weaknesses in second-interval ED conditioning.
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22 believers and 20 skeptics of extrasensory perception (ESP) participated in a telepathy experiment. Subjects were asked to judge the covariation between transmitted symbols and the corresponding feedback given by a receiver. Believers overestimated the number of successful transmissions ('hits'). Skeptics were characterized by accurate hit judgments. For believers, positive correlations between hit-responses, their heart rates, and their experienced arousal were found. In addition, subjective arousal was positively associated with the hit estimates given at the end of the experiment. This response pattern was absent in the group of skeptics. It is concluded that covariation bias as a psychophysiological concept plays an important role in the maintenance of paranormal belief.
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Latent inhibition (LI) is an important model for understanding cognitive deficits in schizophrenia. Disruption of LI is thought to result from an inability to ignore irrelevant stimuli. The study investigated LI in schizophrenic patients by using Pavlovian conditioning of electrodermal responses in a complete within-subject design. Thirty-two schizophrenic patients (16 acute, unmedicated and 16 medicated patients) and 16 healthy control subjects (matched with respect to age and gender) participated in the study. The experiment consisted of two stages: preexposure and conditioning. During preexposure two visual stimuli were presented. one of which served as the to-be-conditioned stimulus (CSp + ) and the other one was the not-to-be-conditioned stimulus (CSp - ) during the following conditioning ( = acquisition). During acquisition, two novel visual stimuli(CSn + and CSn - ) were introduced. A reaction time task was used as the unconditioned stimulus (US). LI was defined as the difference in response differentiation observed between preexposed and non-preexposed sets of CS + and CS - . During preexposure, the schizophrenic patients did not differ in electrodermal responding from the control subjects, neither concerning the extent of orienting nor the course of habituation. The exposure to novel stimuli at the beginning of the acquisition elicited reduced orienting responses in unmedicated patients compared to medicated patients and control subjects. LI was observed in medicated schizophrenic patients and healthy controls, but not in acute unmedicated patients. Furthermore LI was found to be correlated with the duration of illness: it was attenuated in patients who had suffered their first psychotic episode.
Erkunden
Team
- Vaitl (9)
Eintragsart
Thema
- Arousal
- Adolescent (3)
- Adult (8)
- Antipsychotic Agents (1)
- Arrhythmias, Cardiac (1)
- Association Learning (2)
- Attention (2)
- Attitude (1)
- Autonomic Nervous System (1)
- Biofeedback, Psychology (2)
- Blood Pressure (1)
- Concept Formation (1)
- Conditioning, Classical (4)
- Decompression (1)
- Electrocardiography (1)
- Electroshock (1)
- Epilepsy (1)
- Extinction, Psychological (1)
- Female (7)
- Galvanic Skin Response (3)
- Habituation, Psychophysiologic (1)
- Headache (1)
- Heart Rate (4)
- Humans (9)
- Hypertension (1)
- Learning (1)
- Lower Body Negative Pressure (1)
- Male (7)
- Middle Aged (2)
- Neural Inhibition (1)
- Neuromuscular Diseases (1)
- Parapsychology (1)
- Posture (1)
- Psychiatric Status Rating Scales (1)
- Pulse (1)
- Raynaud Disease (1)
- Reaction Time (3)
- Reference Values (1)
- Relaxation Therapy (1)
- Research (1)
- Respiration (1)
- Schizophrenia (1)
- Schizophrenic Psychology (1)
- Telepathy (1)
- Vascular Resistance (1)