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At least 19 recordsLinked to original sources
PubMed1975

False physiological feedback and persuasion: effect of fear arousal vs. fear reduction on attitude change.

Two experiments tested the hypothesis that increases in false physiological feedback of fear arousal will enhance persuasion and that reduction in the arousal feedback is unnecessary for increased persuasion to occur. Prior research has usually found a positive relation between level of arousal and persuasion, but support for the drive reduction hypothesis is tenuous. However, Harris and Jellison (1971) claimed support for such a hypothesis. They manipulated subjects' fear arousal cognitively via false physiological feedback while the subjects listened to a persuasive communication. The present experiments used a similar procedure in an attempt to test an "arousal only" against an "arousal reduction" hypothesis. Subjects listened to a persuasive speech while receiving false feedback via a meter concerning their fear arousal. In Experiment I half of the subjects received high arousal and half received moderate arousal information. Within each of these conditions half of the subjects had their arousal reduced, and the other half did not. In Experiment II subjects received either low arousal, high arousal, or high then low arousal feedback while listening. The results of the two studies generally provided support for the "arousal only" hypothesis. An interpretation in terms of Bem's attribution theory was tentatively suggested.

Arousal↗
PubMed1991

Unresponsiveness of the endorphinergic system to its physiological feedback in obesity.

Beta-endorphin (beta-Ep) plasma levels are higher in obese patients than in normal subjects. To establish that this finding constitutes hyperendorphinemia, 28 obese patients aged 12-55 years, six males and 22 females, (weighing 61-117 kg) were investigated twice by an overnight 1-mg p.o. dose dexamethasone suppression test (DST) before and after weight loss. beta-Ep was measured by radioimmunoassay (RIA). Before body weight loss, beta-Ep was higher than normal and unresponsive to DST, whereas ACTH and cortisol were suppressible. After weight loss, beta-Ep was slightly reduced but still insensitive to DST. ACTH and cortisol were responsive as usual. Findings suggest a resistance to DST in obesity as far as beta-Ep is concerned. The disorder persists even after weight loss, indicating that hyperendorphinemia is not secondary to body weight excess. Accordingly, one can argue that the unresponsiveness of the endorphinergic system to its physiological feedback is a pathophysiological characteristic of obesity.

Adolescent↗
PubMed2005

Gender modulates sequential suppression and recovery of pulsatile growth hormone secretion by physiological feedback signals in young adults.

The basic mechanisms that drive the renewal of GH pulses in the human are not understood. Recent ensemble models predict that pulse regeneration requires quenching of an ongoing GH pulse by somatostatin outflow and evocation of a new burst by rebound GHRH release. We reasoned that related principles might explain why women consistently maintain higher-amplitude GH secretory bursts than men. Accordingly, the present study tests the hypothesis that gender modulates the successive dynamics of GH feedback and escape in the morning fasting, when GH pulses are larger in women. To this end, we infused single iv pulses of recombinant human (rh) GH (0, 1, and 3 microg/kg) in eight young men and six women on separate randomly ordered mornings fasting and quantitated serial inhibition and recovery of GH secretion by frequent sampling, immunochemiluminometry, a deconvolution procedure, and regularity analysis. Statistical contrasts revealed gender-comparable peak concentrations and kinetics of rhGH. However, women differed from men by way of: (1) 3.5- and 4.0-fold less feedback suppression of GH secretory-burst mass; (2) more irregular patterns of GH release during negative feedback; and (3) 12-and 14-fold greater postnadir rebound-like GH secretion after rhGH pulses. Mechanistic analyses based on a minimal feedback construct predicted that women generate higher endogenous secretagogue stimulation per unit somatostatin outflow than men. In summary, negative feedback induced by near-physiological GH pulses unmasks prominent gender-related contrasts in hypothalamo-pituitary autoregulation in young adults. A frugal but sufficient explanation of the ensemble outcomes is that women sustain greater hypothalamo-pituitary agonist input than men.

Adult↗
PubMed1983

Cognitive imagery and physiological feedback relaxation protocols applied to clinically tense young adults: a comparison of state, trait, and physiological effects.

Examined changes in targeted and general tension behaviors as well as reductions in physiological tension associated with cognitive imagery and electromyographic biofeedback relaxation procedures. Three groups of 15 female college students participated. During three weekly sessions each person received either guided cognitive imagery relaxation, frontalis muscle feedback relaxation, or a self-rest control procedure. The Anxiety Differential was administered before and after each session, while frontalis EMG, heart rate, and skin temperature were monitored continuously. A second Temperament Analysis was administered after the final session. The imagery procedure was associated with moderate reductions in physiological tension and significant reductions in state anxiety and three tension-related personality dimensions. Self-rest persons displayed lesser reductions in general tension with little physiological change. While biofeedback persons showed the largest reductions in physiological tension, they displayed only small and variable changes in state anxiety and personality dimensions. The data raise continued questions about the application of physiologically based operant relaxation procedures and support the use of cognitively mediated protocols for the treatment of specific or general anxiety behaviors.

Adolescent↗
PubMed1995

Modification of dysfunctional patterns of sexual response through autonomic arousal and false physiological feedback.

Effects of autonomic arousal and positive-false vaginal blood volume (VBV) feedback were examined to identify how cognitive and physiological mechanisms mediate sexual arousal, and can be modified to reverse dysfunctional processes. Sixty-four matched sexually dysfunctional women were randomly assigned to 4 conditions: autonomic arousal-evoking or neutral-control preexposure film stimulus paired with an erotic stimulus, and positive-false VBV feedback or no feedback. Results revealed the following: (a) general autonomic arousal enhanced genital arousal; false feedback increased (b) expectations of sexual arousal, (c) actual vasocongestive response, and (d) the subsequent experience of sexual arousal; (e) heightened expectations with false feedback were followed by an increase in actual genital response within 30 s, and (f) the combined effects of autonomic arousal and false feedback enhanced expectations and subsequent genital arousal to levels comparable with those of sexually functional women (E.M. Palace & B.B. Gorzalka, 1990) within 3 min.

Adult↗
PubMed2005

Proposal for a framework for optimizing artificial environments based on physiological feedback.

We propose and then evaluate a new framework for finding the physical parameters of an artificial environment which give rise to given target physiological characteristics. We assume that a human is a system that takes as inputs the physical parameters of an artificial environment and outputs physiological parameters in response. We define our task as the inverse problem; we must find the best inputs from given target outputs. Our proposed framework solves the inverse problem using evolutionary computation techniques to optimize an artificial environment. We evaluate this framework using a simulation with a vibration environment and verify that it works.

Environment, Controlled↗
PubMed1998

A model for pharmacokinetics and physiological feedback among hormones of the testicular-pituitary axis in adult male rats: a framework for evaluating effects of endocrine active compounds.

The testicular-hypothalamic-pituitary axis controls reproductive functions in males. A description of the basic physiological interactions in adult rats among testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) was developed, permitting simulation of hormone levels in testes and blood. This model was used to simulate hormone levels in intact, castrate, ethane dimethanesulfonate-treated, and antiandrogen-treated rats. A large gradient of testosterone concentrations from testicular interstitial fluid to low levels in peripheral blood is created by the testicular blood flow. The dominant feedback loop is positive regulation of testosterone synthesis by LH and negative feedback of testosterone on LH and FSH. The utility of the model for placing in vitro data in the context of in vivo physiology was illustrated for the case of continued synthesis of testosterone by the isolated testes. In the absence of blood flow, very low residual testosterone synthesis can substantially increase testosterone concentration in isolated testes. Effects of an exogenous endocrine active compound were illustrated by modeling altered LH and FSH regulation by testosterone in the presence of an antiandrogen acting as a competitive ligand for the androgen receptor. Increasing concentrations have no effect on steady-state hormone levels until sufficient levels of antiandrogen are achieved to reduce negative feedback of testosterone on LH and FSH. In summary, a model has been developed that provides a basis for initiating evaluations of key issues of concern for the risk assessment of endocrine active compounds including in vitro to in vivo extrapolation and their dose-response behaviors.

Animals↗
PubMed1999

Motor feedback physiological control for a continuous flow ventricular assist device.

The response of a continuous flow magnetic bearing supported ventricular assist device, the CFVAD3 (CF3) to human physiologic pressure and flow needs is varied by adjustment of the motor speed. This paper discusses a model of the automatic feedback controller designed to develop the required pump performance. The major human circulatory, mechanical, and electrical systems were evaluated using experimental data from the CF3 and linearized models developed. An open-loop model of the human circulatory system was constructed with a human heart and a VAD included. A feedback loop was then closed to maintain a desired reference differential pressure across the system. A proportional-integral (PI) controller was developed to adjust the motor speed and maintain the system reference differential pressure when changes occur in the natural heart. The effects of natural heart pulsatility on the control system show that the reference blood differential pressure is maintained without requiring CF3 motor pulsatility.

Algorithms↗
PubMed1991

Cognitive and physiological feedback on cold pain tolerance.

Results supported the relevancy of cognitive information effects on pain tolerance, in that subjects who were given a rational and accurate explanation of what to expect showed greater tolerance than those who received irrelevant information. Accurate monitoring of hand temperature did not seem necessarily advantagous as an influence on pain tolerance. It appears merely watching a monitor, regardless of the specific contents of the screen, resulted in longer hand immersion times when compared to no monitor. The monitors seem to serve as distractors and specificity of physiological information was not particularly useful. However, neither information nor physiological monitoring emerged as the primary influence on pain tolerance in this study. Instead, the strongest predictors found were motivation and self-efficacy. The subject's own self prediction of anticipated performance with cold induced pain was closely consistent with actual performance. Although these results alone may not generalize to extended field situations, this study does reinforce the general findings of previous research: namely Bandura's (10) evidence on self-efficacy. While it is obvious cold temperatures have measurable physiological consequences, the experience of pain is also psychologically mediated. Pain associated with cold injury and frostbite in hospital studies show personality correlates are significantly related to the frequency, severity and tragedy of subsequent results (15). A replication of this study will include male subjects even though it is anticipated that findings will be consistent, with perhaps longer immersion times. Future research may want to develop training strategies aimed at teaching self-efficacy and realistic expectations of potential consequences in cold environments rather than scare tactics regarding physiological and psychological cold pain tolerance.

Biofeedback, Psychology↗
PubMed1976

On the self-regulation of the occipital alpha rhythm: control strategies, states of consciousness, and the role of physiological feedback.

In an experiment investigating the self-control of occipital alpha strength, a factorial design was employed with two levels of feedback (available or non-available), three levels of instruction (Cognitive, Oculomotor, and none), and two levels of lighting (on and off), except that the no-feedback-no-instruction group was not run. The Cognitive instructions were based on the strategies reported in the literature: To generate alpha, persons were instructed to relax, "let go", try to feel pleasant and serene, and allow themselves to review pleasant personal experiences; to suppress alpha, persons were instructed to concentrate, try hard, exert themselves mentally, and try to fell anxious or frustrated. The Oculomotor instructions to generate alpha were to visually blur and not focus, and to suppress alpha were to "look" and focus. The results led to the following conclusions: (a) Feedback-augmented enhancement and suppression of occipital alpha strength is always mediated by learned control of oculomotor processes, although sometimes persons are not aware that they are employing this strategy, especially in the case of alpha enhancement; alpha feedback trainees learn to "not look" in order to enhance alpha strength. (b) Whenever Cognitive strategies are successful in producing alpha strength changes, this is due to the fact that they can be efficient mediators of changes in oculomotor processes. (c) Feedback together with simple Oculomotor instructions leads to more successful alpha control than either alone. (d) High or enhanced levels of occipital alpha strength are not invariably accompanied by the "alpha experience", in fact, if a person is not led to expect it, the alpha experience will usually not occur during occipital alpha enhancement feedback. (e) States of nonsensory awareness, such as an absorption in thoughts and feelings, are reliably associated with enhanced occipital alpha strength. This association is what would be expected: Since vision is the dominant sensory modality in humans, it is reasonable that when visual processing is reduced during alpha enhancement feedback that there is also reduced sensory awareness in general and often greater attention to thoughts and feelings. (f) Alpha feedback per se is neither necessary for nor especially facilitative of the achievement of the alpha experience. Thus, if the alpha experience is more likely to occur with alpha feedback than without it, this is due to the special circumstances that make up the feedback situation and not due to alpha feedback per se.

Alpha Rhythm↗
PubMed2002

The treatment of fear of flying: a controlled study of imaginal and virtual reality graded exposure therapy.

The goal of this study was to determine if virtual reality graded exposure therapy (VRGET) was equally efficacious, more efficacious, or less efficacious, than imaginal exposure therapy in the treatment of fear of flying. Thirty participants (Age = 39.8 +/- 9.7) with confirmed DSM-IV diagnosis of specific phobia fear of flying were randomly assigned to one of three groups: VRGET with no physiological feedback (VRGETno), VRGET with physiological feedback (VRGETpm), or systematic desensitization with imaginal exposure therapy (IET). Eight sessions were conducted once a week. During each session, physiology was measured to give an objective measurement of improvement over the course of exposure therapy. In addition, self-report questionnaires, subjective ratings of anxiety (SUDs), and behavioral observations (included here as flying behavior before beginning treatment and at a three-month posttreatment followup) were included. In the analysis of results, the Chi-square test of behavioral observations based on a three-month posttreatment followup revealed a statistically significant difference in flying behavior between the groups [chi(2) (4) = 19.41, p < 0.001]. Only one participant (10%) who received IET, eight of the ten participants (80%) who received VRGETno, and ten out of the ten participants (100%) who received VRGETpm reported an ability to fly without medication or alcohol at three-month followup. Although this study included small sample sizes for the three groups, the results showed VRGET was more effective than IET in the treatment of flying. It also suggests that physiological feedback may add to the efficacy of VR treatment.

Adult↗
PubMed2006

Physiologic regulation of a tetrodotoxin-sensitive sodium influx that mediates a slow afterdepolarization potential in gonadotropin-releasing hormone neurons: possible implications for the central regulation of fertility.

The brain controls fertility through release of gonadotropin-releasing hormone (GnRH), but the mechanisms underlying action potential patterning and GnRH release are not understood. We investigated whether GnRH neurons exhibit afterdepolarizing potentials (ADPs) and whether these are modified by reproductive state. Whole-cell current-clamp recordings of GnRH neurons in brain slices from ovariectomized mice revealed a slow ADP (sADP) after action potentials generated by brief current injection. Generating two or four spikes enhanced sADP amplitude and duration. sADP amplitude was not affected by blocking selected neurotransmitter/neuromodulator receptors, delayed-rectifier potassium channels, calcium-dependent cation channels, or hyperpolarization-activated cation channels but was halved by the calcium channel blocker cadmium and abolished by tetrodotoxin. Cadmium also reduced peak latency. Intrinsic mechanisms underlying the sADP were investigated using voltage-clamp protocols simulating action potential waveforms. A single action potential produced an inward current, which increased after double and quadruple stimulation. Cadmium did not affect current amplitude but reduced peak latency. Pretreatment with blockers of calcium-activated potassium currents (I(KCa)) reproduced this shift and blocked subsequent cadmium-induced changes, suggesting cadmium changes latency indirectly by blocking I(KCa). Tetrodotoxin abolished the inward current, suggesting that it is carried by sodium. In contrast, I(KCa) blockers increased the inward current, indicating that I(KCa) may oppose generation of the sADP. Strong sADPs were suprathreshold, generating repetitive spontaneous firing. I(ADP), sADP, and excitability were enhanced by in vivo estradiol, which triggers a preovulatory surge of GnRH release. Physiological feedback modification of this inward current and resulting sADP may modulate action potential firing and subsequent GnRH release.

Action Potentials↗
PubMed2004

[Mathematical modeling and simulation study of the heart rate feedback regulation system].

The physiological feedback regulation mechanism of the heart rate variation due to the blood pressure variation is studied. The continuous closed-loop mathematical model of the heart rate feedback regulation system is constructed. Numerical simulation is completed based on the above model. The simulation results demonstrate that the regulation system has the ability to constrain the fluctuation of the blood pressure to certain extent. The results are helpful for the pathological studies of some hypertensive diseases.

Blood Pressure↗
PubMedDate not supplied

[The regulatory mechanisms of glomerular filtration: the tubuloglomerular feedback system, physiological aspects and their participation in the physiopathology of kidney diseases].

The tubuloglomerular feedback system (TGF), the main component of the autoregulation mechanism, maintains constant glomerular blood flow and filtration rate. The system is based in the morpho-functional association among the macula densa, the afferent and efferent arterioles, the glomerulus and the extraglomerular mesangial cells. The macula densa cells sense the changes in solute concentrations and osmolarity in the tubular fluid and send vasoconstrictor or vasodilatory signals to the arterioles that modify blood flow and glomerular filtration rate. However, the mechanism by which the macula densa sends signals to the arterioles remains unknown. A chemical mediator such as prostaglandins or adenosine has been postulated. Our studies discarded the participation of prostaglandins as mediators. Further studies from our group with adenosine analogs indicate that this nucleotide participates in the activation of the TGF responses, and suggest alternate activation pathways not previously described. To evaluate the role of TGF feedback in the glomerular hemodynamic changes associated with progression of renal damage, we studied TGF responses in rats with Goldblatt hypertension and partial ablation of the contralateral kidney. Our results suggest that the sensitivity of the system is decreased. This alteration may contribute to glomerular hypertension and progression to renal damage.

Adenosine↗