Continuous measurement of visible persistence.

In the synchrony judgment paradigm, Ss judge whether a click precedes or follows the onset of a light flash and, on other trials, whether or not a click precedes light termination. The interclick interval defines the duration of visible persistence. An elaboration of this method was developed that consisted of 2 phases: In Phase 1, the luminance of a reference stimulus was psychophysically matched to the peak brightness of the test flash. Five luminance values between .1 and 1.0 of the reference stimulus were used subsequently. In Phase 2, a random 1 of the 5 reference stimuli, a test flash, and a click were presented; the Ss judged whether the click occurred before or after the brightness of test flash reached the reference value (on onset trials) or decayed below it (on termination trials). This method was validated on 3 male graduate students with test stimuli whose luminance rose and decayed slowly in time, and then was used to trace out the precise subjective rise and decay (temporal brightness response function) of brief flashes. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social factors and the psychobiology of depression: Relations between life stress and rapid eye movement sleep latency.

Examined psychosocial factors (i.e., life stress) and biological factors (i.e., REM sleep latency) that are hypothesized to be of complementary importance for defining depressive subtypes in a sample of 61 nonpsychotic, endogenous major depressives. Ss were evaluated on several diagnostic scales for life stress, on EEG sleep data, and on 2 symptom measures for depression. As predicted, persons with severe stress that occurred shortly before depression onset had essentially normal REM latency values; patients without such stress had reduced REM latency values. Both stress and REM latency were also associated with greater severity of self-reported depressive symptoms. Alternative explanations of these findings are discussed, with particular emphasis on different roles of preonset and postonset stressors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retention and acquisition of classical trace conditioned responses by rabbits with hippocampal lesions.

Examined the effects of dorsal hippocampal lesions on retention of classical trace conditioned responses (CRs) using the rabbit nictitating membrane preparation. In Exp I, 18 New Zealand albino rabbits were trained to criteria and then lesioned either in the cortex or in the hippocampus and the cortex. Hippocampal damage had no effect on the retention of responses but produced significantly longer onset latencies. A control group of hippocampal Ss acquired CRs at least as quickly as the prelesion Ss and exhibited longer response onset latency. Exp II, with 24 Ss, evaluated the performance of hippocampal-lesioned Ss in classical trace conditioning with either a low-intensity periorbital shock or a corneal air puff as the unconditioned stimulus (UCS). Hippocampal Ss successfully acquired CRs under both conditions but exhibited an alteration of response onset that depended on the form of the UCS. Hippocampal Ss displayed shorter response onset in the air-puff condition and longer response onset in the shock condition. Cortical Ss consistently timed responses regardless of the UCS. Findings suggest that the hippocampus modulates temporal characteristics of learned behavior. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral treatment of Raynaud's disease.

32 20–65 yr olds with idiopathic Raynaud's disease were randomly assigned to receive finger temperature feedback, finger temperature feedback under cold stress, frontalis EMG feedback, or autogenic training. Ss receiving finger temperature feedback demonstrated significant temperature increases, without relaxation, during training and after the removal of feedback. A significant but smaller response was retained 1 yr later, accompanied by a 66.8% reduction in reported attacks. The addition of training under cold stress to temperature feedback significantly improved retention of voluntary vasodilation at follow-up and produced a 92.5% reduction in symptom frequency. These procedures did not change overall levels of tonic peripheral blood flow, recorded over 24 hrs in the natural environment. Following treatment, significantly colder temperatures were needed to produce attacks in these Ss compared to those who had received EMG feedback or autogenic training. These latter techniques produced the expected signs of decreased arousal but were significantly less effective than temperature feedback in increasing finger temperature or decreasing symptom frequency. Cognitive stress management did not significantly affect any procedure. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Escape learning in houseflies ( Musca domestica ).

Performed 4 experiments to examine instrumental escape learning in the housefly ( N = 244). Each experiment allowed Ss to move from a hot, brightly illuminated half of a Plexiglas tube to the other half, which was relatively cool and dark. In Exp I, Ss were able to move freely throughout the tube at all times. The amount of time spent in the lighted half decreased significantly over the course of 20 1-min trials. In Exps II, III, and IV, a gate separating the 2 halves of the tube was used to create a typical shuttle box. In Exp II, escape latency decreased significantly over trials, and the effect was maintained over a 24-hr intersession interval. However, the effect was reversed when heat-absorbing filters were inserted. Exp III and IV showed that repeated exposure to either heat or light was not sufficient to produce the effect. Escape latency decreased only when there was a contingency between the response and escape from heat. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prospective evaluation of vitamin E for hot flashes in breast cancer survivors

PURPOSE: Hot flashes represent a substantial clinical problem for some breast cancer survivors. Although estrogen or progesterone preparations can alleviate these symptoms in many patients, concern remains regarding the use of hormonal preparations in such women. Thus, there is a perceived need for nonhormonal treatments for hot flashes for breast cancer survivors. Based on anecdotal evidence that vitamin E was helpful, we designed a trial to investigate this matter. METHODS: We developed and conducted a placebo-controlled, randomized, crossover trial where, after a 1 week baseline period, patients received 4 weeks of vitamin E 800 IU daily, then 4 weeks of an identical-appearing placebo, or vice versa. Diaries were used to measure potential toxicities and hot flashes during the baseline week and the two subsequent 4-week treatment periods. RESULTS: The 120 patients evaluated for toxicity failed to show any. The 105 patients who finished the first treatment period showed a similar reduction in hot flash frequencies (25% v 22%; P = .90) for the two study arms. A crossover analysis, however, showed that vitamin E was associated with a minimal decrease in hot flashes (one less hot flash per day than was seen with a placebo) (P < or = .05). At the study end, patients did not prefer vitamin E over the placebo (32% v 29%, respectively). CONCLUSION: Although this trial was able to show a statistically significant hot flash reduction with vitamin E compared to a placebo, the clinical magnitude of this reduction was marginal.     

Active and placebo effects in treatment of moderate and severe insomnia.

Examined the efficacy of relaxation training and a highly credible placebo in the treatment of both severe and moderate sleep onset insomnia. The placebo treatment was designed to elicit an expectation for improvement comparable with that of relaxation training. Expectancy of improvement was further controlled by informing Ss to expect improvement only after the 3rd wk of therapy, thus allowing comparisons of the treatments to be made during the counterdemand period (1st 3 wks) and the positive demand period (4th wk and beyond). Responses of 30 18–76 yr old severe and moderate insomniacs were similar across treatment conditions, over weeks, and in response to the counterdemand/positive demand manipulation. Only Ss trained in relaxation techniques improved significantly during the counterdemand period. The active treatment was significantly more effective than the placebo in reducing sleep onset latency during the counterdemand period. After the introduction of positive expectancy of therapy outcome, relaxation was no longer superior to placebo. Findings are discussed in terms of the methodological difficulties inherent in controlling for S expectancy of therapeutic effects in treatment studies of insomnia. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pilot evaluation of venlafaxine hydrochloride for the therapy of hot flashes in cancer survivors

PURPOSE: Hot flashes can be a prominent clinical problem for breast cancer survivors and men who undergo androgen-deprivation therapy. Anecdotal information suggested a low dose of a relatively new antidepressant, venlafaxine, could abrogate this clinical problem. MATERIALS AND METHODS: This study included 28 consecutive assessable patients entered onto a phase II clinical trial. Hot flash data were collected by daily diary questionnaires during a 1-week baseline period and then for 4 weeks, during which time patients received venlafaxine 12.5 mg orally twice daily. RESULTS: Fifty-eight percent of patients who completed the study had a greater than 50% reduction in hot flash scores (frequency times severity) during the fourth treatment week as compared with the baseline week. Median weekly hot flash scores were reduced by 55% from baseline during the fourth week of venlafaxine therapy. Therapy was generally well tolerated and appeared to alleviate fatigue, sweating, and trouble sleeping. CONCLUSION: Venlafoxine appears to represent an efficacious new method to alleviate hot flashes. Further evaluation of this compound for alleviating hot flashes is indicated.     

A behavioral study of temporal processing and visual persistence in young and aged rats.

Young rats were presented with light flash prepulses varying in duration from 1 to 128 msec, with light offset or light onset fixed at 70 msec prior to an acoustic startle stimulus (Experiment 1A), and, with single or paired 1-msec flashes, the 2nd (or only) flash given 100 to 500 msec before the startle, and 1 msec to 400 msec interflash intervals (Experiment 1B). Older rats (10 and 20 mo old) received the same single and double flashes but with the maximum interflash interval extended to 1,500 msec (Experiment 2). Reflex inhibition increased with increased duration from 1 to 8 msec and decreased as light onset progressively exceeded 100 msec. Inhibition for both single and double flashes also declined for onset lead times beyond 100 msec, then increased for a double flash once the interflash interval exceeded 100 msec in young and middle-aged rats and 1,500 msec in the oldest rats. Peak inhibition was much reduced in the oldest rats at short lead times but was greater than that of younger rats at long lead times. These data suggest that aged rats process visual stimuli more slowly than younger rats and show poorer temporal acuity coupled with greater visual persistence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Initial symptom levels and the life-event–depression relationship.

93 undergraduates selected for diversity of initial depression levels were studied longitudinally to explore the relation between stressful events and depression. Ss were chosen on the basis of their scores on an information-processing procedure, the Beck Depression Inventory, the Schedule for Affective Disorders and Schizophrenia—Lifetime Version, and the SCL-90. After the initial screening, Ss completed a 2-hr interview covering current and lifetime diagnostic status and stressful life-event occurrence in the previous 12 mo. Following this, they participated in 4 regular monthly follow-ups. Regression analyses and inspection of individual patterns supported the hypothesis that initial depression status is a critical factor in depression–event associations and that concurrent high-impact negative events contribute significantly but modestly to outcomes. It appeared that nonsymptomatic Ss were relatively resistant to onset even when exposed to high-impact stress events, whereas a subset of initially symptomatic Ss continued to have both more depression and more high-impact events over time. It is suggested that future research on event–depression associations should carefully consider these different outcome patterns: symptom resistance and symptom onset in nondepressed persons and symptom remission and symptom maintenance or recurrence in initially depressed persons. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of Plasmodium falciparum glutamate dehydrogenase-soluble antigen

There are limited data on the factors associated with menopausal hot flashes, a common and potentially morbid condition. The objective of this study was to identify predictors of menopausal hot flashes. To meet this objective, 233 naturally perimenopausal or post-menopausal women (ages 45-65) attending a large urban hospital center primary care clinic, mammography unit, or women's health practice were enrolled. The women responded to a self-administered questionnaire assessing selected demographic factors, reproductive history, and behavioral factors. Sixty-seven percent of respondents experienced hot flashes, with 63% reporting frequent hot flashes (at least one hot flash per day) and 60% with hot flashes describing the hot flashes as severe. Women with hot flashes were significantly more likely to have mothers who experienced hot flashes (OR = 4.4, CI = 2.0-10.0) or to be smokers (OR = 2.0, CI = 1.2-3.5). There were no statistically significant associations between hot flashes and other selected demographic, reproductive, or behavior characteristics. These results reveal that menopausal hot flashes are associated with a maternal history of hot flashes as well as with cigarette smoking. These results may help physicians to counsel their patients about smoking cessation.     

Direct estimates of the apparent duration of a flash.

Substantial evidence now shows that visual persistence can extend the apparent duration of a brief stimulus flash by several hundred msec. A technique of G. Sperling's was applied in which S adjusts a click to coincide, 1st with the apparent onset of a flash, and then with its apparent offset. The interclick interval thus determined is used as a measure of the apparent duration of the flash. Visual persistence is shown when the interclick interval exceeds the actual stimulus duration. When the flash and adapting field luminances were the same, persistence reached 175 msec. for brief flashes (10 msec.), decreased to 60 for longer ones (200 msec.), and was negligible for flashes exceeding 500 msec. When a visual noise field followed the postadaptation field, persistence was determined entirely by the time from the flash offset to noise onset, up to about 200 msec. Beyond that, the noise onset had no effect, presumably because the persistence had already ceased before the noise arrived. Conditions without visual noise, but with different combinations of pre- or postadaptation field, also produced substantial changes in visual persistence. Results show that (a) visual persistence can be estimated rather directly by this technique; (b) persistence is sensitive to adaptation conditions; and (c) visual noise will terminate persistence. Results support a process-stopping interpretation of information processing by visualoise, as distinct from a sensory integration view. (French summary) (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of hypnosis and motivation on resistance to heat stress.

Examined the relative effects of hypnosis, exhortative instructions, and routine task-performance instructions on the performance which individuals who differed in their degree of hypnotic susceptibility rendered on a continuous preformance task under normal and induced stress conditions. 20 high-susceptible (T) and 20 low-susceptible (UT) Ss operated a pursuit rotor at room temperature and then under extreme heat. Performance of all Ss under stress improved after they were either hypnotized or exhorted to perform better; exhortation had a slightly but nonsignificantly greater effect. The initial performance of UTs was not significantly superior to that of Ts. Though the performance of Ts appeared more strongly affected by both hypnosis and exhortation than performance of UTs, this difference proved nonsignificant when subjected to conservative statistical test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Active and placebo treatment effects on moderate insomnia under counterdemand and positive demand instructions.

Assigned 48 sleep-disturbed college students to 1 of 4 conditions: relaxation training, single-item desensitization, placebo, and no treatment. Counterdemand instructions were given during the 1st 3 sessions: Ss were told that improvement in sleep disturbance would not occur until after the 4th session. Relaxation and desensitization procedures produced significantly greater reports of improvement in latency of sleep onset than placebo and no treatment during the counterdemand period, while all 3 treated groups reported significantly greater improvement than no treatment after the 4th (positive demand) session. Results support the effectiveness of relaxation therapy in the treatment of moderate insomnia. Demand characteristics may contribute to S reports, but the use of counterdemand instructions allows for valid comparisons among therapy conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Judgments of synchrony between auditory and moving or still visual stimuli.

The flash-lag effect is a visual illusion wherein intermittently flashed, stationary stimuli seem to trail after a moving visual stimulus despite being flashed synchronously. We tested hypotheses that the flash-lag effect is due to spatial extrapolation, shortened perceptual lags, or accelerated acquisition of moving stimuli, all of which call for an earlier awareness of moving visual stimuli over stationary ones. Participants judged synchrony of a click either to a stationary flash of light or to a series of adjacent flashes that seemingly bounced off or bumped into the edge of the visual display. To be judged synchronous with a stationary flash, audio clicks had to be presented earlier--not later--than clicks that went with events, like a simulated bounce (Experiment 1) or crash (Experiments 2-4), of a moving visual target. Click synchrony to the initial appearance of a moving stimulus was no different than to a flash, but clicks had to be delayed by 30-40 ms to seem synchronous with the final (crash) positions (Experiment 2). The temporal difference was constant over a wide range of motion velocity (Experiment 3). Interrupting the apparent motion by omitting two illumination positions before the last one did not alter subjective synchrony, nor did their occlusion, so the shift in subjective synchrony seems not to be due to brightness contrast (Experiment 4). Click synchrony to the offset of a long duration stationary illumination was also delayed relative to its onset (Experiment 5). Visual stimuli in motion enter awareness no sooner than do stationary flashes, so motion extrapolation, latency difference, and motion acceleration cannot explain the flash-lag effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-dependent improvement in passive avoidance learning of the young chick: Cholinergic mediation?

Studied cholinergic mediation of the age-dependent improvement in response suppression of the young chick by determining the performance of 144 Vantress?×?Arbor Acre 4-day-old chicks, pretreated with scopolamine (SCO), during passive avoidance (PA) and extinction testing. In Exp I, Ss were trained to keypeck for heat reward (prepunishment training), and then tested for PA learning under immediate, 2-sec-delayed, or no shock condition. Half of the Ss in each condition received saline injections before prepunishment training and .5 mg/kg SCO injections after training. The rest received .5 mg/kg SCO injections both before and after training. For Ss in both SCO groups, delaying shock onset resulted in significantly less response suppression than immediate response-contingent shock. In Exp II, 4-day-old Ss injected with saline or SCO were trained to keypeck for heat reward and then tested for resistance to extinction under response-contingent shock or nonshock conditions. Punishment decreased the number of extinction responses for both saline and SCO groups. Results indicte that the age-dependent improvement in response suppression of the young chick cannot be explained solely by a significant increase in central cholinergic functioning. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of presleep stress on sleep-onset insomnia.

10 sleep-onset (SO) insomniacs and 11 noninsomniacs (18–21 yrs old) slept undisturbed for 3 nights but were exposed to brief cognitive stressors before SO on the next 2 nights. Significant between-group differences were found in responses to the cognitive stressors on self-report but not objective measures of SO latency (SOL). Noninsomniac Ss evidenced an increase and insomniac Ss a decrease in SOL on stress nights. Insomniac Ss demonstrated a significantly higher mean heart-rate response before and after the stressors. A variable expressing the relationship between objective and subjective measures of SOL (pseudoidiopathic dimension) for each S was not significantly related to Ss' responses to stress. Results are inconsistent with the hypothesized role of presleep stress in SO insomnia but are consistent with other studies indicating higher levels of physiological arousal of insomniac vs noninsomniac Ss. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relaxation treatment for insomnia: A component analysis.

Compared 4 relaxation treatments—progressive relaxation, progressive relaxation without tension release, imagery with tension release, and imagery without tension release—for sleep onset insomnia with a waiting-list control (no treatment). Analysis of data from 44 19–71 yr old insomniacs recruited from the community showed all treatment conditions to be superior to no treatment in reducing latency of sleep onset and ratings of fatigue. The presence of muscle-tension release was unrelated to outcome. There was a nonsignificant trend for visual imagery treatments to be superior to somatic-focusing treatments in reducing sleep onset latencies. Treatments using visual focusing were superior to somatic-focusing treatments in reducing the number of nocturnal awakenings. At 6 mo follow-up, only the imagery treatments showed significant improvement over pretreatment levels on latency of sleep onset. Visual-focusing treatments produced significantly greater reductions in sleep onset latency at follow-up than did the somatic-focusing treatments. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal homeostasis in pregnant rats during heat stress.

Sprague-Dawley rats exposed to inescapable heat stress maintained a controlled hyperthermia while increasing heat loss by cutaneous vasodilatation and by grooming behavior. In nonpregnant Ss, the evaporation of saliva groomed onto the body surfaces increased exponentially as a function of ambient temperature above 36°C. In contrast, Ss in an advanced stage of pregnancy became dependent on grooming behavior for thermoregulation of ambient temperatures of 30-36°C. This was associated with a decrease in the body temperature threshold for salivary secretion from the submaxillary gland, which then began at approximately the same body temperature as cutaneous vasodilatation. The pregnant Ss maintained a lower level of controlled hyperthermia during heat stress than did nonpregnant Ss. This appeared to result from a decreased production of metabolic heat, reduced insulation on the ventral surface, and an increased motivation to keep cool during heat stress. These changes met the increased need for thermolysis during pregnancy and provided for thermal homeostasis both in the pregnant rat and in the unborn fetuses. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behaviorally functional opioid systems in infant rats: II. Evidence for pharmacological, physiological, and psychological mediation of pain and stress.

Two experiments, with 160 10-day-old Sprague-Dawley rat pups, examined the behavioral characteristics of the neonatal opioid system during distressful situations, using a modification of the hot-plate paw-lick test. Ss were analgesic to heat following intraperitoneal morphine (0.5 mg/kg). Subcutaneous naloxone (0.5 mg/kg) prevented the analgesia. Morphine analgesia was significantly greater in Ss group-isolated from the dam. Saline controls group-isolated from the dam exhibited longer latencies than their nest-housed siblings. Individual isolation for 5 min markedly increased paw-withdrawal latency, and this effect was naltrexone reversible. Analgesia was not seen when Ss were tested directly from the nest or when grouped with others for 5 min. It is suggested that the opioid systems for stress and pain are functional in 10-day-old rats and that short-term isolation from the dam is a probable natural stressor modulated by endogenous opioid release. (51 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)