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PubMedDate not supplied

One-year outcomes of Project Towards No Drug Abuse.

OBJECTIVES: This paper presents the 1-year outcomes evaluation of Project Towards No Drug Abuse (Project TND), a large-scale indicated drug abuse prevention program in southern California applied to continuation high school youth, who are at high risk for drug abuse. METHODS: The efficacy of nine-lesson health motivation--social skills--decision-making curriculum was evaluated in a three-condition experimental design. Twenty-one schools were randomly assigned by block to one of three conditions--standard care (control), classroom program, and classroom program plus a semester-long school-as-community component. A pretest was followed by a 3-week-long drug abuse prevention program and then a posttest at 14 continuation high schools. The 7 standard care schools received only the pretest followed by the posttest (same time duration). Subjects were followed up 1 year later. RESULTS: Changes in use of cigarettes, alcohol, marijuana, and hard drugs were assessed in a pretest-1-year follow-up time interval. The follow-up rate was 67% (analysis n = 1,074). Indicated preventive effects were found on alcohol and hard drug use. No differences were found across the two program conditions. CONCLUSIONS: Project TND is the first program to demonstrate 1-year self-reported behavioral effects on alcohol use and hard drug use among older, high-risk youth by using a school-based, limited-session model.

Adolescent↗
PubMed1977

The effect of transcendental meditation on right hemispheric functioning.

This study reports two experiments investigating the effects of transcendental meditation on right hemispheric functioning. The task used in both experiments was the Seashore Tonal Memory Test. In the first experiment a non-meditator group and an experienced meditator group were run. The design involved three periods: a pretest, a meditation or rest period, and then a posttest. The results showed the experienced meditators were significantly better in both pretest and posttest performance. There were no pretest-posttest differences. The second experiment was done to replicate the first experiment and to control for possible selection bias. The design was the same as the first experiment, except that an additional group of inexperienced meditators was included. The results again showed significantly superior performance for the experienced meditators compared to the non-meditators. In addition, the experienced meditators were superior to the inexperienced meditators. There were no significant differences between the non-meditators and the inexperienced meditators. These results support the hypothesis that meditation facilitates right hemispheric functioning. Alternative explanations, such as selection bias, are also discussed.

Adolescent↗
PubMed1998

Which physiologic tests are useful in patients with constipation?

PURPOSE: Physiologic tests such as manometry, colonic transit times, balloon compliance, defecography, pudendal nerve latency, and electromyography are used to evaluate patients with severe constipation. Patients referred because of severe constipation between 1991 and 1996 were studied to examine the role that physiologic testing played in making a diagnosis and directing treatment. METHODS: Of 139 patients referred for severe idiopathic constipation, physiologic testing was recommended in 127, and 104 patients underwent the studies. The pretesting impression was noted, and test results were evaluated to determine diagnostic accuracy. If a specific initial impression was documented, tests were classified as refuting it, confirming it or confirming and adding significant information. If there was no clear pretest impression, tests were evaluated for their ability to indicate a diagnosis. The patient's history also was evaluated to determine what information was most useful in making a diagnosis. Historical features including duration of constipation, symptoms consistent with outlet obstruction or dysmotility, age, associated urinary incontinence, and prior hysterectomy were analyzed. Data were collected prospectively, then reviewed by an independent observer. RESULTS: Ninety-eight study patients remained after 29 were excluded who did not undergo the recommended studies (19) or because no initial impression was documented (10). In 43 patients (44 percent), testing did not provide additional useful information. In 8 patients, testing confirmed the initial impression and added information impacting the treatment plan. Test results clearly refuted the initial impression in only one patient. In 46 (47 percent) patients the initial impression was uncertain, and in 43 (94 percent) of these, testing aided in making the diagnosis. In three cases, the diagnosis remained uncertain after testing. Prior hysterectomy (P = 0.003), urinary incontinence (P < 0.001), and symptoms of pelvic outlet obstruction (P = 0.03) were associated with a high incidence of rectocele. Defecography and transit times were the most useful tests. Surprisingly, symptoms of outlet obstruction or dysmotility did not show an overall correlation with transit times. CONCLUSIONS: In one-half of these patients with severe constipation, physiologic testing added significant information, leading to a specific diagnosis. Pretesting history and symptoms did not predict which patients were most likely to benefit from these studies.

Adolescent↗
PubMed1993

A core component of the certification examination in internal medicine.

OBJECTIVE: To develop and test the psychometric characteristics of an examination of core content in internal medicine. DESIGN: A cross-sectional pilot test comparing the core examination with the 1988 certifying examination and two pretest examinations. SETTING: The 1988 certifying examination of the American Board of Internal Medicine. PARTICIPANTS: A random sample of 2,975 candidates from 8,968 candidates who took the 1988 certifying examination were given the core examination; similarly drawn samples were each given one of two pretests of traditional questions. INTERVENTIONS: A framework for developing an examination of core internal medicine questions was designed and used to develop a 92-question core test with an absolute pass/fail standard. RESULTS: Candidates answered 74% of core internal medicine questions, compared with 64%, 52%, and 53% of traditional questions on the 1988 certifying examination and the two pretests. The discriminating ability of the core internal medicine examination was lower than that of the certifying examination (r-values were 0.28 and 0.34, respectively). The pass rate was 83% for the core internal medicine examination and 57% for the certifying examination; 27% passed the core examination and failed the certifying examination; 1% passed the certifying examination and failed the core examination. CONCLUSION: Core internal medicine questions were easier than but almost as discriminating as traditional questions of the certifying examination. A small percentage of candidates passed the certifying examination but failed the core examination.

Certification↗
PubMed2003

Combined 201Tl and 67Ga brain SPECT in patients with suspected central nervous system lymphoma or germinoma: clinical and economic value.

BACKGROUND: Surgical resection is costly and an unfavorable prognostic factor for primary central nervous system (CNS) lymphoma and germinoma patients. OBJECTIVE: To assess the diagnostic and economic impact of combined 201Tl and 67Ga brain SPECT on the management of patients suspected of having CNS lymphoma or germinoma. METHODS: Sequential 201Tl and 67Ga brain SPECT was performed in 40 patients with cranial tumors to assess the diagnostic and economic impact of combined 201Tl and 67Ga SPECT on the management of patients suspected of having CNS lymphoma or germinoma. All intracranial masses were pathologically confirmed. The final diagnoses of a total of 47 foci were: 11 non-Hodgkin's lymphomas in 10 patients, 3 germinomas in 2 patients, 10 glioblastomas in 9 patients, 10 cerebral metastases in 8 patients, 13 meningiomas in 11 patients. Decision-tree sensitivity analysis for pretest probability regarding expected cost saving was performed for introduction of the combined study. RESULTS: All but one focus of CNS lymphomas or germinomas (92.9%, 13/14) exhibited more intense uptake of 67Ga than of 201Tl (p < 0.001). All foci of glioblastomas (10/10) and meningiomas (13/13), and 60% of metastatic foci (6/10) exhibited higher uptake of 201Tl than of 67Ga (p < 0.035). Expected cost saving in the 1% to 50% range of pretest probability of CNS lymphoma or germinoma would be from minus dollars 842US to plus dollars 2,047US per patient for introduction of the combined study, because of substitution of stereotactic biopsy for craniotomy. The pretest probability was the key factor for cost saving of the combined study. CONCLUSIONS: A 67Ga-positive and 201Tl-positive pattern with more intense uptake of 67Ga than 201Tl probably suggests CNS lymphoma or germinoma. This combination study appears to be cost-effective only in patients highly suspected of having CNS lymphoma or germinoma.

Adolescent↗
PubMed2002

[The current status of noninvasive cardiac diagnosis in women with suspected coronary heart disease].

BACKGROUND AND OBJECTIVE: Coronary artery disease is the leading cause of mortality among women in the industrial countries. Unfortunately, the routinely available noninvasive tests used to screen the presence of coronary artery disease have been relatively insensitive and nonspecific for women. The aim of this study was to evaluate the importance of pretest coronary artery disease probability and to determine whether the evaluation of left ventricular diastolic parameters is a relevant diagnostic tool in women with suspected coronary artery disease. PATIENTS AND METHODS: Electrocardiography at rest and during exercise, echocardiography at rest with evaluation of systolic and diastolic functional parameters, dobutamine stress echocardiography, exercise thallium myocardial scintigraphy, and coronary angiography were performed in 180 consecutive patients with suspected coronary artery disease. RESULTS: Coronary angiography revealed significant coronary artery disease in 104 patients. Angina pectoris, resting and exercise electrocardiography had a very low pretest probability in women. Dobutamine stress echocardiography, myocardial scintigraphy and the evaluation of left ventricular diastolic function showed less relevant gender-related differences and had a significantly better pretest probability. CONCLUSION: Dobutamine stress echocardiography and exercise thallium myocardial scintigraphy are reliable methods of diagnosing coronary artery disease in women. Echocardiographic assessment of diastolic left ventricular function represents another screening test for the evaluation of suspected coronary artery disease in women. All three methods, however, are not able to discriminate between coronary macro- or microangiopathy.

Aged↗
PubMed2006

Variable performance of weaning-predictor tests: role of Bayes' theorem and spectrum and test-referral bias.

OBJECTIVE: We examined whether variation in reported reliability of the frequency-to-tidal volume ratio (f/V(T)) in predicting weaning success is explained by spectrum and test-referral bias, as reflected by variation in pretest probability of success. DESIGN: Two authors extracted data from all studies on reliability of f/V(T) as a weaning predictor. RESULTS: Prevalence of successful weaning in studies of f/V(T) revealed significant heterogeneity; mean success rate was 0.75. The heterogeneity and high success rate reflects occurrence of spectrum bias, suggested by the lower value of f/V(T) in subsequent studies than in the original report (77.4 vs. 89.1) and test-referral bias, suggested by lower specificity of f/V(T) in subsequent studies than in the original report (0.52 vs. 0.64). When data from studies in the ACCP Task Force's meta-analysis of studies on f/V(T) were entered into a Bayesian model with pretest probability (prevalence of success) as the operating point, observed posttest probabilities were closely correlated with values predicted by the original report on f/V(T): positive-predictive value r = 0.86 and negative-predictive value r = 0.82. Average sensitivity, the most precise measure of screening-test reliability, was 0.87 +/- 0.14 and average specificity 0.52 +/- 0.26. CONCLUSIONS: Much of the heterogeneity in performance of f/V(T) can be explained by variation in pretest probability of successful outcome, which may be secondary to spectrum and test-referral bias. The average sensitivity of 0.87 indicates that f/V(T) is a reliable screening test for successful weaning.

Bayes Theorem↗
PubMed2006

Differential involvement of the endocannabinoid system in short- and long-term expression of incentive learning supported by nicotine in rats.

RATIONALE: We previously reported that the CB1 cannabinoid receptor antagonist, rimonabant, impaired the acquisition and the short-term (24 h), but not long-term (3 weeks), expression of conditioned place preference (CPP) induced by nicotine in rats. OBJECTIVE: To assess the time interval of efficacy of a single pretest injection of rimonabant to abolish nicotine-CPP, and the effects of chronic CB1 receptor blockade on long-term expression of nicotine-CPP. MATERIALS AND METHODS: Wistar rats were conditioned to nicotine (0.06 mg/kg, subcutaneous) using an unbiased one-compartment procedure. Two test sessions were conducted 24 h (without injection) and 1, 2, or 3 weeks later. Rimonabant (3 mg/kg, intraperitoneal) or vehicle was administered daily between the two test sessions. In addition, the CB1-stimulated [(35)S]GTP-gamma-S binding was assessed in rats from the 3-week experiment. RESULTS: The capacity of a single injection of rimonabant (3 mg/kg, 30 min pretest) to block the expression of nicotine-CPP disappeared within 1 week after conditioning. Daily administrations of rimonabant for 6, 13, or 20 days post-acquisition did not impair nicotine-CPP but allowed an additional pretest injection of rimonabant to retain its capacity to abolish long-term expression of nicotine-CPP. The CB1 receptor-mediated G-protein signaling was not altered in various brain areas of rats given rimonabant for 3 weeks. CONCLUSIONS: The endocannabinoid system is essential to the expression of nicotine-CPP during less than 1 week after conditioning but not later. However, endocannabinoid-dependent mechanisms are critically involved in the development of the neuroadaptive changes responsible for the shift from CB1-dependent to CB1-independent expression of nicotine incentive learning.

Animals↗
PubMed2003

fMRI analysis of ankle movement tracking training in subject with stroke.

This study examined whether ankle-movement tracking training could improve ankle function and brain reorganization, evidenced with functional magnetic resonance imagery (fMRI), in a single subject with stroke. Test measurements included self-ratings of functional activities, 15.24 m (50 feet) walk time, ankle range of motion, ankle tracking accuracy, and peak dorsiflexion movement during dorsiflexion phases of tracking. Cortical activation in the frontal and parietal lobes was measured during fMRI with an active voxel count. Additionally, a signal intensity index was determined for the gyrus precentralis (GPrC). Training consisted of 16 sessions of tracking waveforms on a computer screen with ankle motion. Four pretest, four posttest and two follow-up measurements occurred. Data were analyzed by visual inspection and by statistical analysis that examined whether posttest measurements exceeded the pretest mean by at least two standard deviations on at least two consecutive posttest measurements. Posttest results showed that the subject's self report of paretic ankle "catches" (failure of toes to clear floor during swing phase) during gait were eliminated and that peak dorsiflexion movement improved visually but not statistically. Multiple cortical areas showed increased voxel count statistically, as did the intensity index for GPrC. Follow-up results showed that the ankle "catches", peak dorsiflexion movement, and the intensity index remained at the same levels as posttest. Voxel counts returned toward pretest values. We concluded that tracking training produced training effects in both ankle function and brain reorganization.

Ankle↗
PubMed2005

Hand dominance and performance in a laparoscopic skills curriculum.

BACKGROUND: This study evaluated the influence of hand dominance on skill acquisition during a basic laparoscopic skills curriculum. METHODS: A total of 27 surgical residents (5 postgraduate year 3 [PGY-3] and 22 PGY-2 residents) participated in a 4-week laparoscopic skills curriculum. The residents were pre- and posttested on six laparoscopic tasks during weeks 1 and 4. During weeks 2 and 3, the residents attended a proctored practice session. The results were compared using analysis of variance (ANOVA), (with significance determined by a p value less than 0.05. RESULTS: The posttest scores were significantly higher than the pretest scores. On the pretest, lefthand-dominant (LHD) surgeons (n = 4) performed significantly better than righthand-dominant (RHD) surgeons (n = 23). In the analysis of individual task pretest scores, LHD surgeons performed significantly better on pattern cutting and vessel loop application. Posttest analysis of overall performance did not show significant differences between the RHD and LHD surgeons. CONCLUSIONS: Participation in a laparoscopic skills curriculum improved overall performance. The LHD surgeons demonstrated better initial performance, but posttest comparison showed no difference between the two groups.

Adult↗
PubMed1995

Incremental value of exercise electrocardiography and thallium-201 testing in men and women for the presence and extent of coronary artery disease.

Our goal was to assess the incremental value of exercise testing in men and women for the diagnosis and extent of coronary artery disease. With data from one center, incremental logistic algorithms were developed and evaluated in a separate set of 865 patients from four centers. Variables included were pretest (age, sex, symptoms, diabetes, smoking, and cholesterol concentration); exercise electrocardiogram (ECG) (ST-segment depression [millimeters], ST-segment slope, peak heart rate, and change in systolic blood pressure); and thallium-201 scintigram (defect presence, reversibility, and intensity of hypoperfusion). End points were coronary disease presence (50% diameter stenosis) and extent (multivessel disease). Accuracy and incremental value were assessed by receiver operating characteristic (ROC) curve analysis. Incremental ROC curve areas for disease presence were pretest 0.75 +/- 0.02, post-exercise ECG 0.82 +/- 0.01, and post-thallium scintigram 0.85 +/- 0.01 and for disease extent were pretest 0.71 +/- 0.02, post-exercise ECG 0.76 +/- 0.02, and post-thallium scintigram 0.78 +/- 0.02 (p < 0.005 for all increments). Incremental increases in accuracy were similar for men and women. We conclude that when multivariable algorithms derived from one center were applied to a separate group, there was a significant incremental increase in accuracy associated with exercise testing for the presence and extent of coronary disease. This increase in accuracy was similar for men and women.

Adult↗
PubMed1994

Early and intensive physiotherapy accelerates recovery postarthroscopic meniscectomy: results of a randomized controlled study.

The efficacy of an early, intensive, supervised rehabilitation program to accelerate knee strength recovery in the first 3 weeks postmeniscectomy by arthroscopy was evaluated using a randomized controlled trial design. The maximal voluntary isokinetic strength of 31 men, randomly allocated to either a treatment (EXP) or a control (CTL) group, was measured twice by a blind rater: preoperatively (pretest) and 3 weeks postsurgery (posttest), using a computer-controlled Kin-Com dynamometer (Chattecx Corporation, Chattanooga, TN). Strength deficits of the operated leg at the pretest and posttest were established in percent of the values obtained for the sound leg at the pretest. In the interval between the surgery and the posttest, the patients of the EXP group (n = 15) received nine supervised treatments combined to home exercises whereas patients of the control group (n = 16) had no specific physiotherapy treatment but were given instructions in postsurgical management and prescribed exercises by the orthopedic surgeons. Patients of the EXP group had better knee extensor strength recovery than patients of the CTL group (ANCOVA, p < 0.001). The size of the strength difference (3 weeks postsurgery) between EXP and CTL subgroups (n = 8) matched according to preoperative deficits was as large as 26% and the residual deficits of the untreated patients were two to three times larger than those of the treated patients. The results of this study highlight the importance of instituting an early intensive and supervised rehabilitation program, especially for workers returning to a strenuous job requiring good knee extensor muscle function.

Activities of Daily Living↗
PubMed1995

Effects of desipramine and alprazolam on forced swimming behaviour of adult rats exposed to prenatal diazepam.

Pregnant rats were treated with a single daily s.c. injection of diazepam (2 mg/kg) over gestation days 14-20. This treatment led to a reduction in GABA receptor complex function since adult male offspring showed a strong decrease in electrographic hippocampal responses to alprazolam and a strongly increased response to picrotoxin after intra-locus coeruleus injection of the two compounds. No difference in immobility time in the forced swimming test and in spontaneous motor activity was observed between prenatally vehicle- and diazepam-exposed offspring. Conversely, prenatal exposure to diazepam potentiated the anti-immobility effect of subchronic desipramine (10 mg/kg i.p.) and made active a dose of desipramine (5 mg/kg i.p.) that was ineffective in prenatally vehicle-exposed rats. This effect was observed only in pretested rats. Prenatal exposure to diazepam blocked the anti-immobility effect of subchronic alprazolam (15 mg/kg i.p.) in both non-pretested and pretested rats. Spontaneous motor activity was strongly reduced in all groups. These findings suggest that a persistent reduction in GABA receptor complex function, induced by prenatal exposure to diazepam, does not alter the mobility of adult progeny in the forced swimming test, but it may have consequences when drugs acting on the GABA receptor complex are used.

Alprazolam↗
PubMed1986

Failure of pimozide and metergoline to antagonize the RDS-127-induced facilitation of ejaculatory behavior.

Metergoline, a serotonin-receptor antagonist, when administered in either an ascorbic acid or ethanol containing vehicle was without effect on male rat copulatory behavior (3 mg/kg, 90 minutes pretest). When initially dissolved in several drops of acetic acid, however, the same dose of metergoline dramatically suppressed male rat sexual behavior. Thus, one-half of the treated rats failed to intromit and ejaculate, and those displaying the behaviors exhibited elongated intercopulatory and postejaculatory intervals. The administration of the putative dopamine-receptor agonist RDS-127 (2-N,N-di-n-propylamino-4,7-dimethoxyindane; 3 mg/kg, six minutes pretest) induced seminal emission ex copula and drastically reduced intromission frequency and ejaculation latency in copula, as well as effecting lesser reductions in the intercopulatory and postejaculatory intervals in two sequential copulatory series. RDS-127-induced seminal emission was effectively antagonized by pretreatment with the dopamine-receptor antagonist pimozide (250 micrograms/kg, two hours pretest), but not by pretreatment with metergoline. In contrast to seminal emission ex copula, pimozide pretreatment failed to antagonize the RDS-127 facilitation of ejaculatory behavior in copula. Metergoline pretreatment also failed to antagonize the RDS-127-induced facilitation of ejaculatory behavior in copula. However, RDS-127 prevented the suppressive effects of metergoline treatment, suggesting that RDS-127 has some agonistic action at serotonergic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Concussion-induced retrograde amnesia in rats.

Three experiments were conducted to investigate the characteristics of retrograde amnesia (RA) induced by concussion in rats. In Experiment 1, rats receiving experimental concussion shortly after training in a single punishment trial exhibited severe forgetting on a retention test 48 h later. In the second experiment, rats receiving a concussion within 6 h after training showed severe RA, while those receiving concussion one day to five days after training exhibited progressively weaker amnesia. In Experiment 3, amnesic animals in one group received pretest noncontingent foot shock as a reminder treatment. This pretest cue significantly increased the cross-through latency, thus indicating a reduction in the memory deficit resulting from concussion. These results suggest that experimental concussion can be an effective method to induce retrograde memory loss in rats; that the RA caused by concussion is time-dependent; and that concussion-induced RA can be alleviated by a pretest cue indicating that the underlying mechanism of concussion-induced RA is more likely to be a retrieval deficit than a consolidation failure.

Amnesia, Retrograde↗
PubMed1985

Reduction of nicotine-induced hyperactivity by pCPA.

Spontaneous locomotion of female Wistar rats was measured in six to ten minute sessions in an automated tunnel maze consisting of a central arena and six radially symmetrical angled arms. Nicotine (0.2 mg/kg subcutaneous, 20-30 minutes pretest) increased total arm visit frequency, but intrasession habituation and number of repetitive arm visits in the first six choices were not affected. pCPA (300 mg/kg IP three days pretest) reduced arm-visit frequency in nicotine-, but not in saline-treated rats; it had no effect on intrasession habituation or number of repetitions in either treatment group. 5-HTP (50 mg/kg IP 90 minutes pretest) reduced arm entry frequency in saline-, nicotine-, and pCPA-treated groups. Possible reasons for this discrepancy are discussed.

5-Hydroxytryptophan↗
PubMed1988

On the role of endogenous GABA in the forced swimming test in rats.

GABA content was reduced in the nucleus accumbens, cortex and brainstem of rats after 5 but not after 45, 120 min or 24 hr, from the termination of the pretest session. This reduction was not observed in rats performing on rotarod. Intraperitoneal AOAA (25 mg/kg; 24, 5 and 1 hr before the test), reduced at the same extent immobility time regardless whether the animals had been exposed to a pretest session. In pretested animals, reduction in immobility time produced by AOAA (25 mg/kg X 3 times) was similar to that observed following 50 mg/kg, 5 hr before testing. This reduction was not antagonized by GABA antagonists bicuculline (2 mg/kg) or picrotoxin (2 mg/kg), given intraperitoneally 30 and 20 min before the test respectively. Intraperitoneal sodium valproate (200 or 400 mg/kg; 24, 5 and 1 hr before the test) and isoniazide (200 mg/kg) or 4-deoxypyridoxine (400 mg/kg), administered 1 or 1.5 hr before the test, were ineffective. AOAA (25 mg/kg X 3 times) gave a similar increase in GABA levels to 50 mg/kg only once in the brainstem, nucleus accumbens and hypothalamus and a greater increase in the other brain areas. After 5 hr from single dosing, 25 mg/kg AOAA increased GABA levels less than 50 mg/kg AOAA in the brainstem, nucleus accumbens, frontal cortex and striatum, and increased it to same extent in the other areas. Sodium valproate (400 mg/kg X 3 times) increased GABA levels in all brain areas, except hippocampus, although to a lesser extent than AOAA.

Aminooxyacetic Acid↗
PubMed1996

FS stress induces long-lasting memory facilitation: involvement of cholinergic pathways.

We tested in vivo the hypothesis that foot-shock (FS) stress-induced prolongation of latencies in the one-trial step-through passive avoidance learning task in mice occurred through a long-term facilitation process. Whereas behavioral responses in control mice lasted for 24 h, decreasing progressively in the subsequent days, FS-stress exposure for 15 min before training (pretraining), immediately after training (posttraining), or 15 min before the test (pretest) resulted in a profound and sustained enhancement of test latencies that lasted for at least 96 h. These facilitating effects disappeared when FS exposure was delivered with a 2- or 3-h difference with respect to the training trial. Scopolamine (Scop) (1 mg/kg, intraperitoneally) 30 min before the training session caused impairment of test latencies in control and pretest stressed animals, but failed to affect both pre- and posttraining FS stress-induced enhancement. Our working hypothesis is that FS stress may increase the levels of acetylcholine in the presynaptic terminal or the firing rate of cholinergic input. Animals pretreated with FS stress daily for 1 or 4 days followed by the acute schedule described above showed no enhancements of test latencies. Pretraining Scop impaired test latencies in pre- and posttraining and pretest stressed animals, suggesting that unpredictability is a critical factor in activating behavioral long-term facilitation.

Animals↗