Biomedical subjects

L Cahill

Publications and source records attributed to L Cahill.

54 records · Page 3Linked to original sources

PubMed1995

A novel demonstration of enhanced memory associated with emotional arousal.

The relationship between emotional arousal and long-term memory is addressed in two experiments in which subjects viewed either a relatively emotionally neutral short story (presented as a brief slide show) or a closely matched but more emotionally arousing story and were tested for retention of the story 2 weeks later. Experiment 1 provides an essential replication of the results of Heuer and Reisberg (1990) and illustrates the common interpretive problem posed by the use of different stimuli (slides) in the neutral versus emotional stories. In Experiment 2, identical slides (and sequence) were used in both the neutral and arousal stories. Two different stories were created by varying the narration that accompanied each slide. In both experiments, subjects who viewed the arousal story both experienced a greater emotional reaction to the story than did the subjects who viewed the neutral story, and subsequently exhibited enhanced memory for the story. Subjects in Experiment 2 who viewed the arousal story also recalled more slides than did the subjects who viewed the neutral story. This effect was greatest for story phase 2, the phase in which the emotional slide narration occurred. Because this enhanced retention of the story slides cannot be explained by any differences in the slides themselves, the results provide new evidence to support the contention that emotional arousal influences long-term memory in normal human subjects.

Adult↗

PubMed1995

Spared retention of inhibitory avoidance learning after posttraining amygdala lesions.

Previous findings indicate that the memory-impairing effects of posttraining amygdala lesions are attenuated by increasing the number of training trials given prior to the induction of the lesion. The aim of this experiment was to determine whether the degree of impairment is also influenced by the footshock intensity used during training. Rats were given 1 trial of inhibitory avoidance (IA) training with either no footshock or a footshock at 1 of 3 intensities. Sham or neurotoxic amygdala lesions were induced 1 week later. On a retention test performed 4 days after surgery, the performance of all amygdala-lesioned rats given footshock training, including those given the lowest training footshock, was better than that of amygdala-lesioned rats given no training footshock. These findings of preserved retention of IA learning in rats given posttraining amygdala lesions do not support a general hypothesis that the amygdala is a locus of permanent changes underlying aversively motivated learning.

Amygdala↗

PubMed1995

Gambling among methadone patients.

In this paper we assess participation in various forms of gambling activities and establish the prevalence of pathological gambling in a sample of patients (N = 117) enrolled in a large methadone maintenance treatment program in New York City. Respondents were interviewed with a protocol that incorporates the South Oaks Gambling Screen. We found that gambling was a common part of the regular activities of many patients, that 15% of the patients had some problem with gambling, and that an additional 16% were probable pathological gamblers. The implications of our findings are discussed.

Adult↗

PubMed1994

Beta-adrenergic activation and memory for emotional events.

Substantial evidence from animal studies suggests that enhanced memory associated with emotional arousal results from an activation of beta-adrenergic stress hormone systems during and after an emotional experience. To examine this implication in human subjects, we investigated the effect of the beta-adrenergic receptor antagonist propranolol hydrochloride on long-term memory for an emotionally arousing short story, or a closely matched but more emotionally neutral story. We report here that propranolol significantly impaired memory of the emotionally arousing story but did not affect memory of the emotionally neutral story. The impairing effect of propranolol on memory of the emotional story was not due either to reduced emotional responsiveness or to nonspecific sedative or attentional effects. The results support the hypothesis that enhanced memory associated with emotional experiences involves activation of the beta-adrenergic system.

Adult↗

PubMed1994

Amygdala modulation of hippocampal-dependent and caudate nucleus-dependent memory processes.

These experiments investigated the effects, on memory, of injections of d-amphetamine (10 micrograms/0.5 microliter) administered into the amygdala, hippocampus, or caudate nucleus immediately after training in cued or spatial water-maze tasks. In experiment 1, rats received an eight-trial training session on one of the two tasks followed by injections of d-amphetamine or saline. Retention was tested 24 hr later. On the spatial task, intrahippocampal, but not intracaudate, injections of d-amphetamine facilitated retention. In contrast, on the cued task intracaudate, but not intrahippocampal, injections of d-amphetamine facilitated retention. Posttraining intraamygdala injections of d-amphetamine enhanced retention of both tasks. In experiment 2, lidocaine (2% solution; 1.0 microliter) injected intraamygdally prior to the retention test did not block the memory enhancement induced by posttraining intraamygdala injections of d-amphetamine. The findings (i) provide further evidence of a dissociation between the roles of the hippocampus and caudate nucleus in different forms of memory, (ii) indicate that the modulatory role of the amygdala is not limited to either of the two different forms of memory represented in spatial and cued discriminations in a water maze, and (iii) are consistent with previous findings indicating that amygdala influences on memory storage are not mediated by lasting neural changes located within the amygdala.

Amygdala↗

PubMed1994

Tolerability of enalapril initiation by patients with left ventricular dysfunction: results of the medication challenge phase of the Studies of Left Ventricular Dysfunction.

Although converting-enzyme inhibitors are useful for the treatment of congestive heart failure (CHF), there are concerns about adverse reactions especially on initiation of therapy. In the Studies of Left Ventricular Dysfunction, enalapril, 2.5 mg twice per day was given on an open-label outpatient basis for 7 days (mean 6.1, range 2 to 7, and median 7) as a prerandomization drug challenge to 7487 patients with left ventricular dysfunction (ejection fraction < or = 0.35). Four hundred forty-four (5.93%) patients reported side effects, including symptoms attributed to hypotension (in 166 patients [2.2%]). The majority (346 [77.9%] of 444 and 129 [77.7%] of 166 with symptoms attributed to hypotension) of patients who reported side effects were willing to participate in the study and to continue receiving enalapril. Thus only 98 (1.3%) of 7487 patients (0.5% because of symptoms attributed to hypotension) were not willing to continue because of side effects. Women and patients of CHF class III or IV were more likely to report side effects. In conclusion, enalapril is well tolerated by patients with left ventricular dysfunction; treatment can be initiated on an outpatient basis in the majority of patients.

Enalapril↗

PubMed1994

Reduced peak aerobic capacity in asymptomatic left ventricular systolic dysfunction. A substudy of the studies of left ventricular dysfunction (SOLVD). SOLVD Investigator. Studies of Left Ventricular Dysfunction.

BACKGROUND: Peak oxygen consumption is reduced in patients with symptomatic congestive heart failure, but functional capacity of patients with asymptomatic left ventricular systolic dysfunction has not been assessed by measurement of peak oxygen consumption attained during graded exercise testing. METHODS AND RESULTS: Peak oxygen consumption, that is, aerobic capacity (VO2, mL/kg per minute), was determined during graded treadmill exercise using the modified Naughton protocol in 40 patients with left ventricular systolic dysfunction (mean ejection fraction ranging from 14% to 35%; mean, 29%) who, while not receiving any cardiac medications, were totally asymptomatic, and in 41 age-matched normal subjects. Peak exercise duration and VO2 were significantly lower in patients with asymptomatic left ventricular systolic dysfunction than in normal subjects (948 +/- 273 versus 1239 +/- 372 seconds, P < .001, and 22.1 +/- 5.9 versus 29.8 +/- 7.7 mL/kg per minute, respectively, P < .001), while asymptomatic patients and normal subjects reached similar respiratory equivalents (1.14 +/- 0.11 versus 1.11 +/- 0.11 [NS]) and level of perceived exertion, using the modified Borg scale (7.4 +/- 2.6 versus 8.1 +/- 1.5 [NS]). Heart rate, systemic blood pressure, and oxygen pulse response to peak exercise were significantly lower in asymptomatic patients than in normal subjects. CONCLUSIONS: Although patients with left ventricular systolic dysfunction can be totally asymptomatic in their daily activities, they have experienced a substantial reduction in peak aerobic capacity when compared with normal subjects of similar age.

Aged↗

PubMed1992

Characteristics of peak aerobic capacity in symptomatic and asymptomatic subjects with left ventricular dysfunction. The Studies of Left Ventricular Dysfunction (SOLVD) Investigators.

Expired gas analysis was used to determine the aerobic exercise performance of subjects with depressed left ventricular (LV) systolic function and congestive heart failure (CHF). To determine whether subjects with no or minimal CHF have better aerobic exercise performance than do those with overt CHF, oxygen consumption (VO2) at anaerobic threshold (AT) and peak exercise was measured in 184 subjects with LV ejection fraction less than or equal to 0.35 who participated in the Studies of Left Ventricular Dysfunction. Subjects were divided into those with overt CHF needing treatment (treatment trial; n = 20) and those who had neither overt CHF nor treatment for CHF (prevention trial; n = 164). Treatment trial subjects had a lower LV ejection fraction (0.25 +/- 0.07) than did prevention trial ones (0.29 +/- 0.05; p = 0.001), but there were no differences in age, gender, body weight, resting heart rate and blood pressure. Treadmill exercise testing was performed after 2 to 3 weeks of placebo (no angiotensin-converting enzyme inhibitor) treatment. Treatment trial subjects exercised for a shorter time (493 +/- 160 seconds) and attained a lower peak VO2 (13 +/- 4 ml/kg/min) and VO2 at AT (11 +/- 4 ml/kg/min) than did prevention trial ones (842 +/- 277 seconds, and 20 +/- 6 and 16 +/- 5 ml/kg/min, respectively). Analysis of covariance showed that the differences in peak VO2 and VO2 at AT were statistically significant between the 2 trials after adjusting for age, gender, LV ejection fraction and New York Heart Association functional class.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Involvement of the amygdaloid complex in neuromodulatory influences on memory storage.

Neuromodulatory systems activated by training experiences appear to play a role in influencing memory storage processes. The research summarized in this paper examined the effects, on memory, of posttraining administration of treatments affecting adrenergic, opioid peptidergic and GABAergic systems. When administered after training, drugs affecting these systems all produce dose- and time-dependent effects on memory storage. The drug effects on memory are blocked by lesions of the amygdaloid complex as well as lesions of the stria terminalis, a major amygdala pathway. The effects of drugs affecting these neuromodulatory systems are also blocked by injections of beta-adrenergic antagonists administered to the amygdaloid complex. Thus, the findings suggest that the neuromodulatory systems affect memory storage through influences involving the activation of beta-adrenergic receptors within the amygdala. These findings are consistent with the view that the amygdala is involved in regulating the storage of memory in other brain regions.

Amygdala↗

PubMed1990

Amygdaloid complex lesions differentially affect retention of tasks using appetitive and aversive reinforcement.

The hypothesis that the amygdaloid complex (AC) is involved in the formation of stimulus-reward associations was examined. A series of experiments (1A-1C) directly compared the effects of lesions (produced by injection of the excitotoxin N-methyl-D-aspartic acid) on 1-trial appetitive and 1-trial aversive learning in rats. Experiments 1A and 1B, which used different degrees of reinforcement, revealed no effect of lesions on the appetitive task, whereas acquisition of the aversive task was significantly impaired. This impairment depended on the nature of the aversive reinforcement used: Impairment was seen when a highly aversive stimulus (footshock) was used but not when a less aversive stimulus (0.2% quinine solution) was used. Control experiments indicated that the effect of lesions was not due to reduced sensitivity to the foot-shock. In Experiment 2, a novel odor conditioning task examined further the effect of AC lesions on the acquisition of appetitive and aversive stimulus-reinforcement associations. As in Experiment 1, the AC lesions impaired learning of the aversive association but did not significantly influence the appetitive association. It is argued that, although the AC may be involved in some types of appetitively rewarded learning, the findings of a differential effect of AC lesions on aversively rewarded learning suggest a role in learning beyond the formation of stimulus-reinforcement associations.

Amygdala↗

PubMed1986

Acetylcholine, aging and anatomy: differential effects in the hippocampus.

The response to acetylcholine (ACh) administered microiontophoretically was determined for single units in CA1 and CA3-4 areas of the hippocampi of both young (3-5 months) and old (24-26 months) Fisher 344 rats. Single units in CA1 showed a greater response to ACh (20 nA) than single units in CA3-4 in young and in old rats. However, the response to ACh in single units of young rats was significantly greater than in single units of old rats. Baseline firing rates in old rats were lower than those in young rats. However, there was no difference in baseline firing rates between the two areas of the hippocampus indicating that the differential response to ACh as a function of area cannot be attributed to a difference in baseline firing rate.

Acetylcholine↗

PubMed1986

Retrograde memory enhancement by diazepam: its relation to anterograde amnesia, and some clinical implications.

The effect of diazepam on retention of an inhibitory avoidance task was investigated in mice. In Experiment 1, animals were trained in this task, and tested for retention 24 h later. The mice received, 20 min after training, an IP injection of either diazepam (2 mg/kg) or saline; half of the mice in each treatment group were exposed, 40 min after avoidance training (and 20 min after the injections) to a Y maze. Exposure to the Y maze disrupted retention of the avoidance task in the saline-treated animals, and enhanced it in the diazepam-treated mice. Retention of habituation to the Y maze was impaired in the diazepam group. The effect can be explained by an interaction of the drug with the Y maze, by which exposure to the Y maze became facilitatory, instead of deleterious, to retention of the avoidance task. This may or may not be related to anterograde amnesia for the Y maze; and may be related to effects of diazepam seen in clinical practice. In Experiment 2, diazepam was given prior to, instead of after, inhibitory avoidance training; it caused anterograde amnesia for this task, which was not reversed by pre-test diazepam, and was therefore not due to state dependency. In conclusion, the effect of diazepam on inhibitory avoidance learning depends on the time at which the drug is given. A pretraining injection causes amnesia, whereas a post-training injection, while ineffective per se, may facilitate retention of the task when it is followed by exposure to a habituation procedure.

Amnesia↗

PubMed1986

On the expression of H-Y antigen in transsexuals.

Histocompatibility-Y (H-Y) antigen, the presumptive inducer of the mammalian testis, is present in the cells of normal males and not in the cells of normal females. Recent reports have implied that patients with transsexualism exhibit H-Y antigen phenotypes at variance with those of normal males and females and, thus, that H-Y serology might provide a tool for the diagnosis and study of the transsexual condition. We therefore evaluated blood and testicular cells from 21 male-to-female transsexuals using conventional and monoclonal H-Y antibodies. We found no evidence of abnormal H-Y phenotype. Five of the patients were interviewed postoperatively by two examiners and rated for the diagnosis of transsexualism. Three of the five were rated primary transsexual by one or both examiners, and two were rated secondary transsexual.

Adult↗

PubMed1985

H-Y antigen in a 46,XX female with dysgenetic ovaries.

Hypogonadism secondary to ovarian dysgenesis or resistant ovary syndrome was diagnosed in a 19-yr-old obese woman with primary amenorrhea, a 46,XX karyotype, and an H-Y+ cellular phenotype. Small ovoid gonads (1.5 X 0.6 cm) were found found bilaterally; these were encased in a dense venous network. The stroma was ovarian, and primordial follicles and some primary follicles were present, but there were no follicles at or beyond the antrum stage. There was no evidence of testicular tissue and no evidence of malignancy. Analysis of serological data indicated the possibility of residual H-Y antigen in the blood cells of the mother.

Adult↗

PubMed1984

Gonadal tumors in patients with gonadal dysgenesis and sex chromosomal rings and fragments.

Patients with female phenotypes and dysgenetic gonads harboring testicular tissue have a markedly increased risk of developing gonadal tumors. Cytogenetic demonstration of Y chromatin is the currently accepted criterion for performing prophylactic gonadectomies in these women. We studied four patients with dysgenetic gonads containing either testicular tissue or germ cell tumors. All had small sex chromosomal fragments which could not be characterized by conventional cytogenetic studies. Clinical features, DNA replication studies, and immunologic assays of Xga and H-Y antigens failed to correlate consistently with the gonadal histology. We recommend prophylactic gonadectomies and subsequent hormone replacement in all patients with female phenotypes, gonadal dysgenesis, and cytogenetically indeterminate sex chromosomal fragments.

Adolescent↗

PubMed1984

X;Y translocation in a female with streak gonads, H-Y- phenotype, and some features of Turner's syndrome.

In women X;Y translocations usually arise as Xp-Yq exchanges. We describe a 17-year-old female with streak gonads, some minor features of Turner's syndrome, and an X;Y translocation involving an exchange between Xq and Yq. Histological examination of the gonads revealed a fibrous stroma with prominent hilar cells. Cultured fibroblasts and peripheral lymphocytes were typed H-Y-. Examination of a buccal smear revealed a single intranuclear structure with the appearance of both a Barr body and a fluorescent Y body. This finding was consistent with the results of BrdU studies showing that the translocation X chromosome had been inactivated in all cells analyzed.

Adolescent↗

PubMedDate not supplied

Impaired declarative memory for emotional material following bilateral amygdala damage in humans.

Everyday experience suggests that highly emotional events are often the most memorable, an observation supported by psychological and pharmacological studies in humans. Although studies in animals have shown that nondeclarative emotional memory (behaviors associated with emotional situations) may be impaired by lesions of the amygdala, little is known about the neural underpinnings of emotional memory in humans, especially in regard to declarative memory (memory for facts that can be assessed verbally). We investigated the declarative memory of two rare patients with selective bilateral amygdala damage. Both subjects showed impairments in long-term declarative memory for emotionally arousing material. The data support the hypothesis that the human amygdala normally enhances acquisition of declarative knowledge regarding emotionally arousing stimuli.

Adult↗

PubMedDate not supplied

Intact enhancement of declarative memory for emotional material in amnesia.

Emotional arousal has been demonstrated to enhance declarative memory (conscious recollection) in humans in both naturalistic and experimental studies. Here, we examined this effect in amnesia. Amnesic patients and controls viewed a slide presentation while listening to an accompanying emotionally arousing story. In both groups, recognition memory was enhanced for the emotionally arousing story elements. The magnitude of the enhancement was proportional for both amnesic patients and controls. Emotional reactions to the story were also equivalent. The results suggest that the enhancement of declarative memory associated with emotional arousal is intact in amnesia. Together with findings from patients with bilateral amygdala lesions, the results indicate that the amygdala is responsible for the enhancement effect.

Aged↗