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Biomedical subjects

E Fonberg

Publications and source records attributed to E Fonberg.

63 records · Page 4Linked to original sources
PubMedDate not supplied

The suppressing effect of chlorpromazine treatment on alimentary-social differentiation in amygdala dogs.

Experiments were performed on dogs with bilateral electrolytic damage of dorso-medial amygdala. Before the operation dogs were trained in alimentary-social reward differentiation. It consisted in conditioning of instrumental responses of either right or left foreleg to two different tones respectively. Chlorpromazine was injected intramuscularly in 1.5 mg/kg dose during four consecutive days, beginning at third to fifth week after the operation. Amygdala damage produced significant deterioration of the instrumental performance both reinforced by food and by social-sensory rewards. Chlorpromazine produced further dramatic decrease of performance of both responses. It was concluded that chlorpromazine exerts a suppressing effect on motivated behavior reinforced by positive rewards in amygdala dogs. As the effect of chlorpromazine and medial amygdalar damage are summated it may be suggested that the deficit of medial amygdala neurons impairs similar neurochemical mechanisms, (probably dopaminergic and alpha-adrenergic transmission) as does chlorpromazine.

Amygdala↗
PubMedDate not supplied

Amphetamine increases intertrial but not conditional instrumental responding in the cortico-basomedial amygdalar dogs.

The effect of partial cortico-basomedial amygdaloid lesions on dogs' social behavior was investigated. The lesions did not affect the conditional instrumental responding (CRs) reinforced by petting or the dogs' need for petting (US). The lesions increased the number of intertrial responses (ITRs) in all dogs. Subsequently the effect of low amphetamine doses (0.5 mg/l kg) administered intramuscularly to the amygdalar animals on the same behavioral parameters of the social behavior was examined. Amphetamine did not affect CRs but dramatically increased the ITRs and dogs' need for petting. These findings suggest that the cortico-basomedial amygdaloid region may be involved in the cortical inhibitory mechanisms that are indispensable for promoting behavioral acts according to their usefulness and the situational context.

Amphetamine↗
PubMedDate not supplied

Amphetamine effects on unconditional and conditional instrumental responses with alimentary and social rewards in dogs.

The effect of amphetamine dose (0.5 mg per 1 kg) on conditional and unconditional responses based on alimentary and social motivation was investigated in two groups of dogs. Amphetamine resulted in a significant decrease of conditional instrumental responses (CRs) in both groups but did not attenuate significantly the dogs' need for food or petting. On the contrary, the drug drastically increased the dogs' need for petting, and its anorectic effect was mild. The deteriorating effect of amphetamine on mnemonic processes and its facilitatory effect on behaviors directed to get more than the usual amount of pleasant tactile stimulation might underlie the behavioral changes described in this study.

Amphetamine↗
PubMedDate not supplied

Training of instrumental responses in dogs socially reinforced by humans.

The motivational bases of the social reinforcement in human-dog relations were examined. In experiment I, performed on seven dogs, it was found that dogs were able to learn and sustain the natural responses of sitting, paw extension, and lying prostrate to conditional stimuli in the form of vocal commands reinforced only by social rewards given by the experimenter, such as petting and vocal encouragement. Overtraining did not produce deterioration of performance but, on the contrary, the continual decrease of latencies. It was evidenced that tactile stimulation plays an important role in social reward. In experiment II, instrumental responses to the auditory conditional stimuli were elaborated in two groups of dogs. The first group (nine dogs) was reinforced by food, and the second group (eight dogs) was reinforced exclusively by petting. A similar course of learning and level of performance during overtraining sessions in both groups indicated that petting serves as a good reinforcement, with rewarding value comparable to that of food reinforcement. It is suggested that a strong rewarding effect of pleasurable sensory stimuli occurs in the formation of the bond between dog and human and in the learning of different tasks.

Animals↗
PubMedDate not supplied

Does treatment with essential amino acids and hypertonic glucose improve survival in acute renal failure?: A meta-analysis.

We performed a meta-analysis of four randomized trials (RCTs) and one concurrent control study which addressed the following question: Does treatment with amino acid solutions and hypertonic glucose improve survival of seriously ill patients with acute renal failure who are unable to take oral or enteral feedings? Three RCTs compared outcomes with essential amino acid solutions (EAA) and hypertonic glucose against hypertonic glucose alone, and their results were pooled. Use of EAA was associated with an absolute increase in initial survival of 0.24 as compared to glucose (confidence interval: +.015 to +.446). Without weighting the data to reflect the quality of the RCTs, this effect was significant (p = .017). Patients needing dialysis showed a significant treatment effect (p = .015), while those not requiring dialysis did not (p = .11). However, survival to hospital discharge was not significantly improved for the patient population as a whole (p = .10). Using a standardized quality assessment protocol, the four RCTs received scores ranging from .188 to .357 out of a possible 1.00. Any statistically significant treatment effects were abolished by factoring the quality scores of the studies into the data-pooling process. Sensitivity analysis was performed to determine the effect of including the nonrandomized study. Although it had more patients than the other studies combined, the nonrandomized study was of low quality (score: .032) and its inclusion did not change the outcome of data pooling once quality weighting was applied. We conclude that the efficacy of these parenteral nutritional regimens remains uncertain in this clinical setting.

Acute Kidney Injury↗
PubMedDate not supplied

Changes in conditioned performance and general behavior produced by imipramine treatment in dogs.

Dogs with electrolytic damage of dorsomedial amygdala and lateral hypothalamus manifested the syndrome of depression. They were used as models for studying the effects of a tricyclic antidepressant. Imipramine treatment produced increase in general arousal, motility and reactivity as tested by various tests, changes in social behavior and only slight improvement of instrumental conditioned performance. In normal dogs the imipramine administration in most subjects resulted in either no effect or deterioration of various learned tasks. Strong individual differences in the reactivity to drug treatment were observed in both normal and lesioned (depressed) dogs.

Amygdala↗