PubMed Health⌕ Search

Biomedical subjects

E Fonberg

Publications and source records attributed to E Fonberg.

At least 37 records · Page 2Linked to original sources
PubMed1981

The effects of imipramine on socio-emotional and alimentary motivated behavior in dogs.

The effects of imipramine on spontaneous locomotor activity, alimentary motivated behavior and socio-emotional behavior were investigated in five dogs. In all dogs the main imipramine-bound effect was the decrease of locomotor activity in the open field. In four behaviorally normal dogs, performance of other tests was only slightly affected by imipramine treatment. An improvement in performance of various tasks and socio-emotional reactions was observed only in one neurotic dog.

Animals↗
PubMed1980

Electromyographic assessment of spinal reflexes in experimentally depressed dogs treated with antidepressants.

In seven mongrel dogs the syndrome of depression was evoked by bilateral electrolytic lesions in lateral hypothalamus and/or dorsomedial amygdala. The effects of tricyclic antidepressants on general mood, spinal reflexes recorded by electromyographic method, and head rate were tested. The reactivity to most external stimuli was increased and general depression was slightly reduced.

Amitriptyline↗
PubMed1980

Motivational role of social reinforcement in dog-man relations.

Lesions of dorsomedial amygdala (DMA) or lateral hypothalamus (LH) produced prominent impairment of the alimentary behavior in dogs. Besides, various behavioral responses, including social, were depressed. To evaluate whether these changes were either specific for alimentary disturbances or dependent on changes in the general reward system, another type of reward, i.e. social contact with experimenter as a reinforcement for several motor responses was introduced. Damage of amygdalo-hypothalamic system, which produced a syndrome of depression, also impaired socially reinforced responses. This impairment lasted much longer then decrease of food intake. Therefore it was assumed that DMA and LH damage produced impairment not limited to alimentary mechanisms, but involving various aspects of positive motivational system and in particular including the social behavior during man-dog relations. Taking into account various theories of reinforcement in instrumental learning the authors are inclined towards a hedonistic theory of reward.

Amygdala↗
PubMed1979

Spontaneous locomotor activity and food and water intake in rats with medial amygdala lesions.

Locomotor activity was studied with the method of electromagnetic activity meters, before and after operation in rats bilaterally lesioned in medial amygdala, and in a sham-operated control. Two activity tests were performed daily. In the first test spontaneous activity was recorded for a 30 min period without access to food or water. The second test measured 12 h of nocturnal activity with full access to food and water. Bilateral destruction of the medial amygdala resulted in an increase of locomotor activity in the 30 min test and a decrease in locomotor activity in the 12 h test. Postoperative decrease in food and water intake and body weight were only transient. These results point to a participation of the medial amygdala in the complex mechanism of locomotor activity and alimentary motivation.

Amygdala↗
PubMed1979

Alimentary instrumental responses and neurological reflexes in amygdalar cats.

Lesions in ventromedial part of amygdala impaired neither alimentary instrumental reflexes nor food intake, but impaired predatory behavior. Lesions localized in the more dorsal and lateral part of the amygdala produced disorders in instrumental performance and food intake without changes in predatory attack. Both kind of lesions did not impair neurological reflexes, therefore the abolishment of predatory attack after ventromedial amygdala damage was not caused by sensory-motor disturbances. It is concluded that predatory behavior is based on specific mechanisms separate from both alimentary and instrumental ones.

Amygdala↗
PubMed1979

The effects of imipramine treatment on the unconditioned alimentary behavior and classical conditioned salivary reactions in dogs.

In Experiment I the effect of imipramine treatment on the unconditioned food intake in dogs was tested. In Experiment II imipramine was injected in dogs in which classical conditioned salivary reflexes had been previously elaborated. Both conditioned and unconditioned salivation were decreased. The differentiation of conditioned salivation to CS+ and CS- was disturbed during the imipramine treatment, due to the prominent decrease of conditioned salivary reflexes to CS+ and also increase of reactions to CS-. Imipramine treatment produced only a slight decrease of food intake. In most dogs of both groups the increase of general arousal and improvement of social contact was observed. The variability of the imipramine effect on particular parameters of alimentary behavior depended on the individual characteristics of each dog. It is concluded that in the evaluation of the effect of imipramine one should take into consideration its differential influences on various motor, autonomic and emotional, central as well as peripheral components of alimentary behavior and characteristics of the individual subjects.

Animals↗
PubMed1976

Instrumental reactions and food and water intake in medial amygdala rats.

Rats were trained preoperatively to perform instrumental reactions for food and water reward on a continuous reinforcement schedule. Two levers on two opposite sides of the Skinner box were available. Each press of the first lever delivered one drop of water and each press of the second lever - one pellet of solid food. After the electrolytic lesions of the medial part of the amygdaloid complex, rats were hypophagic and hypodipsic. Most of the animals showed, however, only small decreases of total unconditioned daily water and food intake. On the other hand, the instrumental performance was markedly impaired, in particular for water reinforcement. Histological verification showed that lesions were restricted to the amygdaloid complex and involved mainly the ventral part of medial nucleus.

Amygdala↗
PubMed1976

Suppression and disinhibition of instrumental alimentary reactions after successive lesions of the dorsomedial and lateral amygdala in dogs.

Damage of the dorsomedial amygdala produced impairment of instrumental performance to CS(+) with no changes to CS(-). Subsequent lesion of the lateral amygdala resulted in restoration of instrumental performance to CS(+) and transient disinhibition to CS(-). These results support the hypothesis that the dorsomedial amygdala is involved in facilitation, while the lateral amygdala in inhibition of alimmentary reactions.

Amygdala↗
PubMed1975

Improvement produced by lateral amygdala lesions on the instrumental alimentary performance imparied by dorsomedial amygdala lesions in dogs.

The dorsomedial and subsequent lateral amygdala lesions were performed on 6 dogs. Lesions of the dorsomedial part produced transient aphagia, decrease of body weight and either abolishment or impairment of instrumental performance. Subsequent lesions of the lateral amygdala produced restoration or improvement and stabilization of the instrumental performance. It is supposed that the prevailing inhibitory influences from the lateral amygdala are the main cause of the impairment of instrumental performance after dorso-medial amygdalar lesions. The removal of this source of inhibition enabled restoration of instrumental performance and other alimentary positive functions.

Amygdala↗
PubMed1975

Salivary reactions in dogs with dorsomedial amygdalar lesions.

In dogs with chronic parotid fistula, conditioned salivary reactions reinforced by food were established. After bilateral lesions of the dorsomedial part of the amygdaloid complex, the conditioned salivary reactions were greatly diminished. Also the unconditioned salivation decreased. This decrease was greater in dogs which revealed the whole syndrome of amygdalar aphagia, but it was also evident in hypophagic dogs. In some dogs, the disinhibition of the salivation to negatives CS was also observed. Results show that the dorsomedial amygdala, similarly to lateral hypothalamus, is involved in the regulation of salivary reactions.

Amygdala↗