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J Mos

Publications and source records attributed to J Mos.

65 records · Page 4Linked to original sources
PubMed1983

Discriminant analysis of the localization of aggression-inducing electrode placements in the hypothalamus of male rats.

Over 400 sites in the hypothalami of 270 male CPB/WE-zob rats were electrically stimulated in order to induce fights between males. The localization of electrodes inducing fights seems to differ from the localization of electrodes in which no fights can be induced. The differences in localization were detected and tested by a non-parametric discriminant analysis. The results were plotted by computer in a stereotaxic atlas of the hypothalamus of the CPB/WE strain. The method delimits areas within the hypothalamus where the probability to induce aggression is high, intermediate or low. Moreover, the procedure allows discrimination between areas where the thresholds for attack behaviour are generally lower than elsewhere and where the fiercest forms of attack are induced. None of the areas delimited coincide with a classical subdivision of the hypothalamus. Parts of the perifornical, anterior, lateral and ventromedial hypothalamus seem to be involved. The methods developed here may help to relate stimulation-induced aggression to other characteristics of the 'aggressive' area which cannot be obtained directly from fighting rats such as cytological, endocrinological, biochemical or physiological data. In addition, the procedure may help to settle disputes on the specificity of the localization of neural substrates of other stimulation-induced behaviours. The methods to discriminate between overlapping 3-dimensional reconstructions validated here for aggressive responses, can also be applied to other types of stereotaxic data and other types of effects, such as electrical, hormonal or other physiological responses. They may be especially useful if the localization of the neural population involved is not yet known, and unknown current-spread or diffusion of substances complicates the interpretation of stereotaxic data.

Aggression↗
PubMed1983

A locked, non-rotating, completely embedded, moveable electrode for chronic brain stimulation studies in freely moving, fighting rats.

A light-weight, yet rugged moveable electrode assembly is described for chronic brain stimulation studies in small-brained animals. The assembly can be completely embedded in a smooth, unobtrusive dental cement cap and is therefore suitable for use in fighting experiments, where collisions with partners and cage walls will limit the use of other assemblies. It permits a variable electrode distance penetration of 3 mm in 75 mu-steps by using a separate unlocking turning-key. This design excludes the possibility of inadvertent displacement of the electrode tips by the animal itself. Since the electrode itself does not rotate during displacement, extra damage arising from possible eccentricity is avoided. The assembly has been used in a number of hypothalamic penetrations, demonstrating its usefulness and reliability.

Aggression↗
PubMed1982

Aggression induced by stimulation of the hypothalamus: effects of androgens.

Aggressive behavior between male rats induced by electrical stimulation of the hypothalamus (ESH) is stimulated by androgens. This was demonstrated by recording the changes in threshold current intensities (the amount of current needed to induce attack behavior in 50% of the trials), just before castration, after castration, during subsequent treatment with high doses of testosterone propionate, and finally during oil treatment. The results demonstrate that, to induce the same aggressive responses, in absence of androgens more electrical current is needed than when these hormones are present in the general circulation of the ESH stimulated animals.

Aggression↗
PubMed1982

Anti-aggressive effect of a new phenylpiperazine compound (DU27716) on hypothalamically induced behavioural activities.

Using the same hypothalamic electrodes, the following behaviour was evoked in male rats by electrical stimulation at roughly equal current intensities: attacks on a partner, teeth-chattering, switch-off behaviour and locomotion. Current thresholds were determined for each behaviour following the intraperitoneal administration of saline or DU27716, a new phenylpiperazine compound with interesting inhibitory effects on territorial and intermale aggression. DU27716 raised current thresholds for attack and teeth-chattering beginning at the lowest dose (4 mg/kg), whereas there was no effect on switch-off behaviour, and only a slight but significant effect on locomotion thresholds at the highest dose (8 mg/kg). The results provide support for the hypothesis that DU27716 possesses behaviourally selective, anti-aggressive properties, and illustrate the usefulness of hypothalamically induced behaviours as a pharmacological model.

Aggression↗
PubMed1977

[Functional anatomy of the feeding apparatus of the mallard (Anas platyrhynchos L.) structure, movement, electro-myography and electro-neurography (author's transl)].

A causal model for the functioning of the beakapparatus of the mallard during straining is formulated on a qualitative basis. The starting point for this model is an abstraction of the analysed structure of the muscle, bone, ligament system. The system was studied by electromyography and cinematography of the movements. It was attempted to quantify the model. Connections with neurography are shown.

Animals↗