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At least 19 recordsLinked to original sources
PubMed1990

Increase of dendritic branching of CA3 neurons of hippocampus and self-stimulation areas in subjects experiencing self-stimulation of lateral hypothalamus and substantia nigra-ventral tegmental area.

Golgi examination of neurons of self-stimulation areas of the lateral hypothalamus and substantia nigra-ventral tegmental areas of adult Wistar rats that had experienced self-stimulation for 10 days revealed a significantly higher number of dendritic branching points in the two self-stimulation areas, and also in the hippocampus (CA3 pyramidal neurons) than in inexperienced rats.

Animals↗
PubMed1985

[Supplementation of antenatal cardiotocography (nonstress test) by nipple self stimulation].

Self-stimulations of nipples were performed in 155 late pregnant women in connection with antenatal cardiotocography (nonstress test). Cardiotocographs were interpreted using an own score. Uterine contractions could be produced by nipple stimulation in 111 women (71.6 per cent). In 13 cases with score 6 to 8 these contraction contributed to explantation of fetal condition. In additional 11 cases with score 9 to 10 the attention was focussed to the reduced fetal or placental capacity by the suspect cardiotocogram. In this group frequency of caesarean section was increased significantly. In cases with successful nipple stimulation the rate of labour induction with effect was higher. Oxytocin liberation by nipple stimulation may be regarded as endogenous oxytocin stress test. This simple procedure which can be done quickly and without danger is supposed to be a good supplement to nonstress test. Its reliability can be improved and the success of induction of labour estimated.

Breast↗
PubMed1975

Interactions of adrenergic stimulants and blockers on self-stimulation behavior in rats.

Self-stimulation behavior in rats was facilitated by two adrenergic stimulants, amphetamine (0.5 or 1 mg/kg, intraperitoneal, i.p., or 100 mug, intracerebroventricular, i.c.v.) and cocaine (5 mg/kg, i.p.). Three alpha-adrenergic blockers (phenoxybenzamine, dibenamine, phentolamine) and a beta-adrenergic blocker (propranolol) decreased self-stimulation responding at 100 mug i.c.v. doses, but showed very little effect at small i.p. doses. Pretreatment with alpha- and beta-adrenergic blockers (i.c.v.) also decreased amphetamine-facilitated responding. The effects of amphetamine or cocaine (i.p.) were not significantly altered by these blockers at the doses used. The depressant effects of the alpha- and beta-adrenergic blockers on self-stimulation behavior appear to be nonspecific with respect to the type of adrenergic receptors.

Adrenergic alpha-Agonists↗
PubMed1990

Frequency-response characteristics provide a functional separation between stimulation-bound feeding and self-stimulation.

Many lateral hypothalamic electrodes that support self-stimulation also elicit feeding. Refractory period and conduction velocity estimates for the axons supporting these behaviors appear identical, suggesting that these behaviors may be elicited by stimulation of a common directly activated substrate. However, it is not known if the substrate(s) for the two behaviors integrate activity in directly stimulated axons similarly in controlling their respective behaviors. This study generates rate-frequency curves for a range of current intensities for self-stimulation and stimulation-bound feeding, using bar press rate and ingestion rate, respectively, as behavioral measures. For self-stimulation, as is well established, increases in intensity shift rate-frequency curves toward lower frequencies. For stimulation-bound feeding, increases in intensity raise asymptotic ingestion rate, but do not always appreciably change the location of the curve along the frequency axis. The different parametric profiles obtained for the two behaviors suggest different processes of integrating neural activity in the directly activated substrates.

Animals↗
PubMed1992

Modelling drug kinetics with brain stimulation: dopamine antagonists increase self-stimulation.

The rewarding effects of brain stimulation and drugs are believed to depend on a common neural system. However, the pattern of responding produced by drug reinforcers is different from the pattern produced by conventional brain stimulation. Furthermore, pharmacological antagonists of reinforcement increase the rate of drug self-administration but depress self-stimulation. To test the hypothesis that the differences in the characteristics of brain stimulation and drugs as reinforcers are due to differences in the kinetics of drugs and brain stimulation, we modelled drug kinetics with frequency-modulated trains of brain stimulation. We report that animals will self-administer such brain stimulation in a manner that resembles drug self-administration and that, under these conditions, dopamine antagonists can increase the rate of self-stimulation.

Animals↗
PubMed1976

Separation of inhibiting and stimulating effects of morphine on self-stimulation behaviour by intracerebral microinjections.

The effects on self-stimulation behaviour of 5 mug morphine HCl applied into the ventricular system and into different areas throughout the brain were studied. Injections into the ventricular system and in areas intermediate between the posterior hypothalamus and the periaqueductal grey matter had biphasic effects: an inhibition followed by an excitation. Injections into the posterior hypothalamus resulted in increased self-stimulation whereas injections into the periaqueductal grey matter and into the locus coeruleus were only inhibiting.

Animals↗
PubMed1973

Some characteristics of self-stimulation behavior of dogs.

Self-stimulation was studied in dogs chronically implanted with electrodes in different points within the basal forebrain. The animals exhibiting pure self-rewarding behavior were defined as "optimal" and "good self-stimulators", whereas those with concomitant aversive phenomena were incorporated into the third category called "self-stimulation-withdrawal". In "optimal self-stimulators" a remarkable resistance of the response to extinction was noted. A strong negative attitude toward food was found in four dogs upon stimulation of the self-rewarding loci. Penile erection accompanied self-stimulation in two animals. Sniffing at first always followed incentive brain stimulation, but later it appeared at the beginning of each experiment and/or preceded the bouts of pressing. A rise of hypothalamic temperature was noted in mast of the animals. In some cases this was equal to or exceeded 1 degree Celsius. The temperature increase was accompanied by intense panting between the bouts. Seizures appeared locally as contractions of masticatory muscles and sometimes developed into a generalized fit. Anatomically the "reward area" in the dog extends from the septum and the preoptic area to the mammillary bodies and reaches laterally to the internal capsule.

Animals↗
PubMedDate not supplied

Designing of a brain stimulator suitable for intracranial self-stimulation experiments for studying the brain-stimulation reward system.

A circuit design has been developed and described for fabricating and using in the intracranial self-stimulation experiments on rat to study the brain-stimulation reward behaviour, and to explore into the underlying mechanisms of drives and motivated behaviours. The stimulator can be fabricated with parts available in India. It has been continuously used and tested during the last four years in different research studies.

Animals↗
PubMed1991

Cocaine enhances the reward value of medial prefrontal cortex self-stimulation.

Intracranial self-stimulation (ICSS) of at least some brain sites is thought to be mediated by mesolimbic dopamine (DA) neurons. However other ICSS sites, especially those in the medial prefrontal cortex (MFC), have been shown to be relatively insensitive to drugs (e.g. amphetamine, neuroleptics) that alter DA synaptic transmission. In the present study, rats with ICSS electrodes implanted in both the medial forebrain bundle (MFB) and the MFC were treated once per day for 10 days with cocaine (15.0 mg kg-1). Cocaine decreased the thresholds for both MFB (-51.4%) and MFC (-23.0%) ICSS. Cocaine also increased rates of responding for MFC but not MFB ICSS. These data provide additional support for the view that the MFC contributes to the rewarding effects of cocaine.

Animals↗
PubMed1975

A role for dopamine in the psychopharmacology of electrical self-stimulation.

The psychopharmacology of electrical self-stimulation of the lateral hypothalamus was studied using 6-hydroxydopamine, alpha-methyltyrosine, U-14, 624, and d-amphetamine. Reduction of brain dopamine, but not norepinephrine, with 6-hydroxydopamine produced an acute depression of responding which eventually recovered to pretreatment levels. A low dose of alpha-methyltyrosine, which did not affect responding in control rats, significantly depressed responding in the rats with brain dopamine reduced. This treatment did not alter responding of rats with norepinephrine reduced by 6-hydroxydopamine. A dopamine-beta-hydroxylase inhibitor, U-14, 624, depleted norepinephrine an additional 70% yet failed to alter self-stimulation in any of the groups. In other experiments, the 6-hydroxydopamine treatment which reduced brain dopamine was found to block the facilitation of self-stimulation produced by d-amphetamine. This facilitation of lateral hypothalmic self-stimulation was not influenced by treatments which reduced brain norepinephrine. An experiment suggesting that dopamine is of importance to locus coeruleus self-stimulation is also described. Implications of these data indicating a role for dopamine in self-stimulation responding are discussed in relation to the "catecholamine hypothesis of self-stimulation".

Animals↗
PubMed1985

An investigation of the factors affecting development of frontal cortex self-stimulation.

Intracranial self-stimulation (ICSS) of the medial prefrontal cortex (MFC) is acquired gradually, taking 4 or more days to establish. One explanation for this finding is that the stimulation becomes more rewarding with repetition. Four experiments were conducted to test this hypotheses. In Experiment 1, the MFC ICSS frequency thresholds remained constant over the first 3 weeks of testing while the rate of lever pressing response increased. In Experiment 2, it was found that acquisition of MFC ICSS was much more rapid when a motorically simpler response (nose-poking) was employed. Similarly, Experiments 3 and 4 further demonstrated that response factors such as task complexity may ultimately determine the rate of development of frontal cortex ICSS. Overall, these data suggest that independent of the rewarding effects of MFC stimulation there are other effects that initially interfere with learning of complex operant responses.

Animals↗
PubMed1990

Ketamine blocks the plasticity associated with prefrontal cortex self-stimulation.

Intracranial self-stimulation (ICSS) at sites within the medial prefrontal cortex (MFC) is acquired slowly but can be hastened by prior exposure to a regimen of noncontingent stimulation delivered to the MFC ICSS electrode. The facilitatory effects of noncontingent MFC stimulation on subsequent ICSS acquisition were blocked by pretreatment with ketamine, a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptor. These findings provide further support for the view that the NMDA receptor is importantly involved in mechanisms of neural plasticity.

Animals↗