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Biomedical subjects

B Beer

Publications and source records attributed to B Beer.

84 records · Page 5Linked to original sources
PubMed1969

Escape from self-produced rates of brain stimulation.

Rats were allowed to self-stimulate while their responses were being recorded on tape. Subsequently, prerecorded patterns of their brain stimulation were "played back" to them. All subjects learned to escape brain stimulation delivered in exactly the same manner as they had previously elected to receive it.

Animals↗
PubMedDate not supplied

6-Hydroxydopamine and avoidance: Possible role of response suppression.

The intraventricular administration of 6-HD to rats pretreated with pargyline resulted in severe, long-lasting decreases in avoidance responding with little or no effect on escape responding. Despite the fact that the rats failed to avoid, they appeared to be able to discriminate the CS, as was evident from freezing behavior and other symptoms of an apparent fear reaction during the CS. The increase in freezing, a response that was incompatible with avoidance was seen during the first few test sessions after 6-HD treatment and seemed to be largely responsible for a gradual decline in avoidance responding during this same period. The role of CA depletion in the animal's response to aversive stimuli thus appears to be a significant aspect of the avoidance decrement that follows 6-HD administration.

Animals↗
PubMedDate not supplied

Differential effects of intraventricular administration of 6-hydroxydopamine on behavior of rats in approach and avoidance procedures: Reversal of avoidance decrements by diazepam.

The administration of 6-hydroxdopamine (6-HD) and pargyline to rats produced similar selective decreases in responding during the conditioned stimulus (CS) on a discriminated avoidance test where the unconditioned stimulus (US) was shock and on an analogous conditioned approach test where the US was water. Approach behavior during the CS generally recovered, however, while avoidance decrements in the same rats remained for the duration of testing. This suggested that 6-HD-induced avoidance decrement was a result of two independent but interacting processes: (1) a decrease in conditioned behavior as reflected by the similar decrease in responding on both tests; and (2) a hyper-reaction to aversive stimuli that resulted in a tendency to selectively suppress avoidance behavior after the animal received shock. In support of this hypothesis, it was found that 6-HD-induced avoidance decrements could be reversed (1) by treatment with diazpam, a drug that releases suppressed responses; or (2) by delaying avoidance testing until conditioned responding had recovered, thus minimizing the interaction of the two processes.

Animals↗
PubMedDate not supplied

Modification of avoidance behavior in 6-hydroxydopamine-treated rats by stimulation of central noradrenergic and dopaminergic receptors.

Rats showing reliable decrements in conditioned avoidance behavior after the intraventricular administration of 6-hydroxdopamine (6-HD) with pargyline pretreatment were given various dopaminergic and noradrenergic agonists. Intraventricular injections of DA or L-NE or intraperitoneal injections of apomorphine or L-DOPA reversed the avoidance decrements, often restoring performance to pre-6-HD-treatment levels. Furthermore, these agonists all produced behavior characteristic of activity in dopaminergic neurons. Clonidine, a noradrenergic agonist, also reversed avoidance decrements, but did not produce behavior characteristic of stimulation of dopaminergic neurons in the brain. Pretreatment with spiroperidol, a dopaminergic receptor blocker, prevented the recovery induced by all agonists, although clonidine-induced recovery was affected least. The results are discussed in terms of possible separate roles for dopaminergic and noradrenergic neurons in the brain in avoidance behavior.

Animals↗
PubMedDate not supplied

Relationship of brain levels of norepinephrine and dopamine to avoidance behavior in rats after intraventricular administration of 6-hydoxydopamine.

Rats trained on a discriminated avoidance procedure showed long-term decrements in performance after intraventricular administration of 6-hydroxydopamine. Biochemical assay showed that DA levels were correlated with avoidance performance no matter when behavior was measured, but NE levels were most highly correlated with avoidance behavior at those times when suppression of responding appeared to be the major influence on responding. The data are discussed in terms of possible separate roles for NE and DA in avoidance behavior.

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