Drugs that alter dopamine transmission have opposite effects on reward and punishment learning. These opposite effects have been suggested to depend on dopamine in the striatum. Here, we establish for the first time the neurochemical specificity of such drug effects, during reward and punishment learning in humans, by adopting a coadministration design. Participants (N = 22) were scanned on 4 o...

abstract injection of sulpiride (d2 receptor antagonist, antipsychotic drug) into vmn hypothalamus, increased gastric volume secretion and decreased gastric ph. the present study the effect of sch23390 (d1 dopamine receptor antagonist) on the gastric acid secretion and its acidity were studied. 70 rats were divided into 7 groups: two control groups, two sham groups given medicine solvents, a sc...

the central cholinergic system has been associated with cognitive function and memory and acetylcholine plays an important role during the early stages of memory consolidation. in this study, after training mice were tested with one way active avoidance procedure and retention were tested at 4, 8, 12, 16 and 24 hours of training and compared with non-shocked mice, in which it took 24 hours, a s...

The effects of dopamine receptor agonists on urinary bladder function were evaluated in normal and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian cynomolgus monkeys to investigate the therapeutic efficacy in the treatment of urinary symptoms in Parkinson's disease. Under ketamine anesthesia, cystometrograms exhibited significant reduction in the volume threshold for t...

The central cholinergic system has been associated with cognitive function and memory and acetylcholine plays an important role during the early stages of memory consolidation. In this study, mice were trained with one way active avoidance procedure. Different doses of arecoline and physostigmine, with and without scopolamine, were administrated at pre-training, post-training and retrieval phas...

The dedifferentiation theory of aging proposes that a reduction in the specificity of neural representations causes declines in complex cognition as people get older, and may reflect a reduction in dopaminergic signaling. The present pharmacological fMRI study investigated episodic memory-related dedifferentiation in young and older adults, and its relation to dopaminergic function, using a ran...

1 The dedifferentiation theory of aging proposes that a reduction in the specificity of neural 2 representations causes declines in complex cognition as people get older, and may reflect a 3 reduction in dopaminergic signaling. The present pharmacological fMRI study investigated episodic 4 memory-related dedifferentiation in young and older adults, and its relation to dopaminergic 5 function, u...

On most adrenergic and cholinergic nerve terminals, prejunctional α-adrenoceptors belonging to the α2-subtype have been identified. Activation of these receptors will decrease the release of norepinephrine. It has been reported that several isolated tissue preparations contain prejunctional dopamine receptors, the stimulation of which inhibits neurotransmission. It has remained uncertain whethe...

Learning to optimally predict rewards requires agents to account for fluctuations in reward value. Recent work suggests that individuals can efficiently learn about variable rewards through adaptation of the learning rate, and coding of prediction errors relative to reward variability. Such adaptive coding has been linked to midbrain dopamine neurons in nonhuman primates, and evidence in suppor...