The relationship between nicotine and stress is complex and paradoxical. Although people claim they smoke because it relaxes them, nicotine can trigger some of the effects observed with stress, including the release and synthesis of the catecholamines and their biosynthetic enzymes. This study examined one aspect of this confusing relationship between nicotine and stress. Multiple injections of...

Clinical and experimental findings have implicated brain alpha2-adrenoceptors in the regulation of many physiological functions, including sexual activity and stress-related behavior. However, which subtypes of the three alpha2-adrenoceptors that have now been cloned (alpha2A, alpha2B, and alpha2C) are involved in these controls have yet to be established. Here, we investigated the contribution...

The GANE (glutamate amplifies noradrenergic effects) model proposed by Mather et al. attempts to explain how norepinephrine enhances processing in highly activated brain regions. Careful perusal of the sparse data available from recording studies in animals reveals that noradrenergic neurons are excited mainly by any change in the environment - a salient, novel, or unexpected sensory stimulus o...

Uncertainty is an inherent property of the environment and a central feature of models of decision-making and learning. Theoretical propositions suggest that one form, unexpected uncertainty, may be used to rapidly adapt to changes in the environment, while being influenced by two other forms: risk and estimation uncertainty. While previous studies have reported neural representations of estima...

In biological systems, functions and spatial organizations are closely related. Spatial data in biology frequently consist of, or can be assimilated to, sets of points. An important goal in the quantitative analysis of such data is the evaluation and localization of differences in spatial distributions between groups. Because of experimental replications, achieving this goal requires comparing ...

Wakefulness and sleep are accompanied by changes in behavior and neural activity, as well as by the upregulation of different functional categories of genes. However, the mechanisms responsible for such state-dependent changes in gene expression are unknown. Here we investigate to what extent state-dependent changes in gene expression depend on the central noradrenergic (NA) system, which is ac...

Bilateral electrolytic lesions of the locus coeruleus were performed in rats. In comparison with controls, lesioned rats showed decreased acquisition of two-way avoidance response, less intertrial responses, longer latency of avoidance responses on the first day of training, and needed more trials to reach the extinction criterion. It is suggested that locus coeruleus, contrary to the ventral n...

The locus coeruleus (LC), a specific brainstem structure containing noradrenergic neurons [1], has recently attracted much interest because the LC is involved in attention processes and attention modulations [2]. The accurate localisation of LC activity with functional imaging in group studies was questioned since the LC is anatomically difficult to localise on standard functional (EPI) or stru...