Neural Systems Underlying Arousal and Attention: Implications for Drug Abuse^a

Abstract

The monoaminergic and cholinergic systems are implicated in different forms of behavioral arousal that can be dissected in terms of their forebrain targets and the nature of the behavioral processes they modulate in distinct regions. Thus, evidence in rats with selective neurochemical manipulations tested behaviorally using an analog of an attentional task developed for human subjects indicates that the coeruleo-cortical noradrenergic system is implicated in divided and selective attention, the basal forebrain cholinergic system in stimulus detection, the mesostriatal and mesolimbic dopaminergic systems in response speed and vigor, and the mesencephalic serotoninergic or 5-HT systems in response inhibition. Our recent studies have focused on fractionating, in the same task, the differential contributions of the dorsal and median raphé 5-HT systems as well as elucidating the functions of the mesocortical dopaminergic system, each of which may be relevant to understanding the behavioral and cognitive sequelae of cocaine administration in human subjects as well as in experimental animals.

Cholinergic Modulation of Visual Attention and Working Memory: Dissociable Effects of Basal Forebrain 192-IgG-saporin Lesions and Intraprefrontal Infusions of Scopolamine

“…A previous study (Robbins et al 1998) also reported effects of intra-mPFC scopolamine on the 5CSRTT. These authors found that a 10-µg dose of scopolamine significantly reduced attentional accuracy as well as impairing other aspects of performance.…”

Modeling functions of striatal dopamine modulation in learning and planning

“…Indeed, dopamine application increases signal-to-noise ratio of striatal firing rates in vivo (Rolls, 1984;reviewed by Servan-Schreiber et al, 1998a). In addition, pharmacological studies with dopamine agonists and antagonists indicate that dopamine decreases reaction times for behavioral responses and is involved in behavioral activation (Salamone et al, 1997;Robbins et al, 1998). In the proposed model, manipulations of dopamine concentration in the matrisomes have a complex influence on the number of acts in the exploration phase, since the simulated dopamine effects on elevated and on hyperpolarized membrane potentials are antagonistic and therefore sensitive to model parameters values (unpublished results).…”

Multiple Arousal Theory and Daily-Life Electrodermal Activity Asymmetry

“…The scopolamine effect was one of the earliest showing that cortical arousal and behavioral arousal were different (Longo, 1956). Drugs such as diazepam (an anxiolytic), clonidine (an antihypertensive), and haloperidol (an antiemetic) have such different effects that a unitary construct such as diminished arousal or "sedation" has been shown to be inadequate (Robbins et al, 1998). From a neural systems perspective, arousal processes are clearly not unitary; multiple sources of arousal interact in the brain, and have different kinds of effects on the mind and body, while details of their functioning continue to be elucidated.…”