Visual and auditory alertness: modality-specific and supramodal neural mechanisms and their modulation by nicotine.

Full Abstract

Alertness is a nonselective attention component that refers to a state of general readiness that improves stimulus processing and response initiation. We used functional magnetic resonance imaging (fMRI) to identify neural correlates of visual and auditory alertness. A further aim was to investigate the modulatory effects of the cholinergic agonist nicotine. Nonsmoking participants were given either placebo or nicotine (NICORETTE gum, 2 mg) and performed a target-detection task with warned and unwarned trials in the visual and auditory modality. Our results provide evidence for modality-specific correlates of visual and auditory alertness in respective higher-level sensory cortices and in posterior parietal and frontal brain areas. The only region commonly involved in visual and auditory alertness was the right superior temporal gyrus. A connectivity analysis showed that this supramodal region exhibited modality-dependent coupling with respective higher sensory cortices. Nicotine was found to mainly decrease visual and auditory alertness-related activity in several brain regions, which was evident as a significant interaction of nicotine-induced decreases in BOLD signal in warned trials and increases in unwarned trials. The cholinergic drug also affected alerting-dependent activity in the supramodal right superior temporal gyrus; here the effect was the result of a significant increase of neural activity in unwarned trials. We conclude that the role of the right superior temporal gyrus is to induce an "alert" state in response to warning cues and thereby optimize stimulus processing and responding. We speculate that nicotine increases brain mechanisms of alertness specifically in conditions where no extrinsic warning is provided.

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Author information

Author/s: Thiel, Christiane M (CM); Fink, Gereon R (GR);

Affiliation: Institute of Biology and Environmental Science, Fak. V, Carl von Ossietzky University of Oldenburg, 26111 Oldenburg, Germany. christiane.thiel(-atsign-)uni-oldenburg.de

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Journal of neurophysiology (J Neurophysiol), published in United States. (Language: eng)

Reference: 2007-Apr; vol 97 (issue 4) : pp 2758-68

Dates: Created 2007/04/05; Completed 2007/07/10;

PMID: 17287445, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Acoustic Stimulation
Adult
Attention - drug effects; physiology
Auditory Perception - drug effects; physiology
Data Interpretation, Statistical
Female
Frontal Lobe - drug effects; physiology
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging

Magnetic Resonance Imaging
Male
Neural Pathways - drug effects
Nicotine - pharmacology
Nicotinic Agonists - pharmacology
Parasympathetic Nervous System - drug effects; physiology
Parietal Lobe - drug effects; physiology
Photic Stimulation
Reaction Time - physiology
Visual Perception - drug effects; physiology

Associated Chemicals: Nicotinic Agonists (0) ; Nicotine (54-11-5)

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