Muscarinic versus nicotinic modulation of a visual task. a pet study using drug probes.
Neuropsychopharmacology
; 25(4): 555-64, 2001 Oct.
Article
em En
| MEDLINE
| ID: mdl-11557169
ABSTRACT
Little is known about acetylcholine (ACh) modulation of central visual processing in humans. Receptor densities in visual brain regions are differentially distributed suggesting that receptor subtypes have different functions. Using PET, we have previously described the brain regions activated by a simple pattern-flash stimulus in healthy elderly subjects. To evaluate muscarinic and nicotinic contributions to ACh modulation of visual processing, we scanned elderly subjects watching the pattern-flash stimulus during no drug, during physostigmine augmentation, and during scopolamine antagonism of physostigmine's action. These manipulations of ACh significantly altered regional cerebral blood flow (rCBF) in brain regions activated by the task. The pattern of rCBF values across drug conditions suggested that muscarinic and nicotinic effects were dissociated. Muscarinic action predominated in striate cortex (Brodmann Area, BA 17) and lateral visual association areas (BA 18, 19), while nicotinic action predominated in the thalamus and inferior parietal regions (BA 39/40). Both muscarinic and nicotinic actions increased rCBF in some regions while decreasing it in others. A parsimonious reconciliation of these results with functional anatomy suggests that muscarinic action modulates visual attribute processing, while nicotinic action modulates arousal and selective attention to the visual task.
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Base de dados:
MEDLINE
Assunto principal:
Atenção
/
Percepção Visual
/
Receptores Nicotínicos
/
Receptores Muscarínicos
Tipo de estudo:
Clinical_trials
Limite:
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article