Cholinergic enhancement of visual attention and neural oscillations in the human brain.
Cognitive processes such as visual perception and selective attention induce specific patterns of brain oscillations. The neurochemical bases of these spectral changes in neural activity are largely unknown, but neuromodulators are thought to regulate processing. The cholinergic system is linked to attentional function in vivo, whereas separate in vitro studies show that cholinergic agonists induce high-frequency oscillations in slice preparations. This has led to theoretical proposals that cholinergic enhancement of visual attention might operate via gamma oscillations in visual cortex, although low-frequency alpha/beta modulation may also play a key role. Here we used MEG to record cortical oscillations in the context of administration of a cholinergic agonist (physostigmine) during a spatial visual attention task in humans. This cholinergic agonist enhanced spatial attention effects on low-frequency alpha/beta oscillations in visual cortex, an effect correlating with a drug-induced speeding of performance. By contrast, the cholinergic agonist did not alter high-frequency gamma oscillations in visual cortex. Thus, our findings show that cholinergic neuromodulation enhances attentional selection via an impact on oscillatory synchrony in visual cortex, for low rather than high frequencies. We discuss this dissociation between high- and low-frequency oscillations in relation to proposals that lower-frequency oscillations are generated by feedback pathways within visual cortex.
Wellcome Trust Centre for Neuroimaging, University College London, London WC1N3BG, UK. markus.bauer@gmail.com
Markus
M
Bauer
Christian
C
Kluge
Dominik
D
Bach
David
D
Bradbury
Hans Jochen
HJ
Heinze
Raymond J
RJ
Dolan
Jon
J
Driver
D000328:Adult; D001288:Attention / Q000502:physiology; D001921:Brain / Q000378:metabolism*; D001931:Brain Mapping / Q000379:methods*; D058256:Brain Waves / Q000187:drug effects / Q000502:physiology; D018679:Cholinergic Agonists / Q000494:pharmacology; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D018377:Neurotransmitter Agents / Q000378:metabolism; D010775:Photic Stimulation; D010830:Physostigmine / Q000494:pharmacology; D014785:Vision, Ocular / Q000502:physiology*; D014793:Visual Cortex / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
D018679:Cholinergic Agonists; D018377:Neurotransmitter Agents; D010830:Physostigmine