Dopamine modulates involuntary attention shifting and reorienting: an electromagnetic study.
OBJECTIVE
Dopaminergic function has been closely associated with attentional performance, but its precise role has remained elusive.


METHODS
Electrophysiological and behavioral methods were used to assess the effects of dopamine D2-receptor antagonist haloperidol on involuntary attention shifting using a randomized, double-blind, placebo-controlled cross-over design. Eleven subjects were instructed to discriminate equiprobable 200 and 400ms tones in a forced-choice reaction-time (RT) task during simultaneous measurement of whole-head magnetoencephalography and high-resolution electroencephalography.


RESULTS
Occasional changes in task-irrelevant tone frequency (10% increase or decrease) caused marked distraction on behavioral performance, as shown by significant RT increases to deviant stimuli and subsequent standard tones. Furthermore, while the standard tones elicited distinct P1-N1-P2-N2-P3 waveforms, deviant tones elicited additional mismatch negativity (MMN), P3a, and reorienting negativity (RON) responses, indexing brain events associated with involuntary attention shifting. While haloperidol did not affect the source loci of the responses of magnetic N1 and MMN, the amplitude of the electric P3a and that of RON were significantly reduced and the latency of magnetic RON were delayed following haloperidol administration.


CONCLUSIONS
The present results suggest that dopamine modulates involuntary attention shifting to task-irrelevant deviant events. It appears that dopamine may disrupt the subsequent re-orienting efforts to the relevant task after distraction.
Kähkönen
Seppo
S
Cognitive Brain Research Unit, Department of Psychology, University of Helsinki, Helsinki, Finland. seppo.kahkonen@helsinki.fi
Ahveninen
Jyrki
J
Pekkonen
Eero
E
Kaakkola
Seppo
S
Huttunen
Juha
J
Ilmoniemi
Risto J
RJ
Jääskeläinen
Iiro P
IP
D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000187:drug effects / Q000502:physiology*; D018592:Cross-Over Studies; D004298:Dopamine / Q000502:physiology*; D004311:Double-Blind Method; D004569:Electroencephalography / Q000187:drug effects / Q000379:methods; D055590:Electromagnetic Phenomena; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D015225:Magnetoencephalography / Q000187:drug effects / Q000379:methods*; D008297:Male; D009949:Orientation / Q000187:drug effects / Q000502:physiology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
D006220:Haloperidol; D004298:Dopamine