Voluntary attention changes the speed of perceptual neural processing.
While previous studies in psychology demonstrated that humans can respond more quickly to the stimuli at attended than unattended locations, it remains unclear whether attention also accelerates the speed of perceptual neural activity in the human brain. One possible reason for this unclarity would be an insufficient spatial resolution of previous electroencephalography (EEG) and magnetoencephalography (MEG) techniques in which neural signals from multiple brain regions are merged with each other. Here, we addressed this issue by combining MEG with a novel stimulus-presentation technique that can focus on neural signals from higher visual cortex where the magnitude of attentional modulation is prominent. Results revealed that the allocation of spatial attention induces both an increase in neural intensity (attentional enhancement) and a decrease in neural latency (attentional acceleration) to the attended compared to unattended visual stimuli (Experiment 1). Furthermore, an attention-induced behavioural facilitation reported in previous psychological studies (Posner paradigm) was closely correlated with the neural 'acceleration' rather than 'enhancement' in the visual cortex (Experiment 2). In addition to bridging a gap between previous psychological and neurological findings, our results demonstrated a temporal dynamics of attentional modulation in the human brain.
Noguchi
Yasuki
Y
Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, Japan. noguchi@nips.ac.jp
Tanabe
Hiroki C
HC
Sadato
Norihiro
N
Hoshiyama
Minoru
M
Kakigi
Ryusuke
R
D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography; D009434:Neural Pathways / Q000502:physiology; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology*; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D014836:Volition / Q000502:physiology*