Sub-second "temporal attention" modulates alpha rhythms. A high-resolution EEG study.
In the present high-resolution electroencephalographic (EEG) study, event-related desynchronization/synchronization (ERD/ERS) of alpha rhythms was computed during an S1-S2 paradigm, in which a visual cue (S1) predicted a SHORT (600 ms) or LONG (1400 ms) foreperiod, preceding a visual go stimulus (S2) triggering right or left finger movement. Could orienting attention to a selective point in time influence the alpha rhythms as a function of the SHORT vs. LONG foreperiod? Stronger selective attentional modulations were predicted for the SHORT than LONG condition. EEG data from 54 channels were "depurated" from phase-locked visual evoked potentials and spatially enhanced by surface Laplacian estimation (i.e., final data analysis was conducted on 16 subjects having a sufficient number of artifact-free EEG single trials). Low-band alpha rhythms (about 6-10 Hz) were supposed to be related to anticipatory attentional processes, whereas high-band alpha rhythms (10-12 Hz) would indicate task-specific visuo-motor processes. Compared to the LONG condition (foreperiod), the SHORT condition induced a quicker and stronger ERS at low-band alpha rhythm (about 6-8 Hz) over midline and bilateral prefrontal, sensorimotor, and posterior parietal areas. In contrast, the concomitant high-band alpha (about 10-12 Hz) ERD/ERS showed no significant difference between the two conditions. In conclusion, temporal attention for a sub-second delay (800 ms) did modulate low-band alpha rhythm over large regions of both cortical hemispheres.
Babiloni
Claudio
C
Dipartimento di Fisiologia Umana e Farmacologia, Università La Sapienza, Rome, Italy. claudio.babiloni@uniroma 1.it
Miniussi
Carlo
C
Babiloni
Fabio
F
Carducci
Filippo
F
Cincotti
Febo
F
Del Percio
Claudio
C
Sirello
Giulia
G
Fracassi
Claudia
C
Nobre
Anna C
AC
Rossini
Paolo Maria
PM
D000293:Adolescent; D000328:Adult; D000513:Alpha Rhythm / Q000379:methods*; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D013997:Time Factors