Human cortical rhythms during visual delayed choice reaction time tasks. A high-resolution EEG study on normal aging.
Neuroimaging cognitive study of aging requires simple tasks ensuring a high rate of correct performances even in stressful neurophysiological settings. Here two simple delayed choice reaction time tasks were used to unveil event-related desynchronization (ERD) of theta (4-6 Hz) and alpha (6-12 Hz) electroencephalographic rhythms across normal aging. In the first condition, a cue stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s). The explicit demand was visuo-spatial, but the retention could be also based on phonological and somatomotor coding. In the second condition, the cue stimulus remained available along the delay period. Correct performances were higher than 95% in both groups and tasks, although they were significantly better in young than elderly subjects (P < 0.03). During the delay period, theta and alpha ERD accompanying correct responses were recognized in the two groups, the alpha ERD being stronger and prolonged during the memory than non-memory task. On the other hand, the fronto-parietal theta and parietal alpha ERD were stronger in young than elderly subjects during both tasks. Notably, the frontal alpha ERD was negligible in elderly subjects. In conclusion, the present simple tasks unveiled in elderly compared to young subjects (i) a weaker involvement of (para)hippocampal-cortical circuits as revealed by theta ERD and (ii) a weaker involvement of "executive" thalamo-cortical circuits as revealed by frontal alpha ERD. These effects might worsen behavioral performances to the simple cognitive tasks with age. The present protocol is promising for the neuroimaging study of pathological aging.
Babiloni
Claudio
C
Dipartimento di Fisiologia Umana e Farmacologia, Università La Sapienza, P. le Aldo Moro 5, 00185 Rome, Italy. claudio.babiloni@uniroma1.it
Babiloni
Fabio
F
Carducci
Filippo
F
Cappa
Stefano F
SF
Cincotti
Febo
F
Del Percio
Claudio
C
Miniussi
Carlo
C
Vito Moretti
Davide
D
Rossi
Simone
S
Sosta
Katiuscia
K
Rossini
Paolo Maria
PM
D000328:Adult; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology*; D003344:Cortical Synchronization; D003463:Cues; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology*