Human cortical responses during one-bit delayed-response tasks: an fMRI study.
Neuroimaging study of cognition across aging requires simple tasks ensuring: (i) high rate of correct performances in neurophysiological settings; and (ii) significant modulation of cortical activity. As a preliminary step, the present functional magnetic resonance imaging (fMRI) study tested the hypothesis that very simple delayed-response tasks fit these requirements in normal young adults. The short-term memory (STM) variant included a sequence of cue stimulus (two vertical bars), delay period (blank screen for only 5s), go stimulus, and motor response compatible with the taller vertical bar. Noteworthy, the retention (only one bit) could be based on visuo-spatial, phonological, and somatomotor coding. In the control variant (no STM, NSTM), the cue stimulus was present during the delay period. Results showed high rate of correct performances in both tasks (about 95%). Compared to the NSTM task (delay period), the STM task enhanced cortical responses in bilateral dorsolateral prefrontal (Brodmann area 8-9 (BA 8-9)), lateral premotor (BA 6L), medial premotor (BA 6M), inferior parietal (BA 40), and superior parietal (BA 7) areas. In the STM task, cortical responses were stronger in right than left BA 8-9 and BA 6L. These results indicate that, in normal young adults, a simple STM variant of delayed-response tasks (one bit to be retained) is correctly performed and enhances bilateral fronto-parietal responses. Therefore, it may be used for future cognitive neuroimaging studies on aging.
Babiloni
Claudio
C
Dipartimento di Fisiologia Umana e Farmacologia, Sezione di EEG ad Alta Risoluzione, Università degli Studi di Roma La Sapienza, P.le Aldo Moro 5, 00185 Rome, Italy. claudio.babiloni@uniroma1.it
Ferretti
Antonio
A
Del Gratta
Cosimo
C
Carducci
Filippo
F
Vecchio
Fabrizio
F
Romani
Gian Luca
GL
Rossini
Paolo Maria
PM
D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D003463:Cues; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010100:Oxygen / Q000097:blood; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors
D010100:Oxygen