Human cortical responses during one-bit short-term memory. A high-resolution EEG study on delayed choice reaction time tasks.
OBJECTIVE
We investigated whether a very simple short-term memory (STM) demand induces a visible change of EEG rhythms over the two hemispheres.


METHODS
High-resolution EEG was obtained in young adults during two delayed choice reaction time tasks. In the STM condition, a simple cue stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s). The task was visuo-spatial in nature.


RESULTS
In the control (NSTM) condition, the cue stimulus remained available along the delay period. Compared to the control condition, the theta power (4-6 Hz) decreased in left frontal and bilateral parietal areas (delay period). Furthermore, low alpha power (6-8 Hz) decreased in bilateral frontal and left parietal areas, while high alpha power (10-12 Hz) decreased in the left fronto-parietal areas.


CONCLUSIONS
The decrease of the alpha power is as an expression of the efficient information transfer within thalamo-cortical pathways. The significance of the study stands in the fact that even a very simple STM task (only one bit to be memorized) revealed changes in fronto-parietal theta and alpha rhythms.
Babiloni
Claudio
C
Dipartimento di Fisiologia Umana e Farmacologia, Sezione di EEG ad Alta Risoluzione, 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
Moretti
Davide Vito
DV
Rossi
Simone
S
Sosta
Katiuscia
K
Rossini
Paolo Maria
PM
D000328:Adult; D000513:Alpha Rhythm; D001931:Brain Mapping; D003344:Cortical Synchronization; D003463:Cues; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology*; D013826:Theta Rhythm