Cognitive inhibition of number/length interference in a Piaget-like task in young adults: evidence from ERPs and fMRI.
We sought to determine whether the neural traces of a previous cognitive developmental stage could be evidenced in young adults. In order to do so, 12 young adults underwent two functional imaging acquisitions (EEG then fMRI). During each session, two experimental conditions were applied: a Piaget-like task with number/length interference (INT), and a reference task with number/length covariation (COV). To succeed at Piaget's numerical task, which children under the age of 7 years usually fail, the subjects had to inhibit a misleading strategy, namely, the visuospatial length-equals-number bias, a quantification heuristic that is often relevant and that continues to be used through adulthood. Behavioral data confirmed that although there was an automation in the young adult subjects as assessed by the very high number of accurate responses (>97%), the inhibition of the "length equals number strategy" had a cognitive cost, as the reaction times were significantly higher in INT than in COV (with a difference of 230 ms). The event-related potential results acquired during the first session showed electrophysiological markers of the cognitive inhibition of the number/length interference. Indeed, the frontal N2 was greater during INT than during COV, and a P3(late)/P6 was detected only during INT. During the fMRI session, a greater activation of unimodal areas (the right middle and superior occipital cortex) and in the ventral route (the left inferior temporal cortex) was observed in INT than in COV. These results seem to indicate that when fully automated in adults, inhibition processes might take place in unimodal areas.
Leroux
Gaëlle
G
Groupe d'Imagerie Neurofonctionnelle (GIN), UMR 6194, CNRS, CEA, Universités de Caen et Paris-5, France.
Joliot
Marc
M
Dubal
Stéphanie
S
Mazoyer
Bernard
B
Tzourio-Mazoyer
Nathalie
N
Houdé
Olivier
O
D000328:Adult; D001921:Brain / Q000254:growth & development / Q000502:physiology*; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology