Preserved time but altered numerosity processing in epileptic patients with postoperative lesion in the inferior frontal gyrus
Brain and Cognition. 2022-07-01; 160: 105865
DOI: 10.1016/j.bandc.2022.105865
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Monfort V(1), Pfeuty M(2), Masson I(1), Kop JL(3), Brissart H(4), Maillard L(4).
Author information:
(1)Univ. Lorraine, 2LPN, F-57000 Metz, France.
(2)Univ. Bordeaux, CNRS, INCIA, UMR 5287, F-33000 Bordeaux, France. Electronic address: .
(3)Univ. Lorraine, 2LPN, F-54000 Nancy, France.
(4)Univ. Lorraine, CNRS, CRAN, F-54000 Nancy, France.
Previous researches have shown that the inferior frontal gyrus (IFG) is involved
in time and numerosity processing. This study aimed at examining (i) interval
timing and (ii) interaction between duration and numerosity processing in four
drug-resistant epileptic patients with postoperative lesions in the IFG in
comparison with thirteen healthy controls. The duration reproduction and
discrimination tasks performed in the sub- and supra-second ranges did not
reveal any significant differences between patients and controls. The duration
discrimination task of stimuli varying in numerosity (DurN) and the numerosity
discrimination task of stimuli varying in duration (NumD) revealed that only
numerosity judgment was altered in IFG patients. A time-order effect was notably
observed in the NumD task but in opposite directions for the two groups: The
second patch was perceived as more numerous than the first patch in controls and
conversely as less numerous in patients. Finally in the DurN task, we observed a
congruency effect which was dependent on numerical distance in patients but not
in controls. These converging results suggest that the IFG would be more
specifically involved in numerosity than in duration processing, possibly
playing a role in numerical decision.