Figure 5.

Relation between numerosity-dependent EEG modulations in the WM delay and analog versus discretized quantification in the number naming task. A, Top, Within-subjects normalized correlation between the linear slope of the RT increase in the number naming task (compare Fig. 1C, right) and the parametric modulation of prefrontal upper beta (compare Fig. 4). Shallower RT slopes (indicative of analog estimation) are associated with stronger prefrontal beta-band modulations. Bottom, Same as top, for the parametric modulation of posterior alpha (compare Fig. 3). Steeper RT slopes (indicative of discretized quantification) are associated with stronger posterior alpha modulations. B, Within-modalities normalized correlation between the same variables as in A. Also within modalities, in particular in the visual condition, analog estimation is associated with enhanced parametric modulations of prefrontal upper beta. See text for details. C, Median split illustration of the delayed EEG modulation patterns according to quantification strategy. For each modality, subjects were separated into discretizing (dashed lines) or estimating (solid lines) groups, according to their individual RT slopes in the number naming task. Top, Prefrontal upper beta modulation. Bottom, Posterior alpha modulation. Topographical maps show the aggregate parametric modulations after median splitting, collapsed over all estimating (top) and discretizing (bottom) subjects and conditions.