Differentiating amodal familiarity from modality-specific memory processes: an ERP study

Abstract

Distinct event-related potential effects have been related to familiarity and recollection processes underlying recognition memory. Familiarity has been conceptualized as similar either to perceptual priming mechanisms supporting implicit memory or to amodal global-matching processes that should show little sensitivity to perceptual variables. The present experiment manipulated the study modality of words (auditory, visual) that were visually tested for recognition memory. The mid-frontal (300-500 ms) old/new effect often attributed to familiarity was not affected by study modality, so it appears related to an amodal familiarity process. An earlier (176-260 ms) fronto-polar old/new effect was perceptually specific in that it was observed only following visual study. The parietal old/new effect (400-800 ms), often attributed to recollection, was similar following both visual and auditory study. Temporal-spatial PCA clarified the separability of these effects.

Figure 1

Grand-average ERPs from channels representative of the international 10–20 system (Jasper, 1958). Channels are labeled according to Geodesic Electrode Net numbers (see Figure 2) along with their nearest 10–20 equivalent location.

Figure 2

Grand-average ERPs from regions of interest used in ANOVAs. Regions are depicted with black channel groups. LAS is left/anterior/superior. RAS is right/anterior/superior. LPS is left/posterior/superior. RPS is right/posterior/superior.

Figure 3

Mean amplitudes for each spatiotemporal region of interest. Error bars represent the standard error of the old/new difference. a: Mean amplitudes across the LAS and RAS regions from 176 to 260 ms. b: Mean amplitudes across the LAS and RAS regions from 300 to 500 ms. c: Mean amplitudes within the LPS and RPS regions from 400 to 800 ms.

Figure 4

Topography of the old/new differences estimated by spherical-spline interpolations (Srinivasan et al., 1996). The front of the head is depicted at the top of each oval.

Figure 5

The time course of the three primary temporal factors (TF) estimated by PCA.

Figure 6

The topography of the old/new differences for the four primary spatiotemporal factors. VIS is visual. AUD is auditory.