Factor scores of meaningful PCA factors for each modality were submitted to repeated measures ANOVA with condition (old, new) as a within-subjects factor and group (controls, patients) as a between-subjects factor. Because lag emerged as an insufficient manipulation of task difficulty and did not differ between groups, it was not included as an independent variable for electrophysiologic data. Gender was also omitted as a design factor given the imbalance of men and women in each group (3:1 ratio), rendering very small cell sizes for females (n = 5). The ANOVA designs included one or more recording sites at which PCA factor scores were largest and most representative of the associated CSD components (cf. Kayser et al., 2006; Kayser and Tenke, 2006a). Subsets of recording sites consisted of either midline sites or lateral, homologous recording sites over both hemispheres, in which case either site, or site and hemisphere were added as within-subjects factors to the design. However, because recording sites were selected on the premise that they collectively represent sink or source activity targeted in these statistical analyses, site effects were of secondary interest.
