Processing deficits for familiar and novel faces in patients with left posterior fusiform lesions.
Bottom Line: Identification of famous faces was found to be compromised in both expressive and receptive tasks.Interestingly, discrimination of faces that varied in terms of feature identity was considerably better in these patients and it was performance in this condition that was related to the size of the length effects shown in reading.These results suggest that the sequential part-based processing strategy that promotes the length effect in the reading of these patients also allows them to discriminate between faces on the basis of feature identity, but processing of second-order configural information is most compromised due to their left pFG lesion.
Affiliation: Research Centre in Brain and Behaviour, Liverpool John Moores University, UK.Show MeSH
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Mentions: Inspection of Table 3, Table 4 indicates that there appear to be some trade-off between speed and accuracy that differ across severity groups. In order to more effectively compare the results over groups, we computed an inverse efficiency measure (Roberts et al., 2010, Roder et al., 2007). This is derived by dividing the mean correct RT for each condition by the proportion correct, producing a measure comparable to reaction time but corrected for variations in accuracy (see Supplementary Materials for individual data). Repeated-measures ANOVA (Greenhouse-Geisser corrected) on inverse efficiency values revealed significant main effects of severity [F(2, 28) = 15.17, p < .0001], condition [F(2.46, 68.76) = 41.21, p < .0001], and an interaction between the two [F(4.91, 68.76) = 3.27, p = .01]. The form of the interaction can be seen in Fig. 6, which shows that poor patient performance is most pronounced for the second-order configural conditions involving changes in feature spacing or contour spacing, and somewhat more so for the more severe patients. The difference between the cousins and feature-identity condition was equivalent across all groups [t(21) = .06; t(14) = .36; ps > .115]. The difference between the cousins and feature-spacing condition was marginally significantly larger for the mild-moderate patients than controls [t(21) = 1.81 p = .085], but did not differ for the mild-moderate and severe patients [t(14) = 1.20; p = .252]. Similarly, the difference between the cousins and contour-spacing condition was significantly larger for the mild-moderate patients than controls [t(21) = 2.87 p = .0009] but did not differ for the mild-moderate and severe patients [t(14) = 624; p = .543]. Hence, these patients with left pFG damage and reading deficits seemed to show a more marked impairment for the spacing conditions requiring second-order processing relative to the feature-identity condition requiring first-order processing in this task.
Affiliation: Research Centre in Brain and Behaviour, Liverpool John Moores University, UK.