Figure 1.

Alternative explanations for functional deficits revealed by lesion inference. The figure summarizes the findings of a formal reanalysis of the example proposed by Fig. 2 in Sperber and Karnath (2020) with the help of the estimated MSA inference approach (Keinan et al., 2006). The findings are consistent with the two explanatory scenarios outlined by Sperber and Karnath; a functional deficit may arise either from damage of region x, which makes a positive functional contribution, or from disinhibiting and thus boosting region 2, which has a negative functional contribution (i.e. hampers function). Moreover, regions x and 2 show a positive, ‘synergistic’ interaction (i.e. the joint functional contribution of these regions is larger than the sum of their individual contributions; Keinan et al., 2004). Specifically, this interaction can be interpreted as a competition between the contributions of the regions. Of note, on the limited basis of the provided lesion states and associated functional performances (summarized in the table), the formal analysis cannot decide which of the two scenarios is more plausible. Further data or additional context information on the underlying anatomical-physiological interactions of these regions are required in order to explain the observations on functional performance in terms of neural mechanisms (cf. Zavaglia and Hilgetag, 2016).