Figure 2.

CST in wild type and EphA4 conditional knockout mouse. Modified from Serradj et al. (17). (A) CST terminations within the intermediate zone flanking the midline. Wild type mice (left) have a predominantly contralateral projection, whereas the mouse with conditional elimination of the EphA4 gene in the forebrain (right) has a strongly bilateral projection. The insets show labeling in the dorsal column, which is the location of the CST in the mouse; labeling is comparable in the two mice. (B) Color-coded representations of sites in motor cortex where electrical stimulation evoked bilateral movements (e.g., mirror movements; average of five mice in each category). Whereas no “mirror sites” existed in the wild type mice (left), they were ubiquitous in the mutant mice (right).