Regional hypoplasia of somatosensory cortex in growth-retarded mice (grt/grt)

Growth‐retarded mouse (grt/grt) is a spontaneous mutant that is known as an animal model for primary congenital hypothyroidism caused by resistance to TSH signaling. The regional pattern of cerebral cortical hypoplasia was characterized in grt/grt mice. Ex vivo computed tomography (CT)‐based volumetry was examined in four regions of the cerebral cortex, i.e., prefrontal, frontal, parietal and occipito‐temporal regions, which were demarcated by structural landmarks on coronal CT images. A region‐specific reduced volume of the parietal cortical region covering most of the somatosensory cortex was noted in grt/grt mice rather than in both heterozygous (grt/+) and wild‐type (+/+) mice. We concluded that the cortical hypoplasia in grt/grt was seen in identical cortical regions corresponding to human congenital hypothyroidism.