Development of cerebral sulci and gyri in ferrets (Mustela putorius).

The present study aimed to clarify sulcation and gyration patterns in the developing cerebrum of ferrets. While the brain weight and fronto-occipital length of the cerebral hemisphere reached a plateau by postnatal day (PD) 42, the cerebral width reached a plateau at the rostral region by PD 21, and subsequently at the caudal region by PD 42. The ferret cerebrum already showed a convoluted surface with indentations of coronal and rostral suprasylvian sulci on PD 4. The presylvian and cruciate sulci emerged by PD 10, resulting in convolutions of gyri in the rostral half of the cerebrum. The caudal half of the cerebrum was infolded by the emergence of the pseudosylvian sulcus and the rhinal fissure by PD 10, and the caudal suprasylvian and lateral sulci by PD 21. The emergence of those sulci allowed a gyration in the caudal half of the cerebrum. Sexual differences in sulcation were detected by a more distinct convolution of the visual cortex in males than in females on PD 90. Those results, therefore, suggest that the ferret cerebrum experiences cortical maturation with sulcation and gyration in a rostrocaudal gradient manner. The present paper provides neuroanatomic references for normal development of cerebral sulci and gyri in both sexes of ferrets.