Kim Annink

41 The pattern of Purkinje cell injury in neonates with HIE DISCUSSION In this study we investigated PC injury among different locations in the vermis in (near-) term neonates with HIE. We found that both in the folia and the lobules the total PC count was significantly higher at the crowns compared to the bases of the sulci. For several locations the percentage of abnormal PCs was significantly higher at the bases of the sulci than at the crowns. The total number of PCs did not differ between the anterior and posterior lobes of the vermis. To our knowledge this is the first study that describes differences in total PC count within the lobules and folia in the vermis of term born neonates with HIE. The lower PC count at the bases of the cerebellar lobules and folia compared to the crowns might well be explained by a combination of normal anatomy and increased vulnerability (29,30). Regional differences in PC density within the cerebellar folia have been shown previously in healthy human adults and 75-day-old rats (29,30). Both studies found more PCs at the crowns compared to the bases. These studies showed that the apparent differences in PC density were caused by the folding of the cortex; this can also (partly) be an explanation for the difference in total PC number in our population (29,30). In general, our data showed more abnormal PC soma morphology at the bases compared to the crowns. Hence it seems that PCs at the bases of the folia and lobules are more vulnerable to hypoxia. Likewise, Akima et al. showed that PCs at the bases of the sulci were more prone to severe ischemic injury in humans between 0 and 89 years of age (31–33). They hypothesized that the vascular architecture of the cerebellar cortex provided by the meningeal arteries could be an explanation for selective PC vulnerability to hypoxia (31,32). Although this hypothesis remains to be tested, they did describe that the bases of the deeper secondary and tertiary sulci are perfused by very small branches from the larger arteries (33). Because the arterial ramifications at the bases of the sulci are smaller than the arteries at the crown, this might partially explain the higher prevalence of infarctions in the bases of the sulci after severe generalized ischemia (33). The current findings seem remarkably similar to a particular pattern of supratentorial injury called ulegyria, first described by Bresler in 1899 (34). Bresler identified narrowing of the supratentorial cortical gyri because of scar formation in the brain of a mentally impaired patient, which he called ulegyria (34). Ulegyria 2