Quantitative Analysis of the Timing of Development of the Cerebellum and Precerebellar Nuclei in Monotremes, Metatherians, Rodents, and Humans

  title={Quantitative Analysis of the Timing of Development of the Cerebellum and Precerebellar Nuclei in Monotremes, Metatherians, Rodents, and Humans},
  author={Ken W.S. Ashwell and Boaz Shulruf and Yamila Gurovich},
  journal={The Anatomical Record},
We have used a quantitative statistical approach to compare the pace of development in the cerebellum and precerebellar systems relative to body size in monotremes and metatherians with that in eutherians (rodents and humans). Embryos, fetuses, and early postnatal mammals were scored on whether key structural events had been reached in the development of the cerebellum itself (CC—corpus cerebelli; 10 milestones), or the pontine and inferior olivary precerebellar nuclear groups (PC; 4 milestones… 

Cell-Autonomous Processes That Impair Xenograft Survival into the Cerebellum

It is found that human cells survived the engraftment and integrated into the host cerebellum and brain stem up to about 1 month postnatally when they were rejected in both species, consistent with the hypothesis that the slower pace of differentiation of human neural precursors compared to that of rodents restricts the induction of immune-tolerance.



Development of the Cerebellum in the Platypus (Ornithorhynchus anatinus) and Short-Beaked Echidna (Tachyglossus aculeatus)

  • K. Ashwell
  • Biology
    Brain, Behavior and Evolution
  • 2012
The findings indicate that cerebellar circuitry is unlikely to contribute to the coordination of movements in the monotreme peri-hatching period, and those activities are most likely controlled by the spinal cord and medullary reticular formation circuitry.

Quantitative analysis of somatosensory cortex development in metatherians and monotremes, with comparison to the laboratory rat

  • K. Ashwell
  • Biology
    Somatosensory & motor research
  • 2015
Quantitative analysis of isocortical sections held in the collections at the Museum für Naturkunde, Berlin was used to compare the pace of somatosensory cortex development relative to body size and pallial thickness between metatherian groups, monotremes, and the laboratory rat, suggesting that cortical development in the monotreme is slower and subject to different regulatory signals to the therians studied.


It is concluded that the developmental differences between marsupial and placental mammals are best explained by the interaction of several processes including neurogenesis as a potential rate‐limiting step, the developmental requirements of somatic elements, and the extremely short period of organogenesis of mars upial mammals.

Distinct Development of the Cerebral Cortex in Platypus and Echidna

The findings suggest that cortical development in each monotreme follows distinct paths from at least the time of birth, consistent with a long period of independent and divergent cortical evolution.

Development of the basilar pons in the North American opossum: dendrogenesis and maturation of afferent and efferent connections

The data suggest that the time of afferent arrival from the cerebral cortex and deep cerebellar nuclei is closely correlated in time with the initiation of dendritic maturation and the outgrowth of pontocerebellar axons in the North American opossum.

Quantitative comparison of cerebral artery development in metatherians and monotremes with non‐human eutherians

Both aortic outflow and cerebral arterial inflow may be lower in developing monotremes than in therians, particularly at small body size (< 20 mm); cerebral inflow in some developing metatherians than non‐human eutherians; and dasyurids have unusual features of cerebral arteries possibly related to the extreme immaturity and small size at which they are born.

Development of the precerebellar nuclei in the rat: III. The posterior precerebellar extramural migratory stream and the lateral reticular and external cuneate nuclei

Sequential thymidine radiograms from rats injected on day E15 and killed thereafter at daily intervals up to day E22 were analyzed to trace the migratory routes and settling patterns of neurons of

Development of the precerebellar nuclei in the rat: IV. The anterior precerebellar extramural migratory stream and the nucleus reticularis tegmenti pontis and the basal pontine gray

Sequential thymidine radiograms were used to establish the site of origin, migratory route, and settling patterns of neurons of the nucleus reticularis tegmenti pontis and basal pontine gray and indicated that some of the cells that reach the pons are unlabeled, indicating that they represent the early component of neurons generated on day E15.

The formation and growth of the cortical layers in the cerebellum of the opossum

The maturation of the cerebellum in the opossum is a lengthy process lasting approximately 77 days in comparison to rodent cerebellar growth which requires about 25 days (Korneliussen 1968c) and the persistence of the EGL until after PN 105 suggests that synaptic contacts between granule cell axons and Purkinje cells may continue to form after PNs 77.

Development of body, head and brain features in the Australian fat-tailed dunnart (Sminthopsis crassicaudata; Marsupialia: Dasyuridae); A postnatal model of forebrain formation

The benefits of fat-tailed dunnarts as laboratory animals in studies of developmental biology, with an emphasis on how their accessibility in the pouch can help address new experimental questions, especially regarding mechanisms of brain development and evolution.