Brainstem Projections to the Spinal Cord in Fetal Sheep
Author Information
Author(s): Elaine M Stockx, Colin R Anderson, Susan M Murphy, Ian R Cooke, Philip J Berger
Primary Institution: Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University
Hypothesis
Spinally-projecting axons from the neurons responsible for transforming fetal behaviour must arrive at the spinal cord level shortly before G65.
Conclusion
All projections present in the mature fetus at G140 have already arrived at the spinal cord by approximately one third of the way through gestation.
Supporting Evidence
- CTB labelled cells were found in brainstem nuclei similar to those in other mammalian species.
- All spinally-projecting neurons in the brainstem reached the spinal cord by G55.
- The presence of these neurons suggests they are not fully functional until later in development.
Takeaway
The brain sends signals to the spinal cord in fetal sheep earlier than previously thought, but these signals don't start working until later.
Methodology
The study used retrograde tracing with cholera toxin subunit B (CTB) to identify brainstem neurons projecting to the spinal cord in fetal sheep.
Limitations
The study did not explore the functional maturation of the projections after their arrival at the spinal cord.
Participant Demographics
Fetal sheep at gestational ages G55 and G140.
Digital Object Identifier (DOI)
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