tracing neuronal cell development and maturation in the mouse spinal cord kelly probst dr. michael...
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Tracing Neuronal Cell Development and Maturation
in the Mouse Spinal Cord
Kelly Probst
Dr. Michael Gross Laboratory
Sensory Information
Somatosensory
Visual
Auditory
Olfactory
Gustatory
Vestibular
ExteroceptiveTouch, Temperature, Pain
Proprioceptive Body Position
InteroceptiveStatus of Viscera
Somatosensory Information
Sensory Information Flow
BrainSpinal Cord
Body
Visceral Afferents
AA
Dorsal Root Ganglion(DRG))
Spinal Cord
Spinal Cord Innervation by Sensory Neurons
Spinal Relay Interneurons
Thalamus
Hindbrain
Cerebellum
Sensory Neuron
Relay Interneuron
Synaptic Connection
Ventricular Zone
Mantle Zone
SMG1
G2
PMG0
Neurons Born (E10.5 to E13.5)
Early Embryonic Interneuron Populations
VZ
MZ
Isl1-2 = I3
Foxd3 = I2
Lbx1 = I4
Project Objective• Match adult ascending tracts with embryonic
neural tube populations
• Identify when in development these relay axonal projections reach the brain
?
Backfill Analysis
Flour-Dextran
Contralateral
Ipsilateral
Embryo Dissection
Hindbrain
C1 (Atlas)
Cervical Vertebrae
Fill
TMR-dextran Fill
Filled Neuron
Incubation
Spinal Cord/Brain Dissection
Fill Site
Brachial Enlargeme
nt
Cervical Region
Abdominal Region Lumbar Region and
Enlargement
Hindbrain-Spinal Cord Junction
E18.5 Backfilled Spinal Cord
1 cm
Section 27(27 sections X 100 m = 2.7 mm)
Dorsal
Ventral
E17.5 Backfilled Spinal Cord
1 cm
Section 10(10 sections X 100 m = 1.0 mm)
Dorsal
Ventral
E16.5 Backfilled Lbx1 +/- Spinal Cord
1 cm
Section 28(28 sections X 40 m = 1.1 mm)
Dorsal
Ventral
Conclusions
• By embryonic day 16.5, the axons of some relay interneurons have reached the hindbrain
• A subset of these relay interneurons express Lbx1 and therefore are derived from the I4, I5, or I6 embryonic populations
Future Goals
• Backfill younger spinal cords
• Backfill from specific brain regions
• Co-label backfills with more marker combinations
Acknowledgements
Dr. Michael Gross
Dr. Kevin Ahern
Howard Hughes Medical Institute