hindbrain neurons. question: how will the alteration of input affect neurons in the cns dedicated to...
Post on 18-Jan-2016
212 Views
Preview:
TRANSCRIPT
Hindbrain Neurons
Question:
• How will the alteration of input affect neurons in the CNS dedicated to inner ear sensory input processing?
• By manipulating the ear, either by removing it or by adding extra ears, we can determine the effects of afferents on their target neuron(s) in the CNS
Mauthner Cell
• Single, large, pair of reticulospinal neurons at the level of the ear in the hindbrain of most aquatic animals
• Important component of the C-start escape response
25µm
Mauthner Cell• Early, but not late, ear ablation has been shown to
result in the absence of the Mauthner cell• Has been suggested to be a surgical artifact
• Surviving Mauthner cells show a reduction in dendritic branching
• Previous studies each only focused on a single time point of ear removal• I removed the ear at various time points in development to
answer the following questions:
Mauthner Cell Questions• 1) Is there a critical period of a Mauthner cell during
which it depends on the ear for survival?
• 2) Does the stage at which the ear is removed affect the degree of dendritic branching of surviving Mauthner cells?
Dendritic Branching following ear loss
Control Remove and Replace Ear
Ear Removed at Placode (Stage 26) Ear Removed at Late Otic Vesicle (Stage 40)
25µm
23 Terminal Branches 26 Terminal Branches 19 Terminal Branches 24 Terminal Branches
24 Terminal Branches 3 Terminal Branches 32 Terminal Branches 9 Terminal Branches
Dendritic Branching with extra ear
50µm
Extra Ear
50µm
21 Terminal Branches 33 Terminal Branches
Control Remove-Replace RemovePlacode (24-26)
Remove Early Otic Vesicle (27-30)
Remove Late Otic Vesicle (31-40)
Extra Ear0
5
10
15
20
25
30
35
Treatment
Num
ber o
f Den
driti
c Br
anch
es
Dendritic Branching
*** p < 0.001
n = 12 n = 12 n = 12 n = 12n = 12
*** ******
*
n = 10
ControlTreated
* p < 0.05
Control Remove-Replace Remove Placode(24-26)
Remove Early Otic Vesicle
(27-30)
Remove Late Otic Vesicle
(27-30)
Extra Ear
t-test
top related