1. The Effect of Sensory
Deprivation on the Density of
M1 Microglia in the Mouse
Barrel Cortex
Yuhong Wang
The Bronx High School of Science

2. Cells of The Central
Nervous System
Neurons Glia
• Processes, transmits • Maintains homeostasis
information • Includes:
• Astrocytes
• Schwann Cells
• Microglia

3. Microglia
• Resident macrophage of the Central
Nervous System
• Constantly surveying its environment
• Processes engage in phagocytosis of
pathogens and debris
• Releases various cytokines to maintain
homeostasis in the CNS

4. The Barrel Cortex
• In the present study, we are looking at the presence
of microglial cells in the barrel cortex
• Barrel Cortex
o A region of the somatosensory cortex that
processes information from a rodent’s whiskers
o Organized topographically; Each whisker is
represented by a discrete aggregation of
neurons called a barrel
Barrel Cortex

5. The Effect of Sensory
Deprivation
• Trimming a rodent’s whiskers for the first postnatal
month has been shown to result in neuronal
remodeling
But, it seems microglia are also impacted by
sensory deprivation
How So?

6. Previous Studies
• Following trimming,
there is a significant
increase in cell
body area and a
significant
decrease in process
length of microglia
The fact that sensory deprivation leads to a change in microglial
morphology suggests that microglia are changing from a resting
state phenotype to an activated phenotype

7. Activated Microglia
• Expresses 2 distinct phenotypes
o M1 phenotype, or classically activated microglia,
are neurotoxic, as they release reactive oxygen
species and proinflammatory cytokines
o M2 phenotype, or alternatively activated
microglia, are neuroprotective, as they block
proinflammatory responses and instead produce
high levels of anti-inflammatory cytokines and
neurotropic factors.

8. Problem: How are M1
Microglia Impacted by
Sensory Derivation?
Due to the previously described
structural arrangements in the barrel
cortex following trimming, we aim to
determine if sensory deprivation will
have an significant impact on the
density of M1 microglia.

9. Trimming and Perfusion
• Sensory deprivation was achieved in mice by
bilaterally trimming whiskers every other day for
31 days, starting from birth. Some mice were
allocated to the p60 and p90 whisker regrow
group in order to prove that microglial
remodeling occurs in the first 30 days of
development.
• There were untrimmed mice in each group that
served as control
• Respective mice were perfused on the p31,
p61, and p91 days using saline and 4%
paraformaldehyde. Brains were post-fixed for 24
hours in 4% paraformaldehyde.

10. Sectioning and Staining
• Brains were sectioned into 50 μm slices using
a vibratome
• Brain sections were immunohistochemically
stained for microglia using primary antibody
Iba-1
• Sections were double stained with MHC-II
antibody in order to detect microglia
expressing the M1 phenotype.

11. Imaging and Analysis
• Slices were mounted using 0.01M phosphate
buffer saline medium and cover slipped
• Slides were imaged using confocal
microscopy and image stacks will be
analyzed using computer assisted program
Neurolucida 8.0 to determine the quantity
and distribution of M1 microglia.

12. Iba-1 Rhodamine Staining
Stains for all microglial cells

13. MHC-II FITC Staining
Stains for all microglia expressing the M1
phenotype

14. FITC, Rhodamine overlap
The overlap shows the number of M1
microglia (yellow) and the number that is not
expressing that phenotype (remains red)

15. Results
Number of Cells expressing the M1
phenotype in the sensory deprived and
control
30
Number of Cells per 100m3
25
20
15
10
5
0
IBA + MHCII+ IBA + MHCII+
Sensory Deprived Control
Cell Type

16. The percentage of microglia stained MHC-II (M1
phenotype)
1.2
1.0
Percentage MHCII+
0.8
0.6
0.4
0.2
0.0
Sensory Deprived Control
Sensory Deprivation does not seem to have an
effect on M1 expression of microglial cells

17. Conclusions
• Most microglia in the mouse barrel cortex
expresses the M1 phenotype as opposed to
M2
• Sensory deprivation did not have a
significant impact on the density of cells
expressing M1 phenotype, therefore our
hypothesis was proven wrong

18. Future Directions
• M2 microglia plays just as an important
role as M1 microglia does in
neuroplasticity. Future experiments
should characterize the effect of
sensory deprivation on the distribution
of M2 microglial cells.

19. Acknowledgements
• This research was supported by the City University of
New York at Queens College
• Thanks to Dr.Joshua Brumberg, Racheli Wercberger
and Zissy Turner for their contribution and guidance.