| Program#/Poster#: |
399.21/FFF15 |
| Title: |
Long-term dendritic
spine remodeling in the rat lateral amygdala following fear conditioning
involves circuit specific pruning of dendritic spines from low density dendrites
|
| Location: |
Hall F-J |
| Presentation Time: |
Monday, Oct 15, 2012, 8:00
AM - 9:00 AM |
| Authors: |
*D. DUMITRIU1,
Y. S. GROSSMAN1, R. GONZAGA2, C. FARB2,
W. G. JANSSEN1, J. E. LEDOUX2, J. H. MORRISON1;
1Mount Sinai Sch. Med., NEW YORK, NY; 2New York Univ.,
New York, NY |
| Abstract: |
The amygdala is an essential
structure to the development of long-term fear conditioning (FC). To date,
investigation into the local circuit changes involved in FC have primarily
focused on electrophysiological, biochemical and morphological changes in
the lateral amygdala (LA) occurring on the order of minutes to days following
FC. Our present study tested the hypothesis that FC leads to long-lasting
changes in the local circuitry of the rat LA. To test this hypothesis we
performed microinjections in individual LA neurons from FC and naïve rats
following a three week recovery. LA neurons were then analyzed both in terms
of their overall morphology, as well as in terms of their spine density
and size using high resolution 3D imaging and analysis. We found that, compared
to control rats, FC rats had reduced proximal dendritic length and a 22%
decrease in total spine density. Interestingly, remaining spines had shorter
distances to the nearest neighboring spines (i.e. were more clustered) than
the spines from control animals, an effect that could not be replicated
by simulation of random spine loss. To test how pruning results in the observed
increased clustering, we simulated spine loss from our naïve dendrites
using varying weights for several “protective factors”, such as protection
for spines within clusters, protection for large spines and protection for
spines residing on dense dendrites. When spine distributions from simulations
were compared to the spine distribution from FC dendrites, we found that
the primary factor resulting in increase clustering originates from selective
pruning of spines on low density dendrites. In summary, FC leads to circuit-specific
spine pruning in the rat LA following three weeks of recovery, with spine
loss occurring selectively on low density dendrites and resulting in an
effective increase in spine clustering. |
| Support: |
NIH F30 MH083402 |
|
NIH P50 MH58911 |
|
|
|
|
|
|