| INTER-SPECIES VARIATION IN THE MORPHOLOGY OF PYRAMIDAL
CELL DENDRITIC ARBORS AND SPINES IN THE PREFRONTAL CORTEX OF MAMMALS
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| A.B.Rocher1,2*; J.Hao1;
J.J.Radley4; D.Kabaso2,3; W.G.M.Janssen1;
D.J.Christoffel1; J.H.Morrison1; S.L.Wearne1,2,3;
P.R.Hof1,2 |
| 1. Dept of Neuroscience, 2. Computational Neurobiology
and Imaging Center, 3. Dept of Biomathematical Sciences, Mount
Sinai School of Medicine, New York, NY, USA |
| 4. Laboratory of Neuronal Structure and Function, Salk
Inst. for Biological Studies, La Jolla, CA, USA |
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Pyramidal neurons in the prefrontal cortex (PFC) provide
the circuitry for neocortical association areas that are critical
for cognition and attentional processing. Here we compared the morphology
of apical and basal dendritic arbors and spine densities among several
mammalian species, including the mouse, rat, pig, and macaque monkey.
Following perfusion and brief post-fixation, intracellular injections
of Lucifer Yellow were carried out in layer II/III (mouse, n=5; rat,
n=8) and III (pig, n=9; macaque monkey, n=5) pyramidal neurons in
PFC (5-10 cells per animal). Three-dimensional (3-D) neuronal reconstructions
were performed on apical and basal dendrites for the determination
of dendritic length using computer-assisted morphometry at 400x with
Neurolucida and NeuroExplorer softwares (MicroBrightField). 5-15 dendritic
segments from each neuron were selected for analysis of spine density
using a systematic and random sampling strategy. In order to reveal
spines in all angles of orientation, deconvolved optical image stacks
(Zeiss 410 LSM, 5000X magnification, z-step = 0.1  m) of dendritic segments were analyzed in 3-D. Spine
densities were expressed in terms of number/m. Overall, the dendritic
morphology and segment distribution appeared comparable across species.
However, in our preliminary observations we observed a substantial
variation in spine morphologies across species, most notably in pigs.
These data suggest that dendritic arbor morphology scales as well
as species-specific differences in spine numbers and shape occur among
mammals, which may reflect fundamental differences in the connectivity
and function of the prefrontal cortex.
Support Contributed By: AG06647, AG16765, DC04632, MH67034, MH58911and
RR16754.
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