| 1. Natl Ctr Biol Sci, Bangalore, India |
| 2. Ctr for Neural Sci, NYU, NY, NY, USA |
Support Contributed By: DBT,NARSAD,MH38774,MH58911
Poster presentation:Monday, Oct. 25, 3:00 PM - 4:00 PM
Location: NN21
| LeDoux Lab 2004 SfN Abstracts |
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| BIOPHYSICAL CORRELATES OF INTRINSIC AND STRESS-INDUCED MORPHOLOGICAL VARIABILITY IN LATERAL AMYGDALOID NEURONS: A COMPUTATIONAL STUDY | ||
| R.Narayanan1*; L.R.Johnson2; H.H.Alphs2; J.E.LeDoux2; S.Chattarji1 | ||
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| Morphological and physiological characteristics of neurons
located in the dorsolateral and two ventral subdivisions of the lateral
amygdala (LA) have been compared in order to differentiate their roles in
the formation and storage of fear memories (Alphs et al, SfN abs 623.1,
2003). Briefly, in these populations, significant differences are observed
in input resistance, membrane time constant, firing frequency, dendritic
tortuosity, numbers of primary dendrites, dendritic segments and dendritic
nodes. In the present study, we perform computational simulations using
NEURON to (i) build a model of representative LA principal cells in each
of these subpopulations; and (ii) analyze the functional correlates of differences
in their morphology with respect to intrinsic firing properties and synaptic
integration. To this end, we build a model using three-dimensional reconstructions
of LA pyramidal cells in each of the three subdivisions, by imposing eight
ion channels (Na,KDR,KA,BK,KAHP,CaN,CaL,CaT) and comparing the simulation
outcomes with electrophysiological data. Our simulations show that variations
in intrinsic firing properties among populations may be controlled by active
membrane properties rather than being a direct reflection of the morphological
differences. We have previously reported that chronic stress induces dendritic
hypertrophy in LA pyramidal neurons. We use the model developed here for
analyzing the electrophysiological consequences of these variations. We
systematically induced growth in dendritic arbors of neurons to replicate
dendritic hypertrophy. Simulations using these model cells indicate that
hypertrophy reduces intrinsic cell excitability. Our results quantitatively
distinguish the biophysical correlates of morphological variations in (i)
internal dendritic organization structure; and (ii) total dendritic length. Support Contributed By: DBT,NARSAD,MH38774,MH58911 |
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| Program No. 517.7 Poster presentation:Monday, Oct. 25, 3:00 PM - 4:00 PM Location: NN21 |
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