Dynamic Regulation of the Computational Properties of Pyramidal cells During Theta Bursts in Olfacto

1
Dynamic Regulation of the Computational
Properties of Pyramidal cells During Theta Bursts
in Olfactory Cortex.
Fabio M. Simões de Souza, Psychobiology
Sector,Universidade de São Paulo at Ribeirão
Preto, Brazil.James M. Bower, Research Imaging
Center, The University of Texas Health Science
Center at San Antonio,TX.
2
The connectivity of the piriform cortex model.
The connectors in black represent inhibitory
synapses and the connectors in white represent
excitatory synapses. The pyramidal cells are
connected with three classes of interneurons
FeedForward (FF), Feedback (FB), and combined
(FF/FB).
All pyramidal and non-pyramidal model cells are
spatially located in a matrix of 16 x 6 positions
and 15 x 5 positions, respectively .
3
Pyramidal Cell in the Anterior Piriform Cortex
Results Under conditions of the model, the
electronic length, and therefore presumably the
computational properties of pyramidal cells can
vary over the course of a theta frequency burst
of activity. This variation has the effect of
progressively reducing the influence of afferent
inputs on the soma, while increasing the relative
influence of intrinsically generated
activity.  This systematic change could provide
a mechanism  to facilitate convergence during
odor recognition. This effect was dependent on
the amplitude and/or time constant of  NMDA
conductances both of which had to be increased
relative to the original network
model.  Dependance on NMDA suggests that this
effect could also be regulated in the cortex. In
summary, these results suggest another role for
the oscillatory properties of the cerebral
cortex dynamically and systematically regulating
the computational properties of pyramidal cells.
6 weak shocks at 50Hz