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Abstract:
Here we derive measures quantifying the information loss of a
synaptic signal due to the presence of neuronal noise sources as it
electrotonically propagates along a weakly-active dendrite . We
model the dendrite as an infinite linear cable, with noise sources
distributed along its length. The noise sources we consider are
thermal noise, channel noise arising from the stochastic nature of
voltage-dependent ionic channels (K and Na) and synaptic noise due
to spontaneous background activity. We assess the efficacy of
information transfer using a signal detection paradigm where the
objective is to detect the presence/absence of a presynaptic spike
from the post-synaptic membrane voltage. This allows us to
analytically assess the role of each of these noise sources in
information transfer. For our choice of parameters, we find that
the synaptic noise is the dominant noise source which limits the
maximum length over which information be reliably
transmitted.
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