Model of Spike
Propagation Reliability Along the Myelinated Axon
Corrupted by Axonal Intrinsic Noise Sources
E.
KURIŠČÁK, S. TROJAN, Z. WÜNSCH
Institute of Physiology, First Faculty of
Medicine, Charles University, Prague, Czech
Republic
Received January 23, 2001
Accepted September 6, 2001
Summary
We investigated how selected
electromorphological parameters of myelinated
axons influence the preservation of interspike
intervals when the propagation of action
potentials is corrupted by axonal intrinsic
noise. Hereby we tried to determine how the
intrinsic axonal noise influences the performance
of axons serving as carriers for temporal coding.
The strategy of this coding supposes that
interspike intervals presented to higher order
neurons would minimally be deprived of
information included in interspike intervals at
the axonal initial segment. Our experiments were
conducted using a computer model of the
myelinated axon constructed in a software
environment GENESIS (GEneral NEural SImulation
System). We varied the axonal diameter, myelin
sheath thickness, axonal length, stimulation
current and channel distribution to determine how
these parameters influence the role of noise in
spike propagation and hence in preserving the
interspike intervals. Our results, expressed as
the standard deviation of spike travel times,
showed that by stimulating the axons with regular
rectangular pulses the interspike intervals were
preserved with a microsecond accuracy.
Stimulating the axons with pulses imitating
postsynaptic currents, greater changes of
interspike intervals were found, but the
influence of implemented noise on the jitter of
interspike intervals was approximately the same.
Key
words
Axons
· Action Potentials · Stochastic Processes ·
Computer Simulation · Ion Channels
Reprint
requests
E. Kuriščák, Institute of Physiology, First
Faculty of Medicine, Charles University, Albertov
5, 128 00 Prague 2, Czech Republic, e-mail: ekuri@lf1.cuni.cz
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