School of
Information Technology and Electrical Engineering

Stochastic Facilitation Effects Due to Ion Channel Noise in an Auditory Brainstem Neuron Model

Speaker: 
Brett A. SchmerlMark D. McDonnellTue, 26/11/2013 - 11:00
Venue: 
78-420
Host: 
Prof Janet Wiles
Abstract: 

Neuronal membrane potentials fluctuate stochastically due to conductance changes caused by random transitions between the open and close states of ion channels.

Although it has previously been shown that channel noise can nontrivially affect neuronal dynamics, it is unknown whether ion-channel noise is strong enough to act as a noise source for hypothesised noise-enhanced information processing in real neuronal systems, i.e. ‘stochastic facilitation.’ Here, we demonstrate that biophysical models of channel noise can give rise to two kinds of recently discovered stochastic facilitation effects in a Hodgkin-Huxley-like model of auditory brainstem neurons. The first, known as slope-based stochastic resonance (SBSR), enables phasic neurons to emit action potentials that can encode the slope of inputs that vary slowly relative to key time-constants in the model.

The second, known as inverse stochastic resonance (ISR), occurs in tonically firing neurons when small levels of noise inhibit tonic firing and replace it with burst-like dynamics. Consistent with previous work, we conclude that channel noise can provide significant variability in firing dynamics, even for large numbers of channels. Moreover, our results show that possible associated computational benefits may occur due to channel noise in neurons of the auditory brainstem. This holds whether the firing dynamics in the model are phasic (SBSR can occur due to channel noise) or tonic (ISR can occur due to channel noise).

Biography: 

Brett Schmerl has a background in physics and the focus of his PhD is on the Piriform Cortex. He is currently working on designing a model that incorporates feedback to the olfactory bulb.

He is working with Mark McDonnell at the Computational and Theoretical Neuroscience Laboratory, Institute for Telecommunications Research, University of South Australia, SA 5095, Australia.

Seminar Type: 

ITEE Research Seminar

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