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Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
Coherence resonance due to transient thresholds in excitable systems.
Ramana Dodla1, Charles J Wilson
1Department of Biology, University of Texas at San Antonio, 78249, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 28, 2010
Summary
Researchers discovered a new coherence resonance phenomenon in excitable systems by using negative noise pulses to access a second response threshold. This finding reveals a more complex role for noise in these systems.
Area of Science:
- Neuroscience
- Physics
- Applied Mathematics
Background:
- Excitable systems possess multiple response thresholds.
- Previous research on coherence resonance focused on a single threshold.
- The dynamics of a second response threshold in excitable systems remained largely unexplored.
Purpose of the Study:
- To investigate the dynamics of a second response threshold in excitable systems.
- To explore the phenomenon of coherence resonance associated with this second threshold.
- To demonstrate the complex role of noise in modulating the behavior of excitable systems.
Main Methods:
- Utilized the FitzHugh-Nagumo model to simulate excitable system dynamics.
- Employed brief pulses in the negative noise component to access the second response threshold.
- Extended analysis to the more realistic Hodgkin-Huxley model equations.
- Applied probabilistic considerations for analytical predictions.
Main Results:
- Identified a novel coherence resonance phenomenon by transiently reaching the second response threshold.
- Demonstrated that this resonance is dependent on both input amplitude and frequency.
- Validated the findings in both simplified and complex biophysical models.
- Showcased the significant influence of noise on excitable system dynamics.
Conclusions:
- Noise plays a more intricate role in excitable systems than previously understood.
- A second coherence resonance phenomenon can be induced and controlled via specific noise inputs.
- The findings have implications for understanding signal processing in biological and physical systems.
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