Cold-Temperature Coding with Bursting and Spiking Based on TRP Channel Dynamics in Drosophila Larva Sensory Neurons
Natalia Maksymchuk1, Akira Sakurai1, Daniel N Cox1
1Neuroscience Institute, Georgia State University, Atlanta, GA 30302-5030, USA.
International Journal of Molecular Sciences
|October 14, 2023
Summary
Drosophila Class III (CIII) neurons use bursting and spiking patterns to encode cold temperature. Bursting signals rapid temperature changes, while spiking reflects steady cold and rate of change.
Area of Science:
- Neuroscience
- Sensory Biology
- Computational Biology
Background:
- Temperature sensation relies on thermosensitive transient receptor potential (thermoTRP) channels.
- Drosophila larval Class III (CIII) neurons are key cold nociceptors expressing various thermoTRP channels.
- The precise mechanism by which CIII neurons encode temperature remains incompletely understood.
Purpose of the Study:
- To elucidate how Drosophila CIII neurons discriminate and signal different aspects of cold temperature stimuli.
- To investigate the roles of bursting and spiking activity patterns in temperature coding.
- To develop a computational model explaining the generation of these activity patterns.
Main Methods:
- Electrophysiological recordings of CIII neuron activity in response to controlled temperature changes.
- Computational modeling to simulate thermoTRP channel dynamics and neuron firing patterns.
- Analysis of firing rates and patterns (bursting vs. spiking) in relation to temperature stimuli.
Main Results:
- Two distinct cold-evoked activity patterns were identified: bursting and spiking.
- Bursting activity predominantly occurred during rapid temperature drops, correlating with the rate of change.
- Spiking activity, particularly tonic spiking, was observed at steady temperatures and also correlated with the rate of temperature decrease.
- A computational model successfully reproduced these patterns, linking them to thermoTRP current dynamics and a two-parameter activity map.
Conclusions:
- Drosophila CIII neurons utilize distinct firing patterns to encode different thermal information.
- Bursting activity serves as a marker for high rates of temperature change (noxious cold onset).
- Tonic spiking reflects both the rate of temperature change and the magnitude of sustained cold.
- The study provides insights into how TRP channel kinetics contribute to temperature coding in nociceptors.
