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Functional Calcium Imaging in Developing Cortical Networks
Published on: October 22, 2011
Calcium and synaptic dynamics underlying reverberatory activity in neuronal networks
Vladislav Volman1, Richard C Gerkin, Pak-Ming Lau
1School of Physics and Astronomy, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv, Israel. volman@salk.edu
Physical Biology
|August 1, 2007
Summary
A new biophysical model explains how short-term persistent activity in neural networks emerges and terminates. This reverberating activity, crucial for learning, is sustained by residual calcium and asynchronous transmitter release.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Cellular Mechanisms
Background:
- Persistent neural activity is believed to drive neural plasticity and learning.
- Understanding the cellular mechanisms of persistent activity is crucial for advancing learning theories.
Purpose of the Study:
- To develop a biophysically tractable model explaining the emergence, sustenance, and termination of short-term persistent activity.
- To investigate the cellular and synaptic mechanisms underlying reverberating activity in cultured hippocampal neurons.
Main Methods:
- Development of a biophysically tractable computational model.
- Simulation of small networks (50-100 cells) of cultured hippocampal neurons.
- Analysis of model outputs against experimental observations, including polysynaptic current clusters and reverberation dynamics.
Main Results:
- The model successfully reproduced key features of observed reverberating activity.
- Residual pre-synaptic calcium was identified as critical for sustaining reverberations via asynchronous transmitter release.
- Fast synaptic depression underlies oscillatory activation, while slow depression terminates reverberation.
Conclusions:
- Asynchronous transmitter release, modulated by residual calcium, plays a significant role in network reverberations, not just synaptic noise.
- Synaptic depression dynamics (fast and slow timescales) govern the oscillatory and termination phases of reverberant activity.
- The model's simplicity facilitated testable predictions confirmed by experimental manipulations.
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