Related Experiment Videos
Modulation of synaptic transmission in neocortex by network activities
Sylvain Crochet1, Sylvain Chauvette, Sofiane Boucetta
1Department of Anatomy and Physiology, Laval University, Québec, G1K 7P4, Canada.
The European Journal of Neuroscience
|March 25, 2005
Summary
Cortical network activity reduces excitatory postsynaptic potential (EPSP) efficacy due to shunting and increased failures. Safe information transfer requires synchronized presynaptic neuron activity for effective cortical integration.
Area of Science:
- Neuroscience
- Computational Neuroscience
Background:
- Neocortical neurons receive input from thousands of presynaptic neurons.
- Understanding cortical integration requires assessing presynaptic firing impact in active networks.
Purpose of the Study:
- Investigate excitatory postsynaptic potential (EPSP) properties in vivo.
- Determine the impact of network activity on synaptic transmission efficacy.
Main Methods:
- Dual intracellular recordings from synaptically connected neurons.
- Microstimulation in anesthetized cats.
- Studied spontaneous and evoked single-axon EPSPs.
Main Results:
- Active network states decreased EPSP amplitude and duration via shunting.
- Increased EPSP failures and paired-pulse ratio during active states suggest reduced release probability.
- Elevating extracellular Ca2+ increased EPSP amplitude and reduced failures.
Conclusions:
- Synaptic transmission efficacy is low in individual synapses during active cortical states.
- High failure rates, shunting, and dendritic filtering limit presynaptic impact.
- Synchronized activity of large presynaptic populations is crucial for cortical information processing.