Equalization of synaptic efficacy by synchronous neural activity

Area of Science:

• Neuroscience
• Computational Neuroscience
• Synaptic Plasticity

Background:

• The common assumption is that postsynaptic neuron firing follows presynaptic neuron firing (orthodromic firing).
• Asymmetric temporal Hebbian plasticity can challenge the functional integrity of complex neuronal networks.
• Understanding spike timing causality is crucial for network stability.

Purpose of the Study:

• To challenge the notion that orthodromic firing is the sole determinant of neuronal communication.
• To investigate the stabilizing role of reversed spike timing in cortical networks.
• To explore the impact of synchronous neural activity on synaptic plasticity and efficacy.

Main Methods:

• Theoretical analysis of synaptic plasticity.
• Modeling of neuronal network dynamics.
• Investigation of spike-timing-dependent plasticity (STDP) under varying synchrony levels.

Main Results:

• Reversed spike timing is a common phenomenon in the cortex, contributing to network stabilization.
• Synchronous neural activity perturbs synaptic firing causality.
• The degree of neural synchrony principally determines the equilibrium of spike-timing dependent plasticity, with noise-induced synchrony equalizing synaptic efficacy.

Conclusions:

• Reversed spike timing plays a critical role in maintaining the structural integrity of neuronal networks.
• Synaptic efficacy is dynamically regulated by the level of network synchrony.
• Spike-timing-dependent plasticity is sensitive to synchronous activity, offering mechanisms for network homeostasis.