Synaptic scaling rule preserves excitatory–inhibitory balance and salient neuronal network dynamics

• Published in: Nature neuroscience Vol. 19; no. 12; pp. 1690 - 1696
• Main Authors: Barral, Jérémie, D Reyes, Alex
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.12.2016; Nature Publishing Group
• Subjects: 631/378/116/1925; 631/378/116/2393; 631/378/3920; 9/74; Action Potentials - physiology; Animal Genetics and Genomics; Animals; Behavioral Sciences; Biological Techniques; Biomedicine; Brain - physiology; Excitatory Postsynaptic Potentials - physiology; Inhibition (Psychology); Life Sciences; Mice, Transgenic; Nerve Net - physiology; Neurobiology; Neuronal Plasticity - physiology; Neurons; Neurons and Cognition; Neurosciences; Patch-Clamp Techniques - methods; Synapses - physiology; Synaptic Transmission - physiology; New York; United States > US
• ISSN: 1097-6256; 1546-1726
• DOI: 10.1038/nn.4415

In neuronal cultures, synaptic strengths scale with the network size to preserve balance between excitation and inhibition, maintain variable spiking statistics and reduce correlations in spiking as predicted by theory and observed in the intact brain. The balance between excitation and inhibition (E–I balance) is maintained across brain regions though the network size, strength and number of synaptic connections, and connection architecture may vary substantially. We use a culture preparation to examine the homeostatic synaptic scaling rules that produce E–I balance and in vivo -like activity. We show that synaptic strength scales with the number of connections K as ∼ , close to the ideal theoretical value. Using optogenetic techniques, we delivered spatiotemporally patterned stimuli to neurons and confirmed key theoretical predictions: E–I balance is maintained, active decorrelation occurs and the spiking correlation increases with firing rate. Moreover, the trial-to-trial response variability decreased during stimulation, as observed in vivo . These results—obtained in generic cultures, predicted by theory and observed in the intact brain—suggest that the synaptic scaling rule and resultant dynamics are emergent properties of networks in general.