PT  - JOURNAL ARTICLE
AU  - Christopher Ebsch
AU  - Robert Rosenbaum
TI  - Imbalanced amplification: A mechanism of amplification and suppression from local imbalance of excitation and inhibition in cortical circuits
AID  - 10.1101/201269
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 201269
4099  - http://biorxiv.org/content/early/2017/10/11/201269.short
4100  - http://biorxiv.org/content/early/2017/10/11/201269.full
AB  - Understanding the relationship between external stimuli and the spiking activity of cortical populations is a central problem in neuroscience. Dense recurrent connectivity in local cortical circuits can lead to counterintuitive response properties, raising the question of whether there are simple arithmetical rules for relating circuits’ connectivity structure to their response properties. One such arithmetic is provided by the mean field theory of balanced networks, which is derived in a limit where excitatory and inhibitory synaptic currents precisely balance on average. However, balanced network theory is not applicable to some biologically relevant connectivity structures. We show that cortical circuits with such structure are susceptible to an amplification mechanism arising when excitatory-inhibitory balance is broken at the level of local subpopulations, but maintained at a global level. This amplification, which can be quantified by a linear correction to the classical mean field theory of balanced networks, explains several response properties observed in cortical recordings.