Equalizing Excitation-Inhibition Ratios across Visual Cortical Neurons

By Mingshan Xue, Bassam V. Atallah, Massimo Scanziani. Nature, 2014

708 citations recorded by the source corpus.

The relationship between synaptic excitation and inhibition (E/I ratio), two opposing forces in the mammalian cerebral cortex, affects many cortical functions such as feature selectivity and gain. Individual pyramidal cells show stable E/I ratios in time despite fluctuating cortical activity levels. This is because when excitation increases, inhibition increases proportionally through the increased recruitment of inhibitory neurons, a phenomenon referred to as excitation–inhibition balance. However, little is known about the distribution of E/I ratios across pyramidal cells. Through their highly divergent axons, inhibitory neurons indiscriminately contact most neighbouring pyramidal cells. Is inhibition homogeneously distributed or is it individually matched to the different amounts of excitation received by distinct pyramidal cells? Here we discover that pyramidal cells in layer 2/3 of mouse primary visual cortex each receive inhibition in a similar proportion to their excitation. As a consequence, E/I ratios are equalized across pyramidal cells. This matched inhibition is mediated by parvalbumin-expressing but not somatostatin-expressing inhibitory cells and results from the independent adjustment of synapses originating from individual parvalbumin-expressing cells targeting different pyramidal cells. Furthermore, this match is activity-dependent as it is disrupted by perturbing pyramidal cell activity. Thus, the equalization of E/I ratios across pyramidal cells reveals an unexpected degree of order in the spatial distribution of synaptic strengths and indicates that the relationship between the cortex’s two opposing forces is stabilized not only in time but also in space.

Subfields: Cellular and Molecular Neuroscience, Cognitive Neuroscience

View Paper: https://www.semanticscholar.org/paper/241e9f4e9769bff19b05c6628425ae7fe8afbd43

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Citations in the corpus

Efficient codes and balanced networks (2016, background): “Average conductance ratios have indeed been found to remain constant in many systems, which largely corroborates the ideas of E/I (current) balance 13,14,26,27 .”
Receptive field formation by interacting excitatory and inhibitory synaptic plasticity (2016, background): “…plasticity in auditory cortex supports our core assumption that Hebbian inhibitory plasticity aids in establishing an E/I balance (D’amour & Froemke, 2015; Kirkwood, 2015), and parvalbumin-positive interneurons are emerging as potential mediators within the cortical microcircuit (Xue et al., 2014).”
Inferring Synaptic Excitation/Inhibition Balance from Field Potentials (2016, positive): “2008), often combined with pharmacological or optogenetic manipulations (Xue et al. 2014; Reinhold et al. 2015).”
Functional selectivity and specific connectivity of inhibitory neurons in primary visual cortex (2018, neutral): “sim( fi, j(t), f ′ i, j(t)) = 1 N N ∑ j=1 ∑i ∑t fi, j(t) f ′ i, j(t) ( ∑i ∑t f 2 i, j(t)∑i ∑t f ′2 i, j(t) )1/2 (20)”
Fast-spiking, parvalbumin+ GABAergic interneurons: From cellular design to microcircuit function (2014, background): “In addition, inhibition at the output synapses on PV interneurons is stronger in target cells with strong synaptic excitation and high activity levels (86).”
Closed-loop and activity-guided optogenetic control. (2015, positive): “…to infer the times or probabilities of individual action potentials using deconvolution (Andilla and Hamprecht, 2014; Vogelstein et al., 2009, 2010; Yaksi and Friedrich, 2006), template matching (Lü tcke et al., 2013; Oñ ativia et al., 2013; Grewe et al., 2010; Greenberg et al., 2008; Kerr et al.,…”
Age-Related Characteristics of Resting-State Electroencephalographic Signals and the Corresponding Analytic Approaches: A Review (2024, background): “This increase in power slope in the PSD is determined by the balance between excitatory and inhibitory inputs, which consist of fast glutamatergic and slow GABAergic synaptic connections, respectively [80,81].”