Gain Changes in Excitatory and Inhibitory Synapses Are Simultaneous and (Anti)Correlated

<div><p>(A) Excitatory (top, black) and inhibitory (bottom, red) normalized response amplitudes for a natural spike train (different than that shown in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040207#pbio-0040207-g001" target="_blank">Figure 1</a>) are plotted versus stimulus number within the train. Each point is an average of four (EPSCs) or seven (IPSCs) recordings from the same cells. Four control responses, before and after the spike train, are obtained by stimulation at a constant rate of 0.1 Hz. </p> <p>(B) Representative raw EPSC (top, black) and IPSC (bottom, red) responses (synaptic current as a function of time) to a high-frequency epoch, recorded from the same cells as in (A).</p> <p>(C) IPSC and EPSC amplitudes during the train from (A) are plotted versus each other and the correlation is determined as described in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040207#pbio-0040207-g003" target="_blank">Figures 3</a>A–<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040207#pbio-0040207-g003" target="_blank">3</a>C. </p> <p>(D) Average correlation between changes in EPSC and IPSC amplitudes for five different spike patterns. Ten random pairs of cells are selected for each pattern.</p> <p>** indicates <i>p</i> < 10⁻¹⁸. </p>