Experimentally determined PRCs from several types of vertebrate forebrain neurons. Shown are cat somatosensory cortex layer V pyramidal neurons (top left) [Reprinted with permission from Reyes and Fetz (1993).], rat motor cortex layer II/III pyramidal neurons at different firing frequencies (bottom left) [Copyright: 2007 Tsubo et al., Federation of European Neuroscience Societies, and Blackwell Publishing Ltd. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.], rat layer II/III pyramidal neurons with and without cholinergic neuromodulation (top right) [Copyright: 2008 Stiefel et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.], and rat somatosensory cortex interneurons (bottom right) [Reprinted from Biophysical Journal, vol. 102, Tateno T and Robinson HP, Phase resetting curves and oscillatory stability in interneurons of rat somatosensory cortex, p. 683–695, Copyright 2007, with permission from Elsevier.].