Neuronal ensemble recordings. (A) Experimental variations across electrophysiological measurements (shown for condition II, i.e., high baseline state, only) from the contralateral forepaw region. Significant increases and decreases in spiking frequency (ν) within were observed in ~60% and ~10% of the recordings, respectively (top and middle), whereas in ~30% of the recordings the stimulation did not induce any significant changes in n (bottom). The vertical and horizontal bars represent the scales for ν and time, respectively. The thick black horizontal bar represents the stimulus duration. (B and C) The comparison in a small neuronal ensemble (72 neurons) between basal activity achieved with two dosages of α-chloralose shows significantly different spiking frequencies at rest (P < 0.01), whereas upon stimulation the spiking frequencies became similar (P > 0.25). See Smith et al (2002) for details. Modified from Smith et al (2002), Proceedings of National Academy of Sciences, USA.