Figure 4.

Signal characteristics from anesthetized and awake recordings. (a) Power spectral densities of baseline (non-stimulated) μECoG for different experimental conditions (mean ± S.E.M). Noise measurements were taken from an electrode in saline and reflect the total system noise of the headstage electronics and the thermal noise of the electrode. Number of sites per group: awake, epidural=861 (17 recordings), ketamine, subdural=300 (5 recordings), ketamine, epidural=240 (4 recordings), pentobarbital, subdural=120 (2 recordings), and system noise=60 (1 recording). (b) RMS voltage in the 10-100 Hz band for awake recording sessions in two animals spanning 10 weeks. The dashed line indicates the linear regression (slope 0.01 μV/day, p>0.05). Number of sites per day: day 6=108 (48+60, n=2), day 9=110 (50+60, n=2), day 13=60, day 15=39, day20=58, day 22=35, day 23=60, day 28=60, day 30=60, day 35=60, day 37=60, day 42=52, day 45=60, day 56=60, day 73=53. (c) Spatial correlation profiles for four in vivo recording conditions. Vertical lines span the interquartile range of the distribution of correlation per distance and black dashes represent the medians. The number of site-site pairs per group is: ketamine, subdural=8,732, pentobarbital, subdural=3,540, ketamine, epidural=7,080, awake, epidural=23869. (d) e-fold distance for awake recording sessions spanning up to 10 weeks (n=2).