Time domain and spectral analysis of TNF- and IL-1β-mediated neurograms. (A) Plot showing the total CAP counts in the 10-min period immediately after cytokine administration (saline, 200 µL per mouse, N = 6; TNF, 50 µg per mouse, N = 21; IL-1β, 350 ng/kg, N = 10). Values between the saline control and each cytokine are statistically significant (*, P < .05, MW test), but the cytokines are not significantly different from each other (ns, P = .07, t test). (B) Graph depicting the latency (mean ± SEM) for the TNF and IL-1β responses, with no significant difference between values (P = .16, t test). (C) Power spectral densities (PSDs) for the TNF (blue) and IL-1β (green) responses in the 0–30 Hz range for the unfiltered neurogram recordings. (Inset) PSD for the 0–200 Hz range, with the gray rectangle indicating the expanded plot. (D) The areas under the PSDs (0–400 Hz range) were calculated for TNF and IL-1β. The calculated area for each response is shown for TNF (blue) and IL-1β (green). Responses are statistically different (*, P < .05, MW test, N = 7 for each group), suggesting a potential biological substrate for cytokine discrimination within the CNS.