Fig. 2: Spectral analyses of hippocampal and ACC local field potentials.

a, h Power spectral densities (PSD) of each STZ (top) and control (bottom) group. Values are means from all leads from the entire recording session and have been normalized as a proportion of total spectral power. Sessions are on the y-axis and frequency is on the x-axis. b, i Mean power by frequency band. Mean normalized PSD power is on the y-axis and frequency bands are on the x-axis. Error bars show the standard error of the mean. Inset, mean spectral density over all leads per group by frequency (x-axis). c, j Theta/delta ratios. Mean theta power divided by delta power is on the y-axis. d, k Correlation between theta and delta power. Theta power is on the y-axes and delta power on the x-axes. Left, control sessions and right, STZ sessions. e–g, l–m Relationship between delta (e, l) and theta (f, m) power and theta/delta ratio (g, n) with running speed. Cumulative density of leads is shown on the y-axis and correlation values are on the x-axis. h ACC power spectral densities. Mean session long mean values for STZ (top) and control (bottom) animals. o Spectral phenotype analysis. Decoding accuracy by training set size. On the y-axis is percent accurately identified and the x-axis shows the number of LFP signals in each training set group. There were four groups: control ACC, control hippocampus, STZ ACC, STZ hippocampus. Colors show how leads were classified—blue for correct categorization and yellow, red, and green for the three types of incorrect classifications. The white dashed line shows the chance levels derived from 1000 bootstraps of randomly assigned group memberships. Bottom, confusion matrices by training set size. Colors depict the mean posterior probabilities for each category. Note the emergence of yellow on the diagonal as training set sizes increase. p, q Leave one out subject and session. On the y-axis is percent identified and the two groups are shown on the x-axis. Each dot (gray for control; magenta for STZ) shows an individual subject’s or sessions mean percent accurately identified. The white dotted line shows chance levels. In all plots, control values are in gray and STZ are shown in magenta. Dots indicate individual session values. **p < 0.01. Error bars = SEM.