Figure 3: Random vs. predictable/repetition preference with and without CT blockade.

Preference ratios (PR) (total spikes to predictable trials/total spikes to random trials) across all $f_{\text{mods}}$ in response to distinct, less distinct SAM stimuli, less-distinct stimuli with corticothalamic blockade (CT blockade). A: Unit recording from awake rat MGB showed a clear preference for random distinct ${\text{SAM}}_{\mathrm{\Delta }100\text{\%}}$ stimuli. B: Responses to predictable (repeating) SAM stimuli increased from 18% (14/80), to 49% (39/80), in response to ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$ across $f_{\text{mods}}$. C: Optical CT blockade reversed the predictable preference of MGB neurons to 19% (14/80, in response to less ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$ SAM. Significant differences were seen between ${\text{SAM}}_{\mathrm{\Delta }100\text{\%}}$ vs. ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$, ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$ vs. ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}+\text{CT}$ blockade and ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}+\text{CT}$ blockade vs. ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$ + recovery (Chi-Square test, p < 0.05). D: PR values plotted on a continuum of increasing PPI values for each of 54 MGB units showing differential responses to distinct, ${\text{SAM}}_{\mathrm{\Delta }100\text{\%}}$ (blue dots) vs. less-distinct, ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$ stimuli (red dots) and ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$ with CT blockade (green dots). The green trend line shows that CT blockade dramatically decreased the PR in response to ${\text{SAM}}_{\mathrm{\Delta }25\text{\%}}$ (red trend-line) approaching the response to ${\text{SAM}}_{\mathrm{\Delta }100\text{\%}}$ stimuli (blue dots).