Supplementary Figure 7: Excitatory response of MeA neurons to LA input.

Spontaneous firing was measured from neurons in the MeA (posterior) from WT (top; n=36 neurons) and Nrxn rats (bottom; n=59 neurons). Evoked firing was measured from neurons in the MeA (posterior) from WT (n=16 rats) and Nrxn rats (n=11 rats) upon stimulation of LA. All recording and stimulation sites were histologically verified. a) Map of the recording and stimulation sites. Coordinate in lower right of panels indicates the distance from Bregma as mapped onto the atlas of Paxinos and Watson. b) Stimulation of LA induced a short latency excitatory response in MeA neurons (LA→MeA; <8 ms, <3 ms variability, consistent with monosynaptic input) in most neurons that displayed a response (>30% change in firing, n=16/28 neurons, 57% of neurons). The remaining neurons displayed no response (n=8) or >30% inhibition (n=4 neurons). In contrast, few LA neurons displayed an excitatory response upon stimulation of MeA (MeA→LA; n=11/43 neurons, 26% of neurons). In neurons that were responsive, the LA→MeA response was significantly greater than the MeA→LA response (LA→MeA n=16 neurons, MeA→LA n=11 neurons; path x time interaction, p<0.0001, F(78,1482)=1.770, η²=0.045, two-way RM-ANOVA). Displayed here is the mean ± 95% C.I. of these response at 0.6 mA stimulation across time. c) There was a significant difference in the response probability across stimulation intensity between the LA→MeA and MeA→LA paths (main effect of path direction, p<0.0001, F(1,125)=81.87, η²=0.160; direction x intensity interaction, p<0.0001, F(4,125)=15.69, η²=0.123; two-way ANOVA). Data shown here are mean ± 95% confidence intervals except where noted. #p<0.05 two-way ANOVA.

Paxinos, C.W.G. By George Paxinos - The Rat Brain in Stereotaxic Coordinates: 6th (sixth) Edition (Elsevier Science, 2009).