Figure 4. Air-puff-predicting stimuli modulate mPFC→PVT neuron firing rates.

(A) Schematic drawings of viral stereotaxic injection of AAV1-CaMKII-ChR2-eYFP and tetrode bundle into mPFC and optic fiber over PVT. (B) eYFP (green), and DAPI (blue) in mPFC (top) and PVT (bottom) coronal sections from BL6 mice that received AAV1-CaMKII-ChR2-eYFP and tetrode bundle into mPFC and an optic fiber over PVT (scale bar, 100 μm). (C) Example of an identified corticothalamic neuron responding to a sequence of light stimuli (cyan) with action potentials (top) but not when the light stimuli followed spontaneous action potentials (bottom). (D) Antidromically-tagged corticothalamic neurons (blue) and antidromically-tagged corticothalamic neurons that passed collision tests (magenta). White points are neurons that were not identified. Crosses are neurons that passed collision tests, but were not recorded during behavior. (E–F) Average firing rates from example mPFC→PVT neurons showing firing rate increase (E) or decrease (F) to the air puff-predicting cue. Orange: air puff trials. Gray: CS - trials. Gray bars indicate odor presentation. Dashed lines indicate outcome delivery. (G) Scatter plot showing relationship between the change in firing rate to the air puff-predicting cue compared to baseline firing activity. Orange: neurons in which the firing rate during the air puff-predicting cue was significantly different from baseline firing activity ($t$-test, $p<0.05$).

Figure 4—figure supplement 1. Electrode and optic fiber locations.

(A) Drawings illustrate recording sites in mPFC in no air puff (left, $n=3$) and air puff exposed (right, $n=6$) mice. Boxes indicate approximate location of recording sites in each mouse, taking into account any vertical distance traveled during training and the approximate lateral spread of the tetrode bundle. (B) Traces showing virus expression in no air puff (left) and air puff (right) groups. (C) Locations of fiber tips in no air puff (left) and air puff (right) groups in PVT.