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. Author manuscript; available in PMC: 2016 May 6.
Published in final edited form as: Neuron. 2015 Apr 23;86(3):768–782. doi: 10.1016/j.neuron.2015.03.040

Figure 1. Low frequency CT stimuli modulate VPm excitability.

Figure 1

(A) Schematic of the principal pathway for whisker-related sensory processing in rodent forebrain.

(B) Image of a live TC slice (300 μm) from an Ntsr1-Cre mouse injected in barrel cortex with an AAV driving Cre-dependent ChR2-EYFP expression in L6 CT cells; Overlay of EYFP (green) and bright-field (gray). See also Figure S1.

(C) Schematic of recording configuration: Optical stimulation of ChR2-expressing CT axons (green) and whole-cell recording (K+ solution) from a ChR2-negative VPm cell (black).

(D) Top, control activity from a VPm neuron during injection of depolarizing current (overlay of 10 sweeps); middle, same cell and conditions except addition of CT stimulation (arrow, 1 ms flash; trials repeated at 0.1 Hz); bottom, raster plot of cell’s spiking. Control (black) and +CT (blue) trials are plotted as clustered groups for displays, but were interleaved during testing.

(E) Population peri-stimulus time histogram (PSTH: 5 ms bins) plotting difference in spike rates for CT versus control trials (n = 9 cells from 5 mice).

(F) Population PSTH showing the first 225 ms after CT stimulation. For (D–F), cells were injected with 30–110 pA to produce ~12 Hz baseline firing rates. CT stimulus intensities were 2x threshold for IPSPs (mean = 3.02 mW). See also Figure S2.