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. Author manuscript; available in PMC: 2019 Mar 23.
Published in final edited form as: Nature. 2017 May 3;545(7653):181–186. doi: 10.1038/nature22324

Extended Data Figure 2. Optical fiber locations and thalamus photoinhibition.

Extended Data Figure 2

a. Left, schematic of thalamus photoinhibition through an optical fiber. Right, optical fiber locations were overlaid on a coronal section of the Allen Reference Atlas (n = 7 mice).

b. Schematic of thalamus recording during photoinhibition using an optrode.

c. Top, peri-stimulus time histogram (PSTH) of putative thalamic neurons recorded by an optrode during control (black) and photoinhibition (blue) conditions in Gad2-IRES-Cre mice. Virus expressing ChR2 in a cre-dependent manner was injected in the VM/VAL projection zone of TRN. The magnitude of photoinhibition depends on the overlap of light intensity and axonal ChR2 expression. The fiber optic was 1 mm dorsal of VM/VAL, which likely explains that photoinhibition was stronger 1 mm from the fiber than closer to the fiber output. Averaging window, 100 ms. Bottom, normalized spike rate (mean spike rate during photoinhibition divided by mean spike rate during control) versus distance from optical fiber. Error bar indicates standard deviation. n = 26, 41, 17 cells; distances 0.6, 0.8, 1.0 mm respectively. Laser power at the tip of optical fiber, 10 mW.

d. Top, PSTH of thalamic neurons recorded by an optrode during control (black) and photoinhibition (blue) conditions in VGAT-ChR2-EYFP mice. Averaging window, 100 ms. Bottom, normalized spike rate (mean spike rate during photoinhibition divided by mean spike rate during control) versus distance from optical fiber. Error bar indicates standard deviation. n = 34, 42, 38 cells; distances 0.6, 0.8, 1.0 mm respectively. Silencing extended beyond the VM/VAL and included other thalamic nuclei that project to ALM and nearby cortical areas. Silencing using VGAT-ChR2-EYFP was more potent than with Gad2-IRES-Cre mice (c). Laser power at the tip of optical fiber, 10 mW.

e. PSTH of ALM neurons during control (black) and thalamus photoinhibition (blue) conditions. Laser power at the tip of optical fiber 10mW, n = 314 cells. Averaging window 100 ms.