Figure 2.

Optogenetic stimulation of type I GAD65⁺ fungiform TBCs increases CT nerve activity in a dose-dependent manner. A, B, Raw electrophysiological traces from the CT nerve (A) of a mouse expressing ChR2 in GAD65⁺-EYFP TBCs (top), a control Ai32 mouse (middle), which does not express ChR2 (or EYFP), and average responses (B) of both mouse strains. A change in rinse to stimulus presentation was indicated by square waves on the “stimulus” channel. Presentation of light pulses are shown by TTL trigger lines on the “light” channel. As shown, responses to taste stimuli representing sweet, salty, sour, and bitter were not significantly different in transgenic mice expressing ChR2-EYFP in GAD65⁺ cells and Ai32 mice. Nerve activity in GAD65-ChR2-EYFP mice significantly increased with increasing intensity at 1, 3, and 10 Hz, whereas light had no impact on nerve activity in Ai32 mice. The green asterisk and brackets indicate responses significantly different (following Benjamini–Hochberg adjustment) from Ai32 mice. Effect sizes for each contrast test (η²_partial) are labeled next to each significant comparison.