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. 2009 Jul 13;106(30):12518–12523. doi: 10.1073/pnas.0903214106

Fig. 2.

Fig. 2.

LMAN inactivation reveals a contribution of the AFP to vocal learning. (A) Reverse microdialysis probes are implanted bilaterally into LMAN, and tetrodotoxin (TTX) solution is held in a reservoir and diffuses through a porous membrane. (B) Average pitch (Upper) of each rendition of the targeted syllable during a day on which TTX was infused into LMAN (gray dots, pre-TTX; red dots, post-TTX). (Lower) The feedback power played during the targeted syllable (dots represent averages of 10 sequential renditions). Black dots indicate the mean pitch in the morning, preinfusion, and postinfusion. (C) Same as B except vehicle was infused (purple dots). Note that during vehicle infusions the pitch of the targeted syllables continued to exhibit learning in the instructed direction (1.26 ± 0.66Hz/hr, P < 0.03, 2-tailed t test), whereas learning stopped during TTX infusions (−0.50 ± 0.62 Hz/hr, P > 0.7, 2-tailed t test). (D) Feedback noise power, preinfusion versus postinfusion (TTX, red hollow symbols; vehicle, purple filled symbols). Black line indicates unity slope. (E) Histogram of the effect of TTX infusion on pitch (postinfusion minus preinfusion). Note the regression of pitch opposite the ongoing direction of learning (green and blue, learning in upward and downward direction respectively). (F) Histogram of the effect of vehicle infusion on pitch.