Precise sound characteristics drive plasticity in the primary auditory cortex with VNS-sound pairing

Figures

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  Figure 1. VNS paired with the sounds ‘rad’ and ‘lad’ increases the primary auditory cortex response strength to the paired sounds. PSTH primary auditory cortex responses to the paired sounds ‘rad’ and ‘lad’ in experimentally naïve rats and rats that experienced (A) VNS + RL pairing, (B) VNS + RL600 pairing, and (C) VNS + R pairing. The acoustic waveform in each sound is presented behind each PSTH in gray.

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  Figure 2. VNS + RL pairing significantly alters primary auditory cortex responses. A1 responses to the paired sounds are stronger following VNS + RL and VNS + RL600 pairing. Black dots indicate median responses for each group, and gray lines indicate mean responses for each group. Error bars indicate 95% bootstrap confidence intervals of the median. Asterisks indicate experimental groups that are statistically significant from the control group. *p < 0.05; **p < 0.01; ***p < 0.001.

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  Figure 3. VNS + RL pairing significantly alters neural detection accuracy. A1 responses to the paired sounds are more detectable following both 300 or 600 VNS + RL pairings per day. Black dots indicate median responses for each group, gray lines indicate mean responses for each group, and dashed lines indicate neural classifier chance performance (50% correct). Error bars indicate 95% bootstrap confidence intervals of the median. Asterisks indicate experimental groups that are statistically significant from the control group, *p < 0.05; **p < 0.01; ***p < 0.001.

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  Figure 4. VNS + RL pairing significantly alters neural discrimination accuracy. A1 responses to the paired sounds are more discriminable following 300 VNS + RL pairings per day, but not 600 VNS + RL pairings per day or following VNS + R pairing. Black dots indicate median responses for each group, gray lines indicate mean responses for each group, and dashed lines indicate neural classifier chance performance (50% correct). Error bars indicate 95% bootstrap confidence intervals of the median. Asterisks indicate experimental groups that are statistically significant from the control group, *p < 0.05; **p < 0.01; ***p < 0.001.

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  Figure 5. Confusion matrices plotting classifier R vs. L accuracy for each group. The sound presented is plotted on the y axis, and the classifier guess is plotted on the x axis. The color bar indicates the percentage of trials where the classifier assigned the trial to the R or L category. White font indicates the mean ± SEM percentage of trials that the classifier correctly assigned to the correct category, while black font indicates the mean ± SEM percentage of trials that the classifier incorrectly assigned to the wrong category. For each group, the mean ± SEM classifier accuracy is given in the subplot title. There were no significant differences between experimental groups for the percentage of trials that the classifier correctly assigned R when the sound presented was R [χ2(3) = 6.804, p = 0.078, Kruskal-Wallis non-parametric test] or that the classifier correctly assigned L when the sound presented was L [χ2(3) = 3.722, p = 0.293].

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  Figure 6. VNS + RL600 pairing significantly strengthens A1 activity evoked by low frequency tones. VNS + RL pairing and VNS + R pairing do not alter A1 activity evoked by tones. Values plotted are estimated marginal means and standard error. Asterisks indicate experimental groups that are statistically significant from the control group, *p < 0.05; **p < 0.01; ***p < 0.001.