Figure 3

Figure 3

Differential properties of the LD and the AIS during setting the startle threshold. (A) Schematic representation of the setup used to monitor M-cell activity during escape response. (B) Probability of eliciting a startle response in the presence or absence of l-701 as a function of acoustic volume (dB) recorded simultaneously to glutamate-imaging. 50 μM l-701 significantly elevated the probability of startle responses at volumes larger than 83.8 dB (n = p < 0.001, two-sample t-test). No significant difference was observed at 81.8 dB. (C) Glutamate-release at the LD in the presence or absence of l-701 as a function of acoustic volume (dB). We used five different volumes, ranging from 81.8 dB to 91.7 dB, selected in such a way that three of these were well below the threshold level for eliciting an escape response, one near and one above it. Each fish received a series of five acoustic stimuli at each intensity. Fluorescent peak values for each stimulus from the corresponding volumes were averaged and normalized to the fluorescent peak value at the volume above the threshold level (91.7dB). Normalized fluorescent peak values remained unaltered at the LD to pharmacological manipulation (n = 10, 11 for the vehicle, treated respectively). (D) Glutamate-release at the AIS in the presence o absence of l-701 as a function of acoustic volume (dB). Normalized fluorescent peak values significantly increased at the AIS to pharmacological manipulation at volumes larger than 83.8 dB (n = 10, 11 for the vehicle, treated respectively, p < 0.01, two-sample t-test). No significant difference was observed at 81.8 dB. **p < 0.01, ***p < 0.001, ns, not significant.