Figure 4.

Respiration frequency generalization gradients. (A) Sample respiratory waveforms obtained from an NB-Mem subject. Shown are responses to three frequencies, the CS (8.00 kHz) and a lower (2.75 kHz) and higher (15.00 kHz) frequencies on the pre-training day (Before) and 24 h post-training (After). RCI values are the quantified values for each record. Note the large disruption of respiration only at the CS frequency after training (RCI = 0.34). The thick horizontal bars indicate tone presentation. (B) CS-specific induced memory as indexed by differential responses to tone after pairing with NBstm. Group mean respiration responses (RCI) (mean ± SE) for all test tone frequencies (X-axis, square frame for 8 kHz denotes CS frequency during training) for the NB-Mem group. Post-training generalization gradients (“After”, black bars) exhibited CS-specific changes for the group (bracket combining responses at 6.25–11.50 kHz; p < 0.001). The individual frequencies, the CS (8.0 kHz, p < 0.05) and the nearby frequency of 11.5 kHz (p < 0.02) each elicited significantly larger responses following pairing. In the figure, statistically significant paired comparisons (post hoc Tukey’s tests) are indicated with asterisks: *p < 0.05 and ***p < 0.005.