Fig. 7.

Neurons in the ventral nucleus of the lateral lemniscus of α₇-knockout (KO) mice exhibit impaired temporal properties. A: recording sites in the ventral nucleus of the lateral lemniscus (VNLL; dashed line) were marked with Fluororuby tracer deposits delivered from the electrode. Scale bar = 100 μm. B: distribution of characteristic frequencies and minimum thresholds for KO and wild-type (WT) single-unit responses in the VNLL (n = 24 for both groups). C: representative examples of spiking patterns in the VNLL. For responses in both WT (i) and KO (ii) animals, robust spiking was evoked by the sound onset, either with or without a weaker sustained response component. First-spike latency (FSL) and jitter (FSL SD) were determined to assess temporal properties of each response. Purple bars represent the 100-ms characteristic frequency (CF) tone stimulus presented at 20 dB above threshold. D: no relationship was found between response duration and spiking rate for WT neurons (**P < 0.01, Spearman correlation). In contrast, spiking magnitude increased with increasing duration for KO neurons in the VNLL. E: jitter increased with increasing FSL for VNLL neurons in both KO and WT groups (Spearman correlation). Overall, FSL was elevated in the KO group compared with the WT neurons (P = 0.03, Mann-Whitney test).