Figure 3.

Encoding of high frequencies in cultured neurons improves with age (days in culture). (A) Example transfer functions of three neurons, cultured for 13, 17 and 25 days. Vertical dashed lines show 13 Hz, 100 Hz and 150 Hz. Averaged firing rate for the three neurons was 4.18 Hz; 5.08 Hz and 4.6 Hz, respectively. (B) Group-averages of transfer functions of neurons cultured for 11–15 days (N = 12), 16–20 days (N = 12) and 21–25 days (N = 5). (C,D) Correlation between the attenuation of encoding of high frequencies and age (days in culture). Attenuation of encoding of high frequencies was quantified using the ratio of transfer factor at 100 Hz over the transfer factor at 13 Hz (C, 100 Hz/13 Hz) or the ratio of factors at 150 Hz over 13 Hz (D, 150 Hz/13 Hz). Both measures were strongly correlated with age (Spearman-Rho 0.72, p < 0.001 and 0.73, p < 0.001; N = 29).