Figure 2.

BDNF promotes spontaneous activity and survival. A, Left, Calcium signal (blue line) and intracellular recording (black line, action potentials marked with asterisks) show increased activity 5 min after application of 10 ng/ml BDNF. Right, Frequency of calcium activity is enhanced by 10 ng/ml BDNF in 5 min (n = 6). B, Example of inactive neurons (DIV7) becoming active 5 min after application of 10 ng/ml BDNF. C, GABAergic neurons were preferentially recruited by BDNF at DIV5 (n = 7). D, BDNF promoted spontaneous activity while suppressing apoptosis. Calcium imaging with Fluo-4 AM was performed at DIV5, and then the cultures were incubated with or without 10 ng/ml BDNF for 24 h, before the second calcium imaging was performed at DIV6 (n = 5). cnt, Control. *p < 0.05.