Figure 6.

Newborn MSNs are activated during singing in an age-dependent manner. (A) Experimental design: Adult male zebra finches (n = 6 per age group) received BrdU injections and were sacrificed at 21, 31, or 42 dpi after singing. (B) Region specific EGR-1 expression in Area X but not in the surrounding striatum after singing. (C–F) Newborn neuron (31 dpi, arrow) expressed EGR-1 after singing. (G–J) Newborn neuron (31 dpi arrow) expressed DARPP-32. (K) The fraction of new cells (BrdU+) that were activated after singing (EGR-1+) increased significantly between 21 and 42 dpi and between 31 and 42 dpi (shown are mean and SD). (L) The fraction of new cells (BrdU+) that express DARPP-32 increased significantly from 21 to 42 dpi (shown are mean and SD). ^*P ≤ 0.05; ^***P ≤ 0.001. Scale bars: 10 μm (C–J), 100 μm (B).