single brief burst of spikes only at one time in the song (Figure 3D and E). It is assumed that each of the sequentially activated neurons is a part of an assembly of approximately 200 neurons, whose other members remain unseen to the experimenter (Hahnloser et al., 2002). The sequential activation of the assemblies in approximately 600 msec can be conceived as a word and the same word is repeated numerous times in a singing episode.10
