Activity dependent transcription factor binding sites consensus sequences. The height of the letters is proportional to their frequency in the data used to build the matrix. For instance, a large "A" in position one means that "A" belongs to the most probable consensus for that transcription factor binding site. (A) Consensus sequence given by the transfac CRE-binding matrix V$CREB_01. (B) Consensus sequence given by the transfac zif268 binding matrix V$EGR1_01.