Among the signals studied in this system is CaMKII a calcium/calmodulin-regulated serine/threonine kinase which is required for induction by not expression of long-term potentiation. CaMKII mRNA is targeted to dendrites and both protein synthesis and enzyme activity are increased by strong synaptic input. Expression in "Xenopus" indicates that it is associated with the transition to slowed arbor growth. This suggests that activity promotes the reduction of dendrite branch growth and retraction, stabilizing the arbor configuration. The following pattern emerges for this system: