p220fig05.29 Vigilance is a gain parameter on inputs to the orienting system that regulates whether net excitation from bottom-up inputs or inhibition from activated categories will dominate the orienting system.  If excitation wins, then a memory search for a better matching will occur.  If inhibition wins, then the orienting system will remain quiet, thereby enabling resonance and learning to occur.<BR>||  Vigilance control [resonate and learn, reset and search]. ρ is a sensitivity or gain parameter