p012fig01.08 A sigmoidal signal function is a hybrid signal that combines the best properties of [faster, same, slower]-than linear signals.  It can suppress noise and store a partially contrast-enhanced activity pattern. slower-than-linear saturates pattern; approximately linear- preserves pattern and normalizes; faster-than-linear- noise suppression and contrast-enhancement.<BR>||  Sigmoidal signal: a hybrid. (upper) saturates pattern- slower-than-linear; (middle) preserves pattern and normalizes- approximately linear.  (lower) noise suppression and contrast enhancement- faster-than-linear.