Figure 2.

Dynamics of signal functions control pattern in a recurrent architecture. (A) How the choice of four different non-linear signal functions determines network storage behavior including whether noise is amplified or suppressed (Grossberg, 1973). The sigmoidal case is noteworthy, because it features a quenching threshold which enables noise suppression and partially contrast-enhanced activity patterns to be stored in STM. Modulation of the quenching threshold enables the number of stored items to be varied. (B) To analyze the resultant network activity patterns, cells are labeled as winners or survivors, based on whether their activity relative to the network overcomes a winning threshold (WT) or a surviving threshold (ST). (C) Once the network stabilizes after stimulation has ceased, the network pattern can be classified as no pattern storage, partial contrast enhancement, or winner-take-all. A venn diagram of the cell activities and an example (Ex) of a stored pattern are shown for each case.