motifs/Recurrent excitation

A loop that feeds itself. Once driven above threshold the activity persists, which turns a transient input into a maintained state.

**Computes** Holds a value after the input is gone — short-term memory by self-sustaining activity. **Engineering equivalent** Integrator / latch / persistent state register. **Size** 4 neurons, 4 connections

Unlike a brain or a circuit, this artifact is complete: the graph below is the motif, not a pointer to it. Only the LIF parameters are missing before it can run.

Appears in: - heading-ring-attractor — EPG and PEN sustain the heading bump in darkness - worm-chemotaxis — Maintains the current locomotion state between decisions

- Without inhibition to bound it, recurrent excitation saturates — it is almost always paired with feedback inhibition.