1. A computer-implemented method for a video surveillance system to process a sequence of video frames depicting a scene captured by a video camera, comprising: receiving a request to view a visual representation of a percept encoded in a long-term memory of a machine-learning engine, wherein the percept encodes a pattern of behavior learned by the machine-learning engine from analyzing data streams generated from the sequence of video frames; retrieving the requested percept from the long-term memory of the machine-learning engine, wherein the long-term memory stores a plurality of percepts; and generating a visual representation of the requested percept, wherein the visual representation presents a directed graph representing the pattern of behavior encoded by the requested percept; and receiving user input for a metadata attribute of the requested percept, wherein the metadata attribute specifies to publish an alert message upon detecting, from the data streams, an observation of the learned pattern of behavior corresponding to the requested percept.