Fig. 2. Possible paths recorded by the model path integrator. (A) Different versions of the hypothetical path shown in Fig. 1. Three of these paths (black, blue and violet) rely on an external compass for direction information (allothetic), while four of them (red, orange, green and gray) rely on an internal source of direction information (idiothetic). The latter include an arrow for the transverse body axis, signifying that all directions are measured against this. (B) Summary of possible paths from A. All integration mechanisms record the outward path (large black arrows); thereafter they diverge. Idiothetic paths show the final recorded orientation of the body axis (small black arrows) and the angle of the home vector measured against this (colored arcs). Home vectors are all in broken arrows. (C) Hypothetical home vectors for all seven model paths. See text and Table 1 for a description of the path-integration mechanism used to obtain each path.