Fig. 1. Key components of the magnetic resonance imaging techniques for intact, behaving Aplysia californica. (A) Imaging sequence. Gradient echo planar imaging (EPI) sequence with TR (acquisition time)=155 ms, TE (time to echo)=73 ms, acquisition matrix=64x128; FOV (field of view)=6.4 cmx12.8 cm; slice thickness=3 mm. RF, radio frequency. (B) The imaging tank and coil showing the opening through which Aplysia californica is inserted after being placed in the slug holding capsule. (C) The slug holding capsule showing the food spool, seaweed extract tube and strings for positioning the capsule within the tank.