Animal Brachyura Support, Non-U.S. Gov't animal experiment crab electric shock male nonhuman Analgesia Association Learning Avoidance Learning Conditioning, Classical Danger stimulus Data Collection Electroshock Escape Reaction Exploratory Behavior Habituation (Psychophysiology) Male Mental Recall Naloxone Non-painful stimulus Opioid analgesia Pilot Projects Reaction Time Signal Processing, Computer-Assisted Social Environment adaptation analgesia arthropod