Computational model of the jamming avoidance response in the electric fishGymnotus carapo

The unperturbed electric organ discharges of Gymnotus carapo fish are highl y periodic with interpulse intervals around 40 ms. The 'jamming avoidance r esponse' happens when fish interact and is a transitory interval shortening in the fish with the faster discharge that decreases the likelihood that p ulses from it and the other fish will coincide. Our model's basic component s match certain experimentally demonstrated facts. First, recurrence equati ons reproduce the periodic unperturbed discharges. Secondly, when an isolat ed pulse arrives, the two intervals following that with the pulse are short ened by amounts that decrease up to a minimum and then increase. Simulation s demonstrated that this model reproduces satisfactorily the jamming avoida nce response. Two additional conditions were demonstrably necessary: (i) on e was that every pulse arrive within the hot cophase window (and not elsewh ere); (ii) the other condition was that, along successive pulses, the respe ctive cophases decrease by moderate amounts. In short, we conclude that the fish's jamming avoidance response can involve the simple computational rul es implied by the proposed equations. (C) 1998 Elsevier Science Ireland Ltd . All rights reserved.