The Journal of Neuroscience, April 15, 2001, 21(8):2759-2767
Patterns of Neural Circuit Activation and Behavior during
Dominance Hierarchy Formation in Freely Behaving Crayfish
Jens
Herberholz,
Fadi A.
Issa, and
Donald H.
Edwards
Department of Biology, Georgia State University, Atlanta, Georgia
30302-4010
Creation of a dominance hierarchy within a population of animals
typically involves a period of agonistic activity in which winning and
losing decide relative positions in the hierarchy. Among crayfish,
fighting between size-matched animals leads to an abrupt change of
behavior as the new subordinate retreats and escapes from the attacks
and approaches of the dominant (Issa et al., 1999). We used high-speed
videography and electrical recordings of aquarium field potentials to
monitor the release of aggressive and defensive behavior, including the
activation of neural circuits for four different tail-flip behaviors.
We found that the sequence of tail-flip circuit excitation traced the
development of their dominance hierarchy. Offensive tail flipping,
attacks, and approaches by both animals were followed by a sharp rise
in the frequency of nongiant and medial giant escape tail flips and a
fall in the frequency of offensive tail flips of the new subordinate.
These changes suggest that sudden, coordinated changes in the
excitability of a set of neural circuits in one animal produce the
changes in behavior that mark its transition to subordinate status.
Key words:
crayfish; fighting; agonistic interaction; dominance
hierarchy; social behavior; field potential; escape; command neuron; tail flip; neural circuit activation
Copyright © 2001 Society for Neuroscience 0270-6474/01/2182759-09$05.00/0