Dynamics and mechanics of social rank reversal.
Stable social relationships are rearranged over time as resources such as favored territorial positions change. We test the hypotheses that social rank relationships are relatively stable, and although social signals influence aggression and rank, they are not as important as memory of an opponent. In addition, we hypothesize that eyespots, aggression and corticosterone influence serotonin and N-methyl-D: -aspartate (NMDA) systems in limbic structures involved in learning and memory. In stable adult dominant-subordinate relationships in the lizard Anolis carolinensis, social rank can be reversed by pharmacological elevation of limbic serotonergic activity. Any pair of specific experiences: behaving aggressively, viewing aggression or perceiving sign stimuli indicative of dominant rank also elevate serotonergic activity. Differences in the extent of serotonergic activation may be a discriminating and consolidating factor in attaining superior rank. For instance, socially aggressive encounters lead to increases in plasma corticosterone that stimulate both serotonergic activity and expression of the NMDA receptor subunit 2B (NR(2B)) within the CA(3) region of the lizard hippocampus. Integration of these systems will regulate opponent recognition and memory, motivation to attack or retreat, and behavioral and physiological reactions to stressful social interactions. Contextually appropriate social responses provide a modifiable basis for coping with the flexibility of social relationships.
Summers
Cliff H
CH
Biology and Neuroscience, University of South Dakota, 414 East Clark Street, Vermillion, SD 57069-2390, USA. Cliff@USD.Edu
Forster
Gina L
GL
Korzan
Wayne J
WJ
Watt
Michael J
MJ
Larson
Earl T
ET
Overli
Oyvind
O
Höglund
Erik
E
Ronan
Patrick J
PJ
Summers
Tangi R
TR
Renner
Kenneth J
KJ
Greenberg
Neil
N
D000374:Aggression / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology*; D003345:Corticosterone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D008116:Lizards / Q000502:physiology; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D012930:Social Dominance; D013315:Stress, Psychological / Q000378:metabolism*; D013997:Time Factors
D016194:Receptors, N-Methyl-D-Aspartate; D003345:Corticosterone