Effects of captivity and testosterone on the volumes of four brain regions in the dark-eyed junco (Junco hyemalis).
This study investigates the effects of captivity and testosterone treatment on the volumes of brain regions involved in processing visual and spatial information in adult dark-eyed juncos (Junco hyemalis). We treated captive and free-living male juncos with either testosterone-filled or empty implants. Captive juncos had a smaller hippocampal formation (HF) (both in absolute volume and relative to telencephalon) than free-living birds, regardless of hormone treatment. Testosterone-treated males (both captive and free-living) had a smaller telencephalon and nucleus rotundus, but not a smaller HF or ectostriatum, than controls. We found that free-living testosterone-treated males had larger home ranges than free-living controls in agreement with earlier experiments, but we found no corresponding difference in HF volume. We discuss the implications of the effect of captivity on HF volume for past and future laboratory experiments.
Smulders
T V
TV
Department of Psychology, Cornell University, Ithaca, New York 14853, USA. tsmulder@wfubmc.edu
Casto
J M
JM
Nolan
V
V
Ketterson
E D
ED
DeVoogd
T J
TJ
D000818:Animals; D000835:Animals, Wild / Q000502:physiology*; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006702:Homing Behavior / Q000187:drug effects / Q000502:physiology; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D016548:Prosencephalon / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D020308:Songbirds / Q000033:anatomy & histology* / Q000502:physiology*; D013687:Telencephalon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013739:Testosterone / Q000097:blood* / Q000494:pharmacology*; D014795:Visual Pathways / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D012739:Gonadal Steroid Hormones; D013739:Testosterone