Structural changes between seasons in the songbird auditory forebrain.
The song control system (SCS) of seasonal songbirds shows remarkable seasonal plasticity. Male starlings (Sturnus vulgaris) sing throughout the year, but in the breeding season, when concentrations of testosterone are elevated, the song is highly sexually motivated. The main goal of this study was to investigate structural seasonal changes in regions involved in auditory processing and in socio-sexual behavior. Using in vivo Diffusion Tensor Imaging (DTI), we measured in breeding and nonbreeding seasons volume and tissue characteristics of several brain regions of nine adult male starlings. We demonstrate that the songbird brain exhibits an extreme seasonal plasticity not merely limited to the SCS. Volumetric analysis showed seasonal telencephalon volume changes and more importantly also a volumetric change in the caudal region of the nidopallium (NCM), a region analogous to the mammalian secondary auditory cortex. Analysis of the DTI data allowed detection of seasonal changes in cellular attributes in NCM and regions involved in social behavior. This study extends our view on a seasonally dynamic avian brain which not only hones its song control system but also auditory and social systems to be prepared for the breeding season.
De Groof
Geert
G
Bio-Imaging Laboratory, University of Antwerp, Antwerp, Belgium. Geert.DeGroof@ua.ac.be
Verhoye
Marleen
M
Poirier
Colline
C
Leemans
Alexander
A
Eens
Marcel
M
Darras
Veerle M
VM
Van der Linden
Annemie
A
D000704:Analysis of Variance; D000818:Animals; D001303:Auditory Cortex / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging; D008297:Male; D009473:Neuronal Plasticity; D009929:Organ Size; D016548:Prosencephalon / Q000033:anatomy & histology*; D012621:Seasons; D012726:Sexual Behavior, Animal; D012919:Social Behavior; D046749:Starlings / Q000033:anatomy & histology* / Q000097:blood; D013739:Testosterone / Q000097:blood
D013739:Testosterone