Photoperiod and testosterone independently affect vocal control region volumes in adolescent male songbirds

✍ Scribed by Gulledge, Cynthia C. ;Deviche, Pierre

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 104 KB
• Volume: 36
• Category: Article
• ISSN: 0022-3034
• DOI: 10.1002/(sici)1097-4695(19980915)36:4<550::aid-neu8>3.0.co;2-v

✦ Synopsis

Previously, we found that, unlike to long photoperiod without testosterone. Administeradults, adolescent male dark-eyed juncos (Junco hyeing testosterone induced singing, yet increased the volmalis) maintained large Area X volumes despite havume of only one VCR, the robust nucleus of the anteing low plasma testosterone concentrations. Other rior neostriatum (RA). In contrast, long photoperiod studies indicate that photoperiod may act indepenincreased several VCR volumes (Area X, higher vocal dently of testosterone to modulate vocal control region center, and RA) despite low testosterone levels, but did (VCR) volumes in adult songbirds. In the present not induce singing. Our results suggest a limited role study, we investigated the effects of testosterone and for testosterone, but an important role for photoperiod, photoperiod on the volumes of four VCRs in adolesin controlling VCR volumes in adolescent male juncos. cent male juncos. To test the hypothesis that VCR In addition, the results demonstrate that singing behavvolumes in these males are testosterone independent, ior can be induced in adolescent males without a conwe treated birds exposed to short days with testostercomitant increase in most VCR volumes. ᭧ 1998 John one and later compared their VCR volumes with those