BIOS 286 Lecture Notes - Lecture 14: Tachykinin Peptides, Pituitary Gland, Neurochemistry
Document Summary
Sexually dimorphic nucleus (sdn) located in the hypothalamus: Birds sexually dimorphic behavior (singing) is generated by dimorphic neural structures. The development of vocal control regions in the brain and singing. The development of vocal control regions in the brain and singing behavior is under the control of steroid sex hormones. Male zebra finches require sex hormones to organize their vocal control regions (vcrs) at an early stage pf development. Adult male zebra finches also require sex hormones to activate their vcrs when mates are available. If a hatching female zebra finch is exposed to sex hormones (testosterone or estradiol), its vcrs will be larger than those of normal females when it reaches adulthood. If the masculinized female is given more testosterone as an adult, its. Vcrs will grow larger still, and she will then sing like a male. Females that are not exposed to steroids when young are unresponsive to testosterone as adults.
