(Chicken, left; Quail, right)

Dr. Evan Balaban and colleagues at Neurosciences Institute here haddone considerable ground work to identify parts of the quail and chicken brains involved with two functions, crowing and head-bobbing. The researchers then were able to transplant the target cells from two parts of  the brains of Japanese quail embryos into the brains of a two-day-old Plymouth Rock chickens embryos. They accomplished this by cutting minute holes in egg shells.

Animals or cells that include components of more than one species are called chimeras, after the mythical beast that was part goat and part dragon. The scientists allowed the chimerical chickens to hatch and then observed the behavior and vocalizations of the birds on videotape. The researchers were amazed to observe the altered chickens crowing and bobbing in characteristic quail style. As an additional control, chicken-chicken brain transplants were also performed, but no behavioral changes were observed. 

"To our knowledge, this is the first experimental demonstration that species differences  in a complex behavior are built up from separate changes to distinct cell groups in different parts of the brain and that these cell groups have independent effects on individual behavioral components," Balaban notes. 

The research has a number of  evolutionary and therapeutic implications for the study of the brain:

• Suggests that some complex behaviors are 'hard-wired' not learned.
• Confirms that these functions are portable
• Indicates that separate brain regions are involved in coordinated behaviors
• Could help researchers understand how to treat patients with nerve or brain damage
• Could lead to better understanding of neurological disorders in general

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