This project investigates a mechanism of magnetic field receptor and transduction in the Bobolink (Icteridae: Dolichonyx oryzivorus). Little is known about the receptor system for magnetic field information or how the magnetic information is carried to the brain for any vertebrate species; yet behavioral data indicate a sensitivity to magnetic fields. The Bobolink was chosen as an experimental species because it has shown behavioral responses to changes in magnetic field information, it possesses magnetite (a potential transducer), and electrophysiological data indicate a neurological response to changes in the magnetic field. Preliminary results on the Bobolink have been more consistent that with other experimental species. The research proposed here will examine the electrophysiological characteristics of the magnetic field information carried by the trigeminal nerve and how changes in the orientation of the magnetic field affects the rate of spontaneous activity. Behavioral responses of the birds to altered magnetic fields after severing nerves which carry magnetic field information will show whether this information is used by the Bobolink in its migratory orientation. These techniques will provide a great deal of information on how the transducer functions, and help distinguish between the different models.
| Beason, R C; Semm, P (1991) Neuroethological aspects of avian orientation. EXS 60:106-27 |
| Semm, P; Beason, R C (1990) Responses to small magnetic variations by the trigeminal system of the bobolink. Brain Res Bull 25:735-40 |
| Semm, P; Beason, R C (1990) Sensory basis of bird orientation. Experientia 46:372-8 |
