An identifiable molluscan neuron responds to changes in earth-strength magnetic fields

Area of Science:

• Neuroscience
• Animal Behavior
• Geomagnetism

Background:

• Many animals utilize geomagnetic cues for orientation, but the underlying neurophysiological mechanisms remain largely unelucidated.
• The marine mollusc Tritonia diomedea exhibits a magnetic sense, offering a unique model for studying neural magnetic field detection due to its accessible nervous system.

Purpose of the Study:

• To investigate the neurophysiological basis of magnetic field detection in Tritonia diomedea.
• To identify specific neurons involved in processing geomagnetic information.

Main Methods:

• Utilized a semi-intact whole-animal preparation of Tritonia diomedea.
• Performed intracellular recordings from identified neurons, specifically left pedal 5 (LPe5) and right pedal 5 (RPe5).
• Exposed the preparation to controlled changes in ambient earth-strength magnetic fields and monitored neuronal electrical activity.

Main Results:

• Specific neurons, LPe5 and RPe5, demonstrated enhanced electrical activity in response to magnetic field rotations.
• This response, characterized by increased spiking frequency, occurred with a latency of 6-16 minutes after magnetic field alteration.
• Approximately 50 other neurons did not exhibit similar responses to the magnetic stimuli.
• Disruption of neural connections between the brain and periphery abolished the magnetic response in LPe5 neurons.

Conclusions:

• The identified neurons LPe5 and RPe5 are likely involved in the detection of or orientation to the Earth's magnetic field.
• These neurons may form a crucial component of the neural circuit mediating magnetoreception in Tritonia diomedea.