Explain the experiment conducted by Prof, Dickman and colleagues on GPS systems existing in pigeons
Answer:-
GPS (Global Positioning System) is a technology that uses a network of satellites to provide location and time information to users. The technology works by measuring the time it takes for signals to travel from satellites to a receiver on the ground or in a vehicle, and using this information to calculate the user’s position.
Scientists have long known that birds navigate using the earth’s magnetic field. Now, a new study has found subtle mechanics in the brain of pigeons that allow them to find their way. A team at Baylor College of Medicine in the U.S. identified a group of 53 cells in a pigeon’s brain that record detailed information on the Earth’s magnetic field, a kind of internal global positioning system (GPS).
Experiment:
Prof. Dickman and his colleague Le-Qing Wu set up an experiment in which pigeons were held in a dark room and used a 3D coil system to cancel out the planet’s natural geomagnetic field and generate a tunable, artificial magnetic field inside the room.
While they adjusted the elevation angles and magnitude of their artificial magnetic field, they simultaneously recorded the activity of the 53 neurons in the pigeons’ brains which had already been identified as candidates for such sensors.
So, they measured the electrical signals from each one as the field was changed and found that every neuron had its characteristic response to the magnetic field, each giving a sort of 3-D compass reading along the familiar north-south directions as well as pointing directly upward or downward. In life, this could help the bird determine not only it’s heading just as a compass does, but would also reveal its approximate position, the researchers said.
Each cell also showed sensitivity to field strength, with the maximum sensitivity corresponding to the strength of the Earth’s natural field, they added. And like a compass, the neurons had opposite responses to different field “polarity”, the magnetic north and south of a field, which surprised the researchers most of all. Several hypotheses hold that birds’ magnetic navigation arises in cells that contain tiny chunks of metal in their noses or beaks, or possibly in an inner ear organ. However, the most widely held among them was thrown into question when researchers found that purported compass cells in pigeon beaks were a type of white blood cell.