Study On The Central Mechanism Of Sensing Magnetic Field Information In Cage-raised Budgies And Homing Pigeons

Objective It has been proved that more than 20 kinds of birds in nature can use earth's magnetic field information for directional navigation.In this paper,the cage-raised budgies(Melopsittacus undulatus)and the homing pigeons(Columba livia)are used as experimental subjects to investigate the central mechanism of the magnetic field information of cage-raised budgies and homing pigeons by studying the difference in c-fos expression in the brain caused by magnetic fields.In order to provide further experimental research to reveal the mystery of birds using earth's magnetic information directional navigation.Methods Experiment with the cage-raised budgies and homing pigeons,divided into three groups:earth's magnetic field group(37490±1125nT,EMF,N=8),2 times of the earth's magnetic field group(79390±2382nT,2EMF,N=8)and the rotating earth's magnetic field group(37490±1125nT,direction rotates 90°every 30s,REMF,N=8).Before each group of experiments,first adapt to 1 hour,that is,place the experimental animal in the center position of the magnetic field device coil for 1 hour;after the end of the adaptation,the earth's magnetic field is shielded,the coil is energized,and the center of the coil generates a uniform magnetic field under the corresponding experimental conditions,and the magnetic field is stimulated for 1 hour;After the end of the stimulation,the experimental animals are perfused,brain-removed,dehydrated and sectioned.The expression of c-fos in the vestibular nucleus,the optic tectum,dorsal thalamus,cortical HA area and hippocampus are detected by immunohistochemistry.Results(1)The study of the vestibular nucleus shows that there is no significant difference in the expression of c-fos between the 2 times of earth 's magnetic field group and the rotating earth's magnetic field group compared with the earth's magnetic field group of the budgie and the homing pigeon;There is no significant difference in the expression of c-fos between the earth's magnetic field group,the 2 times of earth's magnetic field group and the rotating earth's magnetic field group of the budgie and the homing pigeon in the left and right brain.(2)The study of the optic tectum shows that there is no significant difference in the expression of c-fos between the 2 times of earth's magnetic field group and the rotating earth's magnetic field group compared with the earth's magnetic field group of the budgie,there are significant differences in the expression of c-fos between the 2 times of earth's magnetic field group and the rotating earth's magnetic field group compared with the earth's magnetic field group of the homing pigeon;The expression of c-fos of the budgie's earth's magnetic field group shows that the right brain is higher than the left brain,and there is a significant difference.However,there is no significant difference in the expression of c-fos between the 2 times of earth's magnetic field group and the rotating earth's magnetic field group in the left and right brain.The expression of c-fos of the homing pigeon's earth's magnetic field group and the rotating earth's magnetic field group shows that the right brain is higher than the left brain,and there is a significant difference.However,there is no significant difference in c-fos expression between the left and right brains in the 2 times of earth's magnetic field.(3)The study of the dorsal thalamus,cortical HA area and hippocampus show that there is no significant difference in the expression of c-fos between the 2 times of earth's magnetic field group and the rotating earth's magnetic field group compared with the earth's magnetic field group of the budgie,there are significant differences in the expression of c-fos between the 2 times of earth's magnetic field group and the rotating earth's magnetic field group compared with the earth's magnetic field group of the homing pigeon;The expression of c-fos of the budgie's earth's magnetic field group shows that the left brain is higher than the right brain,and there is a significant difference.However,there is no significant difference in the expression of c-fos between the 2 times of earth's magnetic field group and the rotating earth's magnetic field group in the left and right brain.The expression of c-fos of the homing pigeon's earth's magnetic field group and the rotating earth's magnetic field group shows that the left brain is higher than the right brain,and there is a significant difference.However,there is no significant difference in c-fos expression between the left and right brains in the 2 times of earth's magnetic field.Conclusion(1)The budgie is not sensitive to changes in magnetic field strength and direction,and the homing pigeon is sensitive to changes in magnetic field strength and direction.(2)The brain area of the homing pigeon's optic tectum,dorsal thalamus,cortical HA area and hippocampus participate in sensing and analysis of magnetic field information.The vestibular nucleus do not participate in sensing and analysis of magnetic field information.(3)The homing pigeon's sensing the direction of magnetic field has unilateral advantage,and the left brain is the dominant center.