Identification Of Place Cells And Distribution Properties Analysis Of The Place Field In The Pigeon Hippocampus

The hippocampus is an important brain area participating in learning and memory function in the brain,which plays a vitally important role in situational memory and spatial navigation.Aiming at the neural mechanism underlying spatial cognition of birds,this thesis studies the identification of the place cell in the hippocampus of the pigeon and analyses the distribution properties of place fields,which will be helpful for extending our understanding of the mechanisms underlying spatial cognition of different species,and lay a foundation for future studies on three-dimensional spatial cognition and navigation mechanisms in pigeons,and provide the mechanism support for the nerve rehabilitation of the memory impaired patients.Two kinds of experimental devices,namely circular maze and plus maze,are utilized in this thesis and four different spatial cognitive tasks are designed.The circular maze environment consists of three kinds of tasks,namely,the not setting up landmark foraging task(Task1),with setting up landmarks autonomous activities task(Task2)and foraging task(Task3);with setting up landmarks foraging task in the plus maze(Task4).When the pigeons perform the above tasks,the neural signals in the hippocampus and the trajectories are simultaneously detected,and the inter-electrode correlation method is used to remove the large amplitude interference in the detected Spike signals.Then,the two-dimensional planes of the task space are divided into grids,and the neuron response in the hippocampus is analyzed.According to the detected Spike sequences and the trajectories,the Spike firing rate density matrix is constructed,and the threshold is set to obtain the response grids and the response areas,and then the place cells and its corresponding place fields are identified.239 neurons are recorded and 151 place cells,430 place fields are identified in four different spatial cognitive tasks in this thesis,the proportion of place cells is 63%,and the place fields are mostly near the food and nest.The place cells account for 94.49% of the recorded neurons in the circular maze,and the place cells take up 27.68% in the plus maze.The comparison of three different tasks in the circular maze reveals that the proportion of place cells in task 3 is 100% and in task 1 is 93.75%,while in task 2 is only 68.75%,which is related to not traversing the entire space environment in the autonomous activities.In the distribution of the place fields,as much as 31.13% of the place cells have a single place field,which is the largest proportion.In task 1 and 3,the number of the place fields of one place cell is up to six or seven,which shows a place cell has multiple place fields.While the number of the place fields is one or two in the task 2 and 4.In general,a place cell has an average of 2.85 place fields.The above results indicate that the probability of the place cells in the circular maze is much bigger than that of the plus maze.The environment with setting up landmarks induces more neurons to discharge,and the induced place cells and place fields in the free forging are more than that in the autonomous activities.Most of the place cells have different place fields in the same space environment.