RESUMEN
Biological studies show that place cells are the main basis for rats to know their current location in space. Since grid cells are the main input source of place cells, a mapping model from grid cells to place cells needs to be constructed. To solve this problem, a neural network mapping model of back propagation error from grid cells to place cells is proposed in this paper, which can accurately express the location in a given region. According to the physiological characteristics of border cells' specific discharge to the environment, the periodic resetting of the grid field phase by border cells is realized, and the position recognition in any space is completed by this model. In this paper, we designed a simulation experiment to compare the activity of the theoretical place cell plate, and then compared the time consumption of the competitive neural network model and the positioning error of RatSLAM pose cells plate. The experimental results showed that the proposed model could obtain a single place field, and the algorithm efficiency was improved by 85.94% compared with the competitive neural network model in the time-consuming experiment. In the localization experiment, the mean localization error was 41.35% lower than that of RatSLAM pose cells plate. Therefore, the location cognition model proposed in this paper can not only realize the efficient transfer of information between grid cells and place cells, but also realize the accurate location of its own location in any spatial area.
RESUMEN
Following injection of HRP into the cerebellum of the rat, the retrogradely labeled′spinal border cells′ in L_1-L_3 of the spinal cord were examined electron microscopically for understanding the synaptology. Six types of terminal boutons (S, F, Cf, T, G and P types) which terminated on the surface of cell bodies or dendrites of the spinal border cells were recognized. The S- and F-boutons contain spherical and elliptical vesicles respectively. These two types of boutons had relatively broad area contacting with the surface of either cell bodies or dendrites. They could be derided into two sub-types respectively. One was the elonagted giant bouton and the other was the round. Cf-type contain flattened vesicles and it make membraneous′contact′ lacking in specialized pre-and postsynaptic membrane thickenings. T-type contain spherical and large granular vesicles, and dense body was seen beneath the post synaptic membrane. G-type boutons contain large granular vesicles in area of presynaptic. P-type boutons form synapses upon the large S-type boutons and contain pleomorphic vesicles. The postsynaptic membrane of S-, T- and G-types is apparently thicker than the presynaptic membrane and showed to be asymmetrical. Further study is necessary with regard to the sources of different terminal boutons contacting with different portions of the spinal border cells.