General, theoretical, and mathematical biophysics (including logic of biosystems, quantum biology, and relevant aspects of thermodynamics, information theory, cybernetics, and bionics). PACS. 87.22As -General theory and phenomenology.Abstract. -We investigated different regimes of synchronization in large lattices of chaotic spiking-bursting neurons. The lattices exhibit the following features: developed spatio-temporal disorder with no synchronization; spatial clusters of bursting synchronization; homogeneous bursting synchronization; and complete chaotic synchronization. We observed a bistable synchronization phenomenon in a wide region of the control parameter space. The bistability exists for homogeneous bursting synchronization with long-range correlation and spatial clusters of partial synchronization. The bistable regime appears in lattices with a size larger than the space-scale of these clusters.Introduction. -The analysis of the behavior of large assemblies of chaotic elements has been the subject of recent investigations, and is of interest both from the fundamental [1][2][3][4][5] and modeling points of view [6][7][8][9]. In particular, a network of chaotic elements is currently a very popular ingredient of information processing [7].We report in this letter on the collective dynamics of chaotic neurons with local interactions. Recent work [3][4][5][6] indicates that such lattices often exhibit "non-trivial" cooperative behavior demonstrating a rich variety of phase transitions. Such behavior is "non-trivial" because the chaotic dynamics of these lattices with short-scale interaction must exhibit extensive chaos: the number of Lyapunov exponents increases with the size of the lattice (see, for example, [1,2]). Actually, the cooperative behavior of chaotic lattices depends strongly on the strength of the local connection, variations of which reveal a rich diversity of synchronization.