Amalysis of output of all Purkinje cells controlled by one climbing fiber cell

It was hypothesized earlier that synaptic plasticity of numerous granule cells-Purkinje cell connections might equalize input to climbing 1 fiber cell using the closed loop, climbing fiber cell-Purkinje cells-climbing fiber cell, and bi-directional synaptic plasticity of granule cells-Purkinje cell synapses. This equalization is demonstrated in our computational modeling. The system stability depends on metabotropic (non-electric) action of granule cells synapses. After equalization, Purkinje cell output presents a "restored replica" of extra-cerebellar synaptic input to the climbing fiber cell. Inter-spike intervals of the latter are virtually chaotic and their statistical pattern resembles natural climbing fiber activity. Modes of action of sets of Purkinje cells, controlled with the same climbing fiber cell and of ensembles of climbing fiber cells are treated analytically and qualitatively. Experimental consequences of the described cerebellar modus operandi are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.