Intracellular Calcium Regulation by Burst Discharge Determines Bidirectional Long-Term Synaptic Plasticity at the Cerebellum Input Stage

Abstract

Variations in intracellular calcium concentration ([Ca2ϩ

Spine Ca2+Signaling in Spike-Timing-Dependent Plasticity

“…Uncaging experiments of Ca 2ϩ showed a correlation between the peak level of volume-averaged [Ca 2ϩ ] i and the direction of changes in synaptic strength (Yang et al, 1999). Ca 2ϩ imaging in dendrites and somata also suggested a direct correlation (Hansel et al, 1996(Hansel et al, , 1997Cormier et al, 2001;Ismailov et al, 2004;Gall et al, 2005). Simulations using the volume-averaged peak [Ca 2ϩ ] i amplitude as a readout to determine the direction of change in synaptic efficacy reproduced in part the experimentally determined STDP curves Shouval et al, 2002;Shouval and Kalantzis, 2005).…”

“…A long-standing hypothesis suggests that the peak amplitude of postsynaptic [Ca 2ϩ ] i elevation determines the direction and the magnitude of such modifications (Bear et al, 1987;Artola and Singer, 1993;Hansel et al, 1997). Several studies have supported this hypothesis by measuring dendritic [Ca 2ϩ ] i (Cormier et al, 2001;Ismailov et al, 2004;Gall et al, 2005). Nevertheless, the problem of how a single variable, the increase in global [Ca 2ϩ ] i , can control the differential induction of changes in synaptic efficacy has not been explained conclusively.…”

Altered Neuron Excitability and Synaptic Plasticity in the Cerebellar Granular Layer of Juvenile Prion Protein Knock-Out Mice with Impaired Motor Control

“…However, the alteration of LTP could be more complex and involve additional mechanisms. In fact, membrane depolarization during TBS was larger in slow-spiking PrP 0/0 than in fastspiking granule cells, and the slow time course of NMDA EPSCs suggests that Ca 2ϩ influx, which is needed for LTP induction (D'Angelo et al, 1999;Armano et al, 2000;Rossi et al, 2002;Gall et al, 2005), might be even larger in PrP 0/0 than in wild type. Therefore, the mechanisms of dysfunction may involve alterations in intracellular Ca 2ϩ dynamics, which have been reported in PrP 0/0 cultured cerebellar granule cells (Herms et al, 2000).…”

“…et al, 2004). In certain conditions in which granule cell activation is weakened, long-term depression (LTD) has been reported (Gall et al, 2005;Mapelli and D'Angelo, 2007).…”

The Spatial Organization of Long-Term Synaptic Plasticity at the Input Stage of Cerebellum

“…Golgi cell-granule cell neurotransmission is GABAergic (Brickley et al, 1996;Hamann et al, 2002), whereas mossy fiber-granule cell neurotransmission is glutamatergic and develops NMDA receptor-dependent long-term potentiation (LTP) after high-frequency mossy fiber activation (D'Angelo et al, 1999;Armano et al, 2000;Hansel et al, 2001). According to a bidirectional rule, LTP was shown to require stronger granule cell activation than long-term depression (LTD) (Gall et al, 2005). Golgi cell synaptic inhibition, by controlling membrane potential, may thus regulate the induction of synaptic plasticity between mossy fibers and granule cells and, eventually, determine the spatial organization of plasticity in the granular layer.…”