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Differential induction of bidirectional long‐term changes in neurotransmitter release by frequency‐coded patterns at the cerebellar input
Author(s) -
D’Errico Anna,
Prestori Francesca,
D'Angelo Egidio
Publication year - 2009
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2009.177162
Subject(s) - long term potentiation , neuroscience , cerebellum , depolarization , neurotransmitter , ltp induction , nmda receptor , stimulation , glutamate receptor , synaptic plasticity , chemistry , long term depression , synapse , granule cell , biophysics , biology , receptor , inhibitory postsynaptic potential , excitatory postsynaptic potential , central nervous system , ampa receptor , biochemistry , dentate gyrus
Sensory stimulation conveys spike discharges of variable frequency and duration along the mossy fibres of cerebellum raising the question of whether and how these patterns determine plastic changes at the mossy fibre–granule cell synapse. Although various combinations of high‐frequency bursts and membrane depolarization can induce NMDA receptor‐dependent long‐term depression (LTD) and long‐term potentiation (LTP), the effect of different discharge frequencies remained unknown. Here we show that low‐frequency mossy fibre stimulation (100 impulses−1 Hz) induces mGlu receptor‐dependent LTD. For various burst frequencies, the plasticity–[Ca 2+ ] i relationship was U‐shaped resembling the Bienenstok–Cooper–Munro (BCM) learning rule. Moreover, LTD expression was associated with increased paired‐pulse ratio, coefficient of variation and failure rate, and with a decrease in release probability, therefore showing changes opposite to those characterizing LTP. The plasticity–[Ca 2+ ] i relationship and the changes in neurotransmitter release measured by varying induction frequencies were indistinguishable from those obtained by varying high‐frequency burst duration. These results suggest that different glutamate receptors converge onto a final common mechanism translating the frequency and duration of mossy fibre discharges into a regulation of the LTP/LTD balance, which may play an important role in adapting spatio‐temporal signal transformations at the cerebellar input stage.