Skip to main content
Article thumbnail
Location of Repository

Differential susceptibility to synaptic plasticity reveals a functional specialization of ascending axon and parallel fiber synapses to cerebellar Purkinje cells

By R. E. Sims and Nicholas A. Hartell


Granule cell axons, via their parallel fibers, form synapses with Purkinje cells across large areas of the cerebellar cortex. Evidence for uniform transmission along parallel fibers to Purkinje cells is controversial, however, leading to speculation that the ascending axonal segment plays a dominant role in cerebellar processing. We have compared the relative susceptibilities of ascending axon and parallel fiber synaptic inputs to several forms of synaptic plasticity. We demonstrate that ascending axon synapses have a limited capability to undergo forms of long-term depression and potentiation compared with parallel fiber synapses. These results demonstrate that these two segments of the same axon play fundamentally different roles in cerebellar signaling, and, as such, the synapses formed between granule cells and Purkinje cells should not be treated as a homogenous population.This work was supported by the Biotechnology and Biological Sciences Research Council and the Royal Society

Topics: cerebellum, long-term depression, long-term potentiation, synaptic transmission, granule cell, Purkinje cell
Publisher: Society for Neuroscience
Year: 2006
DOI identifier: 10.1523/JNEUROSCI.4121-05.2006
OAI identifier:

Suggested articles


  1. (2002). A new form of cerebellar long-term potentiation is postsynaptic and depends on nitric oxide but not cAMP. doi
  2. (1999). Ascending granule cell axon: an important component of cerebellar cortical circuitry. doi
  3. (2004). Bidirectional parallel fiber plasticity in the cerebellum under climbing fiber control. doi
  4. (1992). Cerebellar long-term potentiation under suppressed postsynaptic Ca2 activity. doi
  5. (1996). Cyclic-AMPmediates a presynaptic form of LTP at cerebellar parallel fiber synapses. doi
  6. (2005). Differences in transmission properties and susceptibility to long-term depression reveal functional specialization of ascending axon and parallel fiber synapses to Purkinje cells. doi
  7. (2005). Endocannabinoid signaling depends on the spatial pattern of synapse activation. doi
  8. (2005). Endocannabinoids control the induction of cerebellar LTD. doi
  9. (2000). Expression of cerebellar long-term depression requires postsynaptic clathrin-mediated endocytosis. doi
  10. (1982). General discussion: radial connectivity in the cerebellar cortex. A novel view regarding the functional organization of the molecular layer. In: The cerebellum: new vistas (Palay SL, Chan-Palay V, eds), pp 189–194. doi
  11. (2006). Hartell • Ascending Axon Synapses Are Resistant to Plasticity doi
  12. (1994). Induction of cerebellar long-term depression requires activation of glutamatemetabotropic receptors. doi
  13. (1972). Integration by Purkyne cells of mossy and climbing fiber inputs from cutaneous mechanoreceptors. Exp Brain Res 15:498–520. doi
  14. (2001). Intercellular action of nitric oxide increases cGMP in cerebellar Purkinje cells. doi
  15. (1998). Konnerth A doi
  16. (1998). Local calcium signalling by inositol-1,4,5-trisphosphate in Purkinje cell dendrites.
  17. (2002). Modulatory effects of parallel fiber andmolecular layer interneuron synaptic activity on Purkinje cell responses to ascending segment input: amodeling study.
  18. (1994). Morphology of parallel fibres in the cerebellar cortex of the rat: an experimental light and electron microscopic study with biocytin. doi
  19. (1994). Motor deficit and impairment of synaptic plasticity in mice lacking mGluR1. doi
  20. (2001). Nitric oxide is required for the induction and heterosynaptic spread of cerebellar LTP. doi
  21. (2003). No parallel fiber volleys in the cerebellar cortex: evidence from cross-correlation analysis between Purkinje cells in a computer model and in recordings from anesthetized rats.
  22. (2005). NO signalling decodes frequency of neuronal activity and generates synapse-specific plasticity in mouse cerebellum. doi
  23. (1988). Number of parallel fiber synapses on an individual Purkinje cell in the cerebellum of the rat. doi
  24. (1998). Patches of synchronized activity in the cerebellar cortex evoked bymossy-fiber stimulation: questioning the role of parallel fibers. doi
  25. (2002). Properties of unitary granule cell3Purkinje cell synapses in adult rat cerebellar slices.
  26. (1991). Quantitative studies on the mammalian cerebellum. Prog Neurobiol 36:437–463. doi
  27. (2001). Random response fluctuations lead to spurious paired-pulse facilitation.
  28. (2003). Reversing cerebellar long-term depression. doi
  29. (1995). Sequential stimulation of guinea pig cerebellar cortex in vitro strongly affects Purkinje cells via parallel fibres. doi
  30. (1994). Signal transmission in the parallel fiber-Purkinje cell system visualized by highresolution imaging. doi
  31. (1992). Spread of synaptic activity along parallel fibres in cat cerebellar anterior lobe. Exp Brain Res 88:615–622. doi
  32. (1996). Strong activation of parallel fibers produces localized calcium transients and a form of LTD that spreads to distant synapses. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.