Module 10: Figure coincident detection
Coincident detection at the parallel fibre/Purkinje cell synapse.
A rat Purkinje neuron was loaded with the low-affinity Ca2+ indicator Magnesium Green to measure Ca2+. The climbing fibre (CF) or the parallel fibres (PF) could be activated using glass electrodes positioned as shown in a. The changes in Ca2+ were recorded in one of the spiny branches. No Ca2+ signal was recorded following eight stimuli given at 100 Hz to the PF (bottom trace in b). Likewise, a single stimulus to the CF also gave no response. However, when the CF was stimulated together with the PF, there was a large Ca2+ response that greatly exceeded the sum of the two separate responses. This neuronal coincident detection depends critically on the order and timing of the two stimuli. The synergistic response was greatest when the PF stimulation preceded the CF stimulation by 50–200 ms. Reproduced by permission from Macmillan Publishers Ltd: Nat. Neurosci., Wang, S.S.-H., Denk, W. and Häusser, M. (2000) Coincident detection in single dendritic spines mediated by calcium release, 3:1266–1273. Copyright (2000); http://www.nature.com/neuro; see Wang et al. 2000.