Erratum

Presynaptic calcium stores underlie large-amplitude miniature IPSCs and spontaneous calcium transients

I. Llano, J. González, C. Caputo, F. A. Lai, L. M. Blayney, Y. P. Tan and A. Marty

Nat. Neurosci. 3, 1256–1265 (2000)

Figures 6a, 6b and 8 reproduced poorly. The corrected figures appear below. We regret the error.

Fig 6. Ryanodine inhibits Ca²⁺_i rises induced by action potentials at basket cell terminals. (a, b) Two-photon scanning microscope images from presumed basket cell terminals in the close vicinity of a Purkinje cell soma. The presynaptic cell was loaded with a KCl solution containing 200 μM of Oregon Green 1. Images (67 ms exposure) are shown at rest (a) and near the peak of the response to a train of 4 action potentials (b).

Fig 8.Spontaneous Ca²⁺_i transients in presumed presynaptic terminals. (a) Superimposed bright field and fluorescence two-photon images of the preparation. The Purkinje cell layer is roughly vertical near the center of the picture, and the molecular layer is on the right. The soma of the recorded cell is outside the picture, below its lower border. Its labeled axon makes contacts with somata of several Purkinje cells, including one in the white rectangle representing the area analyzed with two-photon imaging and fluo-4 as Ca²⁺ indicator. (b) Two-photon scanning microscope image from the rectangular area in (a), including presumed presynaptic terminals (higher fluorescence counts indicating enlargements of the axon). The bath solution contained TTX and elevated Ca²⁺_o (6 mM). Average of 100 scans (100 ms each) at rest. The cell was filled with a K-gluconate solution containing 380 μM Fluo-4. ROIs 1 and 2 are in direct contact with the soma of the Purkinje cell, whereas ROIs 4–6 represent probable release sites onto the main dendrite of the same cell. ROI 5 is a 'hot spot' that responded to a short train of action potentials with a highly localized Ca²⁺_i rise in an earlier part of the experiment, in normal saline (2 mM Ca²⁺_o, no TTX; this first series of recordings was taken with a smaller scanning area that did not include ROIs 1, 2 or 6). (c, d) Time plots of fluorescence changes during two series of 100 consecutive images (100 ms per image). Each panel depicts the evolution of ROIs 1 through 6. Note that in (c), the transient is restricted to ROIs 1 and 2, whereas in (d), taken 5 min later, the transient is restricted to ROIs 4–6. (e, f) Analysis along the lines drawn in (b), during the two transients. Time runs from bottom to top. The left edge of each scan represents the uppermost point of each line. The transient in (f) spreads over about 5 μm and that in (e) over about twice this length (assuming that the part outside the imaged area falls off with distance like the part within).