In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 95, No. 16 ( 1998-08-04), p. 9596-9601
Abstract:
We compared the transient increase of Ca 2+ in single spines on basal dendrites of rat neocortical layer 5 pyramidal neurons evoked by subthreshold excitatory postsynaptic potentials (EPSPs) and back-propagating action potentials (APs) by using calcium fluorescence imaging. AP-evoked Ca 2+ transients were detected in both the spines and in the adjacent dendritic shaft, whereas Ca 2+ transients evoked by single EPSPs were largely restricted to a single active spine head. Calcium transients elicited in the active spines by a single AP or EPSP, in spines up to 80 μm for the soma, were of comparable amplitude. The Ca 2+ transient in an active spine evoked by pairing an EPSP and a back-propagating AP separated by a time interval of 50 ms was larger if the AP followed the EPSP than if it preceded it. This difference reflected supra- and sublinear summation of Ca 2+ transients, respectively. A comparable dependence of spinous Ca 2+ transients on relative timing was observed also when short bursts of APs and EPSPs were paired. These results indicate that the amplitude of the spinous Ca 2+ transients during coincident pre- and postsynaptic activity depended critically on the relative order of subthreshold EPSPs and back-propagating APs. Thus, in neocortical neurons the amplitude of spinous Ca 2+ transients could encode small time differences between pre- and postsynaptic activity.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.95.16.9596
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
1998
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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