Signaling of layer 1 and whisker-evoked Ca2+ and Na+ action potentials in distal and terminal dendrites of rat neocortical pyramidal neurons in vitro and in vivo

Larkum, M. E., Zhu, J. J. (August 2002) Signaling of layer 1 and whisker-evoked Ca2+ and Na+ action potentials in distal and terminal dendrites of rat neocortical pyramidal neurons in vitro and in vivo. Journal of Neuroscience, 22 (16). pp. 6991-7005. ISSN 0270-6474

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Abstract

Dendritic regenerative potentials play an important role in integrating and amplifying synaptic inputs. To understand how distal synaptic inputs are integrated and amplified, we made multiple simultaneous (double, triple, or quadruple) and sequential (4–12 paired) recordings from different locations of single tufted layer 5 pyramidal neurons in the cortex in vitro and studied the spatial and temporal properties of their dendritic regenerative potential initial zone. Recordings from the soma and from trunk, primary, secondary, tertiary, and quaternary tuft branches of the apical dendrite of these neurons reveal a spatially restricted low-threshold zone ∼550–900 μm from the soma for Ca2+-dependent regenerative potentials. Dendritic regenerative potentials initiated in this zone have a clearly defined threshold and a refractory period, and they can propagate actively along the dendrite before evoking somatic action potentials. The detailed biophysical characterization of this dendritic action potential initiation zone allowed for the further investigation of dendritic potentials in the intact brain and their roles in information processing. By making whole-cell recordings from the soma and varied locations along the apical dendrite of 53 morphologically identified layer 5 pyramidal neurons in anesthetized rats, we found that three of the dendritic potentials characterized in vitro could be induced by spontaneous or whisker inputs in vivo. Thus layer 5 pyramidal neurons of the rat neocortex have a spatially restricted low-threshold zone in the apical dendrite, the activation or interaction of which with the axonal action potential initiation zone is responsible for multiple forms of regenerative potentials critical for integrating and amplifying sensory and modulatory inputs.

Item Type:	Paper
Subjects:	organs, tissues, organelles, cell types and functions > tissues types and functions > cerebral cortex organs, tissues, organelles, cell types and functions > cell types and functions > cell types > dendritic cells > dendritic arbors organs, tissues, organelles, cell types and functions > cell types and functions > cell types > dendritic cells > dendritic arbors organs, tissues, organelles, cell types and functions > cell types and functions > cell types > dendritic cells > dendritic arbors organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons > pyramidal neurons organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons > pyramidal neurons organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons > pyramidal neurons
CSHL Authors:	Zhu, J. Julius
Communities:	CSHL labs > Malinow lab
Depositing User:	Matt Covey
Date:	August 2002
Date Deposited:	08 Jan 2014 17:39
Last Modified:	08 Jan 2014 17:39
Related URLs:	Publisher
URI:	https://repository.cshl.edu/id/eprint/28732

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