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Factors mediating powerful voltage attenuation along CA1 pyramidal neuron dendrites
Author(s) -
Golding Nace L.,
Mickus Timothy J.,
Katz Yael,
Kath William L.,
Spruston Nelson
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2005.086793
Subject(s) - soma , apical dendrite , dendritic spike , dendrite (mathematics) , attenuation , excitatory postsynaptic potential , neuroscience , biophysics , conductance , membrane potential , hippocampal formation , chemistry , hyperpolarization (physics) , materials science , anatomy , biology , inhibitory postsynaptic potential , physics , geometry , optics , mathematics , condensed matter physics , organic chemistry , nuclear magnetic resonance spectroscopy
We performed simultaneous patch‐electrode recordings from the soma and apical dendrite of CA1 pyramidal neurons in hippocampal slices, in order to determine the degree of voltage attenuation along CA1 dendrites. Fifty per cent attenuation of steady‐state somatic voltage changes occurred at a distance of 238 μm from the soma in control and 409 μm after blocking the hyperpolarization‐activated (H) conductance. The morphology of three neurons was reconstructed and used to generate computer models, which were adjusted to fit the somatic and dendritic voltage responses. These models identify several factors contributing to the voltage attenuation along CA1 dendrites, including high axial cytoplasmic resistivity, low membrane resistivity, and large H conductance. In most cells the resting membrane conductances, including the H conductances, were larger in the dendrites than the soma. Simulations suggest that synaptic potentials attenuate enormously as they propagate from the dendrite to the soma, with greater than 100‐fold attenuation for synapses on many small, distal dendrites. A prediction of this powerful EPSP attenuation is that distal synaptic inputs are likely only to be effective in the presence of conductance scaling, dendritic excitability, or both.