RT Journal Article
SR Electronic
T1 Voltage Imaging from Dendrites of Mitral Cells: EPSP Attenuation and Spike Trigger Zones
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 6703
OP 6714
DO 10.1523/JNEUROSCI.0307-04.2004
VO 24
IS 30
A1 Maja Djurisic
A1 Srdjan Antic
A1 Wei R. Chen
A1 Dejan Zecevic
YR 2004
UL http://www.jneurosci.org/content/24/30/6703.abstract
AB To obtain a more complete description of individual neurons, it is necessary to complement the electrical patch pipette measurements with technologies that permit a massive parallel recording from many sites on neuronal processes. This can be achieved by using voltage imaging with intracellular dyes. With this approach, we investigated the functional structure of a mitral cell, the principal output neuron in the rat olfactory bulb. The most significant finding concerns the characteristics of EPSPs at the synaptic sites and surprisingly small attenuation along the trunk of the primary dendrite. Also, the experiments were performed to determine the number, location, and stability of spike trigger zones, the excitability of terminal dendritic branches, and the pattern and nature of spike initiation and propagation in the primary and secondary dendrites. The results show that optical data can be used to deduce the amplitude and shape of the EPSPs evoked by olfactory nerve stimulation at the site of origin (glomerular tuft) and to determine its attenuation along the entire length of the primary dendrite. This attenuation corresponds to an unusually large mean apparent “length constant” of the primary dendrite. Furthermore, the images of spike trigger zones showed that an action potential can be initiated in three different compartments of the mitral cell: the soma-axon region, the primary dendrite trunk, and the terminal dendritic tuft, which appears to be fully excitable. Finally, secondary dendrites clearly support the active propagation of action potentials.