The Journal of Neuroscience, August 22, 2007, ():
Dendritic Spikes in Apical Dendrites of Neocortical Layer 2/3 Pyramidal Neurons
J. Neurosci. Larkum et al.
27: 8999
Supplemental Data
Files in this Data Supplement:
- supplemental material
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Supplementary Figure 1. Suprathreshold spiking patterns of L2/3 pyramidal neurons. A, Example traces of somatic voltage responses in a L2/3 neuron to somatic current injections of 0.5 (left), 0.6 (middle), and 0.7 nA (right). Interspike intervals (ISI) were determined between consecutive APs. B, Average ISIs for the first 6 APs in trains for 8 different current amplitudes above threshold (0-0.7 nA above threshold). Data are from 50 neurons. C, Alternative representation of the same data as in B showing reconstructed spike trains using the average ISIs. For large current injections AP trains were regularly spiking after an initial high-frequency doublet.
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Supplementary Figure 2. Amplitude and half width of dendritic spikes in L2/3 pyramidal neurons. A, Amplitude of the calculated regenerative component (after subtraction of the estimated passive response) of isolated dendritic spikes as a function of distance from the soma. B, Half width of the calculated regenerative component as a function of distance from the soma. In both parts, the filled circles refer to dendritic potentials elicited with an EPSP-shaped waveform and the open circles represent cases where long current injection evoked an isolated dendritic spike. Dashed lines show linear regressions to all data points with correlation coefficients of -0.10 (A) and 0.56 (B), respectively.
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Supplementary Figure 3. Isolated dendritic spikes can be evoked by synaptic stimulation. A and B, isolated dendritic spikes evoked by synaptic stimulation in layer 1 in two different experiments. Top traces show synaptically evoked dendritic (red) and somatic (black) membrane potential traces. Bottom traces show isolated dendritic spikes evoked by dendritic current injection in the same cells. Resting membrane potential at soma and dendrite was -70 mV and -81 mV in (A) and -63 mV and -72 mV in (B), respectively.
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Supplementary Figure 4. Subthreshold depolarization at the soma does not facilitate induction of dendritic spikes. Dendritic (top) and somatic (bottom) membrane potential traces for just-subthreshold and suprathreshold somatic current injection paired with a dendritic current injection (0.9 nA, 7 ms delay). While for subthreshold somatic depolarization a similar dendritic current was required as for dendritic current injection alone (1.2 nA, not shown), the induction of a bAP lowered the threshold to 0.9 nA. The soma was 480 µm from the pia. The dendritic pipette was located 273 µm from the soma. The same result was obtained in another control experiment.
