1. 0
50
20 mv
Hippocampal CA1
100 ms
6.5 pA
0
50
1 10 100
π
0
Cortex
3 mV
1 nA
100 ms
0
10
0
Dendritic
current injection
Soma potential
Transfer
Impedance (ZT)
Amplitude (MΩ)
250um
Recording
Linear model
Frequency (Hz)
Phase (Rad)
Amplitude (MΩ)
1 10 100
600um
π
1) Experimental Basis
Experiments show that a linear model accounts for
the somatic response to a noisy current injection in
the apical trunk
Frequency (Hz)
Phase (Rad)
Zm ZmZm
Soma
Membrane
impedance (Zm)
Transfer impedance
Zm
Zm
...
...
Ra
1 10 100
ZT
Soma
ZT
ZT
Nearby
synapses
Distant
synapse
2) Model Structure
The model consists of cylindrical compart-
ments with a linear surface impedance (Zm)
0 %
100 %
Frequency (Hz)
1 10 100
ZT (150 um)
ZT (650 um)
50 %
250 um
CA1
ZT (distance
from soma)
Dendritic transfer
Amplitude(MΩ)
100
150 um
350
650
0
50
1 10 100
0
100
1 10 100
0
25
Membrane
impedance (Zm)
Amplitude
(MΩ)
Amplitude
KΩcm2
Transfer
impedance (ZT)
1 10 100
250 um
∙
3) Model Results
The full compartmental model perfectly repro-
duced the 2-port results. However, the model is
compatible with many impedance profiles. We
show two, which support different predictions
about the transmission of theta oscillations.
Active dendrites generate and transmit theta oscillations in model
neurons. Alan Schoen , Ali Salehiomran , and Erik Cook Department of Physiology,
McGill University and Department of Electrical and Computer Engineering, McGill University
1
2
2 11
Cortical data from Matthew Larkum
Dendritic transfer
0
100
Amplitude
(MΩ)
KΩcm2
Transfer
impedance (ZT)
1 10 100
0
500
Membrane
impedance (Zm)
1 10 100
250 um
0 %
100 %
1 10 100
50 %
150 um
350
650
0
100
50
1 10 100
ZT (distance
from soma)
Amplitude(MΩ)
0.5
Soma
Dendrites
∙
High Resonance Profile
With a large conductance in the soma, the
model predicts very little attenuation in dendrites
452.06
Dendrites connect the different parts of a neuron
and carry signals between them. The electrical
response of dendrites determines what kinds of
information are carried from one part of a cell to
another. We used linear systems analysis to
characterize the way dendrites respond to current
injection.
The resulting model is accurate and computa-
tionally efficient. Both impedance support the
notion that dendritic membrane plays a role in
generating and transmitting theta oscillations.
Uniform Membrane Profile
The resonant peak indicates that theta oscil-
lations are transmitted more effectively than
other signals
100 ms
1 Hz
80 Hz
10 Hz
ZT Amplitude (MΩ)