Biomedical Engineering Reference
In-Depth Information
(1) Estimate
φ
e
(t)
at the electrode in Fig. 8.5, where three current sources are propagating down a
cable at 300
mm/s
. Assume
dV
2
mm
3
, all distances are in
mm
, and all currents are in
μA/mm
2
.
=
=300mm/s
60
e
=1mS/cm
elec
50
1
-100
Y
X
12
7
5
0
(2) Derive the equations for Fig. 8.2.
Simulation Problems
(1) Modify the program in Ch. 4 simulation problem 2 to compute
φ
e
(t)
at
x
=
1
.
5
cm
and 0
.
2
cm
above the cable. Assume that
σ
e
=
1
mS/cm
.
(2) Show how the shape of
φ
e
changes as the location of the recording electrode is change. Explain
the changes you see.
(3) Show how the shape of
φ
e
changes as
R
i
is changed. Explain the changes you see.
(4) Program Fig. 8.2 assuming
R
e
=
10
cm
,
R
i
=
100
cm
, and
I
ion
is described by the Hodgkin-
Huxely model.
(5) Use the program in problem 2 above to create a strength-duration curve for a stimulus at node 2
in Fig. 8.2.