Biomedical Engineering Reference
In-Depth Information
approximately 1 ms. Note that in the figure on the top,
V
m
reaches steady state before the current
pulse returns to zero, and in the figure on the bottom,
V
m
falls short of the steady state value
reached on the top. The value of the time constant is important in the integration of currents
(packets of neurotransmitter) at the synapse. Each packet of neurotransmitter acts as a current
pulse, as described in Section 12.8. Note that the longer the time constant, the more time the mem-
brane is excited. Most excitations are not synchronous, but because of t, a significant portion of the
stimulus is added together that might cause an action potential.
−
70
−
75
80
−
Current pulse with magnitude of 15 uA
−
85
−
90
0
0.003
0.006
0.009
0.012
0.015
Time (s)
−
70
−
75
−
80
Current pulse with magnitude of 15 uA
−
85
90
−
0
0.003
0.006
0.009
0.012
0.015
Time (s)
