BIOMIMETIC CORTICAL NANOCIRCUITS - Bio-Inspired and Nanoscale Integrated Computing - page 467

1

AP
PSP
PSP2
PSP3
PSP4

0.8

0.6

0.4

0.2

0

− 0.2

0 1 2 3

Time in seconds

4 5 6

× 10 − 11

Figure 17.6. The PSPs for different values of E-channel, the ion emf control.

In a third experiment we decreased the neurotransmitter reuptake control, R,
to slow ruptake of the neurotransmitter and increased it to speed up the reuptake.
The resultant PSPs are shown in Figure 17.5, with the greatest magnitude and
longest duration PSP resulting from the lowest voltage, and the shortest, lowest
magnitude PSP resulting from the maximum value of R. The The ion channel
control, E Channel, is held at 0.8 V, and the ion pump gate voltage at 0.4 V.
A fourth experiment shows the ability of the ion electromotive force,
represented by E-channel voltage, to control the PSP that results from ion
channels opening and closing. E-channel is varied from 0 V to 0.8 V, and the
resulting PSPs are shown in Figure 17.6. The reuptake control, R, is held at 0.3 V,
and the Pump Control voltage at 0.4 V. The PSPs are reduced and eventually
disappear when the ion electromotive force drops to 0 V.
The final experiment (Fig. 17.7) illustrates the temporal summation of PSPs
over time as a result of two successive action potentials at the same synapse.
This synapse is an example of the type of circuit that can be used to model
neural physiology. There are many synaptic variations yet to be included as the
research progresses.

1

APs
PSPs

0.8

0.6

0.4

0.2

0

0 1 2 3

Time in seconds

4 5 6

10 − 11

×

Figure 17.7. Summation of PSPs when action potentials arrive close together.