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Chapter 11: Synaptic Augmentation

An optional Synapse Component, Synaptic Augmentation simulates the effect of Calcium on regulating the current (I) generated by incoming spike messages. During a simulation, each spike received will trigger a release of Calcium in the synapse. This Calcium will quickly decay, but causes the Synaptic Augmentation value to build after a .5 second delay. This Augmentation value should decay more slowly, multiplying the effect of spikes that arrive while it is in effect. For example, after a burst of spikes arrive on a synapse, the Augmentation value builds to 1.34 so that any new spikes that arrive will be multiplied by that amount.
KeywordValueDescription
SYN_AUGMENTATION
N/A
Indicates the start of an Augmentation definition section
TYPE
name(string)
The name which will be used to refer to this object
AUGMENTATION_INIT
mean(real)
stdev(real)
The initial amount of Augmentation being applied to incoming spike messages. This value should be greater than or equal to 1.0.
AUGMENTATION_TAU
mean(real)
stdev(real)
The time constant of Augmentation's decay. This decay rate is considerably longer with a rate of 3 seconds recommended.
MAX_AUGMENTATION
mean(real)
stdev(real)
The maximum amount of Augmentation that can occur on the synapse. A value of 1.5 is recommended. A value less than 1.0 will result in an error.
CA_INTERNAL
mean(real)
stdev(real)
The initial amount of Calcium in a synapse at the start of the simulation
CA_SPIKE_INCREMENT
mean(real)
stdev(real)
The amount of Calcium released into the synapse after a spike arrives. A value of 100 microMoles is recommended.
CA_TAU
mean(real)
stdev(real)
The time constant of Calcium's decay. This decay rate is very short with a rate of 0.07 seconds recommended.
ALPHA
mean(real)
stdev(real)
Alpha determines the impact of Calcium on the Augmentation value. A value of 0.0035 (unit is (microMoles*milliseconds)^-1) is recommended
END_SYN_AUGMENTATION
N/A
Indicates the end of an Augmentation definition section

Example

SYN_AUGMENTATION
	TYPE  			Augment1
	CA_INTERNAL		0.00	0.00
	CA_TAU			0.07	0.001
	CA_SPIKE_INCREMENT	100.0	0.03
	MAX_AUGMENTATION	1.5	0.1
	ALPHA			0.0035	0.0001
	AUGMENTATION_INIT	1.0	0.00
	AUGMENTATION_TAU	3.01	0.2
END_SYN_AUGMENTATION
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Last updated Friday 6/15/2007