Object Type:	leakage

Description:	Provides a constant conductance in series with a battery.
		This is often used to implement a passive "leakage" channel
		having a fixed conductance.

Author:		M. Wilson, Caltech (6/88)

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ELEMENT PARAMETERS

DataStructure:	leakage_type  [in src/segment/seg_struct.h]

Size:		96 bytes

Fields:		Gk		the Gk to be sent in a CHANNEL message
		Ek		the leakage battery
		activation	the leakage conductance used to calculate Ik
		Ik		channel current
		inject		not used

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SIMULATION PARAMETERS

Function:	Leakage  [in src/segment/leakage.c]

Classes:	segment
		channel

Actions:	PROCESS		Calculates Ik
		RESET		Sets Ik = 0
		CHECK 		Checks to see if an incoming VOLTAGE
				message has been established.

Messages:	VOLTAGE Vm

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Notes:		This object is intended to be used as a flexible leakage
		term in conjunction with the membrane model.  As with any
		other type of channel, it normally is used to send its
		conductance (Gk) and reversal potential (the battery in series
		with Gk) to the parent compartment using a CHANNEL message.
		In this case, Gk has a constant value, to be set by the user.
		
		Although this feature is not often used, a leakage element
		also calculates the current, Ik = (Ek - Vm)*activation.  Here,
		Vm is the compartment membrane potential received with a
		VOLTAGE message, and "activation" is a conductance.  This
		would normally be set by the user to the same value as Gk, but
		this is not done automatically.  As Gk does not depend on Vm,
		a VOLTAGE message is not strictly required if Ik not is
		needed.  However, the check command will issue a warning if
		one has not been established.
Example:	
        	create leakage K_leak
	        setfield K_leak Ek {EK} Gk {Gleak}
		addmsg K_leak   ..     CHANNEL Gk Ek
		addmsg ..       K_leak VOLTAGE Vm


See also:	
