passing parameters to a trigger function

I can't figure out how to pass parameters to a trigger function. 

I checked the documentation and saw that trigger functions don't take params in the usual fashion, 
but couldn't find an example of a pl-sql trigger function that used the original row data within the function.


What I want is an on update trigger that creates an entry in a second table.  The second (history)  table has a subset of the columns in the first.

Here's what I have so far: 

-- THIS IS WRONG - CANT PASS PARAMS INTO TRIGGER FUNCTION


CREATE OR REPLACE FUNCTION audit_task ("param type declarations were here") RETURNS TRIGGER AS '	  
	-- create an audit trail record
BEGIN
	-- Perform the insert  
	
	INSERT INTO TASK_h  (id, 

		         updated_by, 
			 updated, 
			 name, 
			 description 
			 ) 
		VALUES ($1, $2, $3, $4, $5);
	
	RETURN NULL;		 
END;

' LANGUAGE plpgsql;


-- THE TRIGGER
CREATE TRIGGER t_audit_task AFTER INSERT OR UPDATE ON task FOR EACH ROW EXECUTE PROCEDURE audit_task();

So the question is, how do I access the row from the original table so I can perform the insert?

Thank you much.