Voltage controlled resistor
You need to change the resistance value of your resistor to one with curly braces.
The component's value is usually something like this

R=20k


You put:

V=V(Vresistance) 


You need to use this for the components value:

R={V(Vresistance)}


Here are other ways to make a variable component:

R={V(Vresistance)}
R={I(Vresistance)}
C={V(Vresistance)}
C={I(Vresistance)}
R={V(Vresistance)*I(Vresistance)}}