Movement of mouse pointer in ParticleHead.js

I want to make some changes in the javascript of ParticleHead.js. Currently the head is moving away from pointer, but i want it to move towards the pointer. This is the link for github repository of the code http://ift.tt/2sNrm0d and this the live working of it http://ift.tt/2s2WGv5 Can anyone of you help me doing this?? Thanks in Advance