Om Shanti. Intellect is one of 3 things which are in the soul. It's function is to judge, to take decision if something is right or wrong. Thought appears in the mind under influence of sanskars(clishe, steriotypes, habbits etc), after that intellect decides whether to make this thought come true or forget about it. If thought becomes an action then sanskar(habbit) becomes stonger, if not then - weaker.
Example: you have a habit (sanskar) to smoke, under this influence a thought to take cigarette appears in your mind. If your intellect takes decision to smoke then habit (sanskar) becomes stronger. And vise versa: if you want to drop smoking you can stop this thought with the power of your intellect. And this sanskar (habit) to smoke will become weaker and weaker because there will be no action (smoking).
As for "Yoga of the intellect": you decide to spent your energy on remembrance by your intellect. Also you sustain your meditation stage by decisions of your intellect. So it is Yoga of your intellect. Your intellect is connected (you have Yoga) with Me during meditation.