What makes me decide to eat the burger or not? Answer is the need. If a certain part of your body needs the nutrition from the hamburger, you will eat it. See picture below.
neurons in brain
Red line indicates connections between different neurons. The words ( Example: "vitamin A", "vitamin B", "brown", "yellow") represent different kinds of neurons. each kind of vitamin is handled by one neuron. Each color is also handled by one neuron. The frequencies from the hamburger goes through your eyes (sight) and your nose (smell). Then the frequencies goes to related neurons.

vitamin neurons
The vitamin neurons are also connected by neurons that represent different body parts.

Then the neurons that represent different body parts actually extend several feet long down the spinal cord, and connect to related body parts. These long neurons are called nerves.
nerves down the body

Remember this picture? Please wait to see picture move.
animal eats
If there are requests from body cells to attract outside chemicals, the animal starts eating.