Do your nerves or your brain tell your eyelids to blink?

Blinking is primarily controlled by the pre-motor brain stem, which means that no concious effort is required in the process.  Much like breathing and digestion, blinking is a spontaneous act that requires no interference by the person.

There is another method of blinking, however, that is controlled by external stimuli.  This is known as reflex blinking, and it occurs in instances such as physical contact with the cornea, or irritation from dust or pollen. 

Interesting blinking facts

• On average, most people blink around 16 times per minute, which equates to 15,000 times per day.
• Throughout an average lifetime, a person will spend roughly 8 to 9 days with their eyes closed from blinking alone.
• Moisture provided to the eyes through the act of blinking both stops the eye from drying out and prevents external objects from entering the eye.
• Eyelashes catch dust and other particles in order to keep the eye clear from external objects.
• If you're blinking too frequently, you should seek medical advice as it could be an indication of a vision issue/