Both wake and sleep pathways play a role in insomnia. Insomnia can occur when your wake and sleep pathways don't work well together.
Science suggests when insomnia occurs, your sleep neurotransmitters may be signaling your brain to sleep, but your wake neurotransmitters may not be turning down like they should. When this happens, it can be hard for your brain to transition from the "awake" mode.
This could be contributing to your insomnia, and help explain why you just aren't getting as much sleep as you want.