2.12 The impressions of works have their roots in afflictions and arise as experience in the present and the future births.
2.13 When the root exists, its fruition is birth, life and experience.
2.14 They have pleasure or pain as their fruit, according as their cause be virtue or vice.
Have you ever tried to get rid of a stubborn weed? One of the reasons why I have forsworn home ownership with a large yard is the difficulty of maintaining a weed free lawn. Some weeds, like the dandelion flowers were, next to impossible to eliminate. I don't like to use harsh chemical on my lawn because of what they do to the ground in the long run, so when I mowed my lawn, I would treat the weeds as part of the lawn itself. What is amazing is how something that was originally a patch of grass became a mix of different weeds in the course of two years.
If the effort was not put into removing the weeds by the roost, they regrew even stronger. The roots would grow bigger, just waiting until the next season to grow back with a vengeance.
Karma stored in our nervous system took root when the seed of impression was planted. If you took a chart of the human nervous system and flipped it upside-down, it would look like a tree. The brain would be the roots and the trunk of the spine extends up the back, breaking off into several branches reaching every part of the body. Rooted in the brain, our reactions to virtue or vice unfold as we experience our lives. Going through the process of deep meditation gives us access to the roots of our problems, so we can pull them up and stop them from regrowing.