subcortical

adjective2

1. •
   Of or pertaining to the subcortex, the portion of the brain located below the cerebral cortex

   • He was diagnosed with subcortical dementia.
2. •
   Beneath the bark of trees.

   • More than two-thirds of the trees evidenced subcortical beetles, but no root decay fungi. The latter, without the former, were found in only 2 to 3 percent of the trees. — 1978