Noun. 1. prefrontal cortex-the anterior part of the frontal lobe. prefrontal lobe. cerebral cortex, cerebral mantle, cortex, pallium-the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum. lobe - (anatomy) a somewhat rounded subdivision of a bodily organ or part; ear lobe.refrontal lobe. cerebral cortex, cerebral mantle, cortex, pallium-the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum. lobe - (anatomy) a somewhat rounded subdivision of a bodily organ or part; ear lobe.
1. igneous rocks: formed by the cooling and hardening of magma (molten rock) from inside Earth. 2. sedimentary rocks: formed by the compaction and cementing of layers of sediment (rock fragments, plant and animal remains, minerals from water) 3. metamorphic rocks: formed by the effect of heat and pressure on other rocks. *Earthâs crust is made-up primarily of igneous rocks.
May 29, 2015. Clastic sedimentary rocks form from the deposition of eroded particles of rock. These particles or clasts are lain horizontally once the transporting agent's energy is expended. They are then consolidated into layers or beds of rocks through compaction or through cementing.