abnormal midbrain morphology brain atrophy midbrain atrophy 2014-01-01T11:30:46Z acquired diminution of the size of the midbrain associated with wasting as from death and reabsorbtion of cells, diminished cellular proliferation, decreased cellular volume, pressure, ischemia, malnutrition, reduced function or malfunction, or hormonal changes MP:0012507 atrophic mesencephalon csmith mesencephalon atrophy atrophic midbrain MPheno.ontology