has part has part has_part characteristic of part of has modifier abnormal pretectal region morphology abnormal pretectal nuclei morphology any structural anomaly of the groups of neurons located between the thalamus and midbrain that receive binocular sensory input from retinal ganglion cells of the eyes and are responsible for maintaining the pupillary light reflex MP:0009638 MPheno.ontology morphology abnormal pretectal nucleus