increased brain size abnormal forebrain size increased forebrain size enlarged prosencephalon MP:0012139 csmith enlarged forebrain greater than average size of the anterior of the three primary divisions of the developing chordate brain or the corresponding part of the adult brain (in vertebrates, includes especially the cerebral hemispheres, the thalamus, and the hypothalamus and especially in higher vertebrates is the main control center for sensory and associative information processing, visceral functions, and voluntary motor functions) MPheno.ontology expanded forebrain increased prosencephalon size expanded prosencephalon 2013-10-09T15:20:00Z