brain / head / chief, principal

(neuroanatomy) midbrain

a function

function (as something), work

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

a piece of research, a study, investigation

to research, to study

(anatomy) the brain / (by extension, figuratively) one's brains, one's mental functioning