( ( While ( ( ( the response ) ( in individuals ) ) ( is ( quite variable ) ) ) ) ( , ( this ( ( can ( ( lead ( to ( blood vessels ) ) ) ( ( ( constricting and ) then ) ( ( ( dilating , ) ( in ( some cases ) ) ) ( leading ( to ( a ( migraine attack ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN While) (S (NP (NP (DT the) (NN response)) (PP (IN in) (NP (NNS individuals)))) (VP (VBZ is) (ADJP (RB quite) (JJ variable))))) (, ,) (NP (DT this)) (VP (MD can) (VP (VB lead) (PP (TO to) (NP (NN blood) (NNS vessels))) (S (VP (VP (VBG constricting)) (CC and) (ADVP (RB then)) (VP (VBG dilating) (, ,) (PP (IN in) (NP (DT some) (NNS cases))) (S (VP (VBG leading) (PP (TO to) (NP (DT a) (JJ migraine) (NN attack)))))))))) (. .)))
While the response in individuals is quite variable, this can lead to blood vessels constricting and then dilating, in some cases leading to a migraine attack.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NP (NN blood) (NNS vessels)) (PP (IN in) (NP (DT the) (NN head)))) (VP (VBP dilate)))) (, ,) (NP (NP (DT a) (NN migraine)) (, ,) (NP (DT a) (JJ severe) (NN headache)) (, ,)) (VP (MD can) (VP (VB occur))) (. .)))