ism ▁writers <0x0A> </s> ▁Stephen ▁J ▁Smith ▁is ▁a ▁Senior ▁Investig ator ▁at ▁the ▁Allen ▁Institute ▁for ▁Bra in ▁Science . ▁ ▁Pre viously , ▁Dr . ▁Smith ▁was ▁Professor ▁of ▁M ole cular ▁and ▁Cell ular ▁Phys i ology ▁at ▁the ▁Stan ford ▁University ▁School ▁of ▁Medicine . ▁ ▁In ▁ 1 9 9 0 , ▁Smith ▁published ▁an ▁article ▁in ▁the ▁journal ▁Science , ▁which ▁proposed ▁that ▁certain ▁gli al ▁cells ▁in ▁the ▁human ▁brain ▁known ▁as ▁ast ro cy tes ▁would ▁be ▁able ▁to ▁communicate ▁through ▁chemical ▁signals , ▁rather ▁than ▁elect rical . ▁ ▁By ▁util izing ▁the ▁ne uro trans mit ter ▁gl ut am ate , ▁he ▁was ▁able ▁to ▁show ▁that ▁these ▁cells , ▁which ▁had ▁once ▁been ▁perce ived ▁as ▁in ert ▁t issue ▁between ▁neur ons , ▁in ▁fact ▁were ▁act ively ▁communic ating ▁with ▁the ▁rest ▁of ▁the ▁brain . ▁ ▁This ▁discovery ▁showed ▁that ▁ast ro cy tes ▁likely ▁play ▁an ▁important ▁role ▁in ▁learning ▁and ▁memory . ▁ ▁Since ▁Smith ' s ▁discovery , ▁ast ro cy tes ▁have ▁become ▁an ▁increasing ly ▁important ▁part ▁of ▁neural ▁research . ▁ ▁Smith ▁has ▁also ▁been ▁a ▁primary ▁leader ▁in ▁the ▁development ▁of ▁array ▁tom ography ▁( AT ), ▁a ▁prote omic ▁imag ing ▁method ▁of ▁vol um et ric ▁micro sc opy , ▁in ▁which ▁ul tr ath in ▁sections ▁of ▁a ▁pl astic - embed ded ▁t issue ▁are ▁s lic ed ▁using ▁an ▁ul tr am icro t ome ,