ds ▁and ▁con es ▁by ▁way ▁of ▁syn apt ic ▁connections ▁in ▁the ▁ret ina . ▁ ▁The ▁ax ons ▁from ▁these ▁gang lia ▁inner v ate ▁regions ▁of ▁the ▁brain ▁related ▁to ▁object ▁recognition , ▁including ▁the ▁superior ▁col lic ulus ▁and ▁d ors al ▁later al ▁gen ic ulate ▁nucle us . ▁ ▁Str ucture ▁ ▁i PR GC ▁re ceptor ▁▁ ▁These ▁phot ore ceptor ▁cells ▁project ▁both ▁throughout ▁the ▁ret ina ▁and ▁into ▁the ▁brain . ▁They ▁contain ▁the ▁phot op ig ment ▁mel an ops in ▁in ▁varying ▁quantities ▁along ▁the ▁cell ▁memb rane , ▁including ▁on ▁the ▁ax ons ▁up ▁to ▁the ▁opt ic ▁disc , ▁the ▁som a , ▁and ▁d end rit es ▁of ▁the ▁cell . ▁ip R GC s ▁contain ▁memb rane ▁re cept ors ▁for ▁the ▁ne uro trans mit ters ▁gl ut am ate , ▁g ly c ine , ▁and ▁G AB A . ▁Ph otos ens itive ▁gang l ion ▁cells ▁respond ▁to ▁light ▁by ▁dep olar izing , ▁thus ▁increasing ▁the ▁rate ▁at ▁which ▁they ▁fire ▁n erve ▁imp uls es , ▁which ▁is ▁opposite ▁to ▁that ▁of ▁other ▁phot ore ceptor ▁cells , ▁which ▁hyper pol ar ize ▁in ▁response ▁to ▁light . ▁ ▁Results ▁of ▁studies ▁in ▁m ice ▁suggest ▁that ▁the ▁ax ons ▁of ▁ip R GC s ▁are ▁un my elin ated . ▁ ▁Mel an ops in ▁ ▁Un like ▁other ▁phot ore ceptor ▁p ig ments , ▁mel an ops in ▁has