rical ▁activity ▁at ▁approximately ▁a ▁single ▁point ▁within ▁a ▁volume ▁of ▁t issue . ▁ ▁Ess entially , ▁classical ▁techniques ▁singular ize ▁a ▁distributed ▁phenomen on . ▁ ▁Interest ▁in ▁the ▁spatial ▁distribution ▁of ▁bio elect ric ▁activity ▁prompt ed ▁development ▁of ▁mole cules ▁capable ▁of ▁em itting ▁light ▁in ▁response ▁to ▁their ▁elect rical ▁or ▁chemical ▁environment . ▁ ▁Ex amples ▁are ▁voltage ▁sensitive ▁d yes ▁and ▁flu ores cing ▁prote ins . ▁After ▁introdu cing ▁one ▁or ▁more ▁such ▁comp ounds ▁into ▁t issue ▁via ▁perf usion , ▁injection ▁or ▁gene ▁expression , ▁the ▁ 1 ▁or ▁ 2 - dimensional ▁distribution ▁of ▁elect rical ▁activity ▁may ▁be ▁observed ▁and ▁recorded . ▁ ▁Int rac ell ular ▁recording ▁Int rac ell ular ▁recording ▁involves ▁meas uring ▁voltage ▁and / or ▁current ▁across ▁the ▁memb rane ▁of ▁a ▁cell . ▁ ▁To ▁make ▁an ▁int rac ell ular ▁recording , ▁the ▁tip ▁of ▁a ▁fine ▁( sharp ) ▁micro elect ro de ▁must ▁be ▁inserted ▁inside ▁the ▁cell , ▁so ▁that ▁the ▁memb rane ▁potential ▁can ▁be ▁measured . ▁ ▁Typ ically , ▁the ▁rest ing ▁memb rane ▁potential ▁of ▁a ▁health y ▁cell ▁will ▁be ▁- 6 0 ▁to ▁- 8 0 ▁m V , ▁and ▁during ▁an ▁action ▁potential ▁the ▁memb rane ▁potential ▁might ▁reach ▁+ 4 0 ▁m V . ▁In ▁ 1 9 6 3 , ▁Alan ▁Lloyd ▁H od g kin ▁and ▁Andrew ▁Field ing ▁H ux ley ▁won ▁the ▁Nobel ▁Prize ▁in ▁Phys i ology ▁or