systems and methods are directed to generating and analyzing light . spatial light response around a human fingertip in response to electrical stimulation is associated with the status of various body organs . a system that provides a particularized response indication based on spatial light response includes a camera , an electrical signal generator , a light source , a circuit , and a computer . the signal generator stimulates emission of light from the finger when the finger is at a position relative to the camera . the light source illuminates the finger at the position . the circuit activates the light source and the camera to obtain a first image of the finger at the position , activates the signal generator and the camera to obtain a second image of the emission of light from the finger at the position , determines a direction from the first image , determines a centroid from the second image , and determines a description of the second image in accordance with the direction and the centroid . the computer receives indicia of the description and provides the particularized response indication in accordance with the description , wherein the particularized response indication describes a status of various body organs .