A system comprising (i) an optical delivery device for delivering light to sub-surface regions of the brain or body, the device comprising: a) an implantable optical transmission element (104, 106, 125, 210, 230, 260, 304, 404) comprising a proximal end and a distal end; b) a light source for producing light from electrical power, wherein the light source is at the proximal end of the transmission element and comprises a light-emitting diode; wherein the implantable optical transmission element is made from a material that is substantially transparent to the light from the light source, the material having an elongated shape that is integrally-formed with and optically coupled to the LED, wherein the optical transmission element substantially encases the light source at the proximal end of the optical transmission element, and that is for delivering the light from the light source to the distal end, and has a distal tip designed to direct light at an angle relative to said axis to change a position of a light stimulus location; c) a fixation portion (112, 114, 130, 262, 312) physically coupled to the optical transmission element for attachment to the patient; and d) a heat dissipation portion (112, 114, 130, 262, 408, 410) having a thermally conductive path for removing heat from near the light source; and (ii) a delivery device comprising a light-responsive protein wherein the delivery device is capable of introducing the light-responsive protein to a neuron. (i) an optical delivery device for delivering light to sub-surface regions of the brain or body, the device comprising: a) an implantable optical transmission element (104, 106, 125, 210, 230, 260, 304, 404) comprising a proximal end and a distal end; b) a light source for producing light from electrical power, wherein the light source is at the proximal end of the transmission element and comprises a light-emitting diode; wherein the implantable optical transmission element is made from a material that is substantially transparent to the light from the light source, the material having an elongated shape that is integrally-formed with and optically coupled to the LED, wherein the optical transmission element substantially encases the light source at the proximal end of the optical transmission element, and that is for delivering the light from the light source to the distal end, and has a distal tip designed to direct light at an angle relative to said axis to change a position of a light stimulus location; c) a fixation portion (112, 114, 130, 262, 312) physically coupled to the optical transmission element for attachment to the patient; and d) a heat dissipation portion (112, 114, 130, 262, 408, 410) having a thermally conductive path for removing heat from near the light source; and a) an implantable optical transmission element (104, 106, 125, 210, 230, 260, 304, 404) comprising a proximal end and a distal end; b) a light source for producing light from electrical power, wherein the light source is at the proximal end of the transmission element and comprises a light-emitting diode; wherein the implantable optical transmission element is made from a material that is substantially transparent to the light from the light source, the material having an elongated shape that is integrally-formed with and optically coupled to the LED, wherein the optical transmission element substantially encases the light source at the proximal end of the optical transmission element, and that is for delivering the light from the light source to the distal end, and has a distal tip designed to direct light at an angle relative to said axis to change a position of a light stimulus location; c) a fixation portion (112, 114, 130, 262, 312) physically coupled to the optical transmission element for attachment to the patient; and d) a heat dissipation portion (112, 114, 130, 262, 408, 410) having a thermally conductive path for removing heat from near the light source; and (ii) a delivery device comprising a light-responsive protein wherein the delivery device is capable of introducing the light-responsive protein to a neuron.