While this pattern of responsiveness is different than the normal retina, it may not preclude a useful visual experience. Behavioral studies in primates demonstrate that the selective pharmacological blockade of ON neurons does not severely impair recognition of shapes or detection of Everolimus light decrements (Schiller et al., 1986). Moreover, in RP patients, electronic retinal prosthetics can restore shape recognition, even though the devices stimulate ON- and OFF-RGCs indiscriminately (Sekirnjak et al., 2009). Hence, while two channels of visual information flow are important for normal vision, simultaneous activation of ON- and OFF-pathways is sufficient for visual perception. AAQ treatment enables RGCs surrounding

an illuminated area to respond with the opposite polarity to those in the center. Since all RGCs respond with the same polarity light response to full-field illumination (Figure 1A), the opposite center versus surround responses to spot illumination suggests that inhibitory neurons that project

laterally invert the sign of the response. It seems likely that the opposite center versus surround response would enhance perception of spatial contrast and facilitate edge detection in downstream visual regions of the brain. But ultimately, the evaluation of the quality of images produced by photoswitch activation of retinal Venetoclax cell line cells will require study in primates or human patients. In AAQ-treated retinas, RGCs respond most

strongly to short wavelength light, consistent with the photochemical properties of the molecule (Fortin et al., 2008). Although MycoClean Mycoplasma Removal Kit 380 nm light is optimal for enhancing firing frequency, longer wavelengths (up to 500 nm) can still generate excitatory light responses, reflecting the spectral range of trans to cis azobenzene photoisomerization. This is important, because unlike in the mouse, the human lens minimally transmits 380 nm light ( Kessel et al., 2010). Newly-developed red-shifted azobenzene derivatives allow K+ channel regulation with even longer wavelengths of light and chemical modification of the azobenzene moiety results in compounds with improved quantum efficiency ( Mourot et al., 2011). Ideally, second-generation AAQ derivatives would enable photostimulation of the retina with intensities and wavelengths experienced during normal photopic vision. Alternatively, a head-mounted optoelectronic visual aid ( Degenaar et al., 2009) designed to intensify and transform the palette of visual scenes to a blue-shifted wavelength could enhance the effectiveness of AAQ and related agents. Such a device might also allow switching of individual RGCs ON and OFF by rapid modulation of shorter- and longer-wavelength light. Except for some of the optogenetic tools, the other vision restoration methods pose no particular spectral challenges. NpHR and ChR2 respond optimally to 580 and 470 nm light, respectively (Nagel et al., 2003 and Zhang et al.