, 2002; Fried et al., 2002; Briggman et al., 2011). Alternative models have been advocated in cortical cells, in which excitation and inhibition often exhibit the largest response in the same direction of motion (Priebe and Ferster, 2005). Here, emergence of DS spiking is thought to be the result of a spatiotemporal shift of excitatory and inhibitory subregions in the receptive field, in combination with a nonlinear threshold mechanism (Adelson and Bergen, selleck products 1985; Priebe and Ferster,

2005). The optic tectum in larval zebrafish is a widely used model for the development and function of vertebrate visual circuits. Questions of axon guidance, retinotopic map Sirolimus manufacturer formation, and laminar specificity have successfully been addressed in this midbrain structure (Karlstrom et al., 1996; Trowe et al., 1996; Xiao et al., 2005). The teleost tectum, which is homologous to the mammalian superior colliculus, plays a role in controlling visual grasping and prey capture (Akert, 1949; Gahtan et al., 2005). Ca2+ imaging

has demonstrated that DS responses in tectal cell somata appear at early stages of retinotectal innervation (Niell and Smith, 2005). Furthermore, DS responses can be entrained by rhythmic visual stimulation (Sumbre et al., 2008). Interestingly, when unilateral lesions are performed that lead to binocular innervation of the remaining tectum, tectal DS neurons exhibit the same directional preference for moving stimuli presented to either eye (Ramdya

and Engert, 2008). Apart from some exceptionally clear examples in the insect and mammalian retina (Borst and Euler, 2011), information on how DS neurons are integrated in a visual circuit has been scarce. In the fly visual system, excitatory presynaptic DS signals are generated by correlation-type movement detectors and distributed to different layers of the lobula plate, Resveratrol according to directional preference (Buchner et al., 1984; Borst et al., 2010). In the mouse visual system, presynaptic axon terminals from genetically distinct DS-RGC subtypes form layer-specific maps in subcortical visual areas (Huberman et al., 2009; Kay et al., 2011; Rivlin-Etzion et al., 2011). By contrast, much less is known about whether the laminar structure and branching patterns of postsynaptic DS neurons correlate with directional preference beyond the retina (Wang et al., 2010). Here, we investigate this question in the larval zebrafish tectum with a combination of multiphoton Ca2+ imaging, in vivo electrophysiology, and morphological analysis (Friedrich et al., 2010). Using the Gal4-UAS system to express the genetically encoded Ca2+ indicator GCaMP3 in specific cell types, we identified individual directionally tuned tectal neurons for subsequent multiphoton-targeted patch-clamp analysis.