In this study, we describe a remarkable correlation between the PD of directionally tuned neurons and their laminar arborization profile in the optic tectum of larval zebrafish. In the tectum, different cell morphologies have been linked to genetic signatures for some cell types (Scott and Baier, 2009; Robles et al., 2011). On the other hand, recent measurements of directional tuning have found DS neurons within a global tectal cell population but without genetic or morphological discrimination (Niell Obeticholic Acid ic50 and Smith, 2005; Ramdya and Engert, 2008; Sumbre et al., 2008). Here, we provide evidence that DS neurons with

different PDs arborize in distinct layers in the superficial, retinorecipient layers of the neuropil. Furthermore, we isolated transgenic lines that express GFP or GCaMP3 in these cell types of opposite directional tuning. selleck chemicals Excitatory synaptic inputs were directionally tuned and matched the PD of spike output in these cells, while inhibitory inputs were often tuned to nonpreferred directions. In conclusion, the correspondence between structure and function of tectal DS neurons suggests that higher stimulus features could be processed and transmitted within specialized sublayers in the tectal neuropil. This indicates that the central principle of laminar-specific

feature extraction may also apply to visual centers beyond the vertebrate retina (Roska and Werblin, 2001; Wässle, 2004). We found two morphologically distinct DS cell types with opposite PDs. One class (“type 1”), selective for RC motion components, was bistratified, with a distal dendritic arborization tightly restricted to a band within the SFGS/SO border region and a smaller arborization between the SFGS and SGC. The morphology of this type resembled that of a bistratified periventricular interneuron type (bs-PVIN), which is selectively targeted using a dlx5/6 enhancer element ( Robles et al., 2011). Those bs-PVINs were found to be negative for GABA immunoreactivity,

unlike the the bistratified type 1 neurons in our study. This raises the possibility that morphologically similar cell types in the tectum could differ in transmitter phenotype, which could be the result of homeostatic or activity-dependent transmitter specification ( Spitzer, 2012). Another cell class (“type 2”) was CR-DS and had a dendritic/axonal tree that was less confined to a narrow band but ramified to a greater extent in the middle and superficial sublaminae of the SFGS (SFGSB,D). Furthermore, it showed a second band of neurites at the border between the SFGS and the SGC. Somata of this cell type did not colocalize with vglut2a:DsRed fluorescence and were positive for GAD65/67, suggesting that they were GABAergic as well. During random selection of neurons for patch-clamp analysis, we also observed a cell type that showed preference for stimuli with UD components, whose dendritic/axonal branches were mostly located in the deeper layers of the SGC.