For two further cells we determined the colocalized pixels between the PSD-GFP and the CD15 immunofluorescence channel (Fig. and the CD15 immunofluorescence channel (Fig. 2= 14 axon terminals). Normally there were 21 ( 18.1 SD) colocalized areas per axon terminal (= 30). Table 1. Analysis of bipolar to ganglion cell connectivity < 0.02) indicating both methods give comparable results. For those cells analyzed, the number of colocalized places was lower when 1 channel was flipped (< 0.02, Wilcoxon rank sum test). We compared the connectivity in the DB6 thin thorny pathway with the well established connectivity in the midget pathway by taking advantage of the fact that OFF midget bipolar cells are labeled in addition to DB6 cells with the antibody against CD15 (Chan et al., 2001). For three midget ganglion cells in peripheral retina, the PSD95-GFP puncta located within 1 m of an OFF midget bipolar axon terminal normally composed 47.8% (SD 9.9, = 9) of the PSD95-GFP puncta in the immediate vicinity of this axon terminal (Table 1). AOM Recognition of thin thorny cells after retrograde labeling Tracer injections into the LGN resulted in retrograde labeling of a variety of ganglion cells. Filter thorny cells (Fig. 3= 9; parasol 273.5 70.2 m, = 7, < 0.02, test), and a higher quantity of dendritic terminals (including thorns) per 100 m2 SKLB610 compared with parasol cells (thin thorny, 3.7 1.4, = 9; parasol 1.2 0.5, = 7; < 0.02, test). The majority (6/9, 67%) of the thin thorny cells stratified in the ON sublamina of the inner plexiform coating, two cells stratified in the OFF sublamina, and one cell was bistratified with processes in the ON and the OFF sublamina. Open in a separate window Number 3. Filter thorny ganglion cells labeled after injection of koniocellular coating K1. < 0.05, 2 test). By contrast, ON- and OFF-type reactions were evenly balanced in coating K3 (> 0.5, 2 test), and blue-ON responses were less common in K1 (1/23, 4.3%) than in K3 (77/228, 33.7%, < 0.05, 2 test). Conversation Filter thorny ganglion cells have been recognized morphologically in the retinas of a variety of primate varieties but no electrophysiological recordings from these cells exist, thus their practical role can only be inferred using their retinal circuitry and the properties of their geniculate focuses on in coating K1. Our results show that a significant proportion of the bipolar input to thin thorny cells derives from DB6 cells. We suggest that the DB6 input is the dominating bipolar input to thin thorny cells because the contacts of the additional bipolar types stratifying in S4 and S5 are well recognized: blue cone bipolar cells contact small bistratified cells (Calkins et al., 1998), pole bipolar cells contact amacrine cells (Grnert and Martin, SKLB610 1991), and invaginating midget bipolar cells contact ON midget ganglion cells (Kolb and DeKorver, 1991; Calkins et al., 1994). Our results further indicate that DB6 cells in addition to amacrine cells preferentially contact thin thorny cells. Additional outputs of DB6 cells go to large sparse (Percival et al., 2011, their Fig. 3D) and inner stratifying melanopsin-expressing ganglion cells (Grnert et al., 2011, their Fig. 3) but these cells experienced on average only 2C3 presumed contacts per DB6 terminal and thus did not display the same limited connectivity as do thin thorny cells (21 contacts per terminal). The only additional ganglion cell type stratifying at the level of the DB6 cells is the small bistratified cell and this cell is known to receive dominating input from blue cone bipolar cells (Calkins et al., 1998). A large proportion of the PSD95-GFP puncta indicated by thin thorny cells were located close to DB6 axons; a similar relationship was seen for OFF midget ganglion/OFF midget bipolar cells. A likely explanation for SKLB610 the nonassociated puncta is definitely that synaptic output from weakly labeled DB6 axons was underestimated. Some nonassociated puncta may arise from overexpression of PSD95-GFP. Electrophysiological recordings show varied response properties in koniocellular pathways (Irvin et al., 1986; White et al., 2001; Xu et al., 2001; Solomon et al., 2002). Specifically, in marmoset and owl monkey limited recordings from neurons in layers K2 and K1 showed receptive fields with high contrast sensitivity, large diameter, high level of sensitivity to high temporal.