Visual response patterns of Y cells before and after synaptic transmission blockade.

<p>The synaptic blocker cocktail consisted of a mixture of excitatory and inhibitory neurotransmitter blockers including L-(+)-2-Amino-4-phosphonobutyric acid (AP-4, 100 µM), 6,7-Dinitroquinoxaline-2,3-dione (DNQX, 20 µM), DL-2-amino-5-phosphonovaleric acid (AP5, 50 µM), Picrotoxin (50 µM ) Strychnine (0.3 µM), and hexamethonimm bromide (200 µM) was added to the oxygenated Ames' medium. (<b>A</b>) visual responses of an ON center (upper) and (<b>C</b>) an OFF center (lower) DRN-projecting RGCs before synaptic transmission blockade. (<b>B</b>) and (<b>D</b>) response patterns of the cells after synaptic transmission blockade. The retinal irradiance of the stimuli was 6.4×10¹³ photons/cm²/sec, λ = 475 nm, and stimulation duration was 20 seconds.</p

Dendritic morphology of DRN-projecting RGCs.

<p>(<b>A</b>) the DRN injection site. The arrow points to the injection site. (<b>B</b>)–(<b>D</b>) morphology of intracellularly injected DRN-projecting RGCs. (<b>B</b>) a large dendritic field alpha cell, (<b>C</b>) a relatively small dendritic field alpha cell, (<b>D</b>) a three dimensional reconstructed DRN-projecting alpha cell immunohistochemically stained with (FITC) and a melanopsin cell immunocytochemically stained for melanopsin (red); note lack of melanopsin immunoreactivity in DRN-projecting RGC. (<b>E</b>) morphology of a DRN-projecting non-alpha cell. The Arrows depict the axon. Scale bars: (<b>A</b>): 500 µm; (<b>B</b>): 200 µm; (<b>C</b>): 100 µm; (<b>D</b>): 100 µm; (<b>E</b>): 60 µm.</p

The distribution pattern of DRN-projecting RGCs.

<p>(<b>A</b>) the distribution pattern of DRN-projecting RGCs in a wholemount retina, (<b>B</b>) two neighboring alpha cells from the retina that have overlapped dendritic fields, (<b>C</b>) DRN-projecting alpha cells distributed in a small retinal area, (<b>D</b>) Higher-magnification view of overlapped dendritic fields of the two cells in (<b>B</b>), Arrow heads show possible synaptic contacts between the two, (<b>E</b>) double labeled RGCs innervate both DRN (red fluorescent staining) and dLGN (green fluorescent staining). (<b>F</b>) double labeled RGCs send their bifurcating axons to both DRN (red fluorescent staining) and SC (green fluorescent staining). The open arrows show RGCs projecting both nuclei and solid arrows illustrate RGCs project to dLGN or SC. The arrow head depicts a RGC that projects to DRN only. Dendritic field size and soma size variation with retinal eccentricity are provided in (<b>G</b>) and (<b>H</b>). Scale bars: A: 1 mm; B: 100 µm; C: 500 µm; D: 25 µm.</p

Physiological response properties of the DRN-projecting RGCs.

<p>(<b>A</b>) the visual response of an ON center Y-cell, (<b>B</b>) receptive field, and (<b>C</b>), dendritic morphology; the arrow reveals axon, (<b>D</b>) spatial frequency tuning of a Y-cell. Note the cell's response reached peak at 0.07 c/d. 3E presents the peristimulus-time histograms of the cell's responses to contrast reversal sinusoidal gratings (spatial frequency: 0.07 cyc/deg, temporal frequency: 2 Hz, contrast: 100%). The numbers to the left of the histograms depict spatial phases. This cell had frequency doubling at two spatial phases, 0° and 180°, respectively. 2F illustrates that, after fast Fourier transformation, the fundamental component (F1) is represented by triangular symbols (Δ) while the second harmonic (F2) is shown with open circular symbols (o).</p