RT Journal Article
SR Electronic
T1 Y-Cell Receptive Field and Collicular Projection of Parasol Ganglion Cells in Macaque Monkey Retina
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 11277
OP 11291
DO 10.1523/JNEUROSCI.2982-08.2008
VO 28
IS 44
A1 Joanna D. Crook
A1 Beth B. Peterson
A1 Orin S. Packer
A1 Farrel R. Robinson
A1 John B. Troy
A1 Dennis M. Dacey
YR 2008
UL http://www.jneurosci.org/content/28/44/11277.abstract
AB The distinctive parasol ganglion cell of the primate retina transmits a transient, spectrally nonopponent signal to the magnocellular layers of the lateral geniculate nucleus. Parasol cells show well-recognized parallels with the α-Y cell of other mammals, yet two key α-Y cell properties, a collateral projection to the superior colliculus and nonlinear spatial summation, have not been clearly established for parasol cells. Here, we show by retrograde photodynamic staining that parasol cells project to the superior colliculus. Photostained dendritic trees formed characteristic spatial mosaics and afforded unequivocal identification of the parasol cells among diverse collicular-projecting cell types. Loose-patch recordings were used to demonstrate for all parasol cells a distinct Y-cell receptive field “signature” marked by a nonlinear mechanism that responded to contrast-reversing gratings at twice the stimulus temporal frequency [second Fourier harmonic (F2)] independent of stimulus spatial phase. The F2 component showed high contrast gain and temporal sensitivity and appeared to originate from a region coextensive with that of the linear receptive field center. The F2 spatial frequency response peaked well beyond the resolution limit of the linear receptive field center, showing a Gaussian center radius of ∼15 μm. Blocking inner retinal inhibition elevated the F2 response, suggesting that amacrine circuitry does not generate this nonlinearity. Our data are consistent with a pooled-subunit model of the parasol Y-cell receptive field in which summation from an array of transient, partially rectifying cone bipolar cells accounts for both linear and nonlinear components of the receptive field.