RT Journal Article
SR Electronic
T1 Suppressive Surrounds and Contrast Gain in Magnocellular-Pathway Retinal Ganglion Cells of Macaque
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 8715
OP 8726
DO 10.1523/JNEUROSCI.0821-06.2006
VO 26
IS 34
A1 Samuel G. Solomon
A1 Barry B. Lee
A1 Hao Sun
YR 2006
UL http://www.jneurosci.org/content/26/34/8715.abstract
AB The modulation sensitivity of visual neurons can be influenced by remote stimuli which, when presented alone, cause no change in the ongoing discharge rate of the neuron. We show here that the extraclassical surrounds that underlie these effects are present in magnocellular-pathway (MC) but not in parvocellular-pathway (PC) retinal ganglion cells of the macaque. The response of MC cells to drifting gratings and flashing spots was halved by drifting or contrast-reversing gratings surrounding their receptive fields, but PC cell responses were unaffected. The suppression cannot have arisen from the classical receptive field, or been caused by scattered light, because it could be evoked by annuli that themselves caused little or no response from the cell, and is consistent with the action of a divisive suppressive mechanism. Suppression in MC cells was broadly tuned for spatial and temporal frequency and greater at high contrast. If perceptual phenomena with similar stimulus contexts, such as the “shift effect” and saccadic suppression, have a retinal component, then they reflect the activity of the MC pathway.