1. We measured the response of macaque ganglion cells to sinusoidally modulated red and green lights as the relative phase, theta, of the lights was varied. 2. At low frequencies, red‐green ganglion cells of the parvocellular (PC‐) pathway with opponent inputs from middle‐wavelength sensitive (M‐) and long‐wavelength sensitive (L‐) cones were minimally sensitive to luminance modulation (theta = 0 deg) and maximally sensitive to chromatic modulation (theta = 180 deg). With increasing frequency, the phase, theta, of minimal amplitude gradually changed, in opposite directions for cells with M‐ and L‐cone centres. 3. At high frequencies (at and above 20 Hz), phasic cells of the magnocellular (MC‐) pathway were maximally responsive when theta approximately 0 deg and minimally responsive when theta approximately 180 deg, as expected from an achromatic mechanism. At lower frequencies, the phase of minimal response shifted, for both on‐ and off‐centre cells, to values of theta intermediate between 0 and 180 deg. This phase asymmetry was absent if the centre alone was stimulated with a small field. 4. For PC‐pathway cells, it was possible to provide an account of response phase as a function of theta, using a model involving three parameters; phases of the L‐ and M‐cone mechanisms and a L/M cone weighting term. For red‐green cells, the phase parameters were monotonically related to temporal frequency and revealed a centre‐surround phase difference. The phase difference was linear with a slope of 1‐3 deg Hz‐1. If this represents a latency difference, it would be 3‐8 ms. Otherwise, temporal properties of the M‐ and L‐cones appeared similar if not identical. By addition of a scaling term, the model could be extended to give an adequate account of the amplitude of responses. 5. We were able to activate selectively the surrounds of cells with short‐wavelength (S‐) cone input to their centres, and so were able to assess L/M cone weighting to the surround. M‐ and L‐cone inputs added linearly for most cells. On average, the weighting corresponded to the Judd modification of the luminosity function although there was considerable inter‐cell variability. 6. To account for results from MC‐pathway cells, it was necessary to postulate a cone‐opponent, chromatic input to their surrounds. We developed a receptive field model with linear summation of M‐ and L‐cones to centre and surround, and with an additional M,L‐cone opponent input to the surround.(ABSTRACT TRUNCATED AT 400 WORDS)
The Journal of Physiology – Wiley
Published: Dec 1, 1992
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera