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This Article Full Text Full Text (PDF) All Versions of this Article: 566/1/77    most recent jphysiol.2005.084095v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stockman, A. Articles by Plummer, D. J Search for Related Content PubMed PubMed Citation Articles by Stockman, A. Articles by Plummer, D. J

¹ Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
² Department of Psychology, University of California San Diego, La Jolla, CA 92093-0109, USA

The luminance pathway has slow (s), spectrally opponent cone inputs in addition to the expected fast (f), non-opponent inputs. The nature of these inputs to luminance flicker perception was further explored psychophysically by measuring middle- (M-) and long-wavelength-sensitive (L-) cone modulation sensitivities, M- and L-cone phase delays, and flicker spectral sensitivities under three conditions of low to moderate long-wavelength adaptation. Under these conditions we find that the luminance channel has fast M- and L-cone input signals (+fM and +fL), and slow, spectrally opponent cone input signals (+sL and –sM). The slow signals found under these conditions are therefore of the opposite polarity to those (+sM and –sL) found under more intense long-wavelength adaptation. At these less intense levels, fast and slow M-cone signals of opposite polarity (–sM and +fM) cancel at low frequencies, but then constructively interfere at intermediate frequencies (ca 12.5–22.5 Hz, depending on adapting level) because of the delay between them. In contrast, fast and slow L-cone signals of the same polarity (+sL and +fL) sum at low frequencies, but then destructively interfere at intermediate frequencies. Importantly, the spectrally opponent signals (+sL and –sM) contribute to flicker nulls without producing visible colour variation. Although its output generates an achromatic percept, the luminance channel has slow spectrally opponent as well as fast non-opponent inputs.

(Received 28 January 2005; accepted after revision 25 April 2005; first published online 28 April 2005)
Corresponding author A. Stockman: Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK. Email: a.stockman{at}ucl.ac.uk

This article has been cited by other articles:

				A. Stockman, D. J Plummer, and E. D Montag Spectrally opponent inputs to the human luminance pathway: slow +M and -L cone inputs revealed by intense long-wavelength adaptation J. Physiol., July 1, 2005; 566(1): 61 - 76. [Abstract] [Full Text] [PDF]