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Updated: May 25, 2026

Assessment of Spatial Lingual Tactile Sensitivity using a Gratings Orientation Test
Published on: September 17, 2021
Psychophysical and physiological responses to gratings with luminance and chromatic components of different spatial
Bonnie Cooper1, Hao Sun, Barry B Lee
1Graduate Center for Vision Research, SUNY College of Optometry, 33 West 42nd St., New York, New York 10036, USA. bcooper@sunyopt.edu
Abstract:
Gratings that contain luminance and chromatic components of different spatial frequencies were used to study the segregation of signals in luminance and chromatic pathways. Psychophysical detection and discrimination thresholds to these compound gratings, with luminance and chromatic components of the one either half or double the spatial frequency of the other, were measured in human observers. Spatial frequency tuning curves for detection of compound gratings followed the envelope of those for luminance and chromatic gratings. Different grating types were discriminable at detection threshold. Fourier analysis of physiological responses of macaque retinal ganglion cells to compound waveforms showed chromatic information to be restricted to the parvocellular pathway and luminance information to the magnocellular pathway. Taken together, the human psychophysical and macaque physiological data support the strict segregation of luminance and chromatic information in independent channels, with the magnocellular and parvocellular pathways, respectively, serving as likely the physiological substrates.
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