Skip to main content
×
Home

The response dynamics of primate visual cortical neurons to simulated optical blur

  • MICHAEL L. RISNER (a1) and TIMOTHY J. GAWNE (a1)
Abstract
Abstract

Neurons in visual cortical area V1 typically respond well to lines or edges of specific orientations. There have been many studies investigating how the responses of these neurons to an oriented edge are affected by changes in luminance contrast. However, in natural images, edges vary not only in contrast but also in the degree of blur, both because of changes in focus and also because shadows are not sharp. The effect of blur on the response dynamics of visual cortical neurons has not been explored. We presented luminance-defined single edges in the receptive fields of parafoveal (1–6 deg eccentric) V1 neurons of two macaque monkeys trained to fixate a spot of light. We varied the width of the blurred region of the edge stimuli up to 0.36 deg of visual angle. Even though the neurons responded robustly to stimuli that only contained high spatial frequencies and 0.36 deg is much larger than the limits of acuity at this eccentricity, changing the degree of blur had minimal effect on the responses of these neurons to the edge. Primates need to measure blur at the fovea to evaluate image quality and control accommodation, but this might only involve a specialist subpopulation of neurons. If visual cortical neurons in general responded differently to sharp and blurred stimuli, then this could provide a cue for form perception, for example, by helping to disambiguate the luminance edges created by real objects from those created by shadows. On the other hand, it might be important to avoid the distraction of changing blur as objects move in and out of the plane of fixation. Our results support the latter hypothesis: the responses of parafoveal V1 neurons are largely unaffected by changes in blur over a wide range.

Copyright
Corresponding author
*Address correspondence and reprint requests to: Michael L. Risner, Department of Vision Sciences, University of Alabama at Birmingham, 924 South 18th Street, Birmingham, AL 35294. E-mail: mlrisner@uab.edu
References
Hide All
Abeles M. & Goldstein M.H. Jr. (1977). Multispike train analysis. Proceedings of the IEEE 65, 762773.
Albrecht D.G. (1995). Visual cortex neurons in monkey and cat: Effect of contrast on spatial and temporal phase transfer function. Visual Neuroscience 12, 11911210.
Allen E.A. & Freeman R.D. (2006). Dynamic spatial processing originate early in the visual pathways. Journal of Neurophysiology 26, 1176311774.
Anderson C.H. & Van Essen D.C. (1987). Shifter circuits: A computational strategy for dynamic aspects of visual processing. Proceedings of the National Academy of Sciences 84, 62976301.
Bobak P., Bodis-Wollner I. & Guillory S. (1987). The effect of blur and contrast on VEP latency: Comparison between check and sinusoidal grating patterns. Electroencephalography and Clinical Neurophysiology 68, 247255.
Bonds A.B. (1991). Temporal dynamics of contrast gain in single cells of the cat striate cortex. Visual Neuroscience 6, 239255.
Bredfeldt C.E. & Ringach D.L. (2002). Dynamics of spatial frequency tuning in macaque V1. The Journal of Neuroscience 22, 19761984.
Carandini M., Heeger D.J. & Movshon J.A. (1997). Linearity and normalization in simple cells in the macaque primary visual cortex. The Journal of Neuroscience 17, 86218644.
Cook R.L., Porter T. & Carpenter L. (1984). Distributed ray tracing. Computer Graphics 19, 137145.
Frazor R.A., Albrecht D.G., Geisler W.S. & Crane A.M. (2004). Visual cortex neurons of monkey and cats: Temporal dynamics of the spatial frequency response function. Journal of Neurophysiology 91, 26072627.
Gamlin P.D.R., McDougal D.H., Pokorny J., Smith V.C., Yau K.-W. & Dacey D.M. (2007). Human and macaque pupil responses driven by melanopsin-containing retinal ganglion cells. Vision Research 47, 946954.
Gatass R., Gross C.E. & Sandell J.H. (1981). Visual topography of V2 in the macaque. The Journal of Comparative Neurology 201, 519539.
Gawne T.J. (1999 a). Temporal coding as a means of information transfer in the primate visual system. Critical Review in Neurobiology 13, 83101.
Gawne T.J. (1999 b). Evidence against cross-orientation inhibition in the responses of macaque V1 cortical complex cells. Society for Neuroscience Abstract 25.
Gawne T.J. (2000). The simultaneous coding of orientation and contrast in the response of V1 complex cells. Experimental Brain Research 133, 293302.
Gawne T.J., Kjaer T.W. & Richmond B.J. (1996). Latency: Another potential code for feature binding in striate cortex. Journal of Neurophysiology 76, 13561360.
Gawne T.J. & Martin J.M. (2002). Responses of primate visual cortical neurons to stimuli presented by flash, saccade, blink, and external darkening. Journal of Neurophysiology 88, 21782186.
Kiorpes L. & Kiper D.C. (1992). Detection of Vernier offsets in the central and peripheral visual field in macaque monkeys. Investigative Ophthalmology & Visual Science 33(Suppl.), 1256.
Kiorpes L. & Kiper D.C. (1996). Development of contrast sensitivity across the visual field in macaque monkeys (Macaca nemestrina). Vision Research 36, 239246.
Lapuerta P. & Schein S.J. (1995). A four-surface schematic eye of macaque monkey obtained by an optical method. Vision Research 35, 22452254.
Lee J., Williford T. & Maunsell J.H.R. (2007). Spatial attention and the latency of the neuronal responses in macaque area V4. The Journal of Neuroscience 27, 96329637.
Leigh J.R. & Zee D.S. (2006). The Neurology of Eye Movements (4th ed.). New York: Oxford University Press.
Marr D. & Poggio T. (1979). A computational theory of human stereo vision. Proceedings of the Royal Society of London 204, 301328.
Mazer J.A., Vinje W.E., McDermott J., Schiller P.H. & Gallant J.L. (2002). Spatial frequency and orientation tuning dynamics in area V1. Proceedings of the National Academy of Sciences 99, 16451650.
Menz M.D. & Freeman R.D. (2003). Stereoscopic depth processing in the visual cortex: Coarse-to-fine mechanism. Nature Neuroscience 6, 5965.
Nishihara H.K. (1984). Practical real-time imaging stereo matcher. Optical Engineering 23, 536545.
Ohzawa I., Sclar G. & Freeman R.D. (1985). Contrast gain control in the cat’s visual system. Journal of Neurophysiology 54, 651667.
Oram M.W., Xiao D., Dritschel B. & Payne K.R. (2002). The temporal resolution of neural codes: Does response latency have a unique role? Philosophical Transactions of the Royal Society of London. Series B 357, 9871001.
Parker D.M., Lishman J.R. & Hughes J. (1997). Evidence for the view that temporospatial integration in vision is temporally anisotropic. Perception 26, 11691180.
Reid R.C., Victor J.D. & Shapley R.M. (1992). Broadband temporal stimuli decrease the integration time of neurons in cat striate cortex. Visual Neuroscience 9, 3945.
Richmond B.J. & Optican L.M. (1990). Temporal encoding of two-dimensional patterns by single units in primate primary visual cortex. II. Information transmission. Journal of Neurophysiology 57, 132146.
Risner M.L. & Gawne T.J. (2007). The response dynamics of visual cortical neurons to simulated blur. Society for Neuroscience Abstract 279.12.
Sclar G. & Freeman R.D. (1982). Orientation selectivity in the cat’s striate cortex is invariant with stimulus contrast. Experimental Brain Research 46, 457461.
Siguenza J., Heide W. & Creutzfeldt O.D. (1987). Representation of edges of variable blur by neuronal responses in the lateral geniculate body and the visual cortex of cats: Limits of linear prediction. Vision Research 27, 17011717.
Skavenski A.A., Robinson D.A., Steinman R.M. & Timberlake G.T. (1975). Miniature eye movements of fixation in rhesus monkey. Vision Research 15, 12691273.
Sokol S. & Moskowitz A. (1981). Effect of retinal blur on the peak latency of the pattern evoked potential. Vision Research 21, 12791286.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Visual Neuroscience
  • ISSN: 0952-5238
  • EISSN: 1469-8714
  • URL: /core/journals/visual-neuroscience
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Full text views

Total number of HTML views: 1
Total number of PDF views: 1 *
Loading metrics...

Abstract views

Total abstract views: 134 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 18th November 2017. This data will be updated every 24 hours.