Biological Cybernetics

, Volume 64, Issue 1, pp 25–31 | Cite as

Population coding of stimulus orientation by striate cortical cells

  • R. Vogels


I have examined the performance of a population coding model of visual orientation discrimination, similar to the population coding models proposed for the coding of limb movements. The orientation of the stimulus is not represented by a single unit but by an ensemble of broadly tuned units in a distributed way. Each unit is represented by a vector whose magnitude and direction correspond to the response magnitude and preferred orientation of the unit, respectively. The orientation of the population vector, i.e. the vector sum of the ensemble of units, is the signalled orientation on a particular trial. The accuracy of this population vector orientation coding was determined as a function of a number of parameters by computer simulation. I have shown that even with broadly orientation tuned units possessing considerable response variance, the accuracy of the orientation of the population vector can be as good as behaviorally measured just noticeable differences in orientation. The accuracy of the population code is shown to depend upon the number of units, the average response strength, the orientation bandwidth, response variability and the response covariance. The results of these simulations were also compared to predictions derived from psychophysical studies of orientation discrimination.


Limb Movement Population Vector Signal Orientation Response Magnitude Vector Orientation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Burbeck CA, Regan D (1983) Independence of orientation and size in spatial discriminations J Opt Soc Am 73: 1691–1694PubMedGoogle Scholar
  2. Caelli T, Brettel H, Rentschler I, Hilz R (1983) Discrimination thresholds in two-dimensional spatial frequency domain. Vision Res 23: 129–133CrossRefPubMedGoogle Scholar
  3. Georgopoulos AP, Schwartz AB, Kettner RE (1986) Neuronal population coding of movement direction. Science 233: 1416–1419PubMedGoogle Scholar
  4. Georgopoulos AP, Kettner RE, Schwartz AB (1988) Primate motor cortex and free arm movements to visual targets in three-dimensional space. II. Coding of the direction of movement by a neuronal population. J Neurosci 8: 2928–2937PubMedGoogle Scholar
  5. Gray CM, Koenig P, Engel AK, Singer W (1989) Oscillatory responses in cat visual cortex exhibit stimulus intercolumnar synchronisation which reflect globla stimulus properties. Nature 338: 334–337CrossRefPubMedGoogle Scholar
  6. Hatta Y, Tsumoto T, Sato H, Hagihara K, Tamura (1988) Inhibition contributes to orientation selectivity in visual cortex of cat. Nature 335: 815–817CrossRefPubMedGoogle Scholar
  7. Kettner RE, Schwartz AB, Georgopoulos AP (1988) Primate motor cortex and free arm movements to visual targets in three-dimensional space. III. Positional gradients and population coding of movement direction from various movement origins. J Neurosci 8: 2938–2947PubMedGoogle Scholar
  8. Lee C, Rohrer WH, Sparks DL (1988) Population coding of saccadic eye movements by neurons in the superior colliculus. Nature 332: 357–360CrossRefPubMedGoogle Scholar
  9. Orban GA (1984) Neuronal operations in the visual cortex. Springer, Berlin Heidelberg New YorkGoogle Scholar
  10. Orban GA, Vogels R (1989) Orientation tuning characteristics of V1 neurons measured in the discriminating monkey. Soc Neurosci (abstr) 15: 324Google Scholar
  11. Orban GA, Devos M, Vogels R (1989) Cheapmonkey: comparing an ANN and the primate brain on a simple perceptual task: orientation discrimination. Proceedings NATO ARW Neurocomputing, Algorithms, Architectures and Applications (in press)Google Scholar
  12. Paradiso MA (1988) A theory for the use of visual orientation information which exploits the columnar structure of striate cortex. Biol Cybern 58: 35–49CrossRefPubMedGoogle Scholar
  13. Paradiso MA, Carney T, Freeman RD (1989) Cortical processing of hyperacuity tasks. Vision Res 29: 247–254CrossRefPubMedGoogle Scholar
  14. Regan D, Beverley KI (1985) Postadaptation orientation discrimination J Opt Soc Am A2: 147–155Google Scholar
  15. Schwartz AB, Kettner RE, Georgopoulos AP (1988) Primate motor cortex and free arm movements to visual targets in three-dimensional space. I. Relations between single cell discharge and direction of movement. J Neurosci 8: 2913–1927PubMedGoogle Scholar
  16. Skottun BC, Bradley A, Sclar G, Ohzawa I, Freeman RD (1987) The effect of contrast on visual orientation and spatial frequency discrimination: a comparison of single cells and behavior. J Neurophysiol 57: 773–786PubMedGoogle Scholar
  17. Thomas JP, Gille J, Baker RA (1982) Simultaneous visual detection and identification: theory and data. J Opt Soc Am 72: 1642–1651PubMedGoogle Scholar
  18. Tolhurst DJ, Movshon JA, Dean AF (1983) The statistical reliability of signals in single neurons in cat and monkey visual cortex. Vision Res 23: 775–786CrossRefPubMedGoogle Scholar
  19. Ts'o D, Gilbert CD, Wiesel TN (1986) Relationships between horizontal interactions and functional architecture in cat striate cortex as revealed by cross-correlation analysis. J Neurosci 6: 1160–1170PubMedGoogle Scholar
  20. Van Gisbergen JAM, Van Opstal AJ, Tax AAM (1987) Collicular ensemble coding of saccades based on vector summation. Neuroscience 21: 541–555CrossRefPubMedGoogle Scholar
  21. Vogels R, Orban GA (1986) Decision processes in visual discrimination of line orientation. J Exp Psychol: Hum Percept Perform 12: 115–132CrossRefGoogle Scholar
  22. Vogels R, Orban GA (1989) Orientation discrimination thresholds of single striate cells in the discriminating monkey. Soc Neurosci (abstr) 15: 324Google Scholar
  23. Vogels R, Spileers W, Orban GA (1989) The response variability of striate cortical neurons in the behaving monkey. Exp Brain Res 77: 432–436CrossRefPubMedGoogle Scholar
  24. Wilson HR, Regan D (1984) Spatial-frequency adaptation and grating discrimination: predictions of a line-element model. J Opt Soc Am A1: 1091–1096Google Scholar

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • R. Vogels
    • 1
  1. 1.Laboratorium voor Neuroen Psychofysiologie, Faculteit der GeneeskundeK.U. LeuvenLeuvenBelgium

Personalised recommendations