Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Functional magnetic resonance imaging of synesthesia: activation of V4/V8 by spoken words

Abstract

In 'colored-hearing' synesthesia, individuals report color experiences when they hear spoken words. If the synesthetic color experience resembles that of normal color perception, one would predict activation of parts of the visual system specialized for such perception, namely the human 'color center', referred to as either V4 or V8. Using functional magnetic resonance imaging (fMRI), we here locate the region activated by speech in synesthetes to area V4/V8 in the left hemisphere, and demonstrate overlap with V4/V8 activation in normal controls in response to color. No activity was detected in areas V1 or V2, suggesting that activity in primary visual cortex is not necessary for such experience. Control subjects showed no activity in V4/V8 when imagining colors in response to spoken words, despite overtraining on word–color associations similar to those spontaneously reported by synesthetes.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Activation maps of synesthetes and controls, combined with a color activation mapping study9.
Figure 2: Orthogonal views of the site of overlap between the current experiment and a color activation mapping study9.

References

  1. Baron-Cohen, S., Wyke, M. & Binnie, C. Hearing words and seeing colours: an experimental investigation of a case of synaesthesia. Perception 16, 761–767 (1987).

    Article  CAS  PubMed  Google Scholar 

  2. Paulesu, E. et al. The physiology of coloured-hearing: a PET activation study of colour–word synaesthesia. Brain 118, 661–676 (1995).

    Article  PubMed  Google Scholar 

  3. Lueck, C. J. et al. The colour centre in the cerebral cortex of man. Nature 340, 386–389 (1989).

    Article  CAS  PubMed  Google Scholar 

  4. Zeki, S. et al. A direct demonstration of functional specialisation in human visual cortex. J. Neurosci. 11, 641–649 (1991).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Hadjikhani, N., Liu, A. K., Dale, A. M., Cavanagh, P. & Tootell, R. B. H. Retinopy and color sensitivity in human visual cortical area V8. Nature Neurosci. 1, 235–241 (1998).

    Article  CAS  PubMed  Google Scholar 

  6. Barbur, J. L. et al. Conscious visual perception without V1. Brain 116,1293–1302 (1993).

    Article  PubMed  Google Scholar 

  7. Zeki, S., Watson, J. D. G. & Frackowiak, R. S. J. Going beyond the information given: the relation of illusory visual motion to brain activity. Proc. R. Soc. Lond. B 252, 215–222 (1993).

    Article  CAS  Google Scholar 

  8. Crick, F. & Koch, C. Are we aware of neural activity in primary visual cortex? Nature 373,121–123 (1995).

    Article  Google Scholar 

  9. Howard, R. J. et al. The functional anatomy of imagining and perceiving colour. NeuroReport 9, 1019–1023 (1998).

    Article  CAS  PubMed  Google Scholar 

  10. Bartels, A. & Zeki, S. The architecture of the colour centre in the human visual brain: new results and a review. Eur. J. Neurosci. 12, 172–193 (2000).

    Article  CAS  PubMed  Google Scholar 

  11. Grossenbacher, P. G. Synaesthesia: Classical and Contemporary Readings (ed. Baron-Cohen, S. & Harrison, J. E.) 148–172 (Blackwell, Oxford, 1997).

    Google Scholar 

  12. Zeki, S. & Marini, L. Three cortical stages of colour processing in the human brain. Brain 121, 1669–1685 (1998).

    Article  PubMed  Google Scholar 

  13. Barnes, J. et al. The functional anatomy of the McCollough contingent colour after-effect. NeuroReport 10, 195–199 (1999).

    Article  CAS  PubMed  Google Scholar 

  14. Hadjikhani, N. & Roland, P. Cross-modal transfer of information between the tactile and the visual representations in the human brain: a positron emission tomographic study. J. Neurosci. 18, 1072–1084 (1998).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Grasby, P. M. et al. Functional mapping of brain areas implicated in auditory–verbal memory function. Brain 116, 1–20 (1993).

    Article  PubMed  Google Scholar 

  16. Andreasen, N. C. et al. Remembering the past: two facets of episodic memory explored with positron emission tomography. Am. J. Psychiat. 152, 1576–1585 (1995).

    Article  CAS  PubMed  Google Scholar 

  17. Fletcher, P. C. et al. Brain systems for encoding and retrieval of auditory–verbal memory: an in vivo study in humans. Brain 118, 401–416 (1995).

    Article  PubMed  Google Scholar 

  18. Maddock, R. J. & Buonocore, M. H. Activation of left posterior cingulate gyrus by the auditory presentation of threat-related words: an fMRI study. Psychiatry Res. 75, 1–14 (1997).

    Article  CAS  PubMed  Google Scholar 

  19. Cytowic, R. E. Synaesthesia: Classical and Contemporary Readings (eds. Baron-Cohen, S. & Harrison, J. E.) 17–39 (Blackwell, Oxford, 1997).

    Google Scholar 

  20. Baron-Cohen, S., Harrison, J., Goldstein, L. H. & Wyke M. Coloured speech perception: is synaesthesia what happens when modularity breaks down? Perception 22, 419–426 (1993).

    Article  CAS  PubMed  Google Scholar 

  21. Ramachandran, V. S. & Hubbard, E. S. Psychophysical investigations into the neural basis of synaesthesia. Proc. R. Soc. Lond., B 268, 979–983 (2001).

    Article  CAS  Google Scholar 

  22. ffytche, D. H. et al. The anatomy of conscious vision: an fMRI study of visual hallucinations. Nature Neurosci. 11, 738–742 (1998).

    Article  Google Scholar 

  23. Grossenbacher, P. G. & Lovelace, C. T. Mechanisms of synesthesia: cognitive and physiological constraints. Trends Cogn. Sci. 5, 36–41 (2001).

    Article  PubMed  Google Scholar 

  24. Tootell, R. B. H. et al. Visual motion aftereffect in human cortical area MT revealed by functional magnetic resonance imaging. Nature 375, 139–141 (1995).

    Article  CAS  PubMed  Google Scholar 

  25. Tong, F. & Engel, S. A. Interocular rivalry revealed in the human cortical blind-spot representation. Nature 411, 195–199 (2001).

    Article  CAS  PubMed  Google Scholar 

  26. Gray, J. A., Williams, S. C. R. Nunn, J. & Baron-Cohen, S. in Synaesthesia: Classical and Contemporary Readings (ed. Baron-Cohen, S. & Harrison, J. E.) 173–181 (Blackwell, Oxford, 1997).

    Google Scholar 

  27. Milner, A. D. & Goodale, M. A. The Visual Brain in Action (Oxford Univ. Press, Oxford, 1995).

    Google Scholar 

  28. Dehay C., Bullier, J. & Kennedy, H. Transient projections from the fronto-parietal and temporal cortex to areas 17, 18 and 19 in the kitten. Exp. Brain Res. 57, 208–212 (1984).

    Article  CAS  PubMed  Google Scholar 

  29. Bailey, M. E. & Johnson, K. J. in Synaesthesia: Classical and Contemporary Readings (eds. Baron-Cohen, S. & Harrison, J. E.) 182–207 (Blackwell, Oxford, 1997).

    Google Scholar 

  30. Baron-Cohen, S., Burt, L., Smith-Leyton, F., Harrison, J. & Bolton, P. Synaesthesia: prevalence and familiality. Perception 25, 1073–1079 (1996).

    Article  CAS  PubMed  Google Scholar 

  31. Gray, J. A. in Neuronal Bases and Psychological Aspects of Consciousness (eds. Taddeo-Ferretto, C. & Musio, C.) 8, 450–457 (World Scientific, Singapore,1999).

    Book  Google Scholar 

  32. Nelson, H. & Willison, J. R. National Adult Reading Test (NART): Test Manual 2nd ed. (NFER-Nelson, Windsor, 1991).

    Google Scholar 

  33. Kiehl, K. A. et al. Neural pathways involved in the processing of concrete and abstract words. Hum. Brain Mapp. 7, 225–233 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Johansson, S. & Hofland, K. Frequency Analysis of English Vocabulary and Grammar Based on the LOB Corpus (Oxford Univ. Press, Oxford, 1982).

    Google Scholar 

  35. Ogawa, S., Lee, T. M., Kay, A. R. & Tank, D.W. Brain magnetic resonance imaging with contrast dependent on blood oxygenation. Proc. Nat. Acad. Sci. USA 8, 9868–9872 (1990).

    Article  Google Scholar 

  36. Bullmore, E. T. et al. Methods for diagnosis and treatment of stimulus-correlated motion in generic brain activation studies using fMRI. Hum. Brain Mapp. 7, 38–48 (1999).

    Article  CAS  PubMed  Google Scholar 

  37. Bullmore E. T. et al. Colored noise and computational inference in neurophysiological (fMRI) time series analysis: resampling methods in time and wavelet domains. Hum. Brain Mapp. 12, 61–78 (2001).

    Article  CAS  PubMed  Google Scholar 

  38. Edgington, E. S. Randomisation Tests 3rd ed. (Dekker, New York, 1995).

  39. Talairach J. & Tournoux, P. Co-planar Stereotactic Atlas of the Human Brain. (Thieme, Stuttgart, 1988).

    Google Scholar 

  40. Brammer, M. J. et al. Generic brain activation mapping in fMRI: a nonparametric approach. Mag. Res. Imaging 15, 763–770 (1997).

    Article  CAS  Google Scholar 

  41. Forman S. D. et al. Improved assessment of significant activation in functional magnetic resonance imaging (fMRI)—use of a cluster size threshold. Mag. Res. Med. 33, 636–647 (1995).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the McDonnell–Pew Foundation and a Consciousness Studies Award from the University of Arizona. We thank John Harrison and Sue Chopping for assistance with various aspects of the research. J.A.G. is currently a fellow at the Center for Advanced Study in the Behavioral Sciences, Stanford University, with financial support from the John D. and Catherine T. Macarthur Foundation, Grant no.32005-0.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to J. A. Nunn.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Nunn, J., Gregory, L., Brammer, M. et al. Functional magnetic resonance imaging of synesthesia: activation of V4/V8 by spoken words. Nat Neurosci 5, 371–375 (2002). https://doi.org/10.1038/nn818

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nn818

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing