Abstract
Previous findings imply that synaesthetic experience may have consequences for sensory processing of stimuli that do not themselves trigger synaesthesia. For example, synaesthetes who experience colour show enhanced perceptual processing of colour compared to non-synaesthetes. This study aimed to investigate whether enhanced perceptual processing was a core property of synaesthesia by contrasting tactile and colour sensitivity in synaesthetes who experience either colour, touch, or both touch and colour as evoked sensations. For comparison the performance of non-synaesthetic control subjects was also assessed. There was a relationship between the modality of synaesthetic experience and the modality of sensory enhancement. Synaesthetes who experience colour have enhanced colour sensitivity and synaesthetes who experience touch have enhanced tactile sensitivity. These findings suggest the possibility that a hyper-sensitive concurrent perceptual system is a general property of synaesthesia and are discussed in relation to theories of the condition.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Aghajanian GK, Marek GJ (1999) Serotonin and hallucinogens. Neuropsychopharmacology 21:16S–23S
Banissy MJ, Ward J (2007) Mirror-touch synaesthesia is linked with empathy. Nat Neurosci 10:815–816
Bargary G, Mitchell KJ (2008) Synaesthesia and cortical connectivity. Trends Neurosci 31:335–342
Barnett KJ, Fox JJ, Molholm S, Kelly SP, Shalgi S, Mitchell KJ, Newell FN (2008) Differences in early sensory-perceptual processing in synaesthesia: a visual evoked potential study. Neuroimage 43:605–613
Blake R, Palmeri TJ, Marois R, Kim CY (2005) On the perceptual reality of synesthetic color. In: Robertson L, Sagiv N (eds) Synesthesia: perspectives from cognitive neuroscience. Oxford University Press, Oxford, pp 47–73
Blakemore SJ, Bristow D, Bird G, Frith C, Ward J (2005) Somatosensory activations during the observation of touch and a case of vision-touch synaesthesia. Brain 128:1571–1583
Cohen Kadosh R, Henik A (2006) When a line is a number: colour yields magnitude information in a digit-colour synaesthete. Neuroscience 137:3–5
Cohen Kadosh R, Henik A (2007) Can synaesthesia research inform cognitive science? Trends Cogn Sci 11:177–184
Cohen Kadosh R, Walsh V (2006) Cognitive neuroscience: rewired or crosswired brains. Curr Biol 16:962–963
Cohen Kadosh R, Walsh V (2008) Synaesthesia and cortical connections: cause or correlation? Trends Neurosci 31:549–550
Cohen Kadosh R, Cohen Kadosh K, Henik A (2007) The neural correlate of bidirectional synaesthesia: a combined ERP and fMRI study. J Cogn Neurosci 19:2050–2059
Cohen Kadosh R, Henik A, Catena A, Walsh V, Fuentes LJ (2009) Induced cross-modal synesthetic experience without abnormal neuronal connections. Psychol Sci 20:258–265
Davidoff J (2001) Language and perceptual categorisation. Trends Cogn Sci 5:382–387
Eagleman DM, Kagan AD, Nelson SS, Sagaram D, Sarma AK (2007) A standardized test battery for the study of synaesthesia. J Neurosci Methods 159:139–145
Goldreich D, Kanics IM (2003) Tactile acuity is enhanced in blindness. J Neurosci 23:3439–3445
Goller A, Otten L, Ward J (2009) Seeing sounds and hearing colours: an event-related potential study of audio-visual synaesthesia. J Cogn Neurosci. doi:10.1162/jocn2009.21134
Grossenbacher PG, Lovelace CT (2001) Mechanisms of synaesthesia: cognitive and physiological constraints. Trends Cogn Sci 5:36–41
Hong SW, Blake R (2008) Early visual mechanisms do not contribute to synaesthetic colour experience. Vision Res 48:1018–1026
Howell DC (2002) Statistical methods for psychology. Thomson Learning, USA
Hubbard EM, Ramachandran VS (2005) Neurocognitive mechanisms of synaesthesia. Neuron 48:509–520
Johnsen KO, Philips JR (1981) Tactile spatial resolution. I. Two-point discrimination, gap detection, grating resolution, and letter recognition. J Neurophysiol 46:1177–1191
Kaplan E (1991) The receptive field of retinal ganglion cells in cat and monkey. In: Leventhal AG (ed) Vision and visual dysfunction. CRC Press, Boston, pp 10–40
Kauffman T, Théoret H, Pascual-Leone A (2002) Braille character discrimination in blindfolded human subjects. Neuroreport 13:571–574
Kim CY, Blake R, Palmeri TJ (2006) Perceptual interaction between real and synesthetic colors. Cortex 42:195–203
Pascual-Leone A, Amedi A, Fregni F, Merabet LB (2005) The plastic human brain cortex. Annu Rev Neurosci 28:377–401
Rich AN, Mattingley JB (2002) Anomalous perception in synaesthesia: a cognitive neuroscience. Nat Rev Neurosci 3:43–52
Robertson D, Davies I, Davidoff J (2000) Colour categories are not universal: replications and new evidence from a stone-age culture. J Exp Psychol 129:369–398
Rouw R, Scholte HS (2007) Increased structural connectivity in grapheme-colour synaesthesia. Nat Neurosci 10:792–797
Saenz M, Koch C (2008) The sound of change: visually-induced auditory synesthesia. Curr Biol 18:650–651
Sagiv N, Ward J (2006) Cross-modal interactions: lessons from synaesthesia. Prog Brain Res 155:263–275
Smilek D, Dixon MJ, Cudahy C, Merikle PM (2001) Synaesthetic photisms influence visual perception. J Cogn Neurosci 13:930–936
Van Boven RW, Johnson K (1994) A psychophysical study of the mechanisms of sensory recovery following nerve injury in humans. Brain 117:149–167
Van Boven RW, Hamilton RH, Kauffman T, Keenan P, Pascual-Leone A (2000) Tactile spatial resolution in blind Braille readers. Neurology 54:2230–2236
Vega-Bermudez F, Johnsen KO (1999) SA1 and RA receptive fields, response variability, and population response mapped with a probe array. J Neurophysiol 81:2701–2710
Wittenberg GF, Werhahn KJ, Wassermann EM, Herscovitch P, Cohen LG (2004) Functional connectivity between somatosensory and visual cortex in early blind humans. Eur J Neurosci 20:1923–1927
Yaro C, Ward J (2007) Searching for Shereshevski: what is superior about the memory of synaesthetes? Q J Exp Psychol 60:681–695
Acknowledgments
MJB is supported by an Economic and Social Research Council Studentship. This work was partly supported by a MRC grant to VW. We would like to thank Gerrit Maus and Clare Jonas for assistance with the research.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Banissy, M.J., Walsh, V. & Ward, J. Enhanced sensory perception in synaesthesia. Exp Brain Res 196, 565–571 (2009). https://doi.org/10.1007/s00221-009-1888-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00221-009-1888-0