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Licensed Unlicensed Requires Authentication Published by De Gruyter June 25, 2014

Neuroscience of synesthesia and cross-modal associations

Marcel Neckar and Petr Bob

Abstract

Synesthesia is a condition in which stimulation of one sensory modality causes unusual experiences in a different, unstimulated modality. Recent findings suggest that research on synesthesia offers a unique opportunity to study the neural basis of subjective experiences in healthy and pathological brains. This review summarizes and reflects current knowledge concerning synesthesia in its various aspects, including its cognitive, neural, and behavioral aspects. In this context, recent data suggest new connections between specific conditions related to synesthesic mechanisms and association processes linked to construction of synesthetic cross-modal metaphors that may play a role in psychopathological thinking and imagination.


Corresponding author: Petr Bob, Center for Neuropsychiatric Research of Traumatic Stress, First Faculty of Medicine, Department of Psychiatry and UHSL, Charles University, Ke Karlovu 11, CZ-128 00 Prague, Czech Republic, e-mail: ; and CEITEC, Masaryk University, Brno, Czech Republic

Acknowledgments

The study was supported by the Charles University grant (PRVOUK and SVV), project provided by Czech Ministry of Education (LH11032), and the project ‘CEITEC–Central European Institute of Technology’ (CZ.1.05/1.1.00/02.0068) from the European Regional Development Fund.

Conflict of interest statement: The authors declare that there are no conflicts of interest.

References

Armel, K.C. and Ramachandran, V.S. (1999). Acquired synesthesia in retinitis pigmentosa. Neurocase 5, 293–296.10.1080/13554799908411982Search in Google Scholar

Asher, J.E., Lamb, J.A., Brocklebank, D. Cazier, J.B., Maestrini, E., Addis, L., Sen, M., Baron-Cohen, S., and Monaco, A.P. (2009). A whole-genome scan and fine-mapping linkage study of auditory-visual synesthesia reveals evidence of linkage to chromosomes 2q24, 5q33, 6p12, and 12p12. Am. J. Hum. Genet. 84, 1–7.10.1016/j.ajhg.2009.01.012Search in Google Scholar PubMed PubMed Central

Baron-Cohen, S., Harrison, J., Goldstein, J.H., and Wyke M. (1993). Coloured speech perception: is synaesthesia what happens when modularity breaks down? Perception 22, 419–426.10.1068/p220419Search in Google Scholar PubMed

Baron-Cohen, S., Burt, L., Smith-Laittan, F., Harrison, J., and Bolton, P. (1996). Synaesthesia: prevalence and familiality. Perception 25, 1073–1079.10.1068/p251073Search in Google Scholar PubMed

Baron-Cohen, S., Bor, D., Billington, J., Asher, J., Wheelwright, S., and Ashwin, C. (2007). Savant memory in a man with colour form-number synaesthesia and Asperger syndrome. J. Conscious. Stud. 14, 237–252.Search in Google Scholar

Brogaard, B. (2013). Serotonergic hyperactivity as a potential factor in developmental, acquired and drug-induced synesthesia. Front. Hum. Neurosci. 7, 657.10.3389/fnhum.2013.00657Search in Google Scholar PubMed PubMed Central

Carmichael, D.A. and Simner, J. (2013). The immune hypothesis of synesthesia. Front. Hum. Neurosci. 7, 563.10.3389/fnhum.2013.00563Search in Google Scholar PubMed PubMed Central

Cohen Kadosh, R., Henik, A., Catena, A., Walsh, V., and Fuentes, L.J. (2009). Induced cross-modal synaesthetic experience without abnormal neuronal connections. Psychol. Sci. 20, 258–265.10.1111/j.1467-9280.2009.02286.xSearch in Google Scholar PubMed

Collier, G.L. (1996). Affective synaesthesia: extracting emotion space from simple perceptual stimuli. Motiv. Emot. 20, 1–32.10.1007/BF02251005Search in Google Scholar

Cytowic, R.E. (1989). Synesthesia and mapping of subjective sensory dimensions. Neurology 39, 849–850.10.1212/WNL.39.6.849Search in Google Scholar PubMed

Cytowic, R.E. (2002). Synesthesia: A Union of the Senses. 2nd ed. (Cambridge, MA, UK: MIT Press).10.7551/mitpress/6590.001.0001Search in Google Scholar

Cytowic, R.E. and Wood, F.B. (1982a). Synesthesia. I. A review of major theories and their brain basis. Brain Cogn. 1, 23–35.10.1016/0278-2626(82)90004-5Search in Google Scholar

Cytowic, R.E. and Wood, F.B. (1982b). Synesthesia. II. Psychophysical relations in the synesthesia of geometrically shaped taste and colored hearing. Brain Cogn. 1, 36–49.10.1016/0278-2626(82)90005-7Search in Google Scholar

Dael, N., Sierro, G., and Mohr, C. (2013). Affect-related synesthesias: a prospective view on their existence, expression and underlying mechanisms. Front. Psychol. 4, 754.10.3389/fpsyg.2013.00754Search in Google Scholar PubMed PubMed Central

Dailey, A., Martindale, C., and Borkum, J. (1997). Creativity, synesthesia, and physiognomic perception. Creativity Res. J. 10, 1–8.10.1207/s15326934crj1001_1Search in Google Scholar

Day, S. (1996). Synaesthesia and synaesthetic metaphors. Psyche 2, 32. http://psyche.cs.monash.edu.au/v2/psyche-2-32-day.html.Search in Google Scholar

Day, S. (2004). Some Demographic and Socio-Cultural Aspects of Synesthesia. Synesthesia: Perspectives From Cognitive Neuroscience. L.C. Robertson and N. Sagiv, eds. (New York: Oxford University Press), pp. 11–33.Search in Google Scholar

Dixon, M.J., Smilek, D., and Merikle, P.M. (2004). Not all synaesthetes are created equal: projector versus associator synaesthetes. Cogn. Affect. Behav. Neurosci. 4, 335–343.10.3758/CABN.4.3.335Search in Google Scholar

Eagleman, D.M. and Goodale, M.A. (2009). Why color synesthesia involves more than color. Trends Cogn. Sci. 13, 288–292.10.1016/j.tics.2009.03.009Search in Google Scholar PubMed

Esterman, M., Verstynen, T., Ivry, R.B., and Robertson, L.C. (2006). Coming unbound: disrupting automatic integration of synaesthetic color and graphemes by TMS of right parietal lobe. J. Cogn. Neurosci. 18, 1570–1576.10.1162/jocn.2006.18.9.1570Search in Google Scholar PubMed

Fitzgibbon, B.M., Enticott, P.G., Rich, A.N., Giummarra, M.J., Georgiou-Karistianis, N., Tsao, J.W., Weeks, S.R., and Bradshaw, J.L. (2010a). High incidence of ‘synaesthesia for pain’ in amputees. Neuropsychologia 48, 3675–3678.10.1016/j.neuropsychologia.2010.07.029Search in Google Scholar PubMed

Fitzgibbon, B.M., Giummarra, M.J., Georgiou-Karistianis, N., Enticott, P.G., and Bradshaw, J.L. (2010b). Shared pain: from empathy to synaesthesia. Neurosci. Biobehav. Rev. 34, 500–512.10.1016/j.neubiorev.2009.10.007Search in Google Scholar PubMed

Fuentes, L., Cohen-Kadosh, R., Catena, A., and Henik, A. (2007). Synesthesia experience under posthypnotic suggestion: evidence in favour of the disinhibition hypothesis. Paper presented at the Synaesthesia, Science & Art: Second International Congress, Granada, Spain.Search in Google Scholar

Galeyev, B.M. (2007). The nature and functions of synesthesia in music. Leonardo 40, 285–288.10.1162/leon.2007.40.3.285Search in Google Scholar

Galton, F. (1883). Enquiries into the human faculty and its development (London: Everyman).10.1037/14178-000Search in Google Scholar

Goller, A.I., Otten, L.J., and Ward, J. (2009). Seeing sounds and hearing colors: an event-related potential study of auditory-visual synesthesia. J. Cogn. Neurosci. 21, 1869–1881.10.1162/jocn.2009.21134Search in Google Scholar

Grossenbacher, P.G. and Lovelace, C.T. (2001). Mechanisms of synesthesia: cognitive and physiological constraints. Trends Cogn. Sci. 5, 36–41.10.1016/S1364-6613(00)01571-0Search in Google Scholar

Harrison, J. and Hare, D.J. (2004). Brief report: assessment of sensory abnormalities in people with autistic spectrum disorders. J. Autism Dev. Disord. 34, 727–730.10.1007/s10803-004-5293-zSearch in Google Scholar PubMed

Hartman, A.M. and Hollister, L.E. (1963). Effect of mescaline, lysergic acid diethylamide and psilocybin on color perception. Psychopharmacolgia 4, 441–451.10.1007/BF00403349Search in Google Scholar PubMed

Hochel, M. and Milan, E.G. (2008). Synaesthesia: the existing state of affairs. Cogn. Neuropsychol. 25, 93–117.10.1080/02643290701822815Search in Google Scholar PubMed

Hubbard, E.M. (2007). Neurophysiology of synesthesia. Curr. Psychiatry Rep. 9, 193–199.10.1007/s11920-007-0018-6Search in Google Scholar PubMed

Hubbard, E.M. and Ramachandran, V.S. (2005). Neurocognitive mechanisms of synesthesia. Neuron 48, 509–520.10.1016/j.neuron.2005.10.012Search in Google Scholar PubMed

Hubbard, E.M., Arman, A.C., Ramachandran, V.S., and Boynton, G.M. (2005). Individual differences among grapheme-color synesthetes: Brain-behavior correlations. Neuron 45, 975–985.10.1016/j.neuron.2005.02.008Search in Google Scholar PubMed

Hubbard, E.M., Brang, D., and Ramachandran, V.S. (2011). The cross activation theory at 10. J. Neuropsychol. 5, 152–177.10.1111/j.1748-6653.2011.02014.xSearch in Google Scholar PubMed

Ione, A. and Tyler, C. (2004). Neuroscience, history and the arts. Synesthesia: is F-sharp colored violet? J. Hist. Neurosci. 13, 58–65.10.1080/09647040490885493Search in Google Scholar

Iturria-Medina, Y., Pérez Fernández, A., Morris, D.M., Canales-Rodríguez, E.J., Haroon, H.A., García Pentón, L., Augath, M., Galán García, L., Logothetis, N., Parker, G.J., et al. (2011). Brain hemispheric structural efficiency and interconnectivity rightward asymmetry in human and nonhuman primates. Cereb. Cortex 21, 56–67.10.1093/cercor/bhq058Search in Google Scholar

Jewanski, J., Simner, J., Day, S.A., and Ward, J. (2011). The development of a scientific understanding of synesthesia from early case studies (1849–1873). J. Hist. Neurosci. 20, 284–305.10.1080/0964704X.2010.528240Search in Google Scholar

Kadosh, R.C. and Walsh, V. (2008). Synaesthesia and cortical connections: cause or correlation? Trends Neurosci. 31, 549–550.Search in Google Scholar

Kadosh, R.C., Henik, A., and Walsh, V. (2007a). Small is bright and big is dark in synaesthesia. Curr. Biol. 17, 834–835.10.1016/j.cub.2007.07.048Search in Google Scholar

Kadosh, R.C., Kadosh, K.C., and Henik, A. (2007b). The neuronal correlate of bi-directional synaesthesia: a combined ERP and fMRI study. J. Cogn. Neurosci. 19, 2050–2059.10.1162/jocn.2007.19.12.2050Search in Google Scholar

Kadosh, R.C., Henik, A., Catena, A., Walsh, V., and Fuentes, L.J. (2008). Induced cross-modal synesthetic experience without abnormal neuronal connections. Psychol. Sci. 20, 258–265.10.1111/j.1467-9280.2009.02286.xSearch in Google Scholar

Kuhbandner, C. and Pekrun, R. (2013). Joint effects of emotion and color on memory. Emotion 13, 375–379.10.1037/a0031821Search in Google Scholar

Lakoff, G. (1993). The Contemporary Theory of Metaphor. Metaphor and Thought. 2nd ed. A. Ortony, ed. (Cambridge, UK: Cambridge University Press).Search in Google Scholar

Lakoff, G. and Johnson, M.H. (1980). Metaphors We Live By (Chicago, IL: University of Chicago Press).Search in Google Scholar

Maddock, R.J. (1999). The retrosplenial cortex and emotion: New insights from functional neuroimaging of the human brain. Trends Neurosci. 22, 310–316.10.1016/S0166-2236(98)01374-5Search in Google Scholar

Marks, L.E. (1975). On colored-hearing synesthesia: cross-modal translations of sensory dimensions. Psychol. Bull. 82, 303–331.10.1037/0033-2909.82.3.303Search in Google Scholar

Marks, L.E. (1978). The Unity of the Senses: Interrelations Among the Modalities (New York: Academic Press).10.1016/B978-0-12-472960-5.50011-1Search in Google Scholar

Marks, L.E. (1982). Synesthetic perception and poetic metaphor. J. Exp. Psychol. Hum. Percept. Perform. 8, 15–23.10.1037/0096-1523.8.1.15Search in Google Scholar

Marks, L.E. (2011). Synesthesia: then and now. Intellectica 55, 47–80.10.3406/intel.2011.1161Search in Google Scholar

Marks, L.E. (2013). Weak Synaesthesia in the General Population. Oxford Handbook of Synaesthesia. J. Simner and E. Hubbard, eds. (Oxford, UK: Oxford University Press).Search in Google Scholar

Marks, L.E. and Mulvenna, C.M. (2013). Synesthesia, at and near its borders. Front. Psychol. 4, 651.10.3389/fpsyg.2013.00651Search in Google Scholar

Martino, G. and Marks, L.E. (2001). Synesthesia: strong and weak. Psychol. Sci. 10, 61–65.10.1111/1467-8721.00116Search in Google Scholar

Milán, E.G., Hochel, M., González, A., Tornay, F., McKenney, K., Díaz Caviedes, R., Mata Martín, J.L., Rodríguez, A., Domínguez, G.E., and Vila, J. (2007). Experimental study of phantom colors in a color blind synaesthete. J. Conscious. Stud. 14, 75–95.Search in Google Scholar

Moller, A.C., Elliot, A.J., and Maier, M.A. (2009). Basic hue-meaning associations. Emotion 9, 898–902.10.1037/a0017811Search in Google Scholar

Mulvenna, C.M. and Walsh, V. (2006). Synesthesia: supernormal integration? Trends Cogn. Sci. 10, 350–352.Search in Google Scholar

Mulvenna, C.M., Hubbard, E.M., Ramachandran, V.S., and Pollick, F. (2004). The relationship between synaesthesia and creativity. J. Cogn. Neurosci. Suppl. 16, 188.Search in Google Scholar

Myles, K.M., Dixon, M.J., Smilek, D., and Merikle, P.M. (2003). Seeing double: the role of meaning in alphanumeric-colour synaesthesia. Brain Cogn. 53, 342–345.10.1016/S0278-2626(03)00139-8Search in Google Scholar

Neufeld, J., Sinke, C., Zedler, M., Dillo, W., Emrich, H.M., Bleich, S., and Szycik, G.R. (2012). Disinhibited feedback as a cause of synesthesia: evidence from a functional connectivity study on auditory-visual synesthetes. Neuropsychologia 50, 1471–1477.10.1016/j.neuropsychologia.2012.02.032Search in Google Scholar PubMed

Nunn, J.A., Gregory, L.J., Brammer M., Williams, S.C.R., Parslow, D.M., Morgan, M.J., Morris, R.G., Bullmore, E.T., Baron-Cohen, S., and Gray, J.A. (2002). Functional magnetic resonance imaging of synesthesia: activation of V4/V8 by spoken words. Nat. Neurosci. 5, 371–375.10.1038/nn818Search in Google Scholar PubMed

Okubo, M. and Ishikawa, K. (2011). Automatic semantic association between emotional valence and brightness in the right hemisphere. Cogn. Emot. 25, 1273–1280.10.1080/02699931.2010.541658Search in Google Scholar PubMed

Palmer, S.E., Schloss, K.B., Xu Z., and Prado-León, L.R. (2013). Music-color associations are mediated by emotion. Proc. Natl. Acad. Sci. USA 110, 8836–8841.10.1073/pnas.1212562110Search in Google Scholar PubMed PubMed Central

Parise, C.V. and Spence, C. (2009). ‘When birds of a feather flock together’: synesthetic correspondences modulate audiovisual integration in non-synesthetes. PLoS One 4, 5664.10.1371/journal.pone.0005664Search in Google Scholar PubMed PubMed Central

Pearce, J.M.S. (2006). Synaesthesia. Eur. Neurol. 57, 120–124.10.1159/000098101Search in Google Scholar PubMed

Perry, A. and Henik A. (2013). The emotional valence of a conflict: implications from synesthesia. Front. Psychol. 26, 978.10.3389/fpsyg.2013.00978Search in Google Scholar PubMed PubMed Central

Radvansky, G.A., Gibson, B.S., and McNerney, M.W. (2011). Synesthesia and memory: color congruency, von Restorff, and false memory effects. J. Exp. Psychol. Learn. Mem. Cogn. 37, 219–229.10.1037/a0021329Search in Google Scholar PubMed

Ramachandran, V.S. and Hubbard, E.M. (2001a). Psychophysical investigations into the neural basis of synaesthesia. Proc. R. Soc. Lond. 268, 979–983.10.1098/rspb.2000.1576Search in Google Scholar PubMed PubMed Central

Ramachandran, V.S. and Hubbard, E.M. (2001b). Synaesthesia: a window into perception, thought and language. J. Conscious. Stud. 8, 3–34.Search in Google Scholar

Ramachandran, V.S. and Hubbard, E.M. (2003). Hearing colors, tasting shapes. Sci. Am. 288, 52–59.10.1038/scientificamerican0503-52Search in Google Scholar PubMed

Ramachandran, V.S. and Rogers-Ramachandran, D. (1996). Synaesthesia in phantom limbs induced with mirrors. Proc. Biol. Sci. 263, 377–386.10.1098/rspb.1996.0058Search in Google Scholar PubMed

Rotenberg, V.S. (2004). The ontogeny and asymmetry of the highest brain skills and the pathogenesis of schizophrenia. Behav. Brain Sci. 27, 863–864.10.1017/S0140525X04320194Search in Google Scholar

Rotenberg, V.S. (2013). Moravec’s paradox: consideration in the context of two brain hemisphere functions. Act. Nerv. Super. (Praha) 55, 108–111.10.1007/BF03379600Search in Google Scholar

Rouw, R. and Scholte, S. (2007). Increased structural connectivity in grapheme-color synesthesia. Nat. Neurosci. 10, 792–797.10.1038/nn1906Search in Google Scholar PubMed

Rouw, R., Scholte, H.S., and Colizoli, O. (2011). Brain areas involved in synaesthesia: a review. J. Neuropsychol. 5, 214–242.10.1111/j.1748-6653.2011.02006.xSearch in Google Scholar

Sagiv, N. and Ward, J. (2006). Cross-modal interactions: lessons from synesthesia. Prog. Brain Res. 155, 259–271.10.1016/S0079-6123(06)55015-0Search in Google Scholar

Schiltz, K., Trocha, K., Wieringa, B.M., Emrich, H.M., Johannes, S., and Munte, T.F. (1999). Neurophysiological aspects of synesthetic experience. J. Neuropsychiatry Clin. Neurosci. 11, 58–65.10.1176/jnp.11.1.58Search in Google Scholar PubMed

Simner, J. (2012a). Defining synaesthesia. Br. J. Psychol. 103, 1–15.10.1348/000712610X528305Search in Google Scholar PubMed

Simner, J. (2012b). Defining synaesthesia: a response to two excellent commentaries. Br. J. Psychol. 103, 24–27.10.1111/j.2044-8295.2011.02059.xSearch in Google Scholar PubMed

Simner, J. (2013). Why are there different types of synesthete? Front. Psychol. 2, 558.Search in Google Scholar

Simner, J. and Hubbard, E. eds. (2013). Oxford Handbook of Synaesthesia. (Oxford: Oxford University Press).10.1093/oxfordhb/9780199603329.001.0001Search in Google Scholar

Simner, J., Gärtner O., and Taylor M. D. (2011). Cross-modal personality attributions in synaesthetes and non-synaesthetes. J. Neuropsychol. 5, 283–301.10.1111/j.1748-6653.2011.02009.xSearch in Google Scholar PubMed

Sinke, C., Halpern, J.H., Zedler, M., Neufeld, J., Emrich, H.M., and Passie, T. (2012). Genuine and drug-induced synesthesia: a comparison. Conscious. Cogn. 21, 1419–1434.10.1016/j.concog.2012.03.009Search in Google Scholar PubMed

Smilek, D., Dixon, M.J., Cudahy, C., and Merikle, P.M. (2001). Synaesthetic photisms influence visual perception. J. Cogn. Neurosci. 13, 930–936.10.1162/089892901753165845Search in Google Scholar PubMed

Smilek, D., Dixon, M.J., and Merikle, P.M. (2005). Synaesthesia: discordant male monozygotic twins. Neurocase 11, 363–370.10.1080/13554790500205413Search in Google Scholar PubMed

Spector, F. and Maurer, D. (2009). Synesthesia: a new approach to understanding the development of perception. Dev. Psychol. 45, 175–189.10.1037/a0014171Search in Google Scholar

Spence, C. (2002). Multisensory attention and tactile information-processing. Behav. Brain Res. 135, 57–64.10.1016/S0166-4328(02)00155-9Search in Google Scholar

Steven, M.S. and Blakemore, C. (2004). Visual synaesthesia in the blind. Perception 33, 855–868.10.1068/p5160Search in Google Scholar

Steven, M.S., Hansen, P.C., and Blakemore, C. (2006). Activation of color-selective areas of the visual cortex in a blind synesthete. Cortex 42, 304–308.10.1016/S0010-9452(08)70356-3Search in Google Scholar

Stuckey, D.E., Lawson, R., and Luna, L.E. (2005). EEG gamma coherence and other correlates of subjective reports during ayahuasca experiences. J. Psychoactive Drugs 37, 163–178.10.1080/02791072.2005.10399798Search in Google Scholar PubMed

Terhune, D.B., Cardena, E., and Lindgren, M. (2010). Disruption of synaesthesia by posthypnotic suggestion: an ERP study. Neuropsychologia 48, 3360–3364.10.1016/j.neuropsychologia.2010.07.004Search in Google Scholar PubMed

Tomson, S.N., Narayan, M., Allen, G.I., and Eagleman, D.M. (2013). Neural networks of colored sequence synesthesia. J. Neurosci. 33, 14098–14106.10.1523/JNEUROSCI.5131-12.2013Search in Google Scholar PubMed PubMed Central

van der Veen, F.M., Aben, H.P., Smits, M., and Röder, C.H. (2014). Grapheme-color synesthesia interferes with color perception in a standard Stroop task. Neuroscience 258, 246–253.10.1016/j.neuroscience.2013.11.018Search in Google Scholar PubMed

Volberg, G., Karmann, A., Birkner, S., and Greenlee, M.W. (2013). Short- and long-range neural synchrony in grapheme-color synesthesia. J. Cogn. Neurosci. 25, 1148–1162.10.1162/jocn_a_00374Search in Google Scholar PubMed

Voskuil, P.H. (2013). Van Gogh’s disease in the light of his correspondence. Front. Neurol. Neurosci. 31, 116–125.10.1159/000343265Search in Google Scholar PubMed

Walsh, R. (2005). Can synesthesia be cultivated? Indications from surveys of meditators. J. Consc. Stud. 12, 5–17.Search in Google Scholar

Ward, J. (2004). Emotionally mediated synaesthesia. Cogn. Neuropsychol. 21, 761–772.10.1080/02643290342000393Search in Google Scholar

Ward, J. (2013). Synesthesia. Annu. Rev. Psychol. 64, 49–75.10.1146/annurev-psych-113011-143840Search in Google Scholar

Ward, J. and Mattingley, J.B. (2006). Synaesthesia: an overview of contemporary findings and controversies. Cortex 42, 129–136.10.1016/S0010-9452(08)70336-8Search in Google Scholar

Ward, J. and Simner, J. (2005). Is synaesthesia an X-linked dominant trait with lethality in males? Perception 34, 611–623.10.1068/p5250Search in Google Scholar

Ward, J., Huckstep, B., and Tsakanikos, E. (2006). Sound-colour synaesthesia: to what extent does it use cross-modal mechanisms common to us all? Cortex 42, 264–280.10.1016/S0010-9452(08)70352-6Search in Google Scholar

Received: 2014-5-2
Accepted: 2014-6-5
Published Online: 2014-6-25
Published in Print: 2014-12-1

©2014 by De Gruyter

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