Genuine and drug-induced synesthesia: A comparison

Consciousness and Cognition

Volumn 21, Issue 3, 2012, Pages 1419-1434

  Sinke, Christopher ^a   Halpern, John H ^b   Zedler, Markus ^a   Neufeld, Janina ^a   Emrich, Hinderk M ^a   Passie, Torsten ^a,b  

^a HANNOVER MEDICAL SCHOOL   (Germany)

^b MCLEAN HOSPITAL   (United States)

Author keywords

Comparison; Drug induced; Genuine; Hallucinogens; Phenomenology; Synesthesia

Indexed keywords

LYSERGIDE; MESCALINE; N,N DIMETHYLTRYPTAMINE; PSILOCYBINE;

ACQUIRED SYNESTHESIA; AFFECT; AUDITORY SYSTEM; BRAIN DEPTH STIMULATION; COMPARATIVE STUDY; DRUG INDUCED SYNESTHESIA; ELECTROENCEPHALOGRAM; GENUINE SYNESTHESIA; HUMAN; LEARNING; NONHUMAN; PHENOMENOLOGY; REVIEW; SENSATION; SMELLING; TASTE; TIME PERCEPTION; TOUCH; VISUAL INFORMATION;

AFFECT; HALLUCINOGENS; HUMANS; PERCEPTUAL DISORDERS;

EID: 84865354711     PISSN: 10538100     EISSN: 10902376     Source Type: Journal    
DOI: 10.1016/j.concog.2012.03.009     Document Type: Review

References (152)

1. Abramson H.A. The use of LSD in psychotherapy and alcoholism 1967, Bobbs-Merill, Indianapolis, New York, Kansas City.
2. Afra P., Funke M., Matuso F. Acquired auditory-visual synesthesia: A window to early cross-modal sensory interactions. Psychology Research and Behavior Management 2009, 2:31-37.
3. Aghajanian G.K., Marek G.J. Serotonin and hallucinogens. Neuropsychopharmacology 1999, 21:16S-23S.
4. Ardis J.A., McKellar P. Hypnagogic imagery and mescaline. Journal of Mental Science 1956, 102:22-29.
5. Armel K.C., Ramachandran V.S. Acquired synesthesia in Retinis Pigmentosa. Neurocase 1999, 5:293-296.
6. Asher J.E., Lamb J.A., Brocklebank D., Cazier J.B., Maestrini E., Addis L., et al. A whole-genome scan and fine-mapping linkage study of auditory-visual synesthesia reveals evidence of linkage to chromosomes 2q24, 5q33, 6p12, and 12p12. American Journal of Human Genetics 2009, 84:279-285.
7. Bargary G., Barnett K.J., Mitchell K.J., Newell F.N. Colored-speech synaesthesia is triggered by multisensory, not unisensory, perception. Psychological Science 2009, 20:529-533.
8. Barnett K.J., Foxe J.J., Molholm S., Kelly S.P., Shalgi S., Mitchell K.J., et al. Differences in early sensory-perceptual processing in synesthesia: a visual evoked potential study. Neuroimage 2008, 43:605-613.
9. Baron-Cohen S., Burt L., Smith-Laittan F., Harrison J., Bolton P. Synaesthesia: Prevalence and familiality. Perception 1996, 25:1073-1079.
10. Baron-Cohen S., Wyke M.A., Binnie C. Hearing words and seeing colours: An experimental investigation of a case of synaesthesia. Perception 1987, 16:761-767.
11. Beeli G., Esslen M., Jäncke L. Synaesthesia: When coloured sounds taste sweet. Nature 2005, 434:38.
12. Beeli G., Esslen M., Jäncke L. Frequency correlates in grapheme-color synaesthesia. Psychological Science 2007, 18:788-792.
13. Beringer K. Der Meskalinrausch 1927, Springer, Berlin.
14. Bleuler E., Lehmann K. Zwangsmässige Lichtempfindung durch Schall und verwandte Erscheinungen 1881, Fues Verlag, Leipzig.
15. Brang D., Hubbard E.M., Coulson S., Huang M., Ramachandran V.S. Magnetoencephalography reveals early activation of V4 in grapheme-color synesthesia. Neuroimage 2010, 53:268-274.
16. 2a receptor activation. Medical Hypotheses 2008, 70:903-904.
17. Brimblecombe R.W., Pinder R.M. Hallucinogenic agents 1975, Wright Scientechnica, Bristol.
18. Buonomano D.V., Merzenich M.M. Cortical plasticity: From synapses to maps. Annual Review of Neuroscience 1998, 21:149-186.
19. Cowey A., Walsh V. Magnetically induced phosphenes in sighted, blind and blindsighted observers. NeuroReport 2000, 11:3269-3273.
20. Cytowic R.E. Synesthesia: A union of the senses 2002, MIT Press. 2nd ed.
21. Cytowic, R. E., & Stump, D. A. (1985). Reduced cortical blood flow in geometrically-shaped taste synesthesia. In International meeting of the Neuropsychological society, San Diego.
22. Damasio A.R. Descartes' error: Emotion, reason, and the human brain 1995, Harper Perennial. 1st ed.
23. Day S. Some demographical and socio-cultural aspects of synesthesia. Synesthesia: Perspectives from cognitive neuroscience 2004, 11-33. Oxford University Press, New York. L.C. Robertson, N. Sagiv (Eds.).
24. de Araujo D.B., Ribeiro S., Cecchi G.A., Carvalho F.M., Sanchez T.A., Pinto J.P., et al. Seeing with the eyes shut: Neural basis of enhanced imagery following ayahuasca ingestion. Human Brain Mapping 2011.
25. Delay J., Gérad H.P., Racamier P.C. Les synesthésies dans l'intoxication Mescalinique. L'Encephale 1951, 40:1-10.
26. Divry P., Bobon J., Collard J. La Lysergo-analyse comme technique propedeutique en psychatrie. Neuro-psycho-pharmacology 1959, 542-545. Elsevier, Amsterdam. P.B. Bradley (Ed.).
27. Dixon M.J., Smilek D., Cudahy C., Merikle P.M. Five plus two equals yellow. Nature 2000, 406:365.
28. Dixon M.J., Smilek D., Duffy P.L., Zanna M.P., Merikle P.M. The role of meaning in grapheme-colour synaesthesia. Cortex 2006, 42:243-252.
29. Dixon M.J., Smilek D., Merikle P.M. Not all synaesthetes are created equal: Projector versus associator synaesthetes. Cognitive, Affective, & Behavioral Neuroscience 2004, 4:335-343.
30. Eagleman D.M., Goodale M.A. Why color synesthesia involves more than color. Trends in Cognitive Sciences 2009, 13:288-292.
31. Eagleman D.M., Kagan A.D., Nelson S.S., Sagaram D., Sarma A.K. A standardized test battery for the study of synesthesia. Journal of Neuroscience Methods 2007, 159:139-145.
32. Edquist J., Rich A.N., Brinkman C., Mattingley J.B. Do synaesthetic colours act as unique features in visual search?. Cortex 2006, 42:222-231.
33. Eichmeier J., Höfer O. Endogene Bildmuster 1974, Urban&Schwarzenberg, München - Berlin - Wien.
34. Emrich H.M., Schneider U., Zedler M. Welche Farbe hat der Montag? 2004, Hirzel, Stuttgart.
35. Esterman M., Verstynen T., Ivry R.B., Robertson L.C. Coming unbound: Disrupting automatic integration of synesthetic color and graphemes by transcranial magnetic stimulation of the right parietal lobe. Journal of Cognitive Neuroscience 2006, 18:1570-1576.
36. Friedrichs H. Die Psychologie des Meskalinrausches 2009, VWB - Verlag für Wissenschaft und Bildung, Berlin.
37. Glennon R.A. Do classical hallucinogens act as 5-HT2 agonists or antagonists?. Neuropsychopharmacology 1990, 3:509-517.
38. Goller A.I., Otten L.J., Ward J. Seeing sounds and hearing colors: An event-related potential study of auditory-visual synesthesia. Journal of Cognitive Neuroscience 2009, 21:1869-1881.
39. Gouzoulis-Mayfrank E., Schreckenberger M., Sabri O., Arning C., Thelen B., Spitzer M., et al. Neurometabolic effects of psilocybin, 3,4-methylenedioxyethylamphetamine (MDE) and d-methamphetamine in healthy volunteers - A double-blind, placebo-controlled PET study with [F-18]FDG. Neuropsychopharmacology 1999, 20:565-581.
40. Grof S. Realms of the human unconsciousness 1975, Viking Press, New York.
41. Grof S. LSD psychotherapy 1980, Hunterhouse, Pomona, CA.
42. Grossenbacher P.G., Lovelace C.T. Mechanisms of synesthesia: Cognitive and physiological constraints. Trends in Cognitive Sciences 2001, 5:36-41.
43. Hancock P. Monozygotic twins' colour-number association: A case study. Cortex 2006, 42:147-150.
44. Hanggi J., Wotruba D., Jancke L. Globally altered structural brain network topology in grapheme-color synesthesia. Journal of Neuroscience 2011, 31:5816-5828.
45. Harrison J., Baron-Cohen S. Synaesthesia: Reconciling the subjective with the objective. Endeavour 1995, 19:157-160.
46. Heimann H. Expressive phenomenology of model psychoses (psilocybin). Comparison with self-description and psychic deficiency of performance. Psychiatria et Neurologia (Basel) 1961, 141:69-100.
47. Hintzen A., Passie T. The pharmacology of LSD 2010, Oxford University Press, Oxford, New York.
48. Hochel M., Milan E.G. Synaesthesia: The existing state of affairs. Cognitive Neuropsychology 2008, 25:93-117.
49. Hoffer A., Osmond H. The hallucinogens 1967, London Academic Press, New York.
50. Holland D. Flashback-Phänomene als Nachwirkung von Halluzinogeneinnahme 2001, Hannover Medical School, Hannover (Germany).
51. Hubbard E.M. Neurophysiology of synesthesia. Current Psychiatry Reports 2007, 9:193-199.
52. Hubbard E.M., Arman A.C., Ramachandran V.S., Boynton G.M. Individual differences among grapheme-color synesthetes: Brain-behavior correlations. Neuron 2005, 45:975-985.
53. Hubbard E.M., Manohar S., Ramachandran V.S. Contrast affects the strength of synesthetic colors. Cortex 2006, 42:184-194.
54. Hubbard E.M., Ramachandran V.S. Refining the experimental lever - A reply to Shanon and Pribram. Journal of Consciousness Studies 2003, 10:77-84.
55. Hupe J.M., Bordier C., Dojat M. The neural bases of grapheme-color synesthesia are not localized in real color-sensitive areas. Cerebral Cortex 2011.
56. Hüther G., Rüther E. Das serotonerge system 2000, Uni-Med, Bremen.
57. Jacobs L., Karpik A., Bozian D. Auditory-Visual synesthesia: Sound-induced photism. Archives of Neurology 1981, 38:211-216.
58. Jacome D.E., Gumnit R.J. Audioalgesic and audiovisuoaglesic synesthesias: Epileptic manifestation. Neurology 1979, 29:1050-1053.
59. James K.H., Martelli M., James T.W., Majaj N.J., Pelli D.G., Gauthier I. fMRI reveals the role of the left anterior fusiform gyrus in letter detection and identification. Journal of Vision 2004, 4.
60. Jancke L., Beeli G., Eulig C., Hanggi J. The neuroanatomy of grapheme-color synesthesia. European Journal of Neuroscience 2009, 29:1287-1293.
61. Kandel E.R., Schwartz J.H., Jessell T.M. Principles of neural science 2000, McGraw-Hill, New York. 4th ed.
62. Kazui H., Ishii R., Yoshida T., Ikezawa K., Takaya M., Tokunaga H., et al. Neuroimaging studies in patients with Charles Bonnet Syndrome. Psychogeriatrics 2009, 9:77-84.
63. Kim I.K., Dryja T.P., Lessell S., Gragoudas E.S. Melanocytoma of the optic nerve associated with sound-induced phosphenes. Archives of Ophthalmology 2006, 124:273-277.
64. Klüver H. Mescal and mechanisms of hallucinations 1966, University of Chicago Press, Chicago.
65. Koike H., Yoshino Y. Polyesthesia - report of two cases. Rhinso Shinkeigaku 1990, 30:193-198.
66. Lessell S., Cohen M.M. Phosphenes induced by sound. Neurology 1979, 29:1524-1526.
67. Leuner H. Die experimentelle Psychose 1962, Springer, Berlin.
68. Leuner, H. (1968). In J. M. Shlien (Ed.), Basic functions involved in the psychotherapeutic effect of psychomimetics. Washington, DC: American Psychological Association, Inc.
69. Leuner H. Halluzinogene - Psychische Grenzzustände in Forschung und Psychotherapie 1981, H. Huber, Bern.
70. Luria A.R. The mind of a mnemonist: A little book about a vast memory 1968, Basic Books, New York.
71. Mann H., Korzenko J., Carriere J.S.A., Dixon M.J. Time-space synaesthesia - A cognitive advantage?. Consciousness and Cognition 2009, 18:619-627.
72. Marks L.E. Colored-hearing synesthesia - Cross-modal translations of sensory dimensions. Psychological Bulletin 1975, 82:303-331.
73. Martino G., Marks L.E. Synesthesia: Strong and weak. Current Directions in Psychological Science 2001, 10:61-65.
74. Masters R.E.L., Houston J. The varieties of psychedelic experience 1966, Holt, Rinehart & Winston, New York/Chicago.
75. Mattingley J.B. Attention, automaticity, and awareness in synesthesia. Annals of the New York Academy of Sciences 2009, 1156:141-167.
76. Mattingley J.B., Rich A.N., Yelland G., Bradshaw J.L. Unconscious priming eliminates automatic binding of colour and alphanumeric form in synaesthesia. Nature 2001, 410:580-582.
77. Maurer D., Mondloch C. Neonatal synesthesia: A re-evaluation. Synesthesia: Perspectives from cognitive neuroscience 2004, 193-213. Oxford University Press. L. Robertson, N. Sagiv (Eds.).
78. Mavromatis A. Hypnagogia: The unique state of consciousness between wakefulness and sleep 1987, Routledge and Kegan Paul, London.
79. Mayer-Gross W. über Synästhesien im Meskalinrausch. Farbe-Ton-Forschungen Bd. III 1931, 266-277. Psychologisch-ästhetische Forschungsgesellschaft, Hamburg. G. Anschütz (Ed.).
80. Meier B., Rothen N. When conditioned responses " fire back": Bidirectional cross-activation creates learning opportunities in synesthesia. Neuroscience 2007, 147:569-572.
81. Merzenich M.M., Kaas J.H., Wall J., Nelson R.J., Sur M., Felleman D. Topographic reorganization of somatosensory cortical areas 3b and 1 in adult monkeys following restricted deafferentation. Neuroscience 1983, 8:33-55.
82. Mills C.B., Boteler E.H., Oliver G.K. Digit synaesthesia: A case study using a Stroop-type test. Cognitive Neuropsychology 1999, 16:181-191.
83. Mroczko A., Metzinger T., Singer W., Nikolic D. Immediate transfer of synesthesia to a novel inducer. Journal of Vision 2009, 9.
84. Muggleton N., Tsakanikos E., Walsh V., Ward J. Disruption of synaesthesia following TMS of the right posterior parietal cortex. Neuropsychologia 2007, 45:1582-1585.
85. Myles K.M., Dixon M.J., Smilek D., Merikle P.M. Seeing double: The role of meaning in alphanumeric-colour synaesthesia. Brain and Cognition 2003, 53:342-345.
86. Neufeld J., Sinke C., Dillo W., Emrich H.M., Szycik G.R., Dima D., et al. The neural correlates of coloured music: A functional MRI investigation of auditory-visual synaesthesia. Neuropsychologia 2011.
87. Nichols D.E. Hallucinogens. Pharmacology & Therapeutics 2004, 101:131-181.
88. Novich S., Cheng S., Eagleman D.M. Is synaesthesia one condition or many? A large-scale analysis reveals subgroups. Journal of Neuropsychology 2011, 5:353-371.
89. Nunn J.A., Gregory L.J., Brammer M., Williams S.C., Parslow D.M., Morgan M.J., et al. Functional magnetic resonance imaging of synesthesia: Activation of V4/V8 by spoken words. Nature Neuroscience 2002, 5:371-375.
90. Oster G. Phosphenes. Scientific American 1970, 222:83-87.
91. Page N.G., Bolger J.P., Sanders M.D. Auditory evoked phosphenes in optic nerve diseases. Journal of Neurology, Neurosurgery and Psychiatry 1982, 45:7-12.
92. Passie T., Halpern J.H., Stichtenoth D.O., Emrich H.M., Hintzen A. The pharmacology of lysergic acid diethylamide: A review. CNS Neuroscience & Therapeutics 2008, 14:295-314.
93. Paulesu E., Harrison J., Baron-Cohen S., Watson J.D., Goldstein L., Heather J., et al. The physiology of coloured hearing. A PET activation study of colour-word synaesthesia. Brain 1995, 118(Pt 3):661-676.
94. Penfield W., Rasmussen T. The cerebral cortex of man 1957, Macmillan, New York.
95. Radvansky G.A., Gibson B.S., McNerney M.W. Synesthesia and memory: Color congruency, von Restorff, and false memory effects. Journal of Experimental Psychology. Learning, Memory, and Cognition 2011, 37:219-229.
96. Ramachandran V.S., Brang D. Tactile-emotion synesthesia. Neurocase 2008, 14:390-399.
97. Ramachandran V.S., Hubbard E.M. Synaesthesia - A window into perception, thought and language. Journal of Consciousness Studies 2001, 8:3-34.
98. Rao A., Nobre A.C., Alexander I., Cowey A. Auditory evoked visual awareness following sudden ocular blindness: an EEG and TMS investigation. Experimental Brain Research 2007, 176:288-298.
99. Riba J., Romero S., Grasa E., Mena E., Carrio I., Barbanoj M.J. Increased frontal and paralimbic activation following ayahuasca, the pan-amazonian inebriant. Psychopharmacology (Berlin) 2006, 186:93-98.
100. Ro T., Farne A., Johnson R.M., Weeden V., Chu Z., Wang Z.J., et al. Feeling sound after a thalamic lesion. Annals of Neurology 2007, 62:433-441.
101. Rothen N., Meier B. Do synesthetes have a general advantage in visual search and episodic memory? A case for group studies. PLoS ONE 2009, 4:e5037.
102. Rouw R., Scholte H.S. Increased structural connectivity in grapheme-color synesthesia. Nature Neuroscience 2007, 10:792-797.
103. Rouw R., Scholte H.S. Neural basis of individual differences in synesthetic experiences. Journal of Neuroscience 2010, 30:6205-6213.
104. Rouw R., Scholte H.S., Colizoli O. Brain areas involved in synaesthesia: A review. Journal of Neuropsychology 2011, 5:214-242.
105. Saenz M., Koch C. The sound of change: Visually-induced auditory synesthesia. Current Biology 2008, 18:R650-R651.
106. Scharfetter C. General Psychopathology 1980, Cambridge University Press, Cambridge.
107. Shanon B. Three stories concerning synaesthesia - A commentary on Ramachandran and Hubbard. Journal of Consciousness Studies 2003, 10:69-74.
108. Shanon B. Colour associates to semantic linear orders. Psychological Research Psychologische Forschung 1982, 44:75-83.
109. Shanon B. The antipodes of the mind 2002, Oxford University Press, Oxford, New York.
110. Shulgin A.T. Basic pharmacology and effects. Hallucinogens - A forensic drug handbook 2003, 67-138. Academic Press, Amsterdam. R. Laing, J.A. Siegel (Eds.).
111. Siegel R.K. Hallucinations - Behavior, experience, and theory 1975, John Wiley & Sons, New York.
112. Siegel R.K., Jarvik M.E. Drug-induced hallucinations in animals and man. Hallucinations: Behavior, experience, and theory 1975, 81-162. John Wiley & Sons, New York. R.K. Siegel, L.J. West (Eds.).
113. Simner J. Defining synaesthesia. British Journal of Psychology 2012, 103:1-15.
114. Simner J., Harrold J., Creed H., Monro L., Foulkes L. Early detection of markers for synaesthesia in childhood populations. Brain 2009, 132:57-64.
115. Simner J., Holenstein E. Ordinal linguistic personification as a variant of synesthesia. Journal of Cognitive Neuroscience 2007, 19:694-703.
116. Simner J., Logie R.H. Synaesthetic consistency spans decades in a lexical-gustatory synaesthete. Neurocase 2007, 13:358-365.
117. Simner J., Mayo N., Spiller M.J. A foundation for savantism? Visuo-spatial synaesthetes present with cognitive benefits. Cortex 2009, 45:1246-1260.
118. Simner J., Mulvenna C., Sagiv N., Tsakanikos E., Witherby S.A., Fraser C., et al. Synaesthesia: The prevalence of atypical cross-modal experiences. Perception 2006, 35:1024-1033.
119. Simner J., Ward J. Synaesthesia: The taste of words on the tip of the tongue. Nature 2006, 444:438.
120. Simner J., Ward J., Lanz M., Jansari A., Noonan K., Glover L., et al. Non-random associations of graphemes to colours in synaesthetic and non-synaesthetic populations. Cognitive Neuropsychology 2005, 22:1069-1085.
121. Simpson L., McKellar P. Types of synaesthesia. Journal of Mental Science 1955, 101:141-147.
122. Smilek D., Dixon M.J., Cudahy C., Merikle P.M. Synaesthetic photisms influence visual perception. Journal of Cognitive Neuroscience 2001, 13:930-936.
123. Smilek D., Dixon M.J., Cudahy C., Merikle P.M. Concept driven color experiences in digit-color synesthesia. Brain and Cognition 2002, 48:570-573.
124. Smilek D., Dixon M.J., Cudahy C., Merikle P.M. Synesthetic color experiences influence memory. Psychological Science 2002, 13:548-552.
125. Smilek D., Dixon M.J., Merikle P.M. Synaesthesia: Discordant male monozygotic twins. Neurocase 2005, 11:363-370.
126. Spector F., Maurer D. Synesthesia: A new approach to understanding the development of perception. Developmental Psychology 2009, 45:175-189.
127. Sperling J.M., Prvulovic D., Linden D.E., Singer W., Stirn A. Neuronal correlates of colour-graphemic synaesthesia: A fMRI study. Cortex 2006, 42:295-303.
128. Steven M.S., Blakemore C. Visual synaesthesia in the blind. Perception 2004, 33:855-868.
129. Strassman R.J. Human psychopharmacology of N,N-dimethyltryptamine. Behavioural Brain Research 1995, 73:121-124.
130. Studerus E., Gamma A., Vollenweider F.X. Psychometric evaluation of the altered states of consciousness rating scale (OAV). PLoS ONE 2010, 5:e12412.
131. Studerus E., Kometer M., Hasler F., Vollenweider F.X. Acute, subacute and long-term subjective effects of psilocybin in healthy humans: A pooled analysis of experimental studies. Journal of Psychopharmacology 2010.
132. van Leeuwen T.M., den Ouden H.E., Hagoort P. Effective connectivity determines the nature of subjective experience in grapheme-color synesthesia. Journal of Neuroscience 2011, 31:9879-9884.
133. van Leeuwen T.M., Petersson K.M., Hagoort P. Synaesthetic colour in the brain: beyond colour areas. A functional magnetic resonance imaging study of synaesthetes and matched controls. PLoS ONE 2010, 5:e12074.
134. Vike J., Jabbari B., Maitland C.G. Auditory-visual synesthesia - Report of a case with intact visual pathways. Archives of Neurology 1984, 41:680-681.
135. Vollenweider F.X. Brain mechanisms of hallucinogens and entactogens. Dialogues in Clinical Neuroscience 2001, 3:265-279.
136. Vollenweider F.X., Geyer M.A. A systems model of altered consciousness: Integrating natural and drug-induced psychoses. Brain Research Bulletin 2001, 56:495-507.
137. Vollenweider F.X., Leenders K.L., Scharfetter C., Maguire P., Stadelmann O., Angst J. Positron emission tomography and fluorodeoxyglucose studies of metabolic hyperfrontality and psychopathology in the psilocybin model of psychosis. Neuropsychopharmacology 1997, 16:357-372.
138. Ward J. Emotionally mediated synaesthesia. Cognitive Neuropsychology 2004, 21:761-772.
139. Ward J. Acquired auditory-tactile synesthesia. Annals of Neurology 2007, 62:429-430.
140. Ward J., Huckstep B., Tsakanikos E. Sound-colour synaesthesia: To what extent does it use cross-modal mechanisms common to us all?. Cortex 2006, 42:264-280.
141. Ward J., Jonas C., Dienes Z., Seth A. Grapheme-colour synaesthesia improves detection of embedded shapes, but without pre-attentive 'pop-out' of synaesthetic colour. Proceedings of the Royal Society B - Biological Sciences 2010, 277:1021-1026.
142. Ward J., Li R., Salih S., Sagiv N. Varieties of grapheme-colour synaesthesia: A new theory of phenomenological and behavioural differences. Consciousness and Cognition 2007, 16:913-931.
143. Ward J., Mattingley J.B. Synaesthesia: An overview of contemporary findings and controversies. Cortex 2006, 42:129-136.
144. Ward J., Simner J. Lexical-gustatory synaesthesia: Linguistic and conceptual factors. Cognition: International Journal of Cognitive Science 2003, 89:237-261.
145. Ward J., Simner J. Is synaesthesia an X-linked dominant trait with lethality in males?. Perception 2005, 34:611-623.
146. Weiss P.H., Fink G.R. Grapheme-colour synaesthetes show increased grey matter volumes of parietal and fusiform cortex. Brain 2009, 132:65-70.
147. Weiss P.H., Zilles K., Fink G.R. When visual perception causes feeling: Enhanced cross-modal processing in grapheme-color synesthesia. Neuroimage 2005, 28:859-868.
148. West L.J. Hallucinations 1962, Grune & Stratton Inc., New York.
149. Wittmann M., Carter O., Hasler F., Cahn B.R., Grimberg U., Spring P., et al. Effects of psilocybin on time perception and temporal control of behaviour in humans. Journal of Psychopharmacology 2007, 21:50-64.
150. Yaro C., Ward J. Searching for Shereshevskii: what is superior about the memory of synaesthetes?. The Quarterly Journal of Experimental Psychology (Hove) 2007, 60:681-695.
151. Zador J. Meskalinwirkung bei Störungen des optischen Systems. Zeitschrift für die gesamte Neurologie und Psychiatrie 1930, 127:30-107.
152. Zubek J.P. Sensory deprivation: Fifteen years of research 1969, Appleton Century Crofts, New York.