Disruption of synaesthesia following TMS of the right posterior parietal cortex

Muggleton, Neil G.; Tsakanikos, Elias; Walsh, Vincent; Ward, Jamie

doi:10.1016/j.neuropsychologia.2006.11.021

Cited by 87 publications

(77 citation statements)

References 16 publications

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“…Thus, 5 out of 6 neuroanatomical studies on developmental grapheme-color synesthesia report parietal results. Given this state of affairs and TMS evidence (Esterman et al 2007;Muggleton et al 2007;Rothen et al 2010), parietal results are consistent enough to define this region (IPS) as a crucial area in grapheme-color synesthesia.…”

Section: The Canonical Regions Of Interestmentioning

confidence: 72%

“…The other focus of interest for anatomical investigation has been the intraparietal sulcus (IPS), which is believed to mediate the hyperbinding of the inducer (e.g., a grapheme) and the concurrent (e.g., one specific color). The left IPS has shown differential activation in grapheme-color functional studies (van Leeuwen et al 2011;Weiss et al 2005), whereas stimulation of the right IPS with transcranial magnetic stimulation (TMS) resulted in the disruption of the Synesthetic Stroop Effect (Esterman et al 2007;Muggleton et al 2007;Rothen et al 2010). Regarding neuroanatomical data, only 2 out of 4 studies of gray matter (GM) reported variations in the FG (Jancke et al 2009;Weiss and Fink 2009) and/ or the IPS (Rouw and Scholte 2010;Weiss and Fink 2009) (for a summary of published data on the neuroanatomy of developmental grapheme-color synesthesia, see Supplementary Material -Introduction: Table 1).…”

Section: Introductionmentioning

confidence: 99%

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Grapheme-color synesthetes show peculiarities in their emotional brain: cortical and subcortical evidence from VBM analysis of 3D-T1 and DTI data

et al. 2013

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Grapheme-color synesthesia is a neurological phenomenon in which viewing achromatic letters/numbers leads to automatic and involuntary color experiences. In this study, voxel-based morphometry analyses were performed on Tl images and fractional anisotropy measures to examine the whole brain in associator grapheme-color synesthetes. These analyses provide new evidence of variations in emotional areas (both at the cortical and subcortical levels), findings that help understand the emotional component as a relevant aspect of the synesthetic experience. Additionally, this study replicates previous findings in the left intraparietal sulcus and, for the first time, reports the existence of anatomical differences in subcortical gray nuclei of developmental grapheme-color synesthetes, providing a link between acquired and developmental synesthesia. This empirical evidence, which goes beyond modality-specific areas, could lead to a better understanding of grapheme-color synesthesia as well as of other modalities of the phenomenon.

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Section: The Canonical Regions Of Interestmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Grapheme-color synesthetes show peculiarities in their emotional brain: cortical and subcortical evidence from VBM analysis of 3D-T1 and DTI data

et al. 2013

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“…Previous studies have reported increased BOLD-MRI activation in parietal cortex during synesthesia (Paulesu et al, 1995;Nunn et al, 2002;Steven et al, 2006). Furthermore, interference related to synesthetic experience has been found to diminish after applying transcranial magnetic stimulation (TMS) to the superior parietal cortex (Esterman et al, 2006;Muggleton et al, 2007). The role of the parietal lobe in synesthesia has been related to its function in cross-sensory integration or "binding," multimodal associations, and multimodal integratory attention (e.g., Muggleton et al, 2007;Robertson, 2003).…”

Section: Shared Mechanisms: Grapheme-color Synesthetes Compared With mentioning

confidence: 99%

“…Moreover, projector synesthetes were contrasted with associator synesthetes. We hypothesized that both shared mechanisms [parietal processes crucial to generating the synesthetic experience (Esterman et al, 2006;Muggleton et al, 2007)] and distinct mechanisms underlie these two subtypes of grapheme-color synesthesia. On the one hand, synesthesia has been found related to modality-specific brain areas (Nunn et al, 2002;Hubbard et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Neural Basis of Individual Differences in Synesthetic Experiences

Rouw¹,

Scholte²

2010

J. Neurosci.

129

146

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Little is known about how the properties of our private mental world relate to the physical and functional properties of our brain. Studying synesthesia, where a particular experience evokes a separate additional sensory experience, offers the unique opportunity to study phenomenological experiences as a stable trait in healthy subjects. A common form of synesthesia is grapheme-color synesthesia, where a particular letter or number evokes a particular color experience. We studied the neural basis of qualitative different properties of the synesthetic experience by using individual differences in grapheme-color synesthesia. Specifically, the synesthetic color can be experienced "in the mind" (associator synesthetes) or "in the outside world" (projector synesthetes). Gray matter structure and functioning (imaged using voxel-based morphometry and functional magnetic resonance imaging, respectively) were examined in grapheme-color synesthetes (N ϭ 42, 16 projectors and 26 associators) and nonsynesthetes. Results indicated partly shared mechanisms for all grapheme-color synesthetes, particularly in posterior superior parietal lobe, which is involved in the integration of sensory information. In addition, the nature of synesthetic experience was found to be mediated by distinct neural mechanisms. The outside-world experience is related to brain areas involved in perceiving and acting in the outside world (visual cortex, auditory cortex, motor cortex) as well as frontal brain areas. In contrast, the in-the-mind experience is related to the hippocampus and parahippocampal gyrus, known for their role in memory. Thus, the different subjective experiences are related to distinct neural mechanisms. Moreover, the properties of subjective experiences are in accordance with functional properties of the mediating brain mechanisms.

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“…The most important of these are anterior lingual gyrus regions [9,44] involved in color naming and categorization, and intraparietal sulcus regions [9,10,45] involved in attention, binding and multisensory processes. Especially given the converging evidence from TMS studies [36,46] the role of parietal cortex in the genesis of synesthesia needs to be taken quite seriously.…”

Section: Summary and Implicationsmentioning

confidence: 99%

Neurophysiology of synesthesia

Hubbard

2007

Curr Psychiatry Rep

105

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[150 words]Synesthesia is an experience in which stimulation in one sensory or cognitive stream leads to associated experiences in a second, unstimulated stream. Although synesthesia is often referred to as a "neurological condition", is not listed in the DSM-IV or the ICD classifications, since it generally does not interfere with normal daily functioning. However, its high prevelance rate (1 in 23) means that synesthesia may be reported by patients who present with other psychiatric symptoms. In this review, I focus on recent research examining the neural basis of the two most intensively studied forms of synesthesia, grapheme → color synesthesia and tone → color synesthesia. These data suggest that these forms of synesthesia are elicited through anomalous activation of color selective areas, perhaps in concert with hyper-binding mediated by the parietal cortex. I then turn to questions for future research, and the implications of these models for other forms of synesthesia.

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Disruption of synaesthesia following TMS of the right posterior parietal cortex

Cited by 87 publications

References 16 publications

Grapheme-color synesthetes show peculiarities in their emotional brain: cortical and subcortical evidence from VBM analysis of 3D-T1 and DTI data

Grapheme-color synesthetes show peculiarities in their emotional brain: cortical and subcortical evidence from VBM analysis of 3D-T1 and DTI data

Neural Basis of Individual Differences in Synesthetic Experiences

Neurophysiology of synesthesia

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