Exceptional Abilities in the Spatial Representation of Numbers and Time

Kadosh, Roi Cohen; Gertner, Limor; Terhune, Devin Blair

doi:10.1177/1073858411402835

Cited by 19 publications

(10 citation statements)

References 72 publications

(158 reference statements)

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“…One striking example is Klüver (1966) report of a complex visual-tactile-conceptual-visual-gustatory-olfactory synaesthesia following the ingestion of mescaline. Similarly, we do not observe any reports of particular well-documented types of synaesthesia such as spatial-sequence synaesthesia (Cohen Kadosh et al, 2012). On the other hand, there are examples of types of induced synaesthesia that are well-documented in the literature including grapheme-color (Brang and Ramachandran, 2008; Luke et al, 2012) and auditory-color synaesthesias (e.g., Hartman and Hollister, 1963).…”

Section: Discussionsupporting

confidence: 47%

The induction of synaesthesia with chemical agents: a systematic review

Luke

Terhune

2013

Front. Psychol.

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Despite the general consensus that synaesthesia emerges at an early developmental stage and is only rarely acquired during adulthood, the transient induction of synaesthesia with chemical agents has been frequently reported in research on different psychoactive substances. Nevertheless, these effects remain poorly understood and have not been systematically incorporated. Here we review the known published studies in which chemical agents were observed to elicit synaesthesia. Across studies there is consistent evidence that serotonin agonists elicit transient experiences of synaesthesia. Despite convergent results across studies, studies investigating the induction of synaesthesia with chemical agents have numerous methodological limitations and little experimental research has been conducted. Cumulatively, these studies implicate the serotonergic system in synaesthesia and have implications for the neurochemical mechanisms underlying this phenomenon but methodological limitations in this research area preclude making firm conclusions regarding whether chemical agents can induce genuine synaesthesia.

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Section: Discussionsupporting

confidence: 47%

The induction of synaesthesia with chemical agents: a systematic review

Luke

Terhune

2013

Front. Psychol.

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“…Whether the current results suggest superior visual perception among projectors in particular merits attention. Color synesthetes display superior color processing, but impaired motion processing ( Banissy et al 2013 ), supporting the view that the benefits conferred by synesthesia have neurological costs ( Cohen Kadosh et al 2012 ). Coupled with the current results, this leads to the prediction that color synesthetes will display elevated (or normal) thresholds for moving phosphenes during MT/V5 stimulation (e.g., Pascual-Leone and Walsh 2001 ).…”

Section: Discussionmentioning

confidence: 72%

Phosphene Perception Relates to Visual Cortex Glutamate Levels and Covaries with Atypical Visuospatial Awareness

Terhune¹,

Murray²,

Near³

et al. 2015

Cereb. Cortex

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Phosphenes are illusory visual percepts produced by the application of transcranial magnetic stimulation to occipital cortex. Phosphene thresholds, the minimum stimulation intensity required to reliably produce phosphenes, are widely used as an index of cortical excitability. However, the neural basis of phosphene thresholds and their relationship to individual differences in visual cognition are poorly understood. Here, we investigated the neurochemical basis of phosphene perception by measuring basal GABA and glutamate levels in primary visual cortex using magnetic resonance spectroscopy. We further examined whether phosphene thresholds would relate to the visuospatial phenomenology of grapheme-color synesthesia, a condition characterized by atypical binding and involuntary color photisms. Phosphene thresholds negatively correlated with glutamate concentrations in visual cortex, with lower thresholds associated with elevated glutamate. This relationship was robust, present in both controls and synesthetes, and exhibited neurochemical, topographic, and threshold specificity. Projector synesthetes, who experience color photisms as spatially colocalized with inducing graphemes, displayed lower phosphene thresholds than associator synesthetes, who experience photisms as internal images, with both exhibiting lower thresholds than controls. These results suggest that phosphene perception is driven by interindividual variation in glutamatergic activity in primary visual cortex and relates to cortical processes underlying individual differences in visuospatial awareness.

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“…A corollary of this account is that synesthetes will display enhanced modality- or dimension-specific working memory pertaining to the modality of their concurrent (see also Simner, Mayo, & Spiller, 2009). For example, we would expect that mirror-touch synesthetes will display superior working memory for tactile information, but not for color information (see also Banissy et al, 2009), or that spatial-sequence synesthetes (Cohen Kadosh, Gertner, & Terhune, 2012) will display superior spatial working memory.…”

Section: Discussionmentioning

confidence: 99%