Intrinsic Network Connectivity Reflects Consistency of Synesthetic Experiences

Dovern, Anna; Fink, Gereon R.; Ac, Fromme; Am, Wohlschläger; Weiss, Peter H.; Riedl, Valentin

doi:10.1523/jneurosci.5401-11.2012

Cited by 63 publications

(67 citation statements)

References 45 publications

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“…We first identified ROIs according to a standard set of networks that Yeo et al (30) recently established in a 1,000-subject dataset. We followed our previous processing pipeline for ICA of fMRI data (54). We applied slice-time correction, realignment, normalization to a standard template, and spatial smoothing using a Gaussian kernel with an FWHM of 6 mm.…”

Section: Methodsmentioning

confidence: 99%

Metabolic connectivity mapping reveals effective connectivity in the resting human brain

Riedl

Utz

Castrillón

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

106

105

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Directionality of signaling among brain regions provides essential information about human cognition and disease states. Assessing such effective connectivity (EC) across brain states using functional magnetic resonance imaging (fMRI) alone has proven difficult, however. We propose a novel measure of EC, termed metabolic connectivity mapping (MCM), that integrates undirected functional connectivity (FC) with local energy metabolism from fMRI and positron emission tomography (PET) data acquired simultaneously. This method is based on the concept that most energy required for neuronal communication is consumed postsynaptically, i.e., at the target neurons. We investigated MCM and possible changes in EC within the physiological range using “eyes open” versus “eyes closed” conditions in healthy subjects. Independent of condition, MCM reliably detected stable and bidirectional communication between early and higher visual regions. Moreover, we found stable top-down signaling from a frontoparietal network including frontal eye fields. In contrast, we found additional top-down signaling from all major clusters of the salience network to early visual cortex only in the eyes open condition. MCM revealed consistent bidirectional and unidirectional signaling across the entire cortex, along with prominent changes in network interactions across two simple brain states. We propose MCM as a novel approach for inferring EC from neuronal energy metabolism that is ideally suited to study signaling hierarchies in the brain and their defects in brain disorders.

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Section: Methodsmentioning

confidence: 99%

Metabolic connectivity mapping reveals effective connectivity in the resting human brain

Riedl

Utz

Castrillón

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

106

105

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“…However, it has yet to be determined whether synesthesia-like experiences in drug-induced altered states of consciousness are qualitatively and mechanistically related to synesthesia experienced outside of this context and it is also worth noting that increased visual to heteromodal cortical functional connectivity has been found in color-grapheme synesthesia (Dovern et al, 2012; Sinke et al, 2012) as well as in the present study.…”

Section: Discussionmentioning

confidence: 61%

The effects of psilocybin and MDMA on between-network resting state functional connectivity in healthy volunteers

Roseman

Leech

Feilding

et al. 2014

Front. Hum. Neurosci.

206

159

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Perturbing a system and observing the consequences is a classic scientific strategy for understanding a phenomenon. Psychedelic drugs perturb consciousness in a marked and novel way and thus are powerful tools for studying its mechanisms. In the present analysis, we measured changes in resting-state functional connectivity (RSFC) between a standard template of different independent components analysis (ICA)-derived resting state networks (RSNs) under the influence of two different psychoactive drugs, the stimulant/psychedelic hybrid, MDMA, and the classic psychedelic, psilocybin. Both were given in placebo-controlled designs and produced marked subjective effects, although reports of more profound changes in consciousness were given after psilocybin. Between-network RSFC was generally increased under psilocybin, implying that networks become less differentiated from each other in the psychedelic state. Decreased RSFC between visual and sensorimotor RSNs was also observed. MDMA had a notably less marked effect on between-network RSFC, implying that the extensive changes observed under psilocybin may be exclusive to classic psychedelic drugs and related to their especially profound effects on consciousness. The novel analytical approach applied here may be applied to other altered states of consciousness to improve our characterization of different conscious states and ultimately advance our understanding of the brain mechanisms underlying them.

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“…Consider first that synaesthetes show explicit enhanced ‘cross-talk’ between otherwise unrelated modalities (e.g., between sound and vision in audio-visual synaesthesia) and that this has been tied to structural and functional differences in the brains of synaesthetes (e.g., Hänggi, Wotrubua, & Jäncke, 2011; Dovern et al, 2012; Rouw & Scholte, 2007; Weiss & Fink 2009; Hubbard, Arman, Ramachandran, & Boynton, 2005). Importantly, synaesthetic experiences are often reflective of non-synaesthetes’ intuitions (see Simner, 2013 for review).…”

Section: Discussionmentioning

confidence: 99%

What is the link between synaesthesia and sound symbolism?

Bankieris

Simner

2015

Cognition

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Sound symbolism is a property of certain words which have a direct link between their phonological form and their semantic meaning. In certain instances, sound symbolism can allow non-native speakers to understand the meanings of etymologically unfamiliar foreign words, although the mechanisms driving this are not well understood. We examined whether sound symbolism might be mediated by the same types of cross-modal processes that typify synaesthetic experiences. Synaesthesia is an inherited condition in which sensory or cognitive stimuli (e.g., sounds, words) cause additional, unusual cross-modal percepts (e.g., sounds trigger colours, words trigger tastes). Synaesthesia may be an exaggeration of normal cross-modal processing, and if so, there may be a link between synaesthesia and the type of cross-modality inherent in sound symbolism. To test this we predicted that synaesthetes would have superior understanding of unfamiliar (sound symbolic) foreign words. In our study, 19 grapheme-colour synaesthetes and 57 non-synaesthete controls were presented with 400 adjectives from 10 unfamiliar languages and were asked to guess the meaning of each word in a two-alternative forced-choice task. Both groups showed superior understanding compared to chance levels, but synaesthetes significantly outperformed controls. This heightened ability suggests that sound symbolism may rely on the types of cross-modal integration that drive synaesthetes’ unusual experiences. It also suggests that synaesthesia endows or co-occurs with heightened multi-modal skills, and that this can arise in domains unrelated to the specific form of synaesthesia.

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Intrinsic Network Connectivity Reflects Consistency of Synesthetic Experiences

Cited by 63 publications

References 45 publications

Metabolic connectivity mapping reveals effective connectivity in the resting human brain

Metabolic connectivity mapping reveals effective connectivity in the resting human brain

The effects of psilocybin and MDMA on between-network resting state functional connectivity in healthy volunteers

What is the link between synaesthesia and sound symbolism?

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