Tag Archives: Local hyperconnectivity

All those years of neuroimaging research on the brains of synaesthetes has found nothing of substance?

Hupé J and Dojat M (2015) A critical review of the neuroimaging literature on synesthesia. Frontiers in Human Neuroscience. 9:103.
doi:10.3389/fnhum.2015.00103

http://journal.frontiersin.org/article/10.3389/fnhum.2015.00103/abstract

“Our critical review therefore casts some doubts on whether any neural correlate of the synesthetic experience has been established yet”

That is a bit of a shock to read. This isn’t the first time that I’ve gotten a big shock after reading a paper in the journal Frontiers in Human Neuroscience. There was that little matter of some of my most amazing neuroscientific ideas published at this blog being ripped-off and used as the guts of an “opinion article” in that journal in 2013. I haven’t forgotten that episode. Who would have thought so much excitement is there to be found inside a science journal? I should make it clear that the researchers who did that thing in 2013 are NOT the authors of the above paper, but at the same time, I’ve got to wonder where Hupé and Dojat got this idea from

“…synesthesia could be reconsidered as a special kind of childhood memory, …”

Sure, they could have thought of that under their own steam, but I still want to point out that the central, seminal idea of this blog, right from the very first post in 2010, has been the idea that synaesthesia is linked in some meaningful way with face memory, in my case with super-recognizer ability in face memory, and there are many articles in this blog that show and hint that the heart of synaesthesia is memories created in childhood and many different types of synaesthesia operate in ways that are so much like memory that the differences are only quantitative. There was even one article published in 2013 at this blog in which I stated that

“…the Proust phenomenon is considered to be a type of memory and many of my observations at this blog have demonstrated that synaesthesia can involve memory, is an element of the “method of loci” memory technique and I would argue operates like memory. Yes, Yes, Yes, the Proust Phenomenon is a close relative of synaesthesia.”

Some ideas that I’d like to (explicitly) lay claim to (right now) in 2014

A very interesting idea from Dr Simner but I’ve got my doubts

This is a quote from Dr Julia Simner’s thought-provoking paper in the British Journal of Psychology about defining synaesthesia:

“To avoid this circular evidence of what synaesthesia is and is not, we might instead define synaesthesia in terms of it neurological basis, and then allow ourselves to consider what types of variants this synaesthesia might then include. If indeed the condition were defined by inherited atypical cross-talk, we might find synaesthesiae in unexpected places. For example, if an inherited predisposition for neurological hyper-association manifested itself, say, in the fronto-temporal language regions that mediate semantics, lexical-forms, and syntax (e.g., see Tyler & Marslen-Wilson, 2008, for review) what would this mean? It might mean we could find ‘synaesthetic’ individuals with unusually strengthened connections in spoken language processing.”

I happened across this picture that is apparently from The Human Connectome Project, or at least from a paper by Liza Gross that was published in PLoS Biology in 2008: http://www.abc.net.au/radionational/programs/allinthemind/the-human-connectome/3706910  I’m guessing that the coloured larger blobs represent the most connected hubs in the brain, and I’m guessing these bits would be made of white matter? I know that there is one type of synaesthesia that is associated with some kind of functional enhancement of white matter, and in general, synaesthesia is thought to be due to hyperconnectivity in the brain, which I guess might mean that it operates the most in regions of the brain that are the most connected? Well, looking at the picture with the red and pink blobs, it seems as though the parts of the brain that are the most connected are towards the rear of the brain, maybe the parietal, occipital and part of the temporal lobes, with most of the frontal lobe and Broca’s area (important in language processing)  left pretty much out of the loop. So I’ve got to wonder how realistic is Dr Simner’s theoretical idea of a type of person who is especially articulate due to a hidden type of synaesthesia based in the “fronto-temporal language regions”. I certainly do think it is probable that there are non-obvious and undiscovered types of synaesthesia linking brain functions that researchers haven’t already known to be hyperconnected, but I suspect that researchers will also find that synaesthesia is more likely in some regions of the brain than others. I’ve long ago noticed that most types of synaesthesia that are known to science (and to me) involve the sense of sight in one way or another (scenes, colours, shapes, faces, visual-spatial landscapes etc), and where is vision processed in the brain? At the rear, where so many of those red blobs are found.

Simner, J. (2012), Defining synaesthesia. British Journal of Psychology, 103: 1–15. doi: 10.1348/000712610X528305  Article first published online: 11 MAR 2011 DOI: 10.1348/000712610X528305 http://onlinelibrary.wiley.com/doi/10.1348/000712610X528305/full

Gross L (2008) From Structure to Function: Mapping the Connection Matrix of the Human Brain. PLoS Biol 6(7): e164. doi:10.1371/journal.pbio.0060164  http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0060164

Human Connectome Project  http://www.humanconnectomeproject.org/

Dr Kevin Mitchell has a blog

I’ve just discovered that Dr Kevin Mitchell from Trinity College in Dublin has a blog and also a lab website. If you asked me to cite the synaesthesia researchers whose work most interests me, for sure Dr Mitchell and also Dr Julia Simner from the University of Edinburgh would be on that list. If you’ve found stuff that I’ve written here about synaesthesia interesting, I think there’s a fair chance that you’d also find Dr Mitchell’s blog of interest.

Wiring the Brain

http://wiringthebrain.blogspot.com/

Developmental Neurogenetics – Dr Kevin Mitchell

http://www.gen.tcd.ie/mitchell/

 

Local brain hyperconnectivity, synaesthesia, autism, music, the temporal lobes and perfect pitch: some interesting reading

Douglas, Ed Perfect pitch. New Scientist Issue 2801 Feb 26th 2011 p. 46-49.

Online title of the article: Finely tuned minds: the secret of perfect pitch. http://www.newscientist.com/issue/2801

This is a most interesting science magazine article about perfect pitch, otherwise known as absolute pitch, the “ability to name or sing any note on demand”, written by someone who himself has perfect pitch. Ed Douglas reports on the findings of studies that have been published in six different science journals, and research scientists mentioned include Daniel Levitin, Sarah Wilson, Elizabeth Theusch, Analabha Basu, Jane Gitschier, Maria Teresa Moreno Sala, Eugenia Costa-Giomi, Patrick Bermudez, Psyche Loui, Diana Deutsch, Luca Tommasi and researchers at the RIKEN Brain Science Institute in Japan.

Douglas explicitly speculates that there could be an association between synaesthesia, autism, and perfect pitch ability, caused by an “excess of wiring in the brain” or hyperconnection. Douglas cites as evidence the study by Psyche Loui and colleagues listed above, and another New Scientist article that reported the interesting “intense world” theory of autism in 2008.

In this article the names of four famous musicians who either had perfect pitch or possibly had it, Beethoven, Ella Fitzgerald, Mozart and Jimi Hendrix are mentioned. The author Ed Douglas does not mention that two of these musicians also experienced coloured music synaesthesia (drug use could have been the cause of Hendrix’s colours). We do not know if Mozart had synaesthesia (my intuition tells me he did), but there has been much speculation over the years that Mozart might have had a range of different neurological peculiarities or disorders. Douglas mentions that Hendrix and Mozart both had an extraordinary savant-like memory for music. Hendrix, Mozart and possibly also Beethoven were left-handed.

Enhanced Cortical Connectivity in Absolute Pitch Musicians: A Model for Local Hyperconnectivity. Psyche Loui, H. Charles Li, Anja Hohmann and Gottfried Schlaug Journal of Cognitive Neuroscience. April 2011, Vol. 23, No. 4, Pages 1015-1026.
(doi: 10.1162/jocn.2010.21500) http://www.mitpressjournals.org/doi/abs/10.1162/jocn.2010.21500

This is one of the studies discussed in the above New Scientist article. Don’t ask me how a journal paper dated “April 2011” can be cited in a science magazine dated “Feb 26th 2011”. The world of science journals is a futuristic world.

Twelve musicians with absolute pitch (AP)/perfect pitch and a matched control group of twelve musicians without perfect pitch were studied. Volume and fibre numbers in some tracts in the left and right hemispheres of the brain were found to be significantly higher in the study subjects who had perfect pitch, but hyperconnectivity was not found all over the place; “Heightened connectivity among AP musicians appears to affect local structures specific to the temporal lobe.” Figure 4 in this paper strikingly shows the difference between the tracts of three groups of study subjects. This paper shows that people with perfect pitch appear to have greater connectivity in the white matter of parts of the temporal lobes that associate and perceive pitch. It looks to me as though greater connectivity in the left hemisphere might be more important regarding perfect pitch. I am not pretending to be a qualified scientist in interpreting this paper.

I believe that greater connectivity in the white matter has been found in grapheme-> colour synaesthetes, in other parts of the brain, so I would not be surprised if music-related synaesthesia might be particularly common in musicians who have perfect pitch. It is no surprise that this paper mentions synaesthesia and has two studies of a synaesthete musician with perfect pitch among its references (see below). Unfortunately synaesthesia is discussed with some negative language in this April 2011 paper; “these disorders” and “abnormal white matter connectivity”. In the discussion of this paper the case is argued that perfect pitch has hyperconnectivity in common with conditions such as synaesthesia, autism and heightened creativity, and the authors identify “increased local connectivity in temporal regions” as a feature that perfect pitch, synesthesia and autism share.

Hänggi Jürgen; Beeli Gian; Oechslin Mathias S; Jäncke Lutz The multiple synaesthete E.S.: neuroanatomical basis of interval-taste and tone-colour synaesthesia. NeuroImage. 2008;43(2):192-203. http://www.ncbi.nlm.nih.gov/pubmed/18692578

This is a journal paper that was mentioned in the 2011 journal paper above. A brain scan study was done comparing E. S., who has perfect pitch and some musical tone-related types of synaesthesia, with other professional musicians and with normal controls. Bilateral areas of hyperconnectivity in the temporal lobes of E. S. were found.

Synaesthesia: when coloured sounds taste sweet. Beeli G, Esslen M, Jäncke L. Nature. 434, 38 (3 March 2005) doi:10.1038/434038a Published online 2 March 2005. http://www.nature.com/nature/journal/v434/n7029/abs/434038a.html

http://www.ncbi.nlm.nih.gov/pubmed/15744291

Another journal article that was mentioned in the 2011 journal paper. Female synaesthete musician E.S. is compared with five non-synaesthete musicians. E.S. experiences flavoured musical tone intervals, which she uses to identify these intervals. It appears that this paper is about the same musician synaesthete with perfect pitch as the one described in the 2008 NeuroImage paper above.

I’m satisfied that there is a real association between synaesthesia and perfect pitch, based on what I have read in the above article and papers, and also based on the fact that perfect pitch seems to be unusually common among musicians who have or had synaesthesia. I believe this association between synaesthesia and perfect pitch is a direct effect of the physical localised hyperconnection within the synesthete brain that gives rise to the synaesthesia and also the increased perception ability, even though I do acknowledge that a type of synaesthesia that gives musical sounds individual colours or flavours could obviously aid in the identification of individual sounds. The question remains though – by what mechanism are the individual sounds identified then each given an identifying taste or colour? Surely a conscious or an unconscious identification of the sounds must precede the allocation of colours to the musical notes.

There is plenty of scientific evidence that various types of synaesthesia give rise to various types of superiority in perception, and it appears that perfect pitch is another example. I do not know if I have any capacity for perfect pitch as I had only the most rudimentary musical education (the same true of my synaesthete close relatives). I’m happy to conclude that simply being synaesthetes makes us especially “at risk” for possessing special powers of perception, including perfect pitch, being a super-recognizer or a superior reader, but it is also clear that specific types of special abilities and specific types of synaesthesia are associated with higher connectivity in specific parts of the brain. So far, my inquiries appear to suggest that the hyperconnectivity in the brains of my kin and I could be limited to the right hemisphere, while perfect pitch might well have as its physical basis higher connectivity in the left, so I guess we could dip out on perfect pitch. If there exists any cost-free test of the capacity for perfect pitch that can be taken by people who do not have musical training, I would love to have a crack at it.

I don’t know about perfect pitch, but I wouldn’t be surprised if there is something a bit atypical about the way our brains process sounds. The enjoyment of music is very important to a number of people in our family, which I’m sure has something to do with the temporal lobes. A lot of the music that we enjoy is sung in non-English languages, languages from all corners of the world. I’m not sure how unusual our taste in music is, but there does seem to be a hunger in our family for listening to exotic phonemes. None of us are language savants like the famous British synaesthete Daniel Tammet, but there is a consistent line of descent in our family of bilingual or multi-lingual people. I also seem to have a thing about unusual voices. I choose to have people in my life who have unusual voices and I love to listen to distinctive singing voices of a range of types. For me, singing voices are easily categorized as interesting or not interesting, and I much prefer the former. The gravel-voiced rap singers Everlast and Tone Loc have interesting voices, and so do all counter-tenors. I recently read an interesting observation about the extraordinary sound of the counter-tenor voice in a newspaper interview article about German counter-tenor Andreas Scholl. “I think these days the audience knows what a countertenor is, but it’s that inability to readily categorise the voice that makes for better communication – you listen with fresh ears, and focus more on the words.” I believe this is an important element of my enjoyment of the voices of countertenors and other singers with interesting voices. The strangeness of the sound draws attention closely, finely, and it also destroys any set of simple musical expectations. I find strange sounds compelling and interesting, and I’m not sure why I find this so very enjoyable, but I do know from experience that when people enjoy doing anything involving thought, they are most likely utilizing some particular area of cognitive strength.

Beth Gibbons from Portishead and Kate Bush are some female singers who have interesting voices. For me, many interesting voices have a colour. Today a rellie and I were having an argument at a supermarket about the colour of the music that we were listening to, as Wuthering Heights by Kate Bush, one of the strangest bits of music to ever hit the top of the charts, was playing on the PA system among the aisles of groceries. Don’t worry about us. We are just a little bit different.