Tag Archives: Proceedings of the National Academy of Sciences

Two recently-published attention-grabbing open-access neuroscience journal papers

Shriki O, Sadeh Y, Ward J (2016) The Emergence of Synaesthesia in a Neuronal Network Model via Changes in Perceptual Sensitivity and Plasticity. PLoS Computational Biology. 12(7): e1004959. doi:10.1371/journal.pcbi.1004959

http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1004959

“The model unifies different causes of synaesthesia within a single theoretical framework and repositions synaesthesia not as some quirk of aberrant connectivity, but rather as a functional brain state that can emerge as a consequence of optimising sensory information processing.”

 

Anders Eklund, Thomas E. Nichols, and Hans Knutsson (2016) Cluster failure: Why fMRI inferences for spatial extent have inflated false-positive rates.
PNAS 2016 ; published ahead of print June 28, 2016, doi:10.1073/pnas.1602413113

http://www.pnas.org/content/early/2016/06/27/1602413113.full

“In theory, we should find 5% false positives (for a significance threshold of 5%), but instead we found that the most common software packages for fMRI analysis (SPM, FSL, AFNI) can result in false-positive rates of up to 70%. These results question the validity of some 40,000 fMRI studies and may have a large impact on the interpretation of neuroimaging results.”

Interesting commentary:

Oxenham, Simon Thousands of fMRI brain studies in doubt due to software flaws. New Scientist. July 18th 2016.

https://www.newscientist.com/article/2097734-thousands-of-fmri-brain-studies-in-doubt-due-to-software-flaws/

 

 

 

This astounding neuroscience rediscovery could be a central piece of the puzzle

Some bold and persistent researchers have rediscovered an unusual bundle of nerve fibres or a “major white-matter fascicle” in the human brain. Nice work! It is now called the vertical occipital fasciculus (VOF). This discovery could be an important new piece in the puzzle in researching and exploring ideas that I’m looking at in this blog, such as the relationship between the many different varieties of synaesthesia and face recognition or face memory and also reading ability. I think this discovery could be highly relevant because the rediscovered structure is a pathway of white matter that connects the occipital lobe at the rear of the brain, where visual processing happens, to other areas of the brain, and there is speculation that information carried by this pathway could play a role in face recognition and reading. I have proposed that synaesthesia might be linked to superiority in face recognition (super-recognition) and superiority in reading, citing myself and close kin as examples. I have also described and written about types of synaesthesia that involve faces or other complex memories of images as the concurrent or the inducer or both. Researchers have found that grapheme-colour synaesthesia is characterized by greater coherence in the white matter network in the brain, and that would presumably include the rediscovered VOF. I have identified the rear of the brain, the right hemisphere of the brain and the fusiform gyrus as the parts of my brain that are most likely be the locations of the events that give rise to my super-recognition and synaesthesia and related interesting goings-on, so this white matter highway at the back of the brain  is very likely involved in these processes.

I’m amazed by the story of how this brain pathway came to be forgotten or discredited by science. Apparently because it was unusual in it’s orientation its very existence conflicted with established thinking at the time, so it became non-existent in the eyes of science. I’m sure that many scientists and neuroscience enthusiasts will be surprised that dogmatic thinking in science can create an important “blind spot” in scientific knowledge, but I’m not one of those people. I’ve seen too much misbehaviour, bias and simple ignorance in neuroscience to believe that the fairy-tale accounts of science as an automatically self-correcting enterprise apply to this corner of the world of science.

http://www.iflscience.com/brain/brain-pathway-rediscovered-after-100-years

http://www.pnas.org/content/early/2014/11/13/1418503111

http://www.washington.edu/news/2014/11/17/major-brain-pathway-rediscovered-after-century-old-confusion-controversy/

Blair, Jenny Lost and Found: How a pair of scientists rediscovered a part of the human brain. Discover. October 1, 2015.

http://discovermagazine.com/2015/nov/5-lost-and-found

 

Randomly finding studies that have un-noted super-recognizers in them

Don’t assume that if face memory researchers find that they have study subjects who get scores typical of super-recognizers that they will note this fact in the paper or will interpret the data to inquire about the characteristics of super-recognizers. In random internet clicking I keep coming across studies that have super-recognizers in them, and which also appear to have no comment in them about this finding.

Joshua M. Davis, Elinor McKone, Hugh Dennett, Kirsty B. O’Connor, Richard O’Kearney and Romina Palermo Individual Differences in the Ability to Recognise Facial Identity Are Associated with Social Anxiety. PLOS One. Published: December 14, 2011. DOI: 10.1371/journal.pone.0028800. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0028800

There are two subjects in this study who got scores in the super-recognizer range (71-72 in the short form of the Cambridge Face Memory Test) and three who were pretty darned close with scores of 70, and there were also eleven subjects who scored in the prosopagnosia range of 42 or less in the CFMT short form.

The study measured social anxiety and other things, so what were the findings in relation to the supers and social anxiety? From what I’ve read the cut-off point for social phobia is 36 or more on the SIAS, and none of the supers were anywhere near that, but that is also true for the majority of the subjects who got face memory scores in the prosopagnosia range. Plenty of study subjects got SIAS scores in the social phobia range, but only one of them also had a CFMT score in the prosopagnosia range. Social phobia clearly isn’t explained by issues in face recognition. The study did find a weak correlation between poorer face memory and social anxiety, but I’m surprised that a stronger positive relationship was not found because I think face memory must be pretty important in social functioning. I offer the Dunning-Kruger Effect as an explanation for the weakness of the correlation found. People who don’t know often don’t know what they don’t know and maybe even don’t know that they don’t know. Ignorance is bliss, so they say, and I see evidence of it all around me every day.

In my opinion, the alternative explanation offered to explain the slight correlation between social anxiety and poorer face recognition, that social anxiety could cause the development of poorer face recognition ability, seems unlikely. Kids who are scared of other kids would surely want to keep tabs on who is who, because such kids are likely to be bully-magnets, and certainly not all kids are bullies. I would think in such a situation, a child would have great personal interest in telling the difference between bullies, allies and the general mob, and face memory would seem to be the best tool for this task. That’s just a theory, and often sensible-sounding theories are totally counter to reality, so more research is definitely desirable on this question.

Here’s another study that has super-recognizers in it, but which doesn’t specifically mention or discuss super-recognizers or superrecognition:

http://www.pnas.org/content/107/11/5238.full

[this article to be completed later]