[-empyre-] questions for Lucette

[Lucette Cysique]

Thanks Anna,

Yes, for me neuroimaging refers to all forms for brain imaging, fMRI is only one
of them and only one the MRI-based imaging.

I have attached a paper from researchers I knew in San Diego that is quite good
on the methodology for fMRI and I think on page 53, there is a good graph of
different methods and what they are looking at (from a functional perspective).
Some are missing here, but electroencephalography, ERPs and MEG can be placed at
the same level or brain organisation. What is missing for example is single
measurement of neurons (measurement of extracellular and intracellular electric
potentials). There are also new methods in these areas that I do not know very
well. Another MRI method is arterial-Spin Labeling MRI which can also be used for
testing cognitive abilities like fMRI. Diffusion Tensor Imaging (DTI) is to look
at white matter integrity. The interest in white matter is relatively new, some
people before thought that only the grey was important..

Basically fMRI has a better spatial resolution than ERPs & MEG which have a
better temporal resolution (in milliseconds versus seconds), But people are
combining more and more and overcoming some of these issues. So it is evolving
fast.

Use of different neuroimaging methods depends on the questions asked.
Schematically, volumes, localization of brain functions and networks are better
investigate with MRI while temporal characteristics of brain functioning is
usually better investigated with ERPs/MEG. Brain metabolism usually is
investigated with PET, or SPECT and now also ASL-MRI. Investigation of brain
metabolites is done with Magnetic Resonance Spectroscopy and some are developing a
functional MRS at the moment for example. So like fMRI but looking at metabolites
changes.

Yes I think some of the findings of fMRI tap into the "sexy" things more than
other methods. But some other methods are older and therefore more standardised,
although fMRI people are very creative at improving things. I think some findings
like this one (http://www.abc.net.au/rn/allinthemind/stories/2008/2346593.htm)
participate to the fame of the method.

But yes there is still a lot to discover and I am always annoyed when I hear some
scientists make delirious predictions where the field is going to be in a few
years. I think because beyond the technologies some philosophical shifts have to
happen.

And Yes the images can be misleading when taken on their own. For example, I have
the impression that because of poor temporal resolution fMRI is to be interpreted
in the future as a method looking at the fine brain vasculature rather than neural
activity per se. There is a relation between neurral activity and blood flow
(deoxigenated blood is what is measure in fMRI), but the relation is partial.
Again some improvement in this domain is coming fast to better understand what we
are truly measuring when doing fMRI.

One thing that improves fMRI interpretation is volumetric and morphometry MRI for
example, we do this by doing a structucal MRI as well as fMRI. In other words, the
size of structures has a complex relation with its functions. While bigger is
often claimed to be better like healthy compared neurodenegrative diseases, this
is obviously simplistic. For example, developmental stages involves a great
reduction in brain connections and some have argued that in Autism a lack of
prunning is responsible for the symptoms of "hyper-perception".

The other big area that relates to plasticity/adaptability is what is interpreted
as compensatory mechanisms. this is really important I think and may be basis for
new learning and partially explain why we see discrepancies between size and
functions etc.. fMRI is quite good to look at this, but again is less powerful in
isolation.

Neuropsychology provides a clinical/cognitive framework that many fMRI studies
would benefit from. But this is coming more and more.

The cultural topic is getting more and more attention. This has been politically
charged for many years and is starting slowly to get away from this. Some have
used the data to promote racist agenda and still do. But careful approach reveals
complex questions about the interactions of environment and brain development
rather than clear cut differences. There has been many studies and it is growing.

I have ordered some books about referring to social neurosciences, I can tell
more in future emails.

I'd like to know more how as artists you get inspired more or less by certain
forms of imaging. How it informs you creativity in details.

Also, I think a lot has been written about what is science or what is not science
and it is a big topic of epistemology and philosophy of sciences. So I will not
participate to the emails exchange on this topic if that's ok.

Regards,
Lucette


Lucette A. Cysique, Ph.D.
Post-Doctoral fellow at Brain Science University of New South Wales, Sydney

Department of Neurology
Xavier Building, Level 4
St. Vincent's Hospital
390 Victoria Street
Darlinghurst 2010 NSW
Australia
Ph: (+61)  2 83824104
fax: (+61) 2 83824101
lcysique at unsw.edu.au
lcysique at ucsd.edu (HNRC email)


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