Individual variability of higher brain functions

trai at tanuki.twics.co.jp trai at tanuki.twics.co.jp
Thu Nov 4 05:55:53 EST 1993


In <2961288583.0.p00907 at psilink.com>
"Richard E. Cytowic MD" <p00907 at psilink.com> writes:

>	There is rather a lot of inter-subject variability not only in 
>gross brain anatomy, but in functional mapping (electrical). On the 
>face of it, you propose to measure what cannot be measured.
.....

    Thank you for your suggestion.  I expected a response like yours.
I searched for the papers you mentioned, but they were so old that
our library(it's a large library, though..) didn't have.  But I found
another article by Ojemann "Cortical language localization in left, dominant
hemisphere", 1989, Journal of Neurosurgery 71:316-326, which notes 
the variability of language localization determined by intraoperative
stimulation.   According to that article, their distributions were mosaic-
patterned, varied regardless of gyration.

    But actually, intersubject averaging is so widely accepted in PET 
activation studies, that without it, no new activated foci can be
detected.   As a matter of course, as you imagine, resolution is not
good(as large as 8-10mm).  What I actually am about to do is non-linear 
transformation.   It means that transforming the brain PET image 
non-linearlly(or distorting) before averaging so that each corresponding
point is overlapped more precisely.  Currently, only linear 
transformation is done.   We expect by non-linear transformation, the 
ability of detection (or signal/noise ratio) is increased compared with
linear transformation, and want the theoretical background.

------
Tetsuji Rai MD      trai at twics.co.jp, 74610.1537 at compuserve.com
Department of Radiology, Hospital attached to University of Tokyo

Home: 5-12-21-301, Toyotamakita, Nerimaku, Tokyo 176, Japan
Tel: +81-3-3557-3936
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