Dear Yehouda Harpaz,
I am afraid that this is no use to me. If you want to send a
presubmission enquiry, that's fine, but I am not going to waste time
looking up information on web sites and such like. If you want us to
consider this properly you are, as I indicated yesterday, going to
have to have to send a fully referenced abstract of the paper with a
letter explaining (somewhat less breathlessly than below) exactly what
it is you think it is you have discovered. I should say, however, that
we use exactly the same kinds of reviewers as Current Biology, and on
the basis of the limited information you have given me already I think
it unlikely that we would interested in considering your paper for
publication.
Sincerely,
Dr Rory Howlett, Nature
______________________________ Reply Separator _________________________________
Subject: Submission to nature about Howard et al.
Author: Yehouda Harpaz <yeh_harlequin.co.uk> at Internet
Date: 21/01/97 13:08
Dear Rory Howlett,
I talked with you on the phone on monday, about submission to nature. The full
text of what I want to submit attached below, but you need a background.
Non-invasive brain imaging (PET and fMRI) are supposed to give us new insights
into the brain. However, while in some cases it gives useful results, in many
cases the results are not useful: they are irreproducible, and cannot be
interpreted within current theories. In these cases, there is a string
tendency to overinterpret the results. Moreover, the researchers in the field
by now accept these overinterpretations, and suppress discussions of their
validity.
The original article by Howard et al ian example of overinterpretation. My
comment highlights some of the important assumptions that they made, and explain
why making these assumption is not reasonable. Added to the fact that the data
is irreproducible, as the authors themselves admit, and the conclusions that
they present become vary unlikely. I submitted this to Current Biology.
The deputy editor sent it to a review. The 'reviewer' recommended not to
publish, based on a review of my text. However, reading his 'review' made
it is clear that he did not read most of my text. The deputy editor did not
accept
this, but I contacted the editor and he agreed. he sent it to another
reviewer. The second reviewer, which was aware of the events up to this point,
wrote a much longer 'review', in which he made false statements, misquote my
text, and other demagogical tricks, and recommend not to publish. Based on
this review, the editor decided not to publish. When I tried to argue he said
he is not an expert, and must accept the opinion of the reviewer.
I contacted some of the editorial board of Current Biology, and the only
answer that I got was that I must accept the editor judgement, and suggested
that I try another journal.
Both the reviews and my comments about them are available at
http://human-brain.org/zeki-index.html
The problem is that the 'reviews' that I got are representative of the opinion
of the researchers in the field, which reject any discussion of these
assumption, which makes their results much less striking. Thus if my text goes
to a reviewer from the field, it is likely to be rejected using nonsense
arguments like the reviews that I got in Current Biology. Thus the editorial
person that deal with it must be aware of this, and be prepared to check if the
review he gets back is actually a sensible one. Without this, it
is a waste of time.
I appreciate that this make it hard work, but the questions I raise are
important, and must be discussed. openly
Yehouda Harpaz
Harlequin Ltd.
Barrington Hall,
Barrington
Cambridge CB2 5RG
UK
yeh_harlequin.co.uk
http://human-brain.org/
--------------------------------------------------------------------
Functional Specialization in the visual Cortex?
Howard et al [1] showed their subjects three pairs of different kind of
stimuli, and use fMRI to measure the activity in their brain. Based on their
results, they conclude that there is "extraordinary degree of functional
specialization in the visual cortex". However, the conclusions do not follow
from their data. There are three major flaws in the logic of the argument that
Howard et al [1] use:
1) The authors ignore the higher level nature of the stimuli, i.e. their
conceptual and emotional significance.
In higher level, the stimuli vary on many dimensions, e.g how
realistic they look, how interesting they are, how attractive they
are. Thus any difference in activity may be attributed to
differences in the significance of the stimuli, rather than to the
way they are processed. These effects must be controlled in some
way, before it can be concluded that the activity seen is wholly a
result of low-level processes.
2) The authors assume that high differential activity is equivalent to
functional significance.
Howard et al [1] measured differential metabolic activity, which
presumably also means differential neuronal activity. However,
differential neuronal activity does not entail functional
significance. In other words, the processing of the input is not
necessarily done where the highest differential activity is seen.
The equivalence of differential activity and functional
significance is widely assumed, presumably because it simplifies
the analysis. However, there is no evidence for it at the
resolution in which Howard et al[1] present their data, and it is
logically implausible. This is because the bulk of the information
in the brain is not coded in level of activity (how many neurons
are active in a specific region), but in the pattern of activity
(which neurons are active and when). Thus processing input (or any
other process) means changes in pattern of activity, not level of
activity. Hence, regions where the processing take place does not
necessarily appear as peaks of differential activity. On the other
hand, peaks of differential activity can arise from other reasons,
including (a) high-level processes, (b) direct effect of the input
(rather than processing it), (c) completely irrelevant effects.
Thus the equivalence cannot be assumed, and must be supported by
evidence.
As the authors themselves point out, the area of differential
activity in their data seems to correlate with the size of the
visual input. On the other, it does not seem to correlate to the
amount of processing that is required for each stimulus. Thus the
data itself seems to hint that the differential activity in this
case is a direct result of the visual input, rather than anything
to do with processing it.
3) The authors regard localization as specialization.
`Specialization`, when applied to body organs, normally means some
physiological modification. Even if it will be shown that specific
kind of stimuli are processed in a specific region, it does not show
that this region is modified in a special way for processing this
kind of stimuli. Thus localization is not equivalent to
specialization.
It can be claimed that localization is a weak form of
specialization, but this is a word game that would just lead to
confusion. Moreover, it is clearly not what Howard et al [1] mean,
as they claim in their conclusions that "there is an extraordinary
degree of functional specialization in the visual cortex".
The patterns of differential activity seen by Howard et al [1] do not match any
patterns seen in
any other investigation, using any method, including, as the authors themselves
say, their own
previous studies. This argues against specialization. As the argument for
specialization is
invalid for any of the three flaws listed above, their data does not support
specialization.
In summary: The data presented by Howard et al[1] shows some degree of
localization of
differential activity when subjects are presented with different stimuli. It
does not show that this
localization is not a result of higher level effects, it does not show that this
activity corresponds
to functional significance, and it does not show any evidence for
specialization, as opposed to
localization.
References:
1. Howard RJ, Brammer I, Wright I, Woodruff PW, Bullmore ET, Zeki S: A
direct
demonstration of functional specialization within motion-related visual and
stodgier
cortex of the human brain. Current Biology 1996, 6:1015-1019.