The name is absent



HIGHLEY ET AL

Fig. 2 Pyramidal cell volumes for hippocampal subregions (bars show means and standard error of the
me
an). Cases have been subdivided according to gender and disease category.


OCE can be used to estimate the
p
ercentage of observed relative variance,
(s.d.=x)2, of each measure which is
a
ccounted for by true inter-individual
variance, as opposed to the stereological
volume estimate (West & Gundersen,
1990; West, 1999). Ideally, this should be
greater than 50%. This was true for all
measures of VN (all 580.2%). The conclu-
sion to be drawn is that the measures are
o
f adequate reliability and accuracy.

Effects of diagnosis, gender
and
side

A bar chart of mean cell volume is given in
F
ig. 2. The mean cell volumes (standard
d
eviations in parentheses) for the subfields
w
ere as follows:

(a) hilus: 4.0861076 (0.8461076) for
co
ntrols and 3.8261076 (1.236
1076) mm3 for patients;

(b) CA2/3: 3.8861076 (1.0961076)mm3
f
or controls and 3.4561076 (1.056
1076) mm3 for patients;

(c) CA1: 2.5461076 (0.5961076)mm3
f
or controls and 2.6061076 (0.676
1076) mm3 for patients;

(d) subiculum:     2.5261076     (0.576

1076) mm3 for controls and 2.256
1076 (0.4661076) mm3 for patients.

There was no significant effect for diag-
nosis, gender or side for any subfield. Thus,
for the hilus, all F(1,24)41.22, P50.2021;
for the CA2/3 subfield, all F(1,24)43.25,
P50.0842; for the CA1 subfield, all
F(1,23)41.35, P50.2574; for the subiculum,
all F(1,23)42.19, P50.1522.

DISCUSSION

The main finding in this study is an absence
of size ch
ange in hippocampal pyramidal
ne
urons in schizophrenia. There have been
fiv
e earlier studies of this parameter of
which w
e are aware (Christison et al,
1989;
West & Gundersen, 1990; Benes et
al
, 1991, 1998; Arnold et al, 1995; Zaidel
et al, 1997; West, 1999); two of them
found no change, and three found a de-
cr
ease in size in schizophrenia. All had
co
mparable numbers of cases of schizo-
phre
nia to the number in the present study.
C
ontrol case numbers were similar to our
st
udy in four studies but were larger in
one o
ther negative study. All studies used
th
e Nissl stain. Only one previous study in
addit
ion to ours looked at both sides of
th
e brain, and only our study sampled the
hi
ppocampus throughout its full extent.

We addressed the potential of regional
specif
icity of changes in schizophrenia by
di
viding the hippocampus into four sub-
fiel
ds. We did not further divide our hippo-
camp
al subfields into anterior and posterior
halves.
It is thus possible that changes in
one h
alf (anterior or posterior) of a subfield
m
ight have been masked or ‘diluted’ by var-
iance
in the other half. In a meta-analysis of
hi
ppocampal volumes in schizophrenia
as
sessed by MRI it was found that inclusion
of
the amygdala, abutting on the anterior
hi
ppocampus, in the region of interest sig-
ni
ficantly increased the size of the reduction
in vo
lume seen in schizophrenia. The re-
co
mmendation was made that in future re-
se
arch relative alterations in anterior and
post
erior hippocampus in schizophrenia
should be assessed separately (Nelson et
al, 1998). It is also possible that our study
m
ight have failed to detect a ‘truereduc-
tion in cell size in some hippocampal sub-
f
ields because of the small sample size
(
type II error).

Decreases in neuronal size have been re-
p
orted for other regions of the brain in
s
chizophrenia - the dorsolateral prefrontal
cortex, anterior cingulate cortex, cerebellar
P
urkinje cells, substantia nigra and locus
c
aeruleus - but not in the motor cortex or
c
alcarine cortex (reviewed by Harrison,
1999). Further studies will be needed before
the primacy of these changes in the disease
can be judged.

ACKNOWLEDGEMENTS

This work was funded by grants from the UK Medi-
cal Research Council and the Wellcome Trust. We
t
hank Drs S. J. Cooper and B. Herron for assistance
w
ith cliinical assessment and post-mortem brain
r
emoval respectively for some of the cases included
i
n this study.

REFERENCES

Altshuler, L. L., Casanova, M. F., Goldberg, T. E., et al
(1990) The hippocampus and parahiippocampus in
schizophrenia, suicide, and control braiins. Archives of
General Psychiatry, 47, 1029^1034.

American Psychiatric Association (1994) Diagnostic
and Statistical Manual of Mental Disorders (4th edn)
(DSM ^ IV).Washington, DC: APA.

Arnold, S. E., Franz, B. R., Gur, R. C., etal (1995)
Smalller neuron size in schizophreniia in hippocampal
su
bf ields that mediate cortical ^ hippocampal
iinteractions. American Journal of Psychiatry, 152,
738^748.

Benes, F. M., Sorensen, I. & Bird, E. D. (19 91)
Re
duced neuronal size in posterior hippocampus of
schizophrenic patiients. Schizophrenia Bulletin, 17,
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7^608.

__ , Kwok, E.W.,Vincent, S. L., et al (1998) A
reduction of nonpyramidal cells iin sector CA2 of
schizophrenics and maniic depressives. Biological
Psychiatry, 44, 88^97.

Bogerts, B., Meertz, E. Schonfeldt-Bausch, R.
(1985) Basall gangllia and liimbic system pathology in
schizophrenia. A morphometriic study of braiin vollume
an
d shrinkage. Archives of General Psychiatry, 42,
784^791.

Bruton, C. J., Crow, T. J., Frith, C. D., et al (1990)
Schizophrenia and the brain: a prospective cliniico-
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Christison, G. W., Casanova, M. F., Weinberger, D. R.,
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schizophrenia. Archives of General Psychiatry, 46,
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Falkai, P. & Bogerts, B. (1986) Cell loss iin the
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416




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