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Journal of Psychiatric Research 39 (2005) 117–127

PSYCHIATRIC

RESEARCH

Prefrontal atrophy in first episodes of schizophrenia associated withlimbic metabolic hyperactivity

Vicente Molina a,*, Javier Sanz b, Fernando Sarramea c, Carlos Benito d,Tomas Palomo b

a Department of Psychiatry, Hospital Clınico Universitario, Paseo de San Vicente, 58-182, E-37007 Salamanca, Spainb Department of Psychiatry, Hospital Doce de Octubre, Madrid, Spain

c Department of Psychiatry, Hospital Reina Sofıa, Cordoba, Spaind Department of Neuroradiology, Hospital Gregorio Maranon, Madrid, Spain

Received 19 January 2004; revised 3 May 2004; accepted 9 June 2004

Abstract

Reduced volume and activity of the prefrontal (PF) cortical gray matter (GM) and hippocampal hypermetabolism are repeated

findings in schizophrenia. There is still an information deficit about the significance of reduction of PF GM in schizophrenia, and a

simultaneous study of PF anatomy and activity and limbic metabolism can contribute to fill that deficit. In order to do so, we used

positron emission tomography (PET) with 18-fluoro-deoxyy-glucose (FDG) during an attention task and magnetic resonance imag-

ing (MRI) to study a sample of first episodes of pscyhosis. We included 21 first episodes (FE) of psychosis and 16 healthy controls. A

diagnosis of schizophrenia was confirmed in the follow-up in eleven of these patients and ruled out in the remaining 10 cases. Vol-

umes of PF GM were determined and also activity in the same region and in the hippocampus. Residual GM was estimated in the

PF region as a quantitative measurement of the degree of atrophy in each individual, using age and intracranial volume data from a

set of 45 healthy controls and linear regression.Patients with schizophrenia had lower PF metabolic activation and greater hippo-

campal activity than controls. FE patients without schizophrenia were no different in any parameter as compared to controls.

Patients with schizophrenia presented an inverse and significant association between GM deficit and hippocampal activity that

was not observed in controls or in patients without schizophrenia. The same association was previously described by our group

using PET in the resting state in recent-onset and chronic patients with schizophrenia. These findings support a loss in PF inhibitory

capacity as a possible link between anatomical and functional alterations in schizophrenia.

� 2004 Elsevier Ltd. All rights reserved.

Keywords: Schizophrenia; Prefrontal; Disinhibition; MRI; PET; Metabolism

1. Introduction

Prefrontal (PF) gray matter (GM) deficit is a repeated

finding in schizophrenia (Shenton et al., 2001), but its

significance is not completely understood. On the otherhand, post mortem data do not support neuronal num-

ber reduction in this region (Selemon et al., 1998), thus

PF lower volume in schizophrenia can hardly be attrib-

0022-3956/$ - see front matter � 2004 Elsevier Ltd. All rights reserved.

doi:10.1016/j.jpsychires.2004.06.008

* Corresponding author. Tel.: 34 923291102; fax: 34 923291383.

E-mail address: vmolinarod@wanadoo.es (V. Molina).

uted to neuronal loss. To better understand the meaning

of PF atrophy it is necessary to study its functional cor-

relate by means of combined anatomical and functional

neuroimaging. An obvious advantage of this approach

is its possible application in vivo in the early stages ofthe disease. Such an approach would control for the ef-

fects of other factors as medication or chronicity that

could inespecifically reduce PF GM in schizophrenia.

Two findings permit us to formulate testable hypoth-

eses about the functional significance of PF atrophy in

schizophrenia. Firstly, there is a reduced PF activation

118 V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127

during the performance of cognitive tasks in this illness

(Andreasen et al., 1992; Buchsbaum et al., 1992; Rubin

et al., 1991; Volz et al., 1999),which suggest an excita-

tory hypofunction. On the other hand there is a close

relationship between excitatory transmission and glu-

cose metabolism in the human brain (Shen et al., 1999;Sibson et al., 1998). If the anatomical deficit were asso-

ciated with that excitatory hypofunction, we would ex-

pect an inverse association between PF atrophy and

metabolic activation.

Secondly, there are data to support a reduced inhibi-

tory function in the PF cortex in schizophrenia. Patients

with schizophrenia tend to overactivate the frontal re-

gion to achieve similar results than controls (Curtiset al., 1999; Stevens et al., 1998). Other findings in this

direction include: reduced density of the neurons

expressing mRNA for glutamic acid decarboxylase

(GAD), the enzyme that controls the synthesis of c-ami-

no-butyrate acid (GABA) (Akbarian et al., 1995; Volk

et al., 2000); upward regulation of the postsynaptic

GABAa receptor (Benes et al., 1992); reduced axonic ter-

minal density of chandelier cells (key elements in the reg-ulation of pyramidal activity) with GABA transporter

(GAT-1) (Pierri et al., 1999) and decreased uptake of

GABA in the PF cortex (Simpson et al., 1989). The in-

creased density of GABAa receptors has been found

to be to be inversely related with that of neurons

expressing GAT-1, giving special support for an inhibi-

tory hypofunction in schizophrenia (Volk et al., 2002).

A disequilibrium between the inhibitory and excitatoryfunction in the PF region resulting in a overactive gluta-

mate function is also supported by the finding of an in-

crease of glutamate uptake sites at that level (Simpson

et al., 1998). From another perspective, an abnormal

GABA/glutamate activity in the PF region in schizo-

phrenia is consistent with the reported excessive release

of dopamine in the basal ganglia (Abi-Dargham et al.,

1998; Laruelle et al., 1996).Interestingly subcortical dop-amine release was inversely related to N-acetyl-aspartate

levels in the PF region in schizophrenia (Bertolino et al.,

1999), suggesting an association between PF anatomical

abnormalities and an hyperactive outflow from this re-

gion in that illness.

A reduced inhibitory PF capacity would lead to a pro-

portional increase in limbic metabolic activity, since cor-

tico-limbic connections are direct and excitatory (Barbas,1992; Fuster, 1997; Huntley et al., 1994).The hypothesis

concerning disinhibition of the PF-limbic connection

would be coherent with the increased metabolic activity

in the hippocampus found in schizophrenia (Heckers

et al., 1998), and with the direct relation between activity

in the hippocampus and positive symptoms (Liddle et al.,

1992; Molina et al., 2003a). Along the same line, it has

been suggested that disinhibition of the medial temporallobe is a critical component in the aetiology of psychosis

(Friston et al., 1992). In the case of PF atrophy associated

with an inhibitory deficit one would expect greater hippo-

campal activity associated with the degree of PF atrophy.

Our group has described this association in the resting

condition in two different samples of 17 recent-onset

and 29 chronic patients with schizophrenia, and this asso-

ciation was absent from 18 healthy controls (Molina etal., 2002a). None of these subjects was included in the

present report.

The hippocampus is especially appropriate for testing

this hypothesis because antispychotics do not seem to in-

crease its activity. These drugs have been reported to not

to cause significant metabolic changes in hippocampus in

humans (Bartlett et al., 1994; Buchsbaum et al., 1987;

Holcomb et al., 1996; Holcomb et al., 1999; Vita et al.,1995) or to decrease its activity, as reported for both typ-

icals (Lahti et al., 2003; Wotanis et al., 2003) and atypi-

cals (Huang et al., 1999; Lahti et al., 2003; Liddle et al.,

2000; Wotanis et al., 2003). This is different in other re-

gions with direct excitatory PF projection (such as the

caudate), where antipsychotics induce important and

long-lasting activity increases (Bartlett et al., 1994; Buc-

hsbaum et al., 1987; Holcomb et al., 1996; Holcomb et al.,1999; Vita et al., 1995). Therefore, by using the hippo-

campus for this purpose we can avoid the bias of having

to exclusively select patients able to cooperate in image

tests during a psychotic episode without any treatment,

probably not representative of schizophrenia in general.

Moreover, by studying the association between pre-

frontal atrophy and metabolic activation in first psy-

chotic episodes we avoid the confusing effects ofprevious treatment. Chronic treatment has been re-

ported to affect activity (Bartlett et al., 1994; Buchsbaum

et al., 1987; Holcomb et al., 1996, 1999; Vita et al., 1995)

and cerebral volumes (Chakos et al., 1994), probably re-

lated with changes in synapse number and morphology

(Konradi and Heckers, 2001).

The aim of this work is to improve the understanding

of some aspects of PF atrophy in schizophrenia by stud-ying its functional correlate. For this purpose, we have

calculated the association between a quantitative meas-

ure of cortical PF GM deficit and metabolic activation

in the same region and the hippocampus in a group of

first episodes (FE) of schizophrenia. We also studied

FE patients without evolution to schizophrenia to rule

out effects due to medication and to study the specificity

of possible findings. Our hypothesis is that PF atrophycan be associated with limbic hyperactivation in

schizophrenia.

2. Methods

2.1. Subjects

Twenty-one right-handed patients with first psychotic

episodes were recruited. These were participants in a

V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127 119

longitudinal study on FE of psychosis, and were re-

cruited during first their stay in the psychiatric unit of

a general hospital. None of these fulfilled criteria of

schizophrenia at the time of the image tests. Inclusion

criteria were a first psychotic episode with symptoms

of more than one week�s duration, not attributable toorganic or toxic causes and not associated with any

other axis I disorder. Patients with relevant stressors

clearly related with the episode or having a greater

intensity than those usual in daily life were not included.

Patients were not excluded if episodes had been trig-

gered by family arguments or adverse, but normal, aca-

demic or work-related events. We follow these criteria in

order to exclude, in accordance with DSM-IV criteria,patients with likely transient psychotic symptoms. By

the time of inclusion, 14 patients met the criteria of

schizophreniform disorder and 7 those of brief psychotic

disorder.

We used follow up information to confirm or rule out

a diagnosis of schizophrenia two years after inclusion

and, therefore, after the image study. Data from other

5 patients were not included since they could not be lo-cated for the follow-up assessment. Two psychiatrists

(VM and JS), blind to the results of PET and MRI, pro-

spectively confirmed the diagnosis using a semi-struc-

tured interview (SCID, clinical version) and

information from the families and the clinical staff.

The duration of symptoms to formulate the diagnosis

according to DSM-IV included the periods before and

after starting treatment. Clinical scores calculated byapplying the PANSS are shown in Table 1.

Of the 21 patients recruited, 11 (6 males) were diag-

nosed at the end of the follow-up period as paranoid

schizophrenia according to DSM-IV criteria. In another

10 patients (7 males), the diagnosis of schizophrenia was

ruled out. Of them, 7 were diagnosed as schizophreni-

form disorder, 2 as brief psychotic episode and one as

bipolar disorder (all DSM_IV criteria). Prefrontal meta-bolic data from these patients were used in another

study on the specificity of hypofrontality in FE schizo-

phrenia (Molina et al, submitted). Besides, structural

Table 1

Clinical and demographic characteristics of the sample

FE with SZ,

(n = 11)

FE without SZ,

(n = 10)

Controls

(n = 16)

Parental SES 2.2(0.9) 2.3(0.9) 2.3(0.9)

Education (year) 11.2(8.1) 12.0(9.1) 10.9(7.4)

Positive symptoms 22.4(8.5) 20.5(4.9)

Negative symptoms 14.5(8.7) 12.3(6.1)

General symptoms 37.1(8.1) 39.9(7.7)

SZ: schizophrenia. Parental SES: parental socioeconomic status,

according to (Hollingshead and Frederick 1953); education is given in

school years. Symptoms scores correspond to PANSS. No significant

differences between groups were found for these variables.

data from these patients have been used for a previous

report, as part of a a larger sample (Molina et al., 2002b)

Sixteen healthy right-handed controls (8 males) were

studied with PET and MRI in the same conditions as

patients. They were recruited among hospital staff with-

out college education after the patients sample was com-pletely recruited, and received a small payment for their

cooperation.To match controls to the patient group,

these had no further education and there were no signif-

icant differences between the groups in age or parental

socioeconomic status (Hollingshead and Frederick,

1953) (Table 1).

Patients (with or without evolution to schizophrenia)

had never been given antipsychotic drugs, although theywere administered a 48-h treatment with 10 mg/d halop-

eridol in liquid form before the PET study. The same

treatment was given to all patients. The nursing staff en-

sured adequate treatment compliance. The medication

was suspended for 12 h before the PET exploration. This

was a practical way of including a sample representative

of the usual form of presentation of schizophrenia by

avoiding selection bias related with the ability of acutepsychotic patients to cooperate in neuroimaging proce-

dures. There are other forms of selection bias that can-

not be controlled for without a larger, randomly

selected sample, such as the bias related to subjects that

gave or not their consent or to those who finished the

procedure vs those who did not.

Exclusion criteria for patients and controls in the ini-

tial selection were: mental retardation, neurological ill-ness, MRI findings considered as clinically relevant

(from a neurological perspective) by a neuroradiologist,

history of cranial trauma- with loss of consciousness and

substance abuse criteria during the previous 6 months,

except for occasional use of hypnotics. Urine analysis

was done in all cases to rule out a toxic cause for the

psychotic episode.

After giving detailed information of the study, in-formed consent was obtained from patients and their

families. The study was first approved by the hospital�sethical committee.

2.2. Image techniques

2.2.1. MRI Acquisition

Magnetic resonance studies were acquired in all caseson a Philips Gyroscan 1.5T scanner using a gradient

echo T1-weighted 3D sequence (matrix size 256 · 256,

pixel size 0.9 · 0.9 mm, flip angle 30�, echo time 4.6

ms, slice thickness 1.1 mm) and a T2-weighted sequence

(Turbo-Spin Echo, turbo factor 15, echo time 120 ms,

matrix size 256 · 256, slice thickness 5.5 mm).

2.2.2. PET Acquisition

PET studies were obtained in a SIEMENS Exact 47

tomograph, 20 min after injecting 370 MBq of

120 V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127

18FDG, while subjects performed a contingent Contin-

uous Performance Test (Rosvold et al., 1956). Subjects

were instructed to push a button if T immediately fol-

lowed the letter L, as presented on a computer screen.

The interstimulus interval was 1 s. After introducing

an intravenous line for FDG administration, the subjectbegan the task, which was divided into 4 blocks of 5 min

each, with a 1-min rest between each two blocks. FDG

was administered 1 min after initiating the task.

The PET studies were performed after a fasting

period of more than 6 h, especially excluding caffeinated

beverages. In all cases, image values were proportionally

normalized to the global count rate for each PET, i.e.,

global normalization was performed using global meanvoxel value (Frackowiak et al., 1997), therefore pixel

values represented relative activity.

2.2.3. Segmentation

To perform the metabolic and volumetric measure-

ments of the different brain structures, a two-step proce-

dure was adopted (Desco et al., 2001). The first step

involved editing the MRI to remove skull and extra cra-nial tissue, registration of PET and MRI, and an initial

segmentation of cerebral tissues into gray matter (GM),

white matter (WM) and cerebrospinal fluid (CSF). In a

second stage, we applied the Talairach method to define

regions of interest (ROIs) and to obtain volume and

metabolic activity data. The software used is part of a

Multimodality Workstation that incorporates a variety

of image processing and quantification tools (Benito

Fig. 1. Axial, sagittal and coronal views of the Talairach grid built for mea

metabolic activity is calculated as the portion of tissue mask contained in the

an edited MRI (i.e., after removind non-cerebral parts) fused with a PET sc

et al., 1999; Desco et al., 1999). We used this method

in previous reports (Molina et al., 2003a; Molina

et al., 2003b).

The edited MRI without extracranial tissue was co-

registered with the PET study using the AIR algorithm

(Woods et al., 1993), which optimizes volume matchingbetween the two images. Fusion results were visually

checked in all cases and the observed fit was always opti-

mal (Fig. 1). Initial segmentation of cerebral tissue into

GM and WM was obtained by using an automatic

method (Ashburner and Friston, 1997) that has been

widely tested and is currently included as a standard

processing tool in the SPM (Statistical Parametric Map-

ping) program. The algorithm classifies all MRI pixelsinto 4 tissue types: GM, WM, CSF and ‘‘other tissues’’

according to a clustering algorithm that starts from �apriori� probability templates. The algorithm also re-

moves the effect of radiofrequency field inhomogeneities

(Ashburner and Friston, 2000). The automatically gen-

erated three-dimension (3D) masks were checked for

inconsistencies and corrected whenever necessary by

an experienced radiologist. Corrected inconsistenciesconsisted of the misidentification as GM of tissue

belonging to extracerebral structures (i.e., bone, muscle

or fat).

The second stage defined the actual ROIs to be meas-

ured by superimposing WM and GM 3D tissue masks

onto each subject�s Talairach co-ordinate system. Basi-

cally, Talairach normalization (Talairach and Tournoux,

1988) consists of a piecewise linear transformation and

suring volume and metabolic activity of the cortex. ROI volume and

group of cells that define the ROI (see Section 2). This figure represents

an. In the axial view, occipital is down and frontal is up.

V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127 121

tessellation of each brain into a grid of 1,056 cells (Fig. 1).

The image processing software is able to automatically

calculate the 3D grid upon manual selection of the ante-

rior and posterior commissures (AC and PC) and the

mid-sagittal plane, on MR images where scalp and cere-

bellum were previously removed. Once the grid was cal-culated and adjusted to each particular brain, the

regions of interest were defined as sets of cells, according

to the Talairach Atlas. ROI volume and activity were

then calculated as the portion of the tissue mask con-

tained in the set of grid cells that define the ROI (Benito

et al., 1999; Desco et al., 1999). On each grid cell, volume

and count rate activity data from the superimposed PET

image were collected.The validity of the Talairach-based procedure as an

automated segmentation tool suitable for schizophrenia

research has been proven (Andreasen et al., 1996; Kates

et al., 1999). All manual procedures involved were per-

formed by a single operator, thus avoiding any potential

inter-rater variability. Reliability of the entire segmenta-

tion procedure was assessed by repeating the measure-

ments three times for fifteen cases selected at random,obtaining mean root mean square (RMS) error values

ranging from 0.2% to 3.2% for volume measurements,

whereas repeatability of metabolic activity values ranged

from 0.93 to 0.99 (Molina et al., 2003b). ThoseRMS error

values, similar to those of other groups, approaches the

size of differences of many structural abnormalities in

schizophrenia, which constitutes a problem in the field.

Analyzed variables included PF lobe (PF GM volumeand metabolic activity) and activity of the hippocampus.

The PF lobe was defined as the region above the AC–PC

plane and anterior to a plane orthogonal to the AC–PC

plane through the AC. Only GM was included. That re-

gion also contains a portion of frontal tissue, which

makes our approach somewhat less valid than manual

tracing of boundaries, although highly reliable. Meas-

urements of hippocampal activity were made consider-ing only GM tissue contained within the appropriate

cells according to the Talairach atlas (Talairach and

Tournoux, 1988): (E2b10 and E3b10). Since we had no

a prioiri specific hemispheric hypothesis, data from both

sides were analyzed together after averaging across

hemispheres.

2.3. Data analysis

Since our objective was to study the relationship be-

tween PF GM deficit due to illness and metabolic acti-

vation, we first calculated a value that would

correspond to a quantitative expression of this GM

deficit (i.e., a measure of atrophy). To do so, the effect

of age and total cranial volume was statistically re-

moved prior to data analysis because these factorsare major determinants of regional cerebral volume

variation. Data transformation was done using regres-

sion parameters obtained from the group of healthy

individuals (n = 45, 24 males), partially following the

procedure described by Pfefferbaum (Pfefferbaum

et al., 1992). Using two successive linear regression

models (for age and intracranial volume) applied to

the data of these controls we obtained the coefficientsneeded to assess residuals in each individual. These res-

iduals represent, if negative, the individual deficit with

respect to a healthy control of the same age and intra-

cranial volume. These 45 subjects included the controls

participating in the present study, and by definition

their mean residual is zero. The residual GM in the

control participants represents the random variation

in a normal population while the residual GM in thepatient group corresponds to the random variability

plus that due to the disease.

We predicted that our patients with schizophrenia

would show atrophy of the PF GM accompanied by

hypofrontality and a hypermetabolic tone in the hippo-

campus, with one or both of these functional abnormal-

ities related to PF atrophy. Therefore, we first assessed

the between-group differences for anatomical and meta-bolic variables using two analyses of covariance

(ANCOVA) and then we assessed the patterns of

anatomo-functional association within each of these

groups.

In the first ANCOVA we compared differences in

residual GM between groups. In this analysis, group

(FE with schizophrenia, FE without schizophrenia and

controls) was included as a factor and gender as a cofac-tor. No other covariables were needed since residuals

had previously corrected the normal influence of indi-

vidual age and intracranial volumes. A second ANCO-

VA was used to compare activity values during

cognitive activation (i.e., PF and hippocampal activi-

ties); in this case age was included as a covariable and

gender as a cofactor. Both analyses were followed cases

by post-hoc comparisons to test the hypothesis of signif-icant abnormalities in the schizophrenia group.

The main working hypothesis (association between

the measure of PF atrophy and activity) was evaluated

using correlation coefficients. Normality of the variables

was first tested (Kolmogorov–Smirnoff test) within each

subgroup. We planned to use Pearson�s r coefficients in

case of normal distribution of both variables in each

pair, and Spearman�s q when at least one variable didnot follow a normal distribution. In all cases, two-tailed

significance was reported. An a priori hypothesis was

formulated that variables were not independent and,

therefore, Bonferroni�s adjustment was not applied.

To demonstrate that the associations between anat-

omy and activity were indeed different, correlation coef-

ficients were compared between groups using Fisher�s Ztransformation (Z = 1/2 loge(1 + r/1 � r), where r wasthe correlation coefficient for each group)(Sokal and

Rohlf, 1995).

122 V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127

In order to explore the biological relevance of find-

ings, a correlation analysis was proposed between the

structural and activity data on the one hand and the

positive and negative symptom scores in patients with

and without schizophrenia on the other.

Table 3

Correlation coefficients (Pearson�s r and Spearman�s q, in italics) with

the significance levels corresponding to the association between

prefrontal cortical GM residues and functional data in patients and

controls

PF activity Hippocampal activity

FE with schiz(n = 11) 0.26(0.43) �0.73(0.01)

FE non-schiz(n = 10) 0.28(0.42) 0.41(0.23)

Controls(n = 16) 0.09(0.77) �0.15(0.61)

Significant coefficients are boldfaced. FE with schiz, first episodes with

schizophrenia; FE non-schiz, first episodes without schizophrenia.

3. Results

The clinical scores were not significantly different be-

tween both groups of patients, and cognitive perform-

ance during PET did not significantly differ (in terms

of omission and commission errors) between any pair

of groups. Anatomical and functional values are shownin Table 2.

In the comparison of PF GM residuals, contrary to

our prediction, there was no significant effect of group

(F = 1.8, df = 2, p = 0.17), although residuals were nega-

tive only in the schizophrenia group (Table 2). There

were no significant group by gender interactions. Post-

hoc analyses showed that patients with schizophrenia

had less residual GM (i.e., greater atrophy) than firstepisode patients without schizophrenia at trend

level(difference between means �5.8 standard error

3.2, 95% CI �0.6 to 12.5, p = 0.07). There were no sta-

tistically significant differences or trends in PF residual

GM between healthy controls and FE with or without

schizophrenia.

The second ANCOVA (metabolic activity) revealed

an effect of group for both hippocampal (F = 2.61df = 2, p = 0.09) and PF activity (F = 3.91, df = 2,

p = .031). In the post hoc comparisons, patients with

schizophrenia had less metabolic prefrontal activity than

healthy controls (difference between means �3.05, SE

1.1, 95% CI �5.3 to �0.7; p = 0.01). Patients with schiz-

ophrenia also had a greater activity in the hippocampus

than controls (difference between means 4.73, SE 2.07,

95% CI 0.5–8.9; p = 0.03). There were no differences inany activity parameter between patients with FE not

developing schizophrenia and healthy controls.

Given the sample sizes, we decided to corroborate

hypofrontality in patients with schizophrenia compared

to controls with a Mann–Whitney test (right U = 42,

Table 2

Prefrontal anatomical and functional values in patients and controls

Patients with schizophrenia (n = 11)

Intracranial volume (cc) 1444.2(151.6)

Age (year) 24.4(4.2)

PF volume (cc) 151.2(14.7)

PF GM residual �2.0(7.4)

PF activity** 105.2(2.8)

Hippocampal activity** 89.2(5.7)

Raw anatomical values (in cc) are shown only for illustrative purposes.

anatomical residuals. Functional data are relative values with respect to globa

the expected values in a set of controls, given individual age and intacranial

z = -2.27, p = 0.02;). In the same way, schizophrenia pa-

tients showed a greater left hippocampal activity value

than controls (U = 45, z = 2.12, p = .0.03).

Residual GM and hippocampal activity data, but not

PF activity, had a normal distribution in the three

groups in all cases. Therefore, correlations between PFactivity and PF GM were calculated with Spearman�s q.

In the group of FE with schizophrenia there was a

clear inverse relation between the PF residual GM and

the activity of the hippocampus (less PF residual GM

was associated with greater hippocampal activity). This

association was not apparent in any of the other groups

(Table 3 and Fig. 2). We found no significant association

between PF GM residuals and PF activity in any group(Table 3).

The correlation coefficient between atrophy and hip-

pocampal activity was significantly different in patients

with schizophrenia as compared to FE without schizo-

phrenia (z = �3.13, p = 0.001) and this comparison

was nearly significant between healthy controls and pa-

tients with schizophrenia (z = �1.82, p = 0.06).

The FE patients with schizophrenia showed an in-verse, statistically significant relation between PF

GM residuals and positive symptoms ( r = �0.80,

n = 11, p = 0.005). Consistently, a direct association

was found between positive symptoms and hippocam-

pal activity in the same group, (r = .60, n = 11,

p = .05). There was no association between activity

data and symptom scores in FE patients without

schizophrenia.

Patients without schizophrenia (n = 10) Controls (n = 16)

1423.35(167.4) 1479.9(141.8)

28.5(7.5) 26.1(5.7)

151.8(18.9) 156.4(15.2)

3.6(7.5) 1.0(8.1)

107.0(2.4) 108.3(3.0)

85.5(6.2) 84.2(4.2)

Between-groups comparisons were made using functional data and

l activity counts and anatomical residuals represent the difference from

volume (see text). *p < 0.10; **p < 0.05.

FE with schizophrenia

PF GM residual3020100-10-20

hipp

ocam

pal a

ctiv

ity110

100

90

80

70

FE without schizophrenia

PF GM residual3020100-10-20

hipp

ocam

pal a

ctiv

ity

110

100

90

80

70

healthy controls

PF GM residual3020100-10-20

hipp

ocam

pal a

ctiv

ity

110

100

90

80

70

Fig. 2. Scatter diagram showing the association between residual cortical GM (excluding the effects of age and intracranial volume) and

hippocampal activation (relative to the global cortical metabolic rate) in the three groups of the study. Women are represented as empty circles and

males as solid circles. The association was statistically significant only in the schizophrenia group (see text).

V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127 123

4. Discussion

According to our data, in first episode patients withschizophrenia there was a significant association be-

tween the amount of PF GM structural deficit and hip-

pocampal metabolic activity. This pattern was not

observed in healthy controls or in FE with a better out-

come. Only FE patients with schizophrenia presented

higher hippocampal activity and less PF activity than

controls. In every case the diagnosis of schizophrenia

was confirmed or discarded after a 2-year follow-up.Our results agree with the proposal of (Deakin and

Simpson, 1997), who viewed functional abnormalities

in the temporal lobe in schizophrenia as related to struc-

tural problems in the frontal regions. Moreover, our

data also fit with the idea of a key role in psychosis

for limbic disinhibition (Friston et al., 1992). Hippocam-

pal hyperactivity in schizophrenia has been described

previously indeed (Heckers et al., 1998). The biological

relevance of this hyperactivity is supported by the asso-

ciation between positive symptoms, hippocampal activ-ity and PF atrophy in the present and previous

reports(Liddle et al., 1992; Molina et al., 2002a; Molina

et al., 2003a). Moreover, the association between PF

atrophy and limbic activity was the same as in the pre-

sent study in two samples of chronic and recent-onset

patients with schizophrenia, entirely different from the

one here reported here (Molina et al., 2002a), giving

support to the hypothesis of a loss of PF inhibitorycapacity in schizophrenia. These samples were studied

with PET in the resting condition, giving additional sup-

port to an association between PF atrophy and limbic

activity in schizophrenia, relatively independent of cog-

nitive state, treatment and chronicity. That decreased

PF inhibitory capacity could be also consistent with

the previously reported excessive amphetamine-induced

124 V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127

dopamine release in that illness (Abi-Dargham et al.,

1998; Laruelle et al., 1996)

From another perspective, our results could reflect an

inefficient overactivation of the fronto-limbic network

during the cognitive task. Recent functional magnetic

resonance studies have shown that patients with schizo-phrenia tend to overactivate the frontal region to achieve

similar results to controls (Callicott et al., 2000; Curtis

et al., 1999; Stevens et al., 1998), which has been inter-

preted as an inefficient function (Weinberger et al., 2001).

Our results indicate that during a relatively simple atten-

tional task (with similar between-groups performance)

this dysfunction could be reflected in a metabolically

overactive hippocampus and a hypoactive PF region.Conceivably, a limbic hypermetabolic tone could

contribute in the long-term to the replicated hippocam-

pal atrophy in schizophrenia. This idea is supported by

the fact that glutamatergic activity is the main determi-

nant of the cerebral metabolic rate (Shen et al., 1999;

Sibson et al., 1998) and that a sustained excitatory trans-

mission may promote localized ‘‘synaptic cell death’’,

i.e., a reduction of the synaptic tree (Mattson et al.,2001). Such a redcution would probably produce a smal-

ler hippocampal volume, as usually observed in schizo-

phrenia. This possibility would be coherent with the

small magnitude of hippocampal atrophy generally

found in schizophrenia (Nelson et al., 1998), since this

mechanism would not necessarily produce neuronal

death. The neurotoxic potential of limbic hyperactiva-

tion seems coherent with the reported association be-tween hippocampal volume and duration of the

disease in its first stages (Matsumoto et al., 2001).

In our study, residual GM values reflect a greater

reduction in GM volume than that produced by the

physiological effects of age, after discounting the influ-

ence of individual intracranial volume (Pfefferbaum

et al., 1992). This reduction only reached trend-level sig-

nificance in our FE patients with schizophrenia as com-pared to other FE patients, which may relate to the

sample size, and/or to their early illness stage. Indeed,

several studies support a PF volume defect in FE schiz-

ophrenia (Nopoulos et al., 1995; Ohnuma et al., 1997),

albeit of a small magnitude, which can make it difficult

to detect depending on sample size. In particular, a sig-

nificant but quantitatively small reduction in frontal vol-

ume was longitudinally described in schizophreniabefore the first psychotic episode (Pantelis et al., 2003).

This could contribute to explaining why PF structural

alterations have not been found by other groups in FE

schizophrenia (Bilder et al., 1994; Cahn et al., 2002;

DeLisi et al., 1991; Gilbert et al., 2001).

The lack of a statistically significant PF atrophy in our

study could also relate to the proportion of female pa-

tients in our group, since females with schizophrenia haveless structural alterations (Nopoulos et al., 1997). How-

ever, the magnitude of atrophy in our cases does not

invalidate the model derived from associations between

anatomy and activity, different in patients with schizo-

phrenia than in the other groups (see Fig. 2). The fact that

limbic hyperactivity was found (and related to PF atro-

phy) only in the FE sample with a posterior disgnosis

of schizophrenia supports a different biological substratefor this illness in comparison with other FE psychoses.

This is consistent with the biological abnormaliites found

in close relatives of schizophrenia patients (Lawrie et al.,

1999; O�Driscoll et al., 1999; Seidman et al., 1999).

All our cases were studied in their first psychotic epi-

sode, and the diagnosis of schizophrenia was confirmed

or discarded after a long follow-up. Hence, our results

suggest that a decline in PF GM already present bythe time of the first episode could explain a large part

of the excess limbic activity. Possible explanations for

the anatomo-functional relationship in our schizo-

phrenic patients should be able to explain a low to mod-

erate loss in cortical volume (like that usually found in

schizophrenia) and an increase in hippocampal activity.

A possible cause for this is a reduction in neuropil, as

proposed by several authors in schizophrenia (McGla-shan and Hoffman, 2000; Selemon and Goldman-Rakic,

1999; Selemon et al., 1998). To agree with our data, this

neuropil reduction should involve a decreased function

of inhibitory neurons, but not necessarily a widespread

reduction of connectivity. For example, if neuropil

reduction includes smaller synaptic trees of interneu-

rons, the axons of pyramidal cells, which do not decline

in number in schizophrenia (Selemon et al., 1998), couldbe partly released from inhibitory activity. Post-mortem

data indeed support a reduced connectivity between

interneurons and pyramidal cells in schizophrenia (Pierri

et al., 1999). This kind of neuropil reduction could lead

to an excess metabolic activity in regions such as the hip-

pocampus where PF pyramidal axons project in excita-

tory mode (Barbas, 1992; Fuster, 1997; Huntley et al.,

1994). Such a possibility would agree with the abnor-mally abundant glutamatergic innervation on the tem-

poral regions proposed by Deakin and Simpson (1997)

and based on post-mortem analyses. On the other hand,

our results may be consistent with the intriguing finding

of a selective loss of hippocampal interneurons in schiz-

ophrenia(Heckers and Konradi, 2002).

Hypofrontality might be related to alterations in

other regions since this was not explained by PF atro-phy. For instance, thalamic abnormalities could contrib-

ute to hypofrontality in schizophrenia, given the

intimate thalamo-PF excitatory connection (Barbas,

1992; Fuster, 1997; Huntley et al., 1994) and the repli-

cated thalamic abnormalities in that illness (Andreasen

et al., 1994; Buchsbaum et al., 1996; Deicken et al.,

2000; Gilbert et al., 2001; Glantz and Lewis, 2000; Pak-

kenberg, 1992).Our study has several limitations. The main one is the

sample size, although the longitudinal confirmation of

V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127 125

the diagnosis offers a clear advantage. Moreover, the pat-

tern of correlations found does not demonstrate a causal

relation between reduced GM and changes in activity.

For instance, both types of alteration could be related

via a third factor, as suggested by consequences of pre-

frontal damage onmonoaminergic transmission (Wilkin-son et al., 1997). The longitudinal study of a cohort at risk

with MRI and PET before and after the first psychotic

episode could overcome this limitation.

On the other hand, patients received minimum treat-

ment in order to avoid selection bias. It is unlikely that

the effect observed in our study was only pharmacologi-

cal since patients who did not evolve to schizophrenia re-

ceived the same treatment and did not present PFhypoactivity or limbic hyperactivity. In a recent study

in animals, both typical and atypical drugs tend to reduce

hippocampal activity (Wotanis et al., 2003), so the in-

creased limbic metabolism cannot be attributable to

treatment. Moreover, as stated previously, PET studies

in humans have not detected significant metabolic effects

of antipsychotics on the hippocampus(Bartlett et al.,

1994; Buchsbaum et al., 1987; Holcomb et al., 1996; Hol-comb et al., 1999; Vita et al., 1995) or to decrease its activ-

ity (Lahti et al., 2003). A possible decline in the global

rate of activity by haloperidol (Bartlett et al., 1994) would

be controlled in our study since the metabolic values were

calculated as rates relative to mean cortical activity. A

similar PF hypoactivation has been found in cases not

treated previously (Buchsbaum et al., 1992), supporting

the validity of our metabolic measures.The main advantages of this study include the simul-

taneous use of MRI and PET and the fact that a group

of similarly treated FE patients are studied in which the

diagnosis of schizophrenia has been ruled out. In con-

clusion, we found a relatively specific significant associ-

ation between PF cortical atrophy and limbic

hyperactivity in patients with first schizophrenic epi-

sodes supporting a common substrate for these altera-tions before manifestation of psychotic symptoms.

Acknowledgements

Supported in part by grants from the Fondo de Inves-

tigaciones Sanitarias (98/1084 and 00/0036) and Fund-

acion La Caixa (99/ 00-42). We specially thank DrReig, Dr Desco and the rest of the people in the Medical

Imaging Laboratory in the General Hospital Gregorio

Maranon (Madrid) for their necessary assistance in im-

age analyses.

References

Abi-Dargham A, Gil R, Krystal J, Baldwin RM, Seibyl JP, Bowers M,

van Dyck CH, Charney DS, Innis RB, Laruelle M. Increased

striatal dopamine transmission in schizophrenia: confirmation in a

second cohort. Am J Psychiatry 1998;155:761–7.

Akbarian S, Kim JJ, Potkin SG, Hagman JO, Tafazzoli A, Bunney Jr

WE, Jones EG. Gene expression for glutamic acid decarboxylase is

reduced without loss of neurons in prefrontal cortex of schizo-

phrenics. Arch Gen Psychiatry 1995;52:258–66, [discussion 267–

278].

Andreasen NC, Rajarethinam R, Cizadlo T, Arndt S, Swayze VW,

2nd, Flashman LA, O�Leary DS, Ehrhardt JC, Yuh WT.

Automatic atlas-based volume estimation of human brain regions

from MR images. J Comput Assist Tomogr 1996;20:98–106.

Andreasen NC, Arndt S, Swayze II V, Cizadlo T, Flaum M, O�LearyD, Ehrhardt JC, Yuh WT. Thalamic abnormalities in schizophre-

nia visualized through magnetic resonance image averaging.

Science 1994;266:294–8.

Andreasen NC, Rezai K, Alliger R, Swayze VWd, Flaum M, Kirchner

P, Cohen GDSOL. Hypofrontality in neuroleptic-naive patients

and in patients with chronic schizophrenia. Assessment with xenon

133 single-photon emission computed tomography and the Tower

of London. Arch Gen Psychiatry 1992;49:943–58.

Ashburner J, Friston KJ. Multimodal image coregistration and

partitioning – a unified framework. Neuroimage 1997;6:209–17.

Ashburner J, Friston KJ. Voxel-based morphometry – the methods.

Neuroimage 2000;11:805–21.

Barbas H. Architecture and cortical connections of the prefrontal

cortex in the rhesus monkey. Adv Neurol 1992;57:91–115.

Bartlett EJ, Brodie JD, Simkowitz P, Dewey SL, Rusinek H, Wolf AP,

Fowler JS, Volkow ND, Smith G, Wolkin A, et al. Effects of

haloperidol challenge on regional cerebral glucose utilization in

normal human subjects. Am J Psychiatry 1994;151:681–6.

Benes FM, Vincent SL, Alsterberg G, Bird ED, SanGiovanni

JP. Increased GABAA receptor binding in superficial layers

of cingulate cortex in schizophrenics. J Neurosci 1992;12:

924–9.

Benito C, Fernandez P, Desco M, Lampreave J, Molina V, Carreras J.

Multimodality imaging analysis in schizophrenia. Eur Radiol

1999;9:304.

Bertolino A, Knable MB, Saunders RC, Callicott JH, Kolachana B,

Mattay VS, Bachevalier J, Frank JA, Egan M, Weinberger DR.

The relationship between dorsolateral prefrontal N-acetyl aspartate

measures and striatal dopamine activity in schizophrenia. Biol

Psychiatry 1999;45:660–7, [see comments].

Bilder RM, Wu H, Bogerts B, Degreef G, Ashtari M, Alvir JM, Snyder

PJ, Lieberman JA. Absence of regional hemispheric volume

asymmetries in first-episode schizophrenia. Am J Psychiatry

1994;151:1437–47.

Buchsbaum MS, Haier RJ, Potkin SG, Nuechterlein K, Bracha HS,

Katz M, Lohr J, Wu J, Lottenberg S, Jerabek PA, et al.

Frontostriatal disorder of cerebral metabolism in never-medicated

schizophrenics. Arch Gen Psychiatry 1992;49:935–42.

BuchsbaumMS, Someya T, Teng CY, Abel L, Chin S, Najafi A, Haier

RJ, Wu J, Bunney Jr WE. PET and MRI of the thalamus in never-

medicated patients with schizophrenia. Am J Psychiatry

1996;153:191–9.

Buchsbaum MS, Wu JC, DeLisi LE, Holcomb HH, Hazlett E,

Cooper-Langston K, Kessler R. Positron emission tomography

studies of basal ganglia and somatosensory cortex neuroleptic drug

effects: differences between normal controls and schizophrenic

patients. Biol Psychiatry 1987;22:479–94.

Cahn W, Pol HE, Bongers M, Schnack HG, Mandl RC, Van Haren

NE, Durston S, Koning H, Van Der Linden JA, Kahn RS. Brain

morphology in antipsychotic-naive schizophrenia: a study of

multiple brain structures. Br J Psychiatry Suppl 2002;43:s66–72.

Callicott JH, Bertolino A, Mattay VS, Langheim FJ, Duyn J, Coppola

R, Goldberg TE, Weinberger DR. Physiological dysfunction of the

dorsolateral prefrontal cortex in schizophrenia revisited. Cereb

Cortex 2000;10:1078–92.

126 V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127

Curtis VA, Bullmore ET, Morris RG, Brammer MJ, Williams SC,

Simmons A, Sharma T, Murray RM, McGuire PK. Attenuated

frontal activation in schizophrenia may be task dependent.

Schizophr Res 1999;37:35–44.

Chakos MH, Lieberman JA, Bilder RM, Borenstein M, Lerner G,

Bogerts B, Wu H, Kinon B, Ashtari M. Increase in caudate nuclei

volumes of first-episode schizophrenic patients taking antipsychotic

drugs. Am J Psychiatry 1994;151:1430–6.

Deakin JF, Simpson MD. A two-process theory of schizophrenia:

evidence from studies in post-mortem brain. J Psychiatr Res

1997;31:277–95.

Deicken RF, Johnson C, Eliaz Y, Schuff N. Reduced concentrations of

thalamic N-acetyl aspartate in male patients with schizophrenia.

Am J Psychiatry 2000;157:644–7.

DeLisi LE, Hoff AL, Schwartz JE, Shields GW, Halthore SN, Gupta

SM, Henn FA, Anand AK. Brain morphology in first-episode

schizophrenic-like psychotic patients: a quantitative magnetic

resonance imaging study. Biol Psychiatry 1991;29:159–75, [pub-

lished erratum appears in Biol Psychiatry 1991 Mar 1;29(5):519].

Desco M, Benito C, Lopez J, Santos A, Reig S, Molina V, Garcia P.

Quantification of multimodality studies in schizophrenia. In:

Lemke H, editor. Computer Assisted Radiology and Sur-

gery. Amsterdam: Elsevier Science; 1999. p. 218–22.

Desco M, Pascau J, Reig S, Gispert JD, Santos A, Benito B, Molina V,

Garcia-Barreno P. Multimodality image quantification using

talairach grid. Proc SPIE Med Imaging 2001;4422:1385–92.

Frackowiak RSJ, Friston KJ, Frith CD, Dolan RJ, Mazziotta JC.

Human Brain function. Academic Press; 1997.

Friston KJ, Liddle PF, Frith CD, Hirsch SR, Frackowiak RS. The left

medial temporal region and schizophrenia. A PET study. Brain

1992;115:367–82.

Fuster J. In: Fuster J, editor. The prefrontal lobe. Philadelphia: Lip-

pincott-Raven; 1997.

Gilbert AR, Rosenberg DR, Harenski K, Spencer S, Sweeney JA,

Keshavan MS. Thalamic volumes in patients with first-episode

schizophrenia. Am J Psychiatry 2001;158:618–24.

Glantz LA, Lewis DA. Decreased dendritic spine density on prefrontal

cortical pyramidal neurons in schizophrenia. Arch Gen Psychiatry

2000;57:65–73.

Heckers S, Konradi C. Hippocampal neurons in schizophrenia. J

Neural Transm 2002;109:891–905.

Heckers S, Rauch SL, Goff D, Savage CR, Schacter DL, Fischman AJ,

Alpert NM. Impaired recruitment of the hippocampus during

conscious recollection in schizophrenia. Nat Neurosci

1998;1:318–23.

Holcomb HH, Cascella NG, Thaker GK, Medoff DR, Dannals RF,

Tamminga CA. Functional sites of neuroleptic drug action in the

human brain: PET/FDG studies with and without haloperidol. Am

J Psychiatry 1996;153:41–9.

Holcomb HH, Medoff DR, Lahti AC, Tamminga CA. Functional

neuroimaging in schizophrenia: symptoms, treatment and ethiol-

ogy. In: Tamminga CA, editor. Schizophrenia in a molecular

age. Washington: America Psychiatric Press; 1999.

Hollingshead A, Frederick R. Social stratification and psychiatric

disorders. Am Soc Rev 1953;18:163–89.

Huang YH, Tsai SJ, Huang HJ, Sim CB. The effect of acute

administration of risperidone on local cerebral glucose utilization

in the rat. Eur J Pharmacol 1999;370:257–61.

Huntley GW, Vickers JC, Morrison JH. Cellular and synaptic

localization of NMDA and non-NMDA receptor subunits in

neocortex: organizational features related to cortical circuitry,

function and disease. Trends Neurosci 1994;17:536–43.

Kates WR, Warsofsky IS, Patwardhan A, Abrams MT, Liu AM,

Naidu S, Kaufmann WE, Reiss AL. Automated Talairach atlas-

based parcellation and measurement of cerebral lobes in children.

Psychiatry Res 1999;91:11–30.

Konradi C, Heckers S. Antipsychotic drugs and neuroplasticity:

insights into the treatment and neurobiology of schizophrenia. Biol

Psychiatry 2001;50:729–42.

Lahti AC, Holcomb HH, Weiler MA, Medoff DR, Tamminga CA.

Functional effects of antipsychotic drugs: comparing clozapine with

haloperidol. Biol Psychiatry 2003;53:601–8.

Laruelle M, Abi-Dargham A, van Dyck CH, Gil R, D�Souza CD,

Erdos J, McCance E, Rosenblatt W, Fingado C, Zoghbi SS,

Baldwin RM, Seibyl JP, Krystal JH, Charney DS, Innis RB. Single

photon emission computerized tomography imaging of ampheta-

mine-induced dopamine release in drug-free schizophrenic subjects.

Proc Natl Acad Sci USA 1996;93:9235–40.

Lawrie SM, Whalley H, Kestelman JN, Abukmeil SS, Byrne M,

Hodges A, Rimmington JE, Best JJ, Owens DG, Johnstone EC.

Magnetic resonance imaging of brain in people at high risk of

developing schizophrenia. Lancet 1999;353:30–3.

Liddle PF, Friston KJ, Frith CD, Hirsch SR, Jones T, Frackowiak RS.

Patterns of cerebral blood flow in schizophrenia. Br J Psychiatry

1992;160:179–86.

Liddle PF, Lane CJ, Ngan ET. Immediate effects of risperidone on

cortico-striato-thalamic loops and the hippocampus. Br J Psychi-

atry 2000;177:402–7, [In Process Citation].

Matsumoto H, Simmons A, Williams S, Pipe R, Murray R, Frangou S.

Structural magnetic imaging of the hippocampus in early onset

schizophrenia. Biol Psychiatry 2001;49:824–31.

Mattson MP, Gary DS, Chan SL, Duan W. Perturbed endoplasmic

reticulum function, synaptic apoptosis and the pathogenesis of

Alzheimer�s disease. Biochem Soc Symp 2001:151–62.

McGlashan TH, Hoffman RE. Schizophrenia as a disorder of

developmentally reduced synaptic connectivity. Arch Gen Psychi-

atry 2000;57:637–48.

Molina V, Reig S, Desco M, Sarramea F, Pascau J, Gispert J, Sanz J,

Misiego J, Aragues M, Palomo T. Multimodality neuroimaging

studies and the neurodevelopmental hypothesis of schizophrenia.

Neurotoxicity Res 2002;4:437–51.

Molina V, Reig S, Pascau J, Sanz J, Sarramea F, Gispert JD, Luque R,

Benito C, Palomo T, Desco M. Anatomical and functional

variables associated with basal symptoms but not to risperidone

response in minimally-treated schizophrenia. Psychiatry Res Neu-

roimaging 2003;124:163–75.

Molina V, Reig S, Sanz J, Benito C, Pascau J, Collazos F, Sarramea F,

Artaloytia J, Gispert J, Luque R, Palomo T, Arango C, Desco M.

Association between relative frontal and temporal cortical CSF

and illness duration in schizophrenia. Schizophrenia Res

2002;58:305–12.

Molina V, Reig S, Sarramea F, Sanz J, Artaloytia J, Luque FR,

Aragues M, Pascau J, Benito C, Palomo T, Desco M. Anatomical

and functional brain variables associated to clozapine response in

treatment-resistant schizophrenia. Psychiatry Res Neuroimaging

2003;124:153–61.

Nelson MD, Saykin AJ, Flashman LA, Riordan HJ. Hippocampal

volume reduction in schizophrenia as assessed by magnetic

resonance imaging: a meta-analytic study. Arch Gen Psychiatry

1998;55:433–40.

Nopoulos P, Flaum M, Andreasen NC. Sex differences in brain

morphology in schizophrenia. Am J Psychiatry 1997;154:1648–54.

Nopoulos P, Torres I, Flaum M, Andreasen NC, Ehrhardt JC, Yuh

WT. Brain morphology in first-episode schizophrenia. Am J

Psychiatry 1995;152:1721–3.

O�Driscoll GA, Benkelfat C, SFlorencio P, Wolff AL, Joober R, Lal S,

CEvans A. Neural correlates of eye tracking deficits in first-degree

relatives of schizophrenic patients: a positron emission tomography

study. Arch Gen Psychiatry 1999;56:1127–34.

Ohnuma T, Kimura M, Takahashi T, Iwamoto N, Arai H. A magnetic

resonance imaging study in first-episode disorganized- type patients

with schizophrenia. Psychiatry Clin Neurosci 1997;51:9–15.

V. Molina et al. / Journal of Psychiatric Research 39 (2005) 117–127 127

Pakkenberg B. The volume of the mediodorsal thalamic nucleus in

treated and untreated schizophrenics. Schizophr Res 1992;7:

95–100.

Pantelis C, Velakoulis D, McGorry PD, Wood SJ, Suckling J, Phillips

LJ, Yung AR, Bullmore ET, Brewer W, Soulsby B, Desmond P,

McGuire PK. Neuroanatomical abnormalities before and after

onset of psychosis: a cross-sectional and longitudinal MRI com-

parison. Lancet 2003;361:281–8.

Pfefferbaum A, Lim KO, Zipursky RB, Mathalon DH, Rosen-

bloom MJ, Lane B, Ha CN, Sullivan EV. Brain gray and white

matter volume loss accelerates with aging in chronic alcoholics:

a quantitative MRI study. Alcohol Clin Exp Res

1992;16:1078–89.

Pierri JN, Chaudry AS, Woo TU, Lewis DA. Alterations in chandelier

neuron axon terminals in the prefrontal cortex of schizophrenic

subjects. Am J Psychiatry 1999;156:1709–19.

Rosvold H, Mirsky A, Sarason I, Bransome E, Beck L. A continuous-

performance test of brain damage. J Consult Psychol 1956;20:

343–52.

Rubin P, Holm S, Friberg L, Videbech P, Andersen HS, Bendsen BB,

Stromso N, Larsen JK, Lassen NA, Hemmingsen R. Altered

modulation of prefrontal and subcortical brain activity in newly

diagnosed schizophrenia and schizophreniform disorder. A regio-

nal cerebral blood flow study. Arch Gen Psychiatry 1991;48:

987–95.

Seidman LJ, Faraone SV, Goldstein JM, Goodman JM, Kremen WS,

Toomey R, Tourville J, Kennedy D, Makris N, Caviness VS,

Tsuang MT. Thalamic and amygdala-hippocampal volume reduc-

tions in first-degree relatives of patients with schizophrenia: an

MRI-based morphometric analysis. Biol Psychiatry 1999;46:

941–54.

Selemon LD, Goldman-Rakic PS. The reduced neuropil hypothesis: a

circuit based model of schizophrenia. Biol Psychiatry 1999;45:

17–25.

Selemon LD, Rajkowska G, Goldman-Rakic PS. Elevated neuronal

density in prefrontal area 46 in brains from schizophrenic patients:

application of a three-dimensional, stereologic counting method. J

Comp Neurol 1998;392:402–12.

Shen J, Petersen KF, Behar KL, Brown P, Nixon TW, Mason GF,

Petroff OA, Shulman GI, Shulman RG, Rothman DL. Determi-

nation of the rate of the glutamate/glutamine cycle in the human

brain by in vivo 13C NMR. Proc Natl Acad Sci USA

1999;96:8235–40.

Shenton ME, Dickey CC, Frumin M, McCarley RW. A review of

MRI findings in schizophrenia. Schizophr Res 2001;49:1–52.

Sibson NR, Dhankhar A, Mason GF, Rothman DL, Behar KL,

Shulman RG. Stoichiometric coupling of brain glucose metabolism

and glutamatergic neuronal activity. Proc Natl Acad Sci USA

1998;95:316–21.

Simpson MD, Slater P, Deakin JF. Comparison of glutamate and

gamma-aminobutyric acid uptake binding sites in frontal and

temporal lobes in schizophrenia. Biol Psychiatry 1998;44:423–7.

Simpson MD, Slater P, Deakin JF, Royston MC, Skan WJ. Reduced

GABA uptake sites in the temporal lobe in schizophrenia. Neurosci

Lett 1989;107:211–5.

Sokal RR, Rohlf FJ. Biometry. third ed.. W.H. Freeman and Co.;

1995.

Stevens AA, Goldman Rakic PS, Gore JC, Fulbright RK, Wexler BE.

Cortical dysfunction in schizophrenia during auditory word and

tone working memory demonstrated by functional magnetic

resonance imaging. Arch Gen Psychiatry 1998;55:1097–103.

Talairach J, Tournoux P. Co-planar stereotaxic atlas of the human

brain. Thieme Medical; 1988.

Vita A, Bressi S, Perani D, Invernizzi G, Giobbio GM, Dieci M,

Garbarini M, Del Sole A, Fazio F. High-resolution SPECT study

of regional cerebral blood flow in drug-free and drug-naive

schizophrenic patients. Am J Psychiatry 1995;152:876–82.

Volk DW, Austin MC, Pierri JN, Sampson AR, Lewis DA. Decreased

glutamic acid decarboxylase67 messenger RNA expression in a

subset of prefrontal cortical gamma-aminobutyric acid neurons in

subjects with schizophrenia. Arch Gen Psychiatry 2000;57:237–45.

Volk DW, Pierri JN, Fritschy JM, Auh S, Sampson AR, Lewis DA.

Reciprocal alterations in pre- and postsynaptic inhibitory markers

at chandelier cell inputs to pyramidal neurons in schizophrenia.

Cereb Cortex 2002;12:1063–70.

Volz H, Gaser C, Hager F, Rzanny R, Ponisch J, Mentzel H, Kaiser

WA, Sauer H. Decreased frontal activation in schizophrenics

during stimulation with the continuous performance test – a

functional magnetic resonance imaging study. Eur Psychiatry

1999;14:17–24.

Weinberger DR, Egan MF, Bertolino A, Callicott JH, Mattay VS,

Lipska BK, Berman KF, Goldberg TE. Prefrontal neurons and the

genetics of schizophrenia. Biol Psychiatry 2001;50:825–44.

Wilkinson LS, Dias R, Thomas KL, Augood SJ, Everitt BJ, Robbins

TW, Roberts AC. Contrasting effects of excitotoxic lesions of the

prefrontal cortex on the behavioural response to DD-amphetamine

and presynaptic and postsynaptic measures of striatal dopamine

function in monkeys. Neuroscience 1997;80:717–30.

Woods RP, Mazziotta JC, Cherry SR. MRI-PET registration with

automated algorithm. J Comput Assist Tomogr 1993;17:536–46.

Wotanis J, Hanak SE, Wettstein JG, Black MD. Comparative analysis

of acute and chronic administration of haloperidol and clozapine

using [3H] 2-deoxyglucose metabolic mapping. Schizophrenia Res

2003;61:195–205.