THE CINGULATE GYRUS IS A cortical area of mixed cytoarchitectonics that links to the limbic system and neocortex.
1 The subcomponents of the cingulate gyrus serve a range of functions, including emotional, cognitive and attentional, nociceptive, and motor processing.
2-4 Grossly, the anterior cingulate cortex (ACC) is differentiated from the posterior cingulate cortex on the basis of cytoarchitecture, projection patterns, and functions.
5-7 For example, the anterior cingulate gyrus is activated by emotional stimuli, whereas the posterior cingulate gyrus is activated by both emotional and nonemotional stimuli and plays an important role in memory access and visuospatial orientation.
5,7 Within the ACC, further parcellation can be made on the basis of functional and anatomical studies.
8 The rostral area of the ACC (the affective subregion) is connected to the nucleus accumbens, amygdala, insula, hippocampus, and orbitofrontal cortex and assesses the salience of emotional and motivational information regulating emotional responses.
8 The caudal (dorsal) area of the ACC (the cognitive subregion) has strong reciprocal interconnections with the lateral prefrontal cortex, parietal cortex, and premotor and supplementary motor areas
9 and modulates attention and executive functions, error detection, and working memory.
7,10-12 The portion of the ACC located inferior to the genu of the corpus callosum (subgenual subregion) has extensive connections to structures implicated in emotional behavior, mood, and autonomic responses to stressors
13 and is the region used for deep-brain stimulation for treatment-resistant depression.
14Abnormalities in these structures play a crucial role in the dysfunction of cognitive and emotional processing in patients with schizophrenia.
15 Magnetic resonance imaging (MRI) studies have demonstrated that anterior
16-21 and posterior
17,22 cingulate gyrus volumes in schizophrenic patients are smaller than in control subjects, although findings have been controversial,
23-25 and may differ by sex.
18,19 Voxel-based morphometry (VBM) studies have reported decreased cingulate gray matter signal density in subjects at high risk for schizophrenia
26 or first-episode schizophrenia (FESZ).
27,28 Studies have also reported decreased gray matter in subjects at high risk of schizophrenia (optimized VBM)
29 and associated with the allele containing the Val158Met polymorphism of the catechol
O-methyltransferase gene in chronic schizophrenia (deformation-based study).
30Decreased volume of the ACC was associated with impaired executive function in schizophrenic patients,
31 which is compatible with results of positron emission tomography studies showing abnormal ACC activity for tasks examining the effects of interference
32 and attention
33,34 in schizophrenia. These studies divided the cingulate gyrus into anterior and posterior parts, without the finer parcellation of the ACC as described in the preceding paragraphs.
8-10,13Abnormalities in the cingulate gyrus have also been reported in affective disorder (mostly bipolar disorder), including smaller subgenual volume
35-40 and decreased functional activity.
2,39 Postmortem studies have reported more prominent nonpyramidal neuronal loss in layer II in the ACC in affective psychosis compared with schizophrenia, although pyramidal (particularly in layer IV) and nonpyramidal neuron loss were present in schizophrenia.
41 However, it remains to be determined whether cingulate gyrus gray matter volumetric abnormalities occur preferentially in schizophrenia or affective disorder, and whether there are specific subregional differences. Patients in their first hospitalization (first-episode patients) present an excellent population in which to examine these issues because they are free of the long-term direct and indirect consequences of the disease, including long-term pharmaceutical treatment.
In addition, longitudinal examination of brain structure in first-episode patients may help determine whether the time of psychotic symptom onset is the critical period for this volume change, and whether this change may be progressive.
42 Unfortunately, there are few longitudinal studies of cingulate gyrus.
16 A longitudinal study using VBM but without a healthy comparison group showed that left ACC gray matter density decreased over time in FESZ, whereas patients with bipolar disorder showed a bilateral decrease in ACC gray matter density.
43 Right ACC gray matter density loss was reported in high-risk subjects developing schizophrenia.
44Abnormalities in the paracingulate sulcus (PCS) pattern may provide a robust marker of the contribution of neurodevelopmental factors to schizophrenia,
45,46 because cerebral folding occurs during the second and third trimester
47,48 and is stable thereafter, unlike volumes, which may change with disease progression.
Herein, we report cross-sectional and longitudinal gray matter volume findings for cingulate gyrus subregions in patients with FESZ or first-episode affective psychosis (FEAFF, mainly bipolar in a manic phase), compared with healthy control subjects (HCs). Paracingu-late sulcus patterns
45 were also examined to investigate the association of gyrification with diagnosis.