Abnormal cortical folding in high-risk individuals: a predictor of the development of schizophrenia?

Reduced brain cortical folding in schizophrenia revealed in two independent samples

“…Although based on a small sample, the results indicate that early onset of schizophrenia may be related to higher lGI in the frontal cortex, and that the association between duration of illness and lGI differs across the cortex. Our finding of a relationship between higher lGI and earlier onset among the younger patients is partly supported by studies of subjects at high risk for developing psychosis, where hypergyria in right prefrontal cortex was found in subjects who later developed schizophrenia compared to subjects who did not (Harris et al, 2004(Harris et al, , 2007, while hypogyria in left hemisphere were found in high-risk subjects compared to controls (Jou et al, 2005).…”

“…Falkai et al, 2007) GI have been found using manual or automated methods on coronal sections of MR images, and one study did not find significant group differences (Highley et al, 2003). Higher GI in prefrontal cortex has been found among high-risk patients who later developed schizophrenia compared to those who did not (Harris et al, 2004(Harris et al, , 2007. Studies using the automated lGI method have shown reduced folding in the right prefrontal cortex among patients with adolescent onset (Janssen et al, 2009) and adult onset schizophrenia (Palaniyappan et al, 2011), and reduced folding in the left insula and medial parieto-occipital cortex in adult onset schizophrenia (Palaniyappan and Liddle, 2012).…”

White matter alterations related to P300 abnormalities in individuals at high risk for psychosis: an MRI–EEG study

“…19 Such increases could also be considered reflective of increased prefrontal cortical folding, as measured by the gyrification index, which can be seen as an indirect measure of axonal connectivity. 66 Increased prefrontal gyrification has been demonstrated in patients with schizophrenia 67 and has been shown to be predictive of transition to psychosis in high-risk cohorts. 68 …”

Abnormal cortical folding patterns within Broca's area in schizophrenia: Evidence from structural MRI

“…Previous studies have shown regional cortical folding abnormalities of gyrification (Harris et al, 2004a;Harris et al, 2004b;Kulynych et al, 1997;Sallet et al, 2003;Vogeley et al, 2000), asymmetry, complexity and variability (Narr et al, 2001;Narr et al, 2004) in patients with schizophrenia. These studies used a variety of methods to compare the spatial distribution of entire gyri and sulci.…”

“…Cortical folding abnormalities in schizophrenia measured using the gyrification index (GI) methodology (Zilles et al, 1988) have been reported in post-mortem (Vogeley et al, 2000) and MRI studies (Harris et al, 2004a;Harris et al, 2004b;Kulynych et al, 1997;Sallet et al, 2003). Since the GI measures the ratio of inner and outer cortical surface contours, these studies were limited to analyses of brain slices in different lobes.…”