Sex, Age, Symptoms and Illness Duration and Their Relation with Gyrification Index in Schizophrenia.

INTRODUCTION: The Gyrification Index (GI) represents the degree of cortical folding and is of special interest in schizophrenia, since alterations in cortical folding indirectly reflect white matter development and axonal connectivity underneath. To the best of our knowledge, very few studies have investigated the effect of sex on GI in schizophrenia. Differences in the GI between patients with schizophrenia and healthy controls and the relation between sex, age symptoms and duration of illness with GI were investigated. METHODS: T1-images were acquired from schizophrenia patients (24 males [SZ-M] and 24 females [SZ-F]) and healthy volunteers (24 males [NC-M] and 24 females [NC-F]) matched for age, sex and handedness. GI analyses were performed using the fully automated CIVET pipeline. RESULTS: Significantly lower GI was found in patients relative to controls bilaterally in frontal, temporal, and parietal cortex. Sex differences were found: negative correlation was found between the duration of illness and the right parietal GI and right occipital GI in SZ-M, while SZ-F was found in the left frontal and bilateral temporal GI. Patients, regardless of sex, showed positive correlations between negative symptoms and GI in the right occipital. NC-F had greater GI values than SZ-F and both male groups. CONCLUSIONS: Since GI reflects, in part, alterations in cerebral development and connectivity, the decrease in GI observed in patients is in agreement with the neurodevelopmental model of disconnectivity in schizophrenia; in addition, we emphasize the importance of sex differences in schizophrenia.

Brain activity associated with the electrodermal reactivity to acute heat pain.

Pain is associated with the activation of many brain areas involved in the multiple dimensions of the experience. Several of those brain areas may also contribute to the monitoring and regulation of autonomic activity but this aspect of pain responses has been largely overlooked in human imaging studies. This functional magnetic resonance imaging (fMRI) study relied on blood-oxygen level dependent (BOLD) signal to investigate subject-related differences in brain activity associated with the individual differences in electrodermal responses evoked by 30 s noxious (pain) and innocuous (warm) thermal stimuli. Pain-related activity (pain-warm) was found in the thalamus, somatosensory cortices (leg area of SI/MI, SII, and insula), the anterior cingulate cortex (ACC), and the amygdala. Brain activation related to stimulus-evoked electrodermal activity was identified by modeling the predicted BOLD responses with the magnitude of each subject's skin conductance reactivity. Subjects showing larger skin conductance reactivity to the innocuous and/or noxious stimuli displayed larger stimulus-evoked brain responses in the somato-motor cortices (SI/MI, SII, and insula), the perigenual and supracallosal ACC, the orbitofrontal cortex and the medulla. Further analyses revealed brain activation more specifically associated with the pain-related skin conductance reactivity in the supracallosal ACC, amygdala, thalamus, and hypothalamus. These findings demonstrate that individual differences in electrodermal reactivity partly reflect differences in pain-evoked brain responses, consistent with a role of these structures in the monitoring/regulation of pain-related autonomic processes.