Supplementary Material for: Neurological Soft Signs and Brainstem Morphology in First-Episode Schizophrenia

<b><i>Background:</i></b> Minor motor and sensory deficits or neurological soft signs (NSS) have frequently been reported in patients with schizophrenia at any stage of their illness. NSS have been demonstrated to correlate with neuroanatomical abnormalities in various brain regions. Despite its important role in the integration and coordination of automatic motor actions, the brainstem has so far rather been ignored in previous neuroimaging studies on NSS in schizophrenia. <b><i>Method:</i></b> We investigated 21 right-handed first-episode schizophrenia patients using high-resolution magnetic resonance imaging at 3 T. The severity of NSS was measured with the Heidelberg Scale. Associations between NSS and both brainstem volume and shape changes were examined. <b><i>Results:</i></b> Higher NSS scores were significantly associated with structural alterations in the brainstem. According to volume measurements higher NSS scores correlated with global changes of the brainstem. Using shape analyses these associations referred to regionally specific morphometric alterations predominantly in the midbrain and pons. <b><i>Conclusion:</i></b> The findings suggest that brainstem morphometric alterations are associated with the severity of NSS in patients with first-episode schizophrenia. They further indicate the involvement of the brainstem in the pathogenesis of schizophrenia

Supplementary Material for: Neurochemical Correlates of Cue Reactivity in Individuals with Excessive Smartphone Use

Background: Excessive smartphone use (ESU), that is, a pattern of smartphone use that shows specific features of addictive behavior, has increasingly attracted societal and scientific interest in the past years. On the neurobiological level, ESU has recently been related to structural and functional variation in reward and salience processing networks, as shown by, for example, aberrant patterns of neural activity elicited by specific smartphone cues. Objectives: Expanding on these findings, using cross-modal correlations of magnetic resonance imaging (MRI)-based measures with nuclear imaging-derived estimates, we aimed at identifying neurochemical pathways that are related to ESU. Methods: Cross-modal correlations between functional MRI data derived from a cue-reactivity task administered in persons with and without ESU and specific PET/SPECT receptor probability maps. Results: The endogenous mu-opioid receptor (MOR) system was found to be significantly (FDR-corrected) correlated with fMRI data, and z-transformed correlation coefficients showed an association (albeit nonsignificant after FDR-correction) between MOR and the Smartphone Addiction Inventory “withdrawal” dimension. Conclusions: We could identify the MOR system as a neurochemical pathway associated with ESU. The MOR system is closely linked to the reward system, which has been recognized as a key player in addictive disorders. Together with its potential link to withdrawal, the MOR system hints toward a biologically highly relevant marker, which should be taken into consideration in the ongoing scientific discussion on technology-related addictive behaviors