This symposium will present recent findings on multimodal imaging, EEG and MRI, in high-risk groups for psychosis and schizophrenia. In the high risk groups, we will have the presentation by Christoph Mulert as well as two presentations on biomarkers for psychosis in 22q11.2 Deletion Syndrome by Maria Carmela Padula and Tonia Rihs. Armida Mucci will present recent findings on biomarkers of negative symptoms in schizophrenia. The aim is to address how EEG and MRI neuroimaging can contribute to the search for biomarkers of psychosis and negative symptoms in participants at high risk for schizophrenia or living with schizophrenia.

Negative symptoms are core aspect of schizophrenia, which might be present in all phases of the disorder and predict poor outcome.

The assessment and definition of negative symptoms underwent important changes during the last decade challenging previous pathophysiological models.

A large consensus accumulated on the subdivision of negative symptoms in two clusters: avolition and expressive deficit. Alterations in several circuits related to the processing of reward, its valuation and translation in goal-directed behavior are hypothesized for the avolition domain, while alterations of cortico-cortical connections might underlie the expressive deficit.

The presentation will review electrophysiological and brain imaging correlates of negative symptoms, critically addressing the role of confounding factors on heterogeneity of findings.

With the aim to find EEG biomarkers for schizophrenia, we investigate EEG microstates during sensory processing and resting state in children and adolescents with 22q11 deletion syndrome, who carry a high genetic risk for schizophrenia in adulthood. In an auditory oddball paradigm we find that the characteristic mismatch response is found in children but not adolescents with 22q11DS. In a paradigm investigating visual illusory contour perception with Kanizsa shapes we observe reduced activity over visual processing areas as well as marked increases of anterior cingulate and medio-dorsal frontal cortex activations. We will discuss how the reduced activity of sensory processing areas and the aberrant activity over anterior cingulate cortex relate to positive and negative symptoms in 22q11DS.

Patients with 22q11.2 deletion syndrome (22q11DS) present an ultra-high risk of developing schizophrenia (30-40%), thus representing a unique model for investigating biomarkers associated to psychosis.

When comparing patients with high and low positive symptoms severity, we found alterations in structural connectivity (measured with diffusion tensor imaging and structural covariance of cortical thickness) and in functional connectivity (measured with resting-state fMRI), which converged in indicating that disconnectivity of the anterior cingulate cortex (ACC) is associated with higher levels of symptoms.

Therefore, we concluded that disconnectivity of the ACC is a valuable biomarker of psychosis in patients with 22q11DS

Christoph Mulert (UKE, Hamburg) will focus on EEG and fMRI findings in subjects in the clinical high-risk state for psychosis (HRP). Recent studies include findings of alterations in EEG microstates, theta- and gamma oscillations. In addition he will present results of simultaneous EEG-fMRI studies in HRP subjects. These findings are discussed as potential markers for the prediction of HRP to frank psychosis.