Schizophrenia research

Beyond the hallmark symptoms of schizophrenia (e.g., hallucinations, thought disorder…), the disease is associated with severe and persistent cognitive and sensory impairments that substantially affect daily functioning. For visual processing, significant behavioral and electrophysiological group differences between patients and controls have previously been found for context integration, face perception and visual attention. We replicated some of those results (Roinishvili et al. 2015, Herzog et al. 2009, Brand et al. 2005) but also showed that not all domains of vision are impaired by the disease (Lauffs et al., 2016; Grzeczkowski et al., 2018; Shaqiri et al., 2018).

Schizophrenia is a heritable, yet the genetic risk for the disease is scattered in hundreds or thousands of genes with individual small effects. Interestingly, some visual processing deficits are also present in the patients’ first-degree relatives. Those heritable markers, also called endophenotypes, are thus of particular interest because they lie along the causal pathway between genetic risks and clinical syndrome. In the last decade, we have proposed visual backward masking as an endophenotype of schizophrenia (Key Publications: Herzog, Kopmann et al., 2004; Chkonia et al., 2010). In addition to large performance deficit in schizophrenia patients, moderate deficits have also been highlighted in their unaffected relatives (da Cruz et al. 2020). Deficits have also been found in genetically-related condition, namely in 22q11 patients, schizoaffective disorder, bipolar disorder and in healthy individuals with subclinical traits but not in depression patients and abstinent alcoholics (Chkonia et al. 2012, Garrobio et al. 2020, Cappe et al. 2012). In the context of a genome-wide association study, the performance to the task was also linked to single nucleotide polymorphisms in the cholinergic system (Bakanidze et al. 2013). The task was also investigated using EEG and electrophysiological group differences in N200 were highlighted for schizophrenia patients and their relatives with respect to healthy controls (Plomp et al. 2013, da Cruz et al. 2020). The lab proposed that the group differences in backward masking is due to a deficit in the attention-mediated mechanism of amplifying the neural response to attended weak sensory stimuli (i.e. target enhancement, see Herzog et al. 2013).

Publications


Endophenotype
EEG
Schizotypy & 22q11
Visual processing
Intact processing in schizophrenia