Impaired Contour Object Perception in Psychosis.

BACKGROUND

Contour integration, the process of joining spatially separated elements into a single unified line, has consistently been found to be impaired in schizophrenia. Recent work suggests that this deficit could be associated with psychotic symptomatology rather than a specific diagnosis such as schizophrenia.

METHODS

Examining a transdiagnostic sample of participants with psychotic psychopathology, we obtained quantitative indices of contour perception in a psychophysical behavioral task. We also measured responses during an analogous task using ultra-high field (7T) functional magnetic resonance imaging (fMRI).

RESULTS

We found impaired contour discrimination performance among people with psychotic psychopathology (PwPP) (n = 63) compared with healthy control participants (n = 34) and biological relatives of PwPP (n = 44). Participants with schizophrenia (n = 31) showed impaired task performance compared with participants with bipolar disorder (n = 18). fMRI showed higher responses in the lateral occipital cortex of PwPP than in control participants. Using task-based functional connectivity analyses, we observed abnormal connectivity between visual brain areas during contour perception among PwPP. These connectivity differences only emerged when participants had to distinguish the contour object from background distractors, suggesting that a failure to suppress noise elements relative to contour elements may underlie impaired contour processing in PwPP.

CONCLUSIONS

Our results are consistent with impaired contour integration in psychotic psychopathology, and especially schizophrenia, that is related to cognitive dysfunction and may be linked to impaired functional connectivity across visual regions.