Visual cortical functional connectivity alterations and their associations with psychotic symptoms in early-onset bipolar disorder.

BACKGROUND

Visual cortical dysfunction has been implicated in the early stages of psychosis and associated with psychotic symptoms. However, the functional connectivity (FC) of visual regions in early-onset bipolar disorder (EOBD) remains poorly understood. This study aimed to examine visual-related FC alterations in EOBD and explore their associations with psychiatric symptoms and clinical characteristics.

METHODS

Eighty-eight EOBD individuals and 56 healthy controls (HCs) underwent resting-state functional MRI. Visual cortical regions were selected by seeds from a probabilistic visual atlas. Twenty-five seed-based FC were compared between groups. Partial correlations with multiple comparison corrections were conducted to examine associations between altered FC and psychiatric symptoms in EOBD.

RESULTS

Compared to HCs, 14 visual cortical seeds showed higher FC with frontal and posterior temporal areas, while 5 visual cortical seeds showed lower FC with temporal and sensorimotor related regions. Higher psychotic positive, negative, and general scores were significantly associated with higher FC in visual and frontal regions, particularly involving the right lateral occipital complex area 1 (LO1), LO2, human middle temporal visual area (hMT/V5), intraparietal sulcus (IPS5), precentral gyri, and superior frontal gyri.

CONCLUSION

Individuals with EOBD exhibited altered visual system connectivity, characterized by higher FC with frontal regions and lower FC with sensorimotor and emotion regulation related regions. These findings suggest that visual-related FC abnormalities may emerge in the early course of BD and are associated with psychotic symptoms, potentially serving as early markers of vulnerability to psychosis.