Reduced prefrontal response to fearful faces in recent mothers with bipolar disorder and its association with mother-infant interaction and infant development

INTRODUCTION: Bipolar disorder (BD) is a severe mood disorder that often involves cognitive impairments, functional disability and reduced quality of life. Additionally, children of individuals with BD face an increased risk of developing mental illness.

OBJECTIVES: This functional magnetic resonance imaging (fMRI) study aimed to assess neural responses to fearful versus happy facial expressions in BD mothers compared to healthy mothers and to explore associations between neural activation and mother infant-interactions and infant development.

METHODS: Twenty-six mothers with BD in remission and 35 healthy mothers underwent fMRI during which they viewed images displaying either fearful or happy faces. All participants completed the facial expression recognition task outside the scanner where they were asked to identify the emotions displayed. Mother infant-interactions and infant development were also assessed.

RESULTS: Mothers with BD displayed reduced left frontal pole response to fearful versus happy faces compared to healthy mothers (p = 0.002) in whole-brain analyses. Lower activation of the left frontal pole was associated with lower dyadic reciprocity in mother-infant interaction (p=0.03). There were no differences in neural response between groups in other emotion processing regions or in facial expression recognition accuracy outside the scanner.

CONCLUSIONS: The selective lower frontal pole response to fearful faces in mothers with BD may contribute to poorer mother-infant interactions. The absence of broader differences in neural activity or facial expression recognition accuracy might signal motherhood-related attenuation of emotional-cognitive difficulties in BD.