Gender Differences in Neural Networks for Color Processing in Mice: A PET/MR Study

Color processing is a central component of mammalian vision. Gender-related differences of color processing revealed by non-invasive functional transcranial Doppler ultrasound suggested right hemisphere pattern for Blue/Yellow chromatic opponency by men, and a left hemisphere pattern by women. The present study measured the blood-flow related accumulation of [18F]fluorodeoxyglucose ([18F]FDG) in mouse brain using small animal positron emission tomography and magnetic resonance imaging (PET/MRI) with statistical parametric mapping during light stimulation with Blue and Yellow filters compared to darkness condition.
PET revealed a reverse pattern compared to previous human studies: Male mice presented with left visual cortex dominance for blueON-channels through the right eye, while female mice presented with right visual cortex dominance for blueON-channel through the left eye. We applied statistical parametric mapping (SPM) to examine gender differences in activated architectonic areas within the orbital and medial prefrontal cortex and their cortico-cortical connections and sub-cortical networks that lead to the striatum, medial thalamus and other brain areas. The connectivity evoked by Blue stimulation spread through a wide range of brain structures implicated in viscerosensory and visceromotor systems in the left intra-hemispheric regions in male mice, but in the right-to-left inter-hemispheric regions in female mice. Spatial and chromatic opponency was maintained using a yellowON-OFF push-pull interaction in male mice, but a blueON-ON push-forward interaction in female mice. Color functional ocular dominance plasticity was noted in the right eye in male mice but in the left eye in female mice. This animal model could be used in the study of color processing mechanisms and gender complementarity in normal and pathological brain conditions.