Neurocognitive processing of infant stimuli in mothers and non-mothers: psychophysiological, cognitive and neuroimaging evidence.

Emerging evidence indicates that mothers and non-mothers show different neurocognitive responses to infant stimuli. This study investigated mothers' psychophysiological, cognitive and neuronal responses to emotional infant stimuli. A total of 35 mothers with 4-month-old infants and 18 control women without young children underwent computerized tests assessing neurocognitive processing of infant stimuli. Their eye gazes and eye fixations, galvanic skin responses (GSRs) and facial expressions towards infant emotional stimuli were recorded during the tasks. Participants underwent functional magnetic resonance imaging during which they viewed pictures of an unknown infant and, for mothers, their own infants. Mothers gazed more and had increased GSR towards infant stimuli and displayed more positive facial expressions to infant laughter, and self-reported more positive ratings of infant vocalizations than control women. At a neural level, mothers showed greater neural response in insula, dorsolateral prefrontal cortex and occipital brain regions within a predefined 'maternal neural network' while watching images of their own vs unknown infants. This specific neural response to own infants correlated with less negative ratings of own vs unknown infants' signals of distress. Differences between mothers and control women without young children could be interpreted as neurocognitive adaptation to motherhood in the mothers.

The maternal brain: Neural responses to infants in mothers with and without mood disorder.

Mothers' sensitive responses to their infants have evolutionary importance and are likely hardwired into the maternal brain. Mood disorders are associated with aberrant neural processing of emotion in regions overlapping with 'maternal sensitivity networks' which could compromise maternal processing of infant signals. This systematic review aimed to integrate findings from studies of neural responses to infant stimuli in healthy mothers and in mothers with mood disorders. We included original studies using functional brain imaging and electrophysiological techniques. The databases psycINFO and PubMed were searched for eligible articles until January 2019. Twenty-seven studies met the inclusion criteria, none of which investigated mothers with bipolar disorder or remitted unipolar disorder. Studies were characterized by large methodological heterogeneity. The most consistent findings were that healthy mothers exhibit stronger and faster neural responses to infant stimuli than non-mothers in key emotional processing regions including the amygdala, insula and orbitofrontal cortex, which is accentuated for own infants. Motherswith acute depression display blunted neural responses within these regions which correlates with greater depression severity.