Background and aims Behavioural and physiological changes have been recorded in newborns following exposure to maternal odours. We aimed to investigate the cortical activation following the presentation of maternal breast odours (MBO).
Methods We used a multichannel NIRS device to record bilaterally cortical activation in the orbito-frontal gyri (OFG), prefrontal (PFC) and primary somatosensory (S1) cortices during 50 s (10 s baseline, 10 s presentation, 30 s post-stimuli). Odours were presented in controlled conditions (silent room, active sleep, randomised order) using cotton cloths: clean (CC) and worn by the mother in her bra during preceding 12 h (MBO). Seventeen full-term infants were included. After systematic artefact removal HbO2 changes from baseline and between odours were compared using ANOVA and post-hoc analysis.
Results We found no S1 activation following any odour. MBO (and not CC) induced an increase bilaterally in the OFG (p > 0,001).
MBO as compared to CC elicited a higher increase (p < 0,05) in the OFG bilaterally and in the left PFC.
The mean increase of HbO2 from baseline during the 30 s post stimuli were higher in MBO as compared to CC:
· 3,3 (0,7–5,9) μmol/l vs 0,8 (-1,4–3,0) μmol/l in the left OFG.
· 2,4 (-0,3–5,2) μmol/l vs 1,1 (-1,2–3,4) μmol/l in the right OFG.
Conclusions Newborn infants can detect their MBO at a cortical level and discriminate it from a control smell. As MBO is used in the NICU it is of great interest to further investigate how hospitalised infants react cortically to MBO.