Cortical Face-Selective Responses Emerge Early in Human Infancy

Area of Science:

• Neuroscience
• Developmental Psychology
• Cognitive Science

Background:

• Multiple cortical regions, including the occipital face area (OFA), fusiform face area (FFA), superior temporal sulcus (STS), and medial prefrontal cortex (MPFC), are known to respond robustly to faces in adults.
• The developmental trajectory of face selectivity in these distinct cortical regions during infancy remains an active area of research.

Purpose of the Study:

• To investigate the emergence of face selectivity in OFA, FFA, STS, and MPFC during human development.
• To determine if face selectivity is present in these regions in early infancy and how it develops over time.

Main Methods:

• Combined two awake infant functional magnetic resonance imaging (fMRI) datasets, resulting in a larger sample size (n=65 infants, 2.6-9.6 months).
• Infants viewed movies of faces, bodies, objects, and scenes while fMRI data were collected.
• Utilized cross-validated functional region of interest analyses to assess face selectivity strength and nature.

Main Results:

• Individual subject whole-brain activation maps revealed face-selective responses in the approximate locations of OFA, FFA, STS, and MPFC.
• Across the larger sample, face responses in OFA, FFA, STS, and MPFC were significantly greater than responses to bodies, objects, and scenes.
• Infants as young as 2-5 months exhibited significant face-selective responses in FFA, STS, and MPFC, though not in OFA.

Conclusions:

• Face selectivity emerges in multiple cortical regions within months of birth.
• These findings provide significant constraints for theories explaining cortical development and face processing.
• Early-developing face selectivity in FFA, STS, and MPFC suggests a rapid maturation of social cognition circuits.