The functional foetal brain: A systematic review and meta-analysis.

Area of Science:

• Neuroscience
• Developmental Biology
• Medical Imaging

Background:

• Previous research on fetal sensory evoked responses yielded inconsistent results due to methodological variability.
• This review expands on prior work by including studies on fetuses at risk for or exhibiting atypical development.

Purpose of the Study:

• To provide a comprehensive understanding of fetal sensory development, particularly auditory and visual evoked responses.
• To investigate the influence of fetal and maternal risk factors on sensory development.
• To identify key factors influencing response characteristics and suggest improvements for future research and clinical applications.

Main Methods:

• Systematic review and meta-analysis of 46 studies measuring fetal auditory and visual evoked responses using functional magnetic resonance imaging (fMRI) and fetal magnetoencephalography (fMEG).
• Inclusion of studies examining both healthy and atypically developing fetuses during the third trimester.

Main Results:

• Auditory stimuli primarily activate temporal brain regions, while visual stimuli activate frontal regions.
• Fetal evoked responses show comparable latencies and amplitudes between auditory and visual modalities.
• Atypical development negatively affects response latencies and amplitudes, with modality-specific moderating factors.
• Older fetuses exhibit increased response rates and decreased latencies compared to younger fetuses, irrespective of modality.

Conclusions:

• Fetal sensory systems, including auditory and visual processing, demonstrate functional capabilities in the third trimester.
• Atypical development poses a significant challenge to normal sensory maturation.
• Standardizing methodologies in fetal neuroimaging is crucial for developing reliable clinical assessment tools.