Functional connectivity in the developing brain: a longitudinal study from 4 to 9months of age

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• Intrinsic connectivity networks (ICNs) are fundamental to brain function.
• Understanding the developmental trajectory of ICNs is crucial for identifying typical and atypical brain development.
• Resting-state functional magnetic resonance imaging (fMRI) is a key tool for studying brain connectivity in infants.

Purpose of the Study:

• To characterize the developmental changes in ICNs between 4 and 9 months of infant age.
• To investigate alterations in functional network connectivity (FNC) strength and organization during this period.
• To explore age-related changes in specific brain regions, such as the posterior cingulate cortex.

Main Methods:

• Resting-state fMRI was conducted on sleeping infants (4-9 months) without sedation.
• Independent Component Analysis (ICA) was employed for data analysis at two model orders (30 and 100 components).
• Functional network connectivity (FNC) maps were generated and compared between age groups.

Main Results:

• The overall FNC map showed similarity between 4 and 9 months.
• Connectivity strength decreased within local networks but increased between distant networks by 9 months.
• Connectivity strength increased within the default-mode network (DMN) with age.
• Increased low-frequency power was observed with age in the posterior cingulate cortex and posterior DMN.

Conclusions:

• Infant brain development shows a pattern of increasing long-range functional connectivity from 4 to 9 months.
• This period is characterized by a shift towards greater integration across distributed brain networks.
• The findings suggest a significant developmental role for the posterior cingulate cortex during this early stage of life.