Six-dimensional dynamic tractography atlas of language connectivity in the developing brain

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Developmental Neuroscience

Background:

• Verbal conversation involves complex linguistic processing stages supported by interconnected cortical networks.
• Temporal and extratemporal lobes contain specialized regions for distinct language functions like phonology and semantics.

Purpose of the Study:

• To quantitatively map the strength, dynamics, and directionality of direct inter-lobar neocortical networks supporting linguistic processing across brain development.
• To investigate how age influences effective connectivity within language networks.

Main Methods:

• Utilized six-dimensional tractography to visualize direct inter-lobar effective connectivity.
• Analyzed intracranial electrocorticography data from 37 children (aged 5-20) with focal epilepsy.
• Employed single-pulse electrical stimulation to quantify direct effective connectivity and measured spectral responses.

Main Results:

• Direct effective connectivity was strongest between extratemporal and temporal lobe sites during the response preparation period.
• Older age correlated with increased inter-lobar effective connectivity, especially during response preparation.
• The arcuate fasciculus was a major pathway for temporal-to-extratemporal language-related connectivity.

Conclusions:

• Provides a novel atlas quantifying and animating inter-lobar neural communications in language areas.
• Demonstrates age-dependent strengthening of language-related effective connectivity, even after age 5.