Functional Connectivity Disruption in Neonates with Prenatal Marijuana Exposure

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Pediatrics

Background:

• Prenatal marijuana exposure (PME) is associated with neurodevelopmental issues, but findings are inconsistent.
• Type-1 cannabinoid receptors (CB1R) are crucial for fetal neurodevelopment and mediate PME's impact on brain circuitry.
• Early brain development occurs before significant postnatal environmental influences.

Purpose of the Study:

• To investigate the effects of PME on the development of early brain functional circuitry.
• To examine brain connectivity in infants exposed to marijuana, other substances, or neither.

Main Methods:

• Resting-state functional connectivity was measured in infants (2-6 weeks old) during sleep.
• Participants included infants with PME (+MJ), infants exposed to other drugs (-MJ), and drug-free controls (CTR).
• Connectivity of subcortical regions with high fetal CB1R expression was analyzed.

Main Results:

• Infants with PME (+MJ) exhibited significantly reduced connectivity in the anterior insula and striatal regions compared to -MJ and CTR groups.
• Specific marijuana-linked alterations included hypo-connectivity in anterior insula-cerebellum and caudate-cerebellum circuits.
• Both +MJ and -MJ groups showed altered amygdala and thalamus connectivity compared to controls, indicating broader drug vulnerability.

Conclusions:

• PME-associated hypo-connectivity in striatal and insula circuits may underlie neurobehavioral deficits in attention, motor skills, and language.
• Disrupted anterior insula connectivity could affect interoception, decision-making, and later substance use risk.
• Early PME impacts brain functional circuitry development, highlighting the need for interventions.