Anesthesia targeting gamma-aminobutyric acid can regulate the timing of brain development in infants, according to the Northeastern study.
Early exposure to general anesthetics accelerates learning in infants, according to Northeastern University research, a finding that raises questions about the use of such drugs during critical periods of brain development.
“This opens up our ability to think about complicated forms of learning in early life,” says Laurel Gabard-Durnam, an assistant professor of psychology and director of the Plasticity in Neurodevelopment Lab at Northeastern University. “It’s going to help us understand why some learning outcomes or developmental outcomes may be happening and start to figure out what better support might look like in terms of timing, in terms of type of support, and in terms of interventions.”
The research — published in the Proceedings of the National Academy of Sciences — focuses on the chemical gamma-aminobutyric acid (GABA).
GABA is the main inhibitory chemical in the brain, and animal studies have shown it is particularly active during what Gabard-Durnam calls “windows of learning,” when the brain develops intensely to learn and retain new information.
The research finds that GABA similarly regulates brain development in infants.
But GABA is also the target for general anesthesia.
And research in infant rodents has found that prolonged exposure to general anesthesia resulted in neurological impairments as the rat aged.
“We know that surgical drugs are safe in a clinical sense, but we hadn’t really asked whether or not these drugs may be changing plasticity and brain learning in these infants in the same way that they seem to in the mouse models,” Gabard-Durnam says. “So we designed the study to ask that question.”
Gabard-Durnam and colleagues evaluated 93 infants with different amounts of exposure to general anesthesia shortly after birth, scanning their brain activity while they responded to black-and-white visual images. The infants were assessed at 3, 5, and 10 months of age.
Like in mice, babies exposed to general anesthesia in very early infancy showed accelerated brain development relative to their peers who were not exposed to the drug.
By 10 months of age, there was no difference between those who were and were not exposed to general anesthesia, according to the research.
Gabard-Durnam notes it may seem counterintuitive to think of accelerated learning as potentially harmful. But early exposure to trauma or other adverse conditions can also lead to accelerated brain development — and have been shown to have long-term consequences.
“If your kid gets something quickly in a rich and safe learning environment, that’s great, but not everybody has that environment,” Gabard-Durnam says. “You don’t necessarily want to learn things as fast as you can; you want to learn things as well as you can.”
Instead, Gabard-Durnam presents GABA as a “Goldilocks situation.”
“You want the right amount of GABA relative to other chemicals in your brain,” Gabard-Durnam says. “You don’t want too little — that’s when you end up with seizure-like activity in the brain; and you don’t want too much or we’d all be anesthetized.”
So, what does this mean for children — and their parents — who are weighing surgeries in which a general anesthetic will be used?
“We absolutely recommend that children have surgeries that are going to save their lives and improve their quality of lives,” Gabard-Durnam says.
She adds that parents and doctors should talk about perhaps scheduling more elective surgeries — for example, circumcision — after the first 12 months of life when possible in part to protect this early important window of brain learning.
“Not everything meets those criteria, and there may be good reasons to do things within the first year — even if they are ‘not elective’ — for quality of life,” Gabard-Durnam continues. “But these are active conversations that doctors and patients are having all the time.”
Meanwhile, Gabard-Durnam says researchers are currently testing drugs for infants that do not target GABA to manage pain and consciousness during surgeries.
And she hopes that the study will be continued so that researchers can follow the infants as they age.
“They are turning 5 to 6 years old and we’re starting to explore what behavioral outcomes look like for them when they’re young children now,” Gabard-Durnam says. “We’re excited to follow that up.”