If you struggled with math as a child, blame your neurotransmitters.
Researchers have long thought that brain excitement and inhibition levels are related to learning, especially during formative developmental years. Precisely how the activity related to complex learning over decades, however, has remained a mystery.
Roi Cohen Kadosh, a researcher at the University of Surrey, looked into how to improve cognitive functioning and realized math — something he loves that isn’t exactly a universally beloved subject — could be an instructive metric.
“I love math,” he tells Inverse. “But from a less selfish perspective, it is a critical ability that many struggle with — it takes years to master it to some degree, and it has an impact throughout our lives.”
To quantify this, Kadosh and his colleagues took a novel approach to find answers: a study analyzing the concentration of key neurotransmitters and mathematical ability over time. They concluded that math ability is "associated with concentrations of the neurotransmitters GABA and glutamate." This research could lead to better strategies to help students learn math, a vital skill for the welfare of society.
The researchers’ results, published today in PLOS Biology researchers from the University of Oxford note that mathematical ability is “associated with factors that are central to the welfare of the entire society including educational progress, socioeconomic status, employment, salary, mental and physical health, and financial difficulties.”
The background — To better understand these complex neurobiological processes associated with learning, researchers from the University of Oxford focused on two neurotransmitters associated with neural plasticity and learning: GABA and glutamate. These two chemical messengers have complementary roles — GABA inhibits neurons, while glutamate makes neurons more active.
How these neurotransmitters are associated with learning and “school-based skills” has been hard to study because much of what we know comes from rodent experiments in the lab.
What they did — To understand how these neurotransmitters are associated with learning in humans, researchers measured the levels of these GABA and glutamate in 255 people.
- The participants’ ages ranged from six years old to college students
- While their brain activity was being measured, participants took a math achievement test
- They then repeated the process 1.5 years later with the same participants to determine if GABA and glutamate levels could predict later math ability
This longitudinal design, the researchers say, “allowed us to further examine whether neurotransmitter concentration is linked to Mathematical Ability as well as predict Mathematical Ability in the future. Crucially, adopting this design allowed us to discern the selective effect of glutamate and GABA in response to natural (i.e., learning in school) stimulation.”
What’s new — The researchers found two distinct, age-dependent processes:
- In young participants, high GABA levels in a part of the brain called the left intraparietal sulcus (IPS) were associated with high performance on the math tests. Notably, in these same young subjects, low glutamate levels in the IPS were associated with low performance on the math tests.
- When they looked at the university participants, the researchers found the opposite: In older participants, high glutamate levels in the IPS were associated with greater math ability. Lower GABA levels in the IPS were associated with worse math ability.
Cohen Kadosh believes the difference between older and younger students needs to be further explored, but he has a few hypotheses. “It might link to different reasons. We mostly attributed it to sensitive periods in development when have to go through a lot of changes and learning, while at an older age it may link to other existing knowledge and involve different changes,” he says.
What’s clear, Cohen Kadosh says, is “The role of GABA and glutamate might not be the same at different developmental stages.”
When they compared the neurotransmitter levels with each of the math tests, the researchers found that young participants with high GABA levels did better both on the initial test and the test 1.5 years later; in older adults, the same was true with glutamate. In other words, the neurotransmitter levels could accurately predict math ability 1.5 years later.
What’s next — This study gives researchers a better understanding of learning and these two neurotransmitters associated with brain plasticity, particularly during ages crucial to brain development. By evaluating students over a period of years, we now have insight into the process of brain development instead of a narrower window of individual stages.
Cohen Kadosh says, “We hope that this knowledge will allow us to understand why some, at different levels, are struggling with learning and perform suboptimally at the cognitive level. We then hope to find how we could work on those mechanisms to examine if we can improve learning and cognition.”
These learning interventions could come in different forms, he adds. For example, he says, “cognitive (or some call it brain) training, neurofeedback, nutrition/pharmacology, and one that we work quite a lot with, which is non-invasive brain stimulation.”
Cohen Kadosh believes many people could benefit from more targeted learning interventions.
“I hope that we could achieve that,” he says. “It would be great.”
Abstract: Previous research has highlighted the role of glutamate and gamma-aminobutyric acid (GABA) in learning and plasticity. What is currently unknown is how this knowledge translates to real-life complex cognitive abilities that emerge slowly and how the link between these neurotransmitters and human learning and plasticity is shaped by development. While some have suggested a generic role of glutamate and GABA in learning and plasticity, others have hypothesized that their involvement shapes sensitive periods during development. Here we used a cross-sectional longitudinal design with 255 individuals (spanning primary school to university) to show that glutamate and GABA in the intraparietal sulcus explain unique variance both in current and future mathematical achievement (approximately 1.5 years). Furthermore, our findings reveal a dynamic and dissociable role of GABA and glutamate in predicting learning, which is reversed during development, and therefore provide novel implications for models of learning and plasticity during childhood and adulthood.