The study, published in Nature’s Scientific Reports, tested whether - and to what extent - ingestion of the food supplement GABA improves planning and controlling different actions, a crucial skill in real-life environments such as driving a car in stop and go traffic.
“In order to accomplish a task goal, real-life environments require us to develop different action control strategies in order to rapidly react to fast-moving visual and auditory stimuli,” explained the team – led by Laura Steenbergen and Lorenza Colzato from the Leiden Institute of Brain and Cognition. “When engaging in complex scenarios, it is essential to prioritise and cascade different actions.”
The team noted that controlling different and multiple actions while also responding to ever changing stimulus is something that is controlled by a variety of ‘cascades’ and systems in the brain – with one of the main systems involved in ‘action selection’ thought to be controlled by the inhibitory neurotransmitters gamma aminobutyric acid (GABA).
“The present study aims to provide converging and direct evidence to verify the possible pivotal role of the GABA-ergic system in modulating the efficiency of action cascading,” wrote the team – who reported that people supplemented with 800 mg of GABA performed significantly better in tests than those who received a placebo.
“Even if preliminary, these results show that food supplements that include GABA, and perhaps foods rich in GABA, are a healthy and cheap way to increase our ability to prioritize planned actions,” commented Colzato. “For instance, people driving a car may benefit from additional GABA.”
Stop-change trial
Steenbergen, Colzato, and their colleagues assessed the role of the GABA-ergic system in controlling the efficiency of action cascading in a double-blind, randomised trial that saw 30 healthy adults receive supplementation with either 800 mg of GABA or a placebo of 800 mg oral of microcrystalline cellulose.
Participants then performed a stop-change paradigm test, designed to assess the reaction time to a changing signal. In the test, participants are required to stop an ongoing response to a GO stimulus whenever a STOP and then CHANGER stimulus are presented.
“The STOP stimulus is followed by a CHANGE stimulus, signalling participants to shift to an alternative response,” explained the team – noting that the time between the STOP and CHANGE signals are manipulated to either happen simultaneously or with a short delay.
“While reaction times (RTs) to the GO stimuli are assumed to reflect the efficiency of response execution, RTs on stop-change trials can be taken to reflect the efficiency of action cascading, with shorter RTs reflecting a more efficient action selection,” they explained.
Improved performance
Results from the stop-change test showed that supplementation with GABA, compared to placebo, increased action selection response time both when the stop and change signals were presented simultaneously and also when there was a short delay in the change signal.
“In addition, the lack of any group difference in responding to the GO trials demonstrates the specific importance of synthetic GABA for stop-change processes, as opposed to (easy) automatic responding processes,” said the team. “This is in line with the idea that the GABA-ergic system plays a crucial and specific role in the selection of and the coordination between different actions by suppressing competing response options.”
As a result, the authors said their findings offer the first ‘substantial support’ for the idea of a crucial role of GABA and the GABA-ergic system in action cascading.
Source: Scientific Reports
Issue 5, Article number: 12770 (2015), doi: 10.1038/srep12770
“γ-Aminobutyric acid (GABA) administration improves action selection processes: a randomised controlled trial”
Authors: Laura Steenbergen, et al