A new study conducted at the Centre for Neuroscience at the University of California, Davis, published recently in the journal Cognitive Neuroscience, suggests that entrainment (or synchronisation) of theta brain waves (often occurring during periods of intense monitoring) not only enhances the activity thereof, but may also boost memory function.
Previous work performed by Professor Charan Ranganath and colleagues from the Centre of Neuroscience has found that higher theta wave activity prior to a memory task predicted superior performance.
Now, to find out whether an intervention designed to entrain theta waves in the brain could enhance memory, Brooke Roberts – a postdoctoral researcher in Ranganath’s lab – obtained a commercially available theta wave entrainment device and enrolled 50 volunteers for a series of tests.
While the type of device used in the study is often sold with the promise of relieving anxiety, sleep issues, low mood, and sub-standard learning capacity (none of which is supported by much in the way of scientific evidence), Roberts wanted to know if such devices could be successfully used to aid the formation and retrieval of memories.
Volunteers either used the device (which exposes the brain to audio-visual stimuli designed to enhance activity at 5.5 Hz) for 36 minutes, or listened to white noise for the same duration, and then performed a simple memory test. Results showed both improved memory performance and enhanced theta wave activity.
The second experiment used the same design, only this time the control group received beta wave stimulation, rather than listening to white noise. Beta waves are typically associated with normal waking consciousness.
Results of the second experiment were nearly identical to those of the first one. “What’s surprising is that the device had a lasting effect on theta activity and memory performance for over half an hour after it was switched off,” commented Ranganath.
In opposition to some other neuroscientists, who are of the opinion that theta brain waves are an epiphenomenon of regular brain function, Ranganath thinks they might play an active role in coordinating the interplay between different brain regions.
“The neurons are more excitable at the peak of the wave, so when the waves of two brain regions are in sync with each other, they can talk to each other,” said Ranganath.