Researchers recorded electrical activity across the brain in people with severe, drug-resistant epilepsy who had electrodes implanted before surgery. The implants helped doctors locate the brain region causing seizures, and while hospitalised the patients performed two types of memory tasks.
One task, called a treasure hunt, focused on spatial memory and resembled a video game in which patients navigated an environment and remembered object locations. In the other task, patients memorised sequences of English letters and later attempted to recall them. Anup Das, a postdoctoral fellow in Joshua Jacobs' lab, analysed the electrode signals and identified distinct spatial wave patterns.
The team described several clear wave forms, including:
- waves that travelled in straight lines,
- waves that curled into spirals,
- waves that acted like outward sources or inward sinks.
Patterns tended to vary across individuals, so the same task could produce different wave shapes in different people, yet each person showed consistent patterns over time. Using only wave shape, researchers could decode behaviour about 70% of the time (chance level 50%). G. Bard Ermentrout said researchers now see brain activity as organised into various wave types and that features such as wave direction and strength can affect memory performance. Senior author Joshua Jacobs said the next steps are to build mathematical models to understand wave origins and eventually test brain stimulation approaches to strengthen helpful waves; such work could lead to brain–computer interfaces or transcranial magnetic stimulation therapies. The study appears in Nature Communications.
Difficult words
- epilepsy — neurological disorder with repeated seizures
- electrode — small metal sensor that detects electrical activityelectrodes
- spatial memory — ability to remember locations and space
- spiral — curved shape that winds around a centrespirals
- decode — find the meaning or pattern in a signal
- transcranial magnetic stimulation — noninvasive technique using magnets to affect brain
- brain–computer interface — system connecting a brain to an external devicebrain–computer interfaces
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- What benefits could brain–computer interfaces or transcranial magnetic stimulation offer people with epilepsy or memory problems?
- How might individual differences in wave patterns affect the design of treatments or devices?
- Do you think decoding behaviour from brain activity raises privacy or ethical concerns? Why or why not?
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