Fascinating new research about your brain.
- Like nearly all complex machines, your brain runs on electricity. Every time a neuron fires in order to communicate with another neuron, a little burst of electricity courses through the cell to power the message. Scientists use these electric pulses to measure and track activity in the brain, and this research has contributed to a lot of what we know about what different brain regions do.
- One way researchers measure electrical activity is a method known as EEG (electroencephalography), where a person wears a cap made of a web of electrodes that sits on top of their head. However, because the electrodes are reading neural activity through the scalp, EEG recordings aren’t very precise. It can tell you roughly when and what type of activity is happening but not where.
- A more spatially accurate — but much more invasive — technique is to implant electrodes directly into a person’s brain. This type of research only happens on the rare occasions that someone is already undergoing brain surgery because even the most obsessed neuroscientist wouldn’t suggest opening up your skull just to take a look inside. Many people who’ve had deep brain recordings taken suffer from severe epilepsy, which is a disorder defined by abnormal electrical activity in the brain — what we know of as a seizure.
- In the most severe cases of epilepsy, scientists need to identify the precise location where the seizures start in order to treat them. To do so, they place electrodes either directly onto the cortex (the outer layer of the brain) or implant them deeper into the tissue; then they record for several days until they can find the foci of the seizures. During that time, while the electrodes are already in the brain, some psychologists and neuroscientists also conduct a little research — with the patient’s explicit permission, of course.
- One study from 2018 used this method to track the electrical activity of 16 epilepsy patients’ thoughts as they performed simple tasks. Tracking neural activity across different brain regions, the researchers found that seeing or hearing a word activates the visual or auditory processing parts of the brain (not surprising). Next, the neural activity moved into the prefrontal cortex, which is involved in higher order cognitive processes like planning for the future or working memory. The scientists speculate that people are processing information in the prefrontal cortex, deciding what to do next. Lastly, the motor cortex gets activated when an action is decided upon and a response is to be made, whether it’s pushing a button or speaking a word. Interestingly, there is an overlap in activity between the prefrontal and motor regions, as if the brain is primed to respond with an action even before it’s decided what the action will be.
[Source: Elemental, Dana Smith, Feb, 2021]