"Something about being outdoors changes brain activity," lead author Joanna Scanlon explained in an article that appeared in Science Daily. "In addition to dividing attention between the task and riding a bike, we noticed that brain activity associated with sensing and perceiving information was different when outdoors, which may indicate that the brain is compensating for environmental distractions."
For the study, the research team mounted mobile EEG equipment into backpacks, which were given to participants. They then rode a bicycle outside while performing a standard neuroscience task. This involved an oddball auditory paradigm where they identified changes in pitch in a series of beeping sounds. The task had a previous iteration which was conducted on stationary bikes inside the lab, but the current study was able to measure brain activity using portable equipment.
Using the task, researchers were able to build a way to reliably measure event-related potentials (ERPs), which are defined as "very small voltages generated in the brain structures in response to specific events or stimuli." ERPs appear in the EEG as indicators for activities related to a person's sensory, motor, or cognitive events.
Common ERP waveforms include the following:
- P50 wave – This waveform measures the "sensory gating" process of the brain, that is, its ability to select relevant stimuli and information and leave out all the rest.
- N1 wave (also called N100) – This is recorded as a negative deflection that is noted when a person is presented with an unexpected stimulus.
- P2 wave (also called P200) – This refers to the positive deflection that is seen after a stimulus is presented. This refers to the brain's sensation-seeking behavior.
- N2 wave (also called N200) – This is a negative deflection in the ERP that is seen during a difference in presented stimulus.
- N300 – It is a waveform that has been recently associated with semantic congruity and expectancy.
- P3 wave (also called P300) – In auditory stimuli, the P3 wave indicates the speed that the stimulus is classified from an event to the other.
- N400 – This is a negative wave that is related to the brain's expectation of a given word to end the sentence.
- P600 – This effect happens when we process sentences that contain a violation of syntax.
The current study evaluated how the environment can play a factor in affecting auditory (ERPs) – in particular, with P2 (the wave that processes if a stimulus is noticed) and P3 (the wave that interprets stimulus to relevant information).
The tests noted that the P3 component of the ERP was significantly reduced during the outdoor test as a result of the brain function. However, what increased was the N2 wave of the ERP, which is responsible for noticing various stimuli in the environment. (Related: Tylenol found to dull the brain and make people less likely to notice errors… the dumbing down of America continues at full pace.)
According to the researchers, the study ultimately aims to evaluate ERP to events that naturally happen in the world. This will provide a deeper understanding of how the brain adapts to everyday situations. Future studies will involve measuring auditory P2 brain function inside the laboratory, as well as explore how the reduction of the P2 component can be influenced by different degrees of distraction, such as that of a quiet path or a busy roadway.
"If we can understand how and what humans are paying attention to in the real world, we can learn more about how our minds work," said Scanlon. "We can use that information to make places more safe, like roadways."
Learn more about the brain and its various functions by heading to Brain.news today.
Sources include:
BioRxIV.org [PDF]
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