The price difference in an EEG system is usually due to the number of electrodes, the quality of the digitization, the quality of the amplifier, and the number of snapshots per second the device can take (this is the sampling rate in Hz).
EEG usually has a high sampling rate and is one of the fastest-applied imaging techniques. A hundred years ago, the time course of the EEG was plotted on paper. The current system continuously displays voltage data on the screen in digital form.
How to interpret EEG data?
When EEG monitors the time course of electrical activity generated by the brain, it can explain which areas of the cortex are responsible for processing information at a given time:
occipital cortex
This part of the brain is primarily responsible for processing visual information. EEG experiments with visual stimuli (videos, images) typically focus on the occipital region.
parietal cortex
The parietal cortex is primarily responsible for motor functions and is active in self-referential tasks (for example, when we encounter objects or information that are important to us).
temporal cortex
The side of the temporal cortex is responsible for language processing and speech production. During spatial navigation, the medial (inner) region is more active.
frontal cortex
The frontal lobe of the human brain is enlarged compared to most other mammals. Basically, the frontal cortex is all about executive function: it helps us maintain control, plan for the future, and monitor our behavior. 