Remember the first time you explored a new city that you just moved to for studies or work: You are stumbling out of an arbitrary Metro station in the city center, and all of a sudden you are surrounded by unknown buildings, stores, and people, your senses are overwhelmed by traffic noise and unfamiliar smells. You might feel lost, but while it is quite a lot to take in, you keep on moving.
You explore the streets, follow street signs and find your way to scenic places. After a day or so, you already feel much more comfortable in your new surroundings. While on the first day you might have just walked trodden paths, got lost or made a lot of detours, now you might even know shortcuts from one place to the next. Over time, you get settled, and you will notice that the places that you have been are not separated islands anymore – your mind has connected the dots, generated an internal representation and associated places with mental pictures of the things you did and the people that you met there.
All of these actions, your thoughts, memories, emotions, and experiences of the world are generated by your brain. Both in structure and in function, it is an exceptionally complex organ. No matter whether you are asleep or awake, prepare the next meeting or take a leisure stroll around town, your brain is constantly active, absorbing all information and integrating it into the existing “brain network”.
Neurons are the building blocks of your brain (adults have about 100 billion of them), and they are heavily interconnected via synapses. A synaptic connection is “switched on” by means of neurotransmitter emission, changing the flow of ions across the cell membrane. “Flipping the switch” generates a tiny electrical field, which is generally referred to as postsynaptic potential (PSP). Of course, the PSP of a single neuron might be too small for being detected at all. However, if PSPs occur at the same time for hundreds of thousands of similarly oriented neurons, they sum up and are conducted at nearly the speed of light throughout brain tissue, skull and scalp. Now the PSPs across the billions of neurons never occur at exactly the same time but rather mix in very a complicated fashion, resulting in oscillations (that is, repetitive variations in time).
Several oscillatory frequencies
Several oscillatory frequencies have been identified which are seemingly reflecting cognitive or emotional states. The most common frequencies are delta (0.5 – 3 Hz; associated with sleep), theta (4 – 8 Hz; mental load), alpha (8 – 12 Hz; sensory processing), beta (13 – 25 Hz; motor control), and gamma (> 25 Hz; stimulus binding). One part of the oscillatory mixture is elicited by external and internal events (so-called event-related potentials, or ERPs). Another part is the result of ongoing oscillations, mostly driven by feedback loops both within and across functionally specialized brain areas.
What is EEG?
Electro-Encephalography (encephalon = brain), or EEG, is the technology for recording this kind of electricity from the scalp surface. Applied first to humans in the 1920s by German neurologist Hans Berger, the electroencephalogram records the net sum of all electric fields generated by the brain from sensors (so-called electrodes) attached to the scalp. EEG is a non-expensive, non-invasive and completely passive recording technique. It has an excellent temporal resolution, that is, it can take hundreds to thousands of snapshots of electric activity across multiple sensors within a single second! This makes EEG an ideal candidate to study the precise time-course of cognitive and emotional processing.
The application range for EEG is extremely wide, ranging from clinical applications (e.g., diagnosis and treatment of neurodegenerative brain diseases) to engineering projects (e.g., Brain-Computer-Interfaces) or academic and commercial human behavior research (e.g., neuromarketing). To an increasing amount, all of these disciplines utilize multi-dimensional and synchronized data collection strategies for EEG and facial expressions, saccades/fixations (eye tracking), limb movements (motion capture), galvanic skin response (GSR), muscular responses (EMG) or heart rate (ECG), ideally integrated into a single software platform.
Brain imaging experts all over the globe are working hard to learn more about how your brain is wired – not only in the context of wayfinding and exploring new cities but for any cognitive and behavioral processes – it also determines how your mind is wired!
We found this really cool video visualizing a 3D brain and its brain waves in real-time, posted by the awesome people at Neuroscapelab.
Learn more about Software for measuring EEG here: https://imotions.com/products/