Spatial Intuition for Neurosity Crown Electrode Placement

Fellow Neurosity Crown users, here’s a quick spatial debrief on where the electrodes on the device are placed and the significance of this assortment.

Here’s a link to the Crown’s specs: https://neurosity.co/tech-specs

The electrode sensors are in positions CP3, C3, F5, PO3, PO4, F6, C4, CP4. What do these correspond to?

They correspond to coordinates on the 10–10 system of electrodes.

The 10–10 system is an extension of the original 10–20 system and includes more electrodes to provide a higher spatial resolution of EEG recordings. Here is a brief explanation of each electrode label:

• C3 and C4: These electrodes are located over the left (C3) and right (C4) central regions of the brain.
• CP3 and CP4: These electrodes are positioned over the left (CP3) and right (CP4) centro-parietal regions.
• F5 and F6: These electrodes are positioned over the left (F5) and right (F6) frontal regions, slightly more lateral and anterior compared to F3 and F4.
• PO3 and PO4: These electrodes are located over the left (PO3) and right (PO4) parieto-occipital regions.

You can see these electrodes on the diagram below. LPA to RPA is ear to ear with Cz being the centre point of the head.

Significance of this Placement

CP3 and CP4 (Centro-Parietal Regions):

• These positions are effective for detecting sensorimotor rhythms (SMRs) and event-related potentials (ERPs) related to motor planning and execution. They are also good for monitoring cognitive processes and attention mechanisms.
• Useful in BCIs for motor imagery tasks, as well as for detecting attention and cognitive load.

C3 and C4 (Central Regions):

• These are classical placements for detecting alpha (α) and beta (β) rhythms, which are prominent in motor and sensory processing. They are crucial for motor control studies and can be used to assess readiness potentials (Bereitschaftspotential) before voluntary movements.
• Ideal for studies involving motor control, movement-related brain activity, and even some cognitive functions like decision-making.

F5 and F6 (Frontal Regions):

• These electrodes can detect frontal theta (θ) and beta (β) waves, which are associated with executive functions, working memory, and decision-making. They are also important for detecting prefrontal cortex activities related to complex cognitive processes.
• Useful for cognitive neuroscience research focusing on executive function, decision-making, and frontal lobe-related tasks.

PO3 and PO4 (Parieto-Occipital Regions):

• These placements are effective for detecting occipital alpha (α) and beta (β) rhythms, which are involved in visual processing and spatial attention. They can also pick up signals related to the visual cortex and parietal areas involved in sensory integration.
• Ideal for visual perception studies, attention research, and tasks requiring visuospatial processing.

The Neurosity Crown electrode sensor placement is very well poised to pick up ERPs and MI neurosignals with a placement that emphasises spatial resolution in the central and parietal regions of the brain. A breakdown of the biosignals that are measured for accurate BCI applications can be read over here.

Hope this was a useful debrief. I found it overwhelming buying the headset initially and not knowing why it would work or what to expect. Reach out to me for any questions or collaborations -> suraj_tirupati@yahoo.com

Create the future!

SJ