Measuring Visual Perception


#1

Hi

I would like to know where can i find visual perception of external visual stimuli on the Muse data stream.
Are there any OSC paths that show this?
I found somewhere that Fp1, Fp2, O1 and O2 sensor positions are used to monitor visual perception.
O1 and O2 are placed on the occipital lobe where the visual cortex is.
Muse has Fp1 and Fp2 but there are no sensors for position O1 and O2.
Where can i look for signals related to visual stimuli on Fp1 or Fp2 or EEG data or DSP paths?

:slight_smile:


#2

Hi Ventolinmono,

The SDK does not include any data streams that provide pre-computed indicators of Visual Evoked Potentials (VEP). The only visually-related path available right now is the /dsp/blink path. You can definitely explore detecting VEPs using the raw data from Muse, though.

You’re right that the occipital locations are very commonly used for VEP studies because of their proximity to the visual cortex. However, the forehead locations also are known to display certain components of VEP waveforms, as mentioned in this paper, for instance: http://bit.ly/1x3R3Wa

To learn more about how VEPs are typically measured and analyzed I’d also recommend looking at the VEP Standard (2004): http://bit.ly/1t8VuKe

Both the ear and forehead electrodes pick up useful information about eye movement and position. Since the eye itself forms a dipole (called the corneoretinal potential) that runs from the front to the back of the head, if it moves or changes (say because you are looking around or blinking or refocusing), the potential that appears to the electrodes will change. There are lots of papers and resources on this stuff - here’s one good example: http://bit.ly/10SY0i9