» Go to news main

Variability and bias between magnetoencephalography systems in localization of the primary visual cortex

Posted by Krista Whitehouse on July 6, 2020 in Neuroradiology
Primary Visual Cortex
Primary Visual Cortex

Dr. Steven Beyea and Dr. Timothy Bardouille have published a new paper. See full text


  • Most visual response characteristics do not differ between MEG systems.
  • There is a latero-medial bias in the localization of the primary visual cortex.
  • The median difference in localization between systems is 10.5 mm.



When using MEG for pre-surgical mapping it is critically important that reliable estimates of functional locations, such as the primary visual cortex (V1) can be provided. Several different models of MEG systems exist, each with varying software and hardware configurations, and it is not currently known how the system type contributes to variability in V1 localization.

Patients and Methods

In this study, participants underwent MEG sessions using two different systems (Vector View and CTF) during which they were presented with a repeating grating stimulus to the lower-left visual quadrant to generate a visual evoked field (VEF). The location, amplitude and latency of the VEF source was compared between systems for each participant.


No significant differences were found in latency and amplitude between systems, however, a significant bias in the latero-medial position of the localization was present. The median inter-system Euclidian distance between V1 localization across participants was 10.5 mm.


Overall, our results indicate that mapping of V1 can be reliably reproduced within approximately one centimetre by different MEG systems.


This result provides knowledge of the useful limits on the reliability of localization which can be taken into consideration in clinical practice.


All comments require a name and email address. You may also choose to log-in using your preferred social network or register with Disqus, the software we use for our commenting system. Join the conversation, but keep it clean, stay on the topic and be brief. Read comments policy.

comments powered by Disqus