EP researchers reveal evidence for mnemonic templates using MEG
- 4 February 2016
In a new study, published in eLife, researchers in the labs of Mark Stokes and Kia Nobre investigated how visual search templates are reactivated to act as input filters for target detection. How the brain maintains a template of what you are currently searching for (your house keys, for example) has been a much-debated topic in neuroscience for the past 30 years. Previous research has indicated that neurons specialized for detecting the sought-after object when it is in view are also pre-activated when we are seeking it. This would mean that these ‘template’ neurons are active the entire time that we are searching.
The new study recorded brain activity from human volunteers using a non-invasive technique called magnetoencephalography (MEG) as they tried to detect when a particular shape appeared on a computer screen. The patterns of brain activity could be analyzed to identify the template that observers had in mind, and to trace when it became active. This revealed that the template was only activated around the time when a target was likely to appear, after which the activation pattern quickly subsided again. The brief activation of the template suggests templates may come online just in time to filter new sensory input.