Deletion and duplication of 16p11.2 are associated with opposing effects on visual evoked potential amplitude

Original research article by J.J. LeBlanc and C.A. Nelson (2016).

Read the abstract here.

This article examines the effects that 16p11.2 deletions and duplications (both of which are 16p11.2 copy number variants, or CNVs) have on cortical processing. Cortical processing is the brain’s translation of sensory stimuli the eye receives into usable information, such as the production of a memorable image from something a person saw.

In many neurodevelopmental disorders, the interpretation of sensory information is reduced. This means there may be a problem with cortical processing that can lead to cognitive and behavioral difficulties. A previous study on cortical processing in people with the 16p11.2 CNVs reported that auditory (hearing) responses were delayed in deletion carriers but not in duplication carriers. The study’s authors sought to learn whether the differences between people with the two types of CNVs would also affect how these people process visual information.

To test how people with 16p11.2 CNVs interpret visual information, the authors used pattern-reversal visual evoked potentials (VEPs).

This is a noninvasive method of tracking the neuronal response of visual pathways from the eye to the optic nerve and finally to the brain, where the information is processed. VEPs take the form of a wavelength recorded through imaging technology; this visualization helps determine the response a person has to various stimuli.

For this study, 19 deletion carriers, 9 duplication carriers, and a control group of 13 children with no CNV, all between the ages of 3 and 14, were examined using an electroencephalograph (EEG) to record VEPs. The VEP recordings from the deletion carriers had, on average, higher amplitudes (peak in blue on the graph), and those from the duplication carriers had lower amplitudes (peak in green on the graph). These differences were in comparison to the recorded values for the control group (peak in black on the graph). There was no significant difference in how quickly people with the CNV and people in the control group processed the visual images.

All of the 16p11.2 CNV participants in this study were enrolled through Simons Searchlight.