Poster E99, Monday, March 26, 2:30-4:30 pm, Exhibit Hall C
Electroretinographic Markers of NMDA-dependent Functions in Healthy Controls and Patients with Schizophrenia
Angus MacDonald III1, Pantea Maghimi1, Theoden Netoff1, Robert Miller1; 1University of Minnesota
The capacity for the non-invasive measurement of individual differences in NMDA receptor functioning has the potential to allow for efficient screening for NMDA-linked disorders, such as schizophrenia, as well as for understanding how variance in NMDA functioning relates to cognitive performance. Measured from the eye, electroretinography (ERG) signals such as the pattern (p) ERG and photopic negative response (PhNR), reflect the activity of NMDA-dominated retinal ganglion cells. The current study examined ERG signals in a final sample of 23 patients with schizophrenia or schizoaffective disorder (5 unmedicated) and 23 demongraphically-similar controls. Participants also completed tasks associated with visual pattern recognition (Jittered Orientation Visual Integration) and cognitive control (Dot Pattern Expectancy task), two cognitive processes thought to depend on NMDA functioning in cortex. PERG results suggest the P50 wave (an initial waveform rise following a change in brightness) is nominally more impaired in psychosis (T(44)=1.39, p=.08, ES=.41) relative to the N95 (the subsequent fall of the waveform, T(44)=-.90, p=.19, ES=-.27). These group differences are markedly magnified when comparing only the medicated patients to control and the two signals are equally discriminating (P50 T(39)=1.89, p=.034, ES=.59; N95 T(39)=-1.72, p=.046, ES=-.54). Machine learning analyses suggest informative timepoints are spread across the entire waveform, including points before the initial rise. In addition, these waveforms relate to individual differences in cortically-mediated behavioral tasks. These findings suggest medicated patients experience perceptual signal degradation even at the earliest perceptual entry points, and that PhNR and pERG may provide insights into cortical abnormalities in NMDA receptor function.
Topic Area: PERCEPTION & ACTION: Vision