While working at the UC Irvine Health Neuropsychiatric Center, Sandy Hoang’s mentor suggested working to expand understanding of P50 sensory gating by investigating neural responses in the gamma range. She feels that her results are revolutionary because gamma band responses can be used to diagnose psychiatric patients more accurately and objectively. Sandy says that her favorite part of her research experience was interacting with the test participants, who she found to be very supportive of her work. After graduation, Sandy plans to continue her studies by applying to dental school.

Gamma band responses may account for the deficiency in P50 sensory gating in patients with neuropsychiatric disorders. The intent of this study was to use P50 sensory gating data of patients with schizophrenia or bipolar I disorder to observe the contribution of gamma band power on P50 and examine whether there were any differences in their evoked gamma responses to paired clicks in comparison to controls and each other. It was hypothesized that individuals with schizoaffective, paranoid schizophrenia and bipolar I disorder would have longer latencies, lower peak to peak amplitudes, larger S2/S1 ratios, and smaller S1-S2 differences than controls. In addition, it was hypothesized that these variables would significantly differ between each group. To test this prediction, individuals were recruited from the University of California, Irvine Neuropsychiatric Center and the local community. Electrophysiological information was recorded while a series of paired clicks, stimulus 1 and stimulus 2, were presented. From this data, the P50 sensory gating was filtered between 30 and 50 Hz to analyze gamma oscillations. Consistent with the hypothesis, there were significant differences in latencies, peak to peak amplitudes, and S1 and S2 differences between each group. This suggests that the abnormal sensory gating in P50 is influenced by neural activities in the gamma range.

Julie Patterson School of Medicine

Sensory gating is the ability of the brain to inhibit irrelevant or redundant stimuli, preserving needed resources for effectively processing relevant information. It is quantified using the amplitude of evoked brain potentials derived from the EEG (EPs). Neural synchrony of oscillations in the gamma band is thought to relate to the integration of features into a recognizable whole, essential for sensory and cognitive processing. Sandy’s findings suggested that the sensory gating EP reflects synchronized gamma activity and thus may provide evidence of intact or impaired neural synchrony in psychiatric disorders. UROP is a valuable opportunity for students to personally experience the research process. My students have consistently reported their very positive benefits from UROP and its significant contribution to their applications for higher education.