The "incredible shrinking" P50 event-related potential.

The P50 component of the auditory evoked response has been utilized in studies of sensory gating in schizophrenia for over 15 years. As P50 gating studies have had a greater impact in neuroscience research, investigators have refined several key variables (e.g., filtering) to enhance signal-to-noise ratios. A comprehensive review of P50 reports suggests P50 amplitude has been steadily decreasing over the years. Certain methodological "advances" are suggested as key reasons for this apparent reduction in P50 amplitude. Gating studies continue to yield interesting findings in neuropsychiatric research, especially when ratio vs. absolute difference scores are used.