 The cortical column is a fundamental computational circuit in the brain, consisting of distinct layers of neurons. To determine the boundaries separating these layers, researchers must first identify the input layer, which is often difficult to do in vivo. Current source density, CSD, analysis is the gold standard for identifying laminar boundaries in electrophysiological recordings, but it requires averaging over reliable evoked responses and is difficult to obtain in less studied cortical regions. Researchers have developed a new technique based on linear array recordings that can quickly and accurately identify the input layer in multiple cortical areas in two different species. This technique is more robust than CSD analysis and does not require averaging or specific evoked activity. It can also be used to validate CSD measurements or to estimate laminar boundaries when other methods are impractical. This article was authored by Zachary W. Davis, Nicholas M. Dotson, Tom P. Franken and others. We are article.tv, links in the description below.