Electrophysiological evidence that release from proactive inhibition reflects late semantic processing

While proactive inhibition (PI) frequently occurs in response to novel stimuli due to interference from previously learned information, shifts in semantic category on a preceding trial lead to the attenuation of learning interference effects such as PI, resulting in significantly improved performance on short-term memory tasks. This study examined how the release from PI also leads to a reduction in semantic inhibition, as measured primarily through an event-related potential (ERP) electroencephalography (EEG) design. The study used Chinese characters denoting different categories (word nouns for categories such as plants, clothes, and flowers) to test short-term memory recall in a control group (same category/no PI release) and experimental group (different category/PI release). Both behavioral data (recall accuracy) and ERP responses for the N400 and Late Positive Component (LPC) at frontal, central, and parietal electrode sites were collected. Behaviorally, recall accuracy declined continuously on the initial three consecutive trials, regardless of group, while recall increased significantly on the last trial specifically for the experimental group, due to the shift in semantic category. We reported a significant interaction between group and electrode site for the LPC component, indicating that inhibition effects were still active for both groups at the initial memory encoding stage (corresponding to N400), with inhibition release in the experimental group occurring through later LPC processing. These results provide electrophysiological evidence that release from PI can be distinguished from semantic forms of processing through changes in amplitude over the course of learning.