Anterograde Interference From Perceptual Learning on New Neuroplastic Impulses is Caused by Consolidation Failure, Rather than Immediate Blockage of the Impulses

Abstract

Established learning prevents subsequent new learning from being developed. This phenomenon is called anterograde interference and provides important insights into plasticity and stability in learning. Here we challenge the assumption that interference results from an outright prevention of neuroplasticity/learning. In one experiment (n = 12), we applied high-frequency repetitive visual stimulation (H-RVS) with one orientation to a group of subjects without preceding visual training. Visual perceptual learning (VPL) occurred specifically for the stimulated orientation, as was shown in other studies. This confirmed that H-RVS caused neuroplastic impulses that lead to VPL. In the main experiment, using a two-interval forced choice (2IFC) paradigm, we trained a new group of subjects (n = 32) to better detect two orientations for 7 days. Subsequently, the subjects received H-RVS. Given that H-RVS led to VPL without preceding VPL, as shown in the first experiment, the prevention of further VPL by H-RVS due to established VPL should be regarded as a result of anterograde interference. As predicted, training-based VPL remained, while further VPL by H-RVS did not occur. However, unexpectedly, this anterograde interference was not observed to instantly block further VPL. After H-RVS, training-based VPL was severely disrupted and then returned to the prestimulation level on the following day. These findings indicate that anterograde interference by established VPL does not result from immediately blocking new neuroplastic impulses. Instead, anterograde interference may be a result of established VPL being greatly disturbed by new neuroplastic impulses before these impulses disappear without being integrated with established VPL activity patterns.