Topic: prediction error signals

In the canonical view of the neocortical microcircuit, first-order thalamic projections target layer 4 (L4), which in turn projects onto layer 2/3 (L2/3) pyramidal cells (PCs) and then finally onto layer 5 (L5) PCs. Although this is a motif found throughout the neocortex, the functional role of this architecture has remained unclear. Here, inspired by recent observations showing that first-order thalamic input also targets L5 pyramidal cells, we propose that the canonical microcircuit enables the brain to learn through temporal self-supervision. In our model, L2/3 PCs learn to predict thalami

Animals can discriminate time intervals ranging from microseconds to days, which serves to regulate functions as diverse as sound localization to circadian rhythmicity (Mauk and Buonomano, 2004; Buhusi and Meck, 2005). While the mechanisms that enable temporal processing at the microsecond and day scales are relatively well understood (Jeffress, 1948; Rosbash and Hall, 1989), those that enable animals to discriminate time in the behaviorally relevant seconds to minutes scale are not clear. It is believed that there might be at least two distinct interval timing mechanisms, one involving the ce