Peter Dayan, Angela J. Yu
Acetylcholine (ACh) has been implicated in a wide variety of tasks involving attentional processes and plasticity. Following extensive animal studies, it has previously been suggested that ACh reports on uncertainty and controls hippocampal, cortical and cortico-amygdalar plasticity. We extend this view and consider its effects on cortical representational inference, arguing that ACh controls the balance between bottom-up inference, in(cid:3)uenced by input stimuli, and top-down inference, in(cid:3)uenced by contextual information. We illustrate our proposal using a hierarchical hid- den Markov model.