title: Generalized perceptual learning in the absence of sensory adaptation.
abstract: Repeated performance of visual tasks leads to long-lasting increased sensitivity to the trained stimulus, a phenomenon termed perceptual learning. A ubiquitous property of visual learning is specificity: performance improvement obtained during training applies only for the trained stimulus features, which are thought to be encoded in sensory brain regions [1-3]. However, recent results show performance decrements with an increasing number of trials within a training session [4, 5]. This selective sensitivity reduction is thought to arise due to sensory adaptation [5, 6]. Here we show, using the standard texture discrimination task [7], that location specificity is a consequence of sensory adaptation; that is, it results from selective reduced sensitivity due to repeated stimulation. Observers practiced the texture task with the target presented at a fixed location within a background texture. To remove adaptation, we added task-irrelevant ("dummy") trials with the texture oriented 45° relative to the target's orientation, known to counteract adaptation [8]. The results indicate location specificity with the standard paradigm, but complete generalization to a new location when adaptation is removed. We suggest that adaptation interferes with invariant pattern-discrimination learning by inducing network-dependent changes in local visual representations.
authors.affiliation: Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Hila
authors.initials: H
authors.lastname: Harris
authors.forename: Michael
authors.initials: M
authors.lastname: Gliksberg
authors.forename: Dov
authors.initials: D
authors.lastname: Sagi
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology*; D033281:Nontherapeutic Human Experimentation; D009949:Orientation / Q000502:physiology; D012677:Sensation; D014796:Visual Perception / Q000502:physiology*