Abstract
Following initial encoding and consolidation of a perceptual memory, perception thresholds continue to gradually improve over multiple training sessions, similar to other forms of procedural learning (Censor, Sagi and Cohen, 2012). Here we show, that following initial training, brief periods in which the encoded visual memory is reactivated are sufficient to enable perceptual learning, comparable to learning achieved with repeated standard practice sessions. Participants trained with the texture discrimination task (Karni and Sagi, 1991). The texture stimulus was presented for 10ms, followed by a 100ms patterned mask. Observers decided whether an array of 3 diagonal bars embedded in an array of horizontal bars (19×19) was horizontal or vertical. The target-to-mask asynchrony (SOA) was randomly varied within the session (14 SOAs of 40-340ms, 18 trials per SOA) to obtain a psychometric curve, from which the SOA discrimination threshold was derived. The memory was first encoded and consolidated following a full session on Day1. Participants returned for three daily reactivation sessions (Days 2-4) of only 5 trials each, at a near-threshold SOA. On Day5, participants performed a full test session (identical to Day1). Learning, measured as improvement in discrimination thresholds from Day1 to Day5, was significant (31.7±12.0ms, mean±SE, P< 0.02) and comparable (P=0.45) to total learning in a control group of subjects performing five regular full daily sessions (39.4±11.4ms, P< 0.005). Learning in the reactivation group was long-term and retained for months, with retention even more pronounced than in the full practice group. Thus, brief reactivations of consolidated perceptual memories enable perceptual learning, possibly via reactivation-reconsolidation cycles of memory strengthening (Lee, 2008; Dudai, 2012; Nader and Hardt, 2009). This interpretation may have an important role in understanding the mechanisms underlying perceptual learning, and facilitate novel strategies geared to substantially reduce the amount of practice needed for learning in normal and neurological conditions.
Meeting abstract presented at VSS 2016