Task-specific disruption of perceptual learning

Abstract

For more than a century, the process of stabilization has been a central issue in the research of learning and memory. Namely, after a skill or memory is acquired, it must be consolidated before it becomes resistant to disruption by subsequent learning. Although it is clear that there are many cases in which learning can be disrupted, it is unclear when learning something new disrupts what has already been learned. Herein, we provide two answers to this question with the demonstration that perceptual learning of a visual stimulus disrupts or interferes with the consolidation of a previously learned visual stimulus. In this study, we trained subjects on two different hyperacuity tasks and determined whether learning of the second task disrupted that of the first. We first show that disruption of learning occurs between visual stimuli presented at the same orientation in the same retinotopic location but not for the same stimuli presented at retinotopically disparate locations or different orientations at the same location. Second, we show that disruption from stimuli in the same retinotopic location is ameliorated if the subjects wait for 1 h before training on the second task. These results indicate that disruption, at least in visual learning, is specific to features of the tasks and that a temporal delay of 1 h can stabilize visual learning. This research shows that visual learning is susceptible to disruption and elucidates the processes by which the brain can consolidate learning and thus protect what is learned from being overwritten.iving organisms are constantly learning new skills and improving their abilities. When does the learning of something new disrupt that which has already been learned? For more than a century, the process of stabilization has been a central issue in the research of learning and memory (1, 2). Namely, after a skill or memory is acquired, it must undergo a period of consolidation before it becomes resistant to disruption by subsequent learning of a similar task (3). Although it is clear that there are many cases in which learning can be disrupted, the process of disruption and its specificity are unclear.Disruption of learning has been best detailed in studies of motor learning. These studies show that skill acquisition from a task (A) is disrupted or interfered with by subsequent practice of a second task (B). For instance, subjects in a hand-reaching task can learn to adapt to a force field, which alters their movements. This learning persists on subsequent days of testing. If subjects first adapt to force field A and then adapt to force field B, they no longer show improvements for force field A when tested on the following day (3-6). Similar disruption has been found in tasks of visual-motor sequence learning (7). Disruption has also been found in visual-motor reaching tasks, but only between tasks involving similar visual-motor transformations (8). Some motor studies show that the disruption of A does not occur if there is a waiting period of a few hours before the training o...

Time-Limited Consolidation and Task Interference: No Direct Link

“…B, The first seven sessions for the ⌬1 h interval. These plots show the two intervals that are comparable to the intervals used in the paper of Seitz et al (2005), who found time-dependent behavioral interference between two Vernier tasks during early learning. A repeated-measures ANOVA on our data [Condition (E 135 , C 135 ) ϫ Session (7) ϫ P1-P2 Interval (⌬0 h, ⌬1 h)] failed to find a significant interaction between Condition and Interval (F (1,8) ϭ 0.330, p ϭ 0.581).…”

“…Therefore, high-level networks involved in memory storage in two subsequent tasks may overlap or not, based on variables that are difficult to control. Consequently, opposite conclusions in similar studies of behavioral interference are reported (Seitz et al, 2005;Aberg and Herzog, 2010), although Hung and Seitz (2011) suggest an additional explanation involving eye-movement control and procedural divergences.…”

“…It is not a universal finding (Aberg and Herzog, 2010), and in studies that did report interference, it was found for widely varying time intervals, from 0 h up to 4 h in some studies (Brashers-Krug et al, 1996;Shadmehr and Holcomb, 1997;Seitz et al, 2005), to 24 h up to a week in others (Goedert and Willingham, 2002;Caithness et al, 2004;Zhang et al, 2008). These findings raise fundamental questions about the notion of time-limited consolidation and its relation to behavioral interference.…”

“…The latter factor may contribute to the variable results in prior studies, which have limited themselves to the very first session (Brashers-Krug et al, 1996;Shadmehr and Holcomb, 1997;Goedert and Willingham, 2002;Caithness et al, 2004) or first few sessions (Seitz et al, 2005;Zhang et al, 2008) of skill learning. During early learning, networks in high-level cortical regions orchestrate strategic choices, as well as attentional and motivational allocation in response to specific task demands, instructions, and context (Willingham, 1999;Hochstein and Ahissar, 2002;Doyon et al, 2003).…”

When more equals less: overtraining inhibits perceptual learning owing to lack of wakeful consolidation

“…Various training conditions and subsequent sleep deprivation can interfere with consolidation, and thus the learning of perceptual skills. For example, training on an additional task while the first skill is still being consolidated [4] or repeated within-day training (overtraining) [5] can prevent learning. Investigating the conditions under which perceptual learning does not occur can help us to better understand the mechanisms of consolidation of cortical changes that produce long-term learning.…”