Neuronal mechanisms of visual perceptual learning

Abstract

Numerous psychophysical studies have described perceptual learning as long-lasting improvements in perceptual discrimination and detection capabilities following practice. Where and how long-term plastic changes occur in the brain is central to understanding the neural basis of perceptual learning. Here, neurophysiological research using non-human primates is reviewed to address the neural mechanisms underlying visual perceptual learning. Previous studies have shown that training either has no effect on or only weakly alters the sensitivity of neurons in early visual areas, but more recent evidence indicates that training can cause long-term changes in how sensory signals are read out in the later stages of decision making. These results are discussed in the context of learning specificity, which has been crucial in interpreting the mechanisms underlying perceptual learning. The possible mechanisms that support learning-related plasticity are also discussed.

Perceptual learning leads to long lasting visual improvement in patients with central vision loss

“…In addition to the effect of PL on lateral interactions, the PL effect we observed with a temporal-2AFC may be related to the addition of an auditory feedback during the task, thus maximizing in decision mechanisms the read-out of sensory signals through reward (Kumano & Uka, 2013;Petrov et al, 2005). Indeed there is psychophysical evidence that inner reward/feedback can improve performance (Gibson & Gibson, 1955;Herzog & Fahle, 1998;Petrov, Dosher, & Lu, 2006;Shibata, Yamagishi, Ishii, & Kawato, 2009;Sasaki, Nanez, & Watanabe, 2010).…”

“…Whereas in both tasks learning may improve sensory signals and modulate lateral interactions, feedback in the temporal-2AFC task may reinforce learning by maximizing decision mechanism through reward (Petrov, Dosher, & Lu, 2005;Lu & Dosher, 2010;Kumano & Uka, 2013).…”

“…Giorgi and colleagues (2004) showed that a temporal-2AFC task is a suitable procedure to measure collinear facilitation as a function of the target-to-flankers distance, and it is more effective than a spatial-2AFC. In addition, PL with a temporal-2AFC task combined with auditory feedback may reinforce learning by maximizing decision mechanism through reward (Kumano & Uka, 2013), which in turn may affect PL and transfer tasks differently from a Yes/No task without feedback.…”

Training shortens search times in children with visual impairment accompanied by nystagmus

“…However, the mechanisms underlying PL often remain unclear (Fiorentini and Berardi, 1980). Fiorentini rightfully questioned: “Where does this learning occur?” A review on the neural basis of PL reported that training has no effect on, or only weakly alters, sensitivity of neurons in early visual areas, but instead constitutes to long-term changes in high level decision making stages that read out sensory signals (Kumano and Uka, 2013). We recently demonstrated that PL not only induces specific learning effects on the trained task in children with visual impairment (VI), but also transfers to improvements in near visual acuity (NVA) (Huurneman et al, 2013).…”

The application of online transcranial random noise stimulation and perceptual learning in the improvement of visual functions in mild myopia

“…This change can be attributed to a specific and localised plasticity in V1 or alternatively to a more complex network involving changes in the inputs V1 receives from other higher order brain regions following practice (top-down modulation). Additionally, PL may maximize in decision mechanisms the read-out of sensory signals through internal reward (Kumano & Uka, 2013;Lu, Liu, & Dosher, 2010;Petrov, Dosher, & Lu, 2005).…”