Decoding Reveals Plasticity in V3A as a Result of Motion Perceptual Learning

Abstract

Visual perceptual learning (VPL) is defined as visual performance improvement after visual experiences. VPL is often highly specific for a visual feature presented during training. Such specificity is observed in behavioral tuning function changes with the highest improvement centered on the trained feature and was originally thought to be evidence for changes in the early visual system associated with VPL. However, results of neurophysiological studies have been highly controversial concerning whether the plasticity underlying VPL occurs within the visual cortex. The controversy may be partially due to the lack of observation of neural tuning function changes in multiple visual areas in association with VPL. Here using human subjects we systematically compared behavioral tuning function changes after global motion detection training with decoded tuning function changes for 8 visual areas using pattern classification analysis on functional magnetic resonance imaging (fMRI) signals. We found that the behavioral tuning function changes were extremely highly correlated to decoded tuning function changes only in V3A, which is known to be highly responsive to global motion with human subjects. We conclude that VPL of a global motion detection task involves plasticity in a specific visual cortical area.

Sharpened cortical tuning and enhanced cortico-cortical communication contribute to the long-term neural mechanisms of visual motion perceptual learning

“…This idea is consistent with other perceptual learning studies on form discrimination (Zhang et al, 2010a), orientation discrimination (Jehee et al, 2012), and motion detection (Shibata et al, 2012). However, it should be noted that these studies only measured the neural changes immediately after training, but not longer-term changes.…”

“…Shibata et al (2012) also found that motion detection training only affected V3A. These findings seem to contradict the long-standing belief that MT+ is the neural substrate of motion perceptual learning as demonstrated by earlier studies (Zohary et al, 1994;Vaina et al, 1998).…”

Perceptual learning modifies the functional specializations of visual cortical areas

“…We reasoned that if training could improve the neural representations of the motion stimuli (especially in the trained direction), as suggested by the TMS and psychophysical results, it was possible that decoding accuracies for the orthogonal directions could be improved by training. Similar approaches have been used previously (19)(20)(21). Before training, a repeated-measures ANOVA revealed a significant main effect of stimulus coherence level and a significant interaction between stimulus coherence level and area [V3A and MT+; both F(1,11) > 7.87l P < 0.05; Fig.…”

Short-term plasticity of the human adult visual cortex measured with 7T BOLD

“…Perceptual learning requires long training sessions repeated over several days in combination with positive reward (13)(14)(15)(16)(17)(18). In spite of extensive research, it is still debated whether perceptual learning fine-tunes the neuronal responses at level of primary visual cortex or whether the effect primarily lies in associative cortices (18)(19)(20)(21)(22)(23)(24), which usually retain a higher level of plasticity in adulthood. More recently, psychophysical studies have revealed a form of adult plasticity after short-term deprivation, probably associated with an alteration of primary visual cortex processing, where deprivation paradoxically leads to enhanced sensitivity.…”