Perceptual Learning:
    Repeated exposures or trainings improve our perceptual/sensory abilities, and cause neural re-organizations in the brain. Such experience-induced improvement and the accompanying neural change are called perceptual learning and neural plasticity, respectively.

    We are constantly exposed to an overwhelming amount of sensory signals. It is necessary to make quick and precise action to important signals while ignoring or discounting less important signals. By directing attention only to signals important to us, or being repeatedly exposed to signals in an important context, our sensory systems learn to process these important signals more efficiently than less significant signals.

    In our recent study with visual learning (Yotsumoto, Watanabe, & Sasaki, 2008), we found that the performance improvements due to perceptual learning were accompanied with greater neural activation on trained visual cortex. However, while performance levels then saturated and were maintained at a constant level, brain activation in the corresponding areas decreased to the level observed before training. This result suggests that there are distinct patterns of neural activations caused by different stages in the perceptual learning and neural consolidation.

    A growing body of evidence suggests that sleep plays an important role in consolidation of memory and learning. However, it is still controversial where, when and how in the brain consolidation takes place during sleep. We are interested in whether or not oscillatory activities including slow-wave activity are involved in consolidation of motor skill learning, employing a multimodal neuroimaging technique in combination of magnetoencephalogram (MEG) and anatomical magnetic resonance imaging (MRI).