Jun joined the lab as a postdoc in 2005 after completing his PhD from University of Tokyo. Jun played a leading role in a number of new directions for the lab. He demonstrated that adaptation was not merely a process of canceling a perturbation, but rather re-optimization, i.e., finding a new way to maximize probability of acquiring reward. This implied that there could not be a ‘desired trajectory’ in the brain, but rather that all learning was ultimately a search for reward. He discovered that in cerebellar disease, there was intact learning from reward prediction errors, but a specific impairment in learning from sensory prediction errors. In this way, it was possible to improve performance of cerebellar patients, something that had been very difficult to do before Jun’s work. He discovered that in autism, children exhibited an abnormally strong sensitivity proprioception during learning. Perhaps the most important of his many contributions is the idea that the brain maintains multiple learning systems, and that during motor learning, two systems cooperate: a reward based learning system, and a sensory prediction based learning system. The former is spared in people with cerebellar damage. He discovered a way to behaviorally examine the consequence of learning with each system. He is currently Associate Professor in the Faculty of Engineering, Information, and Systems, University of Tsukuba, Japan.
Reward dependent modulation of movement variability. Sarah E Pekny, Jun Izawa, and Reza Shadmehr (2015) Journal of Neuroscience 35:4015-4024
Cerebellar contributions to reach adaptation and learning sensory consequences of action. J Izawa, SE Criscimagna-Hemminger, and R Shadmehr (2012) Journal of Neuroscience 32:4230-4239.
Motor learning relies on integrated sensory inputs in ADHD, but over-selectively on proprioception in Autism spectrum conditions. J Izawa, SE Pekny, MK Marko, C Haswell, R Shadmehr, and SH Mostofsky (2012) Autism Research 5:124-136
Stimulation of the human motor cortex alters generalization patterns of motor learning. JJ Orban de Xivry, MK Marko, SE Pekny, D Pastor, J Izawa, P Celnik, and R Shadmehr (2011) Journal of Neuroscience, 31:7102-7110.
Learning from sensory and reward prediction errors during motor adaptation. J Izawa and R Shadmehr (2011) PLoS Computational Biology 7:e1002012
Representation of internal models of action in the autistic brain. C Haswell, J Izawa, L Dowell, SH Mostofsky, and R Shadmehr (2009) Nature Neuroscience 12:970-972.
Online processing of uncertain information in visuomotor control. J Izawa and R Shadmehr (2008) Journal of Neuroscience 28:11360-11368.
Motor adaptation as a process of reoptimization. J Izawa, T Rane, O Donchin, and R Shadmehr (2008) Journal of Neuroscience 28:2883-2891.
Publications
Publications
Jun Izawa
Jun Izawa