Tsuyoshi Ikegami

• Ph.D
• Researcher at National Institute of Information and Communications Technology

Our social skills are critically determined by our ability to understand and appropriately respond to actions performed by others. However despite its obvious importance, the mechanisms enabling action understanding in humans have remained largely unclear. A popular but controversial belief is that parts of the motor system contribute to our abilit...

Human dexterity with tools is believed to stem from our ability to incorporate and use tools as parts of our body. However tool incorporation, evident as extensions in our body representation and peri-personal space, has been observed predominantly after extended tool exposures and does not explain our immediate motor behaviours when we change tool...

Movement error is a driving force behind motor learning. For motor learning with discrete movements, such as point-to-point reaching, it is believed that the brain uses error information of the immediately preceding movement only. However, in the case of continuous and repetitive movements (i.e., rhythmic movements), there is a ceaseless inflow of...

As long as we only focus on kinematics, rhythmic movement appears to be a concatenation of discrete movements or discrete movement appears to be a truncated rhythmic movement. However, whether or not the neural control processes of discrete and rhythmic movements are distinct has not yet been clearly understood. Here, we address this issue by exami...

Understanding how the brain learns motor skills remains a very challenging task. To elucidate the neural mechanism underlying motor learning, we assessed brain activation changes on a trial-by-trial basis during learning of a multi-joint discrete motor task (kendama task). We used multi-channel near-infrared spectroscopy (NIRS) while simultaneously...

[This corrects the article DOI: 10.1371/journal.pone.0269297.].

Motor adaptation can be achieved through error-based learning, driven by sensory prediction errors, or reinforcement learning, driven by reward prediction errors. Recent work on visuomotor adaptation has shown that reinforcement learning leads to more persistent adaptation when visual feedback is removed, compared to error-based learning in which c...

Plasticity after visual loss is a remarkable characteristic of the brain. Previous studies in blind individuals have shown that the occipital cortex, which corresponds to the visual cortex in sighted individuals, can be reorganized and repurposed for nonvisual perception and cognitive functions. To our knowledge, however, no studies have directly e...

Humans have the amazing ability to learn the dynamics of the body and environment to develop motor skills. Traditional motor studies using arm reaching paradigms have viewed this ability as the process of ‘internal model adaptation’. However, the behaviors have not been fully explored in the case when reaches fail to attain the intended target. Her...

In people with normal sight, mental simulation (motor imagery) of an experienced action involves a multisensory (especially kinesthetic and visual) emulation process associated with the action. Here, we examined how long-term blindness influences sensory experience during motor imagery and its neuronal correlates by comparing data obtained from bli...

Humans have the amazing ability to learn the dynamics of the body and environment to develop motor skills. Traditional motor studies using arm reaching paradigms have viewed this ability as the process of internal model adaptation. However, the behaviors have not been fully explored in the case when reaches fail to attain the intended target. Here...

Motor contagions are implicit effects of observed actions performed by another individual on one's own actions. There are two types of motor contagions. First, action-imitative contagions are induced simply by action observation and cause one's action to become similar to the observed action. Second, prediction error-induced contagions are induced...

The first systematic collaboration between cognitive scientists and sports psychologists considers the mind–body relationship from the perspective of athletic skill and sports practice. This landmark work is the first systematic collaboration between cognitive scientists and sports psychologists that considers the mind–body relationship from the pe...

Motor contagions refer to implicit effects on one's actions induced by observed actions. Motor contagions are believed to be induced simply by action observation and cause an observer's action to become similar to the action observed. In contrast, here we report a new motor contagion that is induced only when the observation is accompanied by predi...

This corrects the article DOI: 10.1038/ncomms5524.

The question of how humans predict outcomes of observed motor actions by others is a fundamental problem in cognitive and social neuroscience. Previous theoretical studies have suggested that the brain uses parts of the forward model (used to estimate sensory outcomes of self-generated actions) to predict outcomes of observed actions. However, this...

Motor contagions refer to implicit effects on one's actions induced by observation of other's actions. Motor contagions are believed to be induced simply by action observation and cause an observer's action to become similar to the observed action. In contrast, here we report a new motor contagion that is induced only when the observation is accomp...

When you see an individual holding a baby in front of an elevator, you instinctively move to open the door for him. This seemingly obvious helping action is possible because you are able to immediately characterize, recognize and then understand his actions—that is, recognize the intention behind the observed individual’s actions, estimate the outc...