Kenji Ogawa

Internal monitoring or state estimation of movements is essential for human motor control to compensate for inherent delays and noise in sensorimotor loops. Two types of internal estimation of movements exist: self-generated movements, and externally generated movements. We used functional magnetic resonance imaging to investigate differences in brain activity for internal monitoring of self- versus externally generated movements during visual occlusion. Participants tracked a sinusoidally movin

Behavioral studies have shown that humans can adapt to conflicting sensorimotor mappings that cause interference after intensive training. While previous research works indicate the involvement of distinct brain regions for different types of motor learning (e.g., kinematics vs dynamics), the neural mechanisms underlying joint adaptation to conflicting mappings within the same type of perturbation (e.g., different angles of visuomotor rotation) remain unclear. To reveal the neural substrates tha

Abstract The neural mechanisms underlying visuomotor transformation are examined based on deficits in tracing and copying, as well as functional neuroimaging studies. The developmental process of copying and tracing, as well as lesion studies with adults showing disability in drawing, are reviewed, then two experiments are introduced. In Experiment 1, a behavioral analysis of copying and tracing by individuals with Williams Syndrome (WS) was presented. In Experiment 2, the brain activity involve

This study used event-related functional magnetic resonance imaging to investigate the neural basis underlying the sequential involvement of syntactic processing in the course of sentence comprehension. In experiments, a noun, case particle, and verb were presented one by one, constituting simple sentences in Japanese. Participants judged whether the sentence was syntactically correct (syntactic judgment) or whether the particle and verb had the same vowel (phonological judgment). During particl

While common semantic representations for individual words across languages have been identified, a common meaning system at sentence-level has not been determined. In this study, fMRI was used to investigate whether an across-language sentence comprehension system exists. Chinese-Japanese bilingual participants (<i>n</i> = 32) were asked to determine whether two consecutive stimuli were related (coherent) or not (incoherent) to the same event. Stimuli were displayed with three different modalit

Visually guided reaching involves the transformation of a spatial position of a target into a body-centered reference frame. Although involvement of the posterior parietal cortex (PPC) has been proposed in this visuomotor transformation, it is unclear whether human PPC uses visual or body-centered coordinates in visually guided movements. We used a delayed visually guided reaching task, together with an fMRI multivoxel pattern analysis, to reveal the reference frame used in the human PPC. In exp