Shinji Kakei

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A central problem in motor research has been to understand how sensory signals are transformed to generate a goal-directed movement. This problem has been formulated as a set of coordinate transformations that begins with an extrinsic coordinate frame representing the spatial location of a target and ends with an intrinsic coordinate frame describing muscle(More)
An increasing number of projects in neuroscience requires the statistical analysis of high dimensional data sets, as, for instance, in predicting behavior from neural firing or in operating artificial devices from brain recordings in brain-machine interfaces. Linear analysis techniques remain prevalent in such cases, but classical linear regression(More)
An increasing number of projects in neuroscience require statistical analysis of high-dimensional data, as, for instance, in the prediction of behavior from neural firing or in the operation of artificial devices from brain recordings in brain-machine interfaces. Although prevalent, classical linear analysis techniques are often numerically fragile in high(More)
In this paper, we propose a new method to make a quantitative evaluation for movement disorders. Based on the EMG signals, we analyzed the movement disorders for cerebellar patients at the motor command level. As an experimental task, we asked subjects to perform step-tracking wrist movements with a manipulandum, and simultaneously recorded wrist joint(More)
  • Hiroshi Mitoma, Keya Adhikari, Daniel Aeschlimann, Partha Chattopadhyay, Marios Hadjivassiliou, Christiane S. Hampe +11 others
  • 2015
In the last few years, a lot of publications suggested that disabling cerebellar ataxias may develop through immune-mediated mechanisms. In this consensus paper, we discuss the clinical features of the main described immune-mediated cerebellar ataxias and address their presumed pathogenesis. Immune-mediated cerebellar ataxias include cerebellar ataxia(More)
We propose a new method to provide a functional interpretation of motor commands (i.e., muscle activities) and their relationship to movement kinematics. We evaluated our method by analyzing the motor commands of normal controls and patients with cerebellar disorders for visually guided tracking movement of the wrist joint. Six control subjects and six(More)
The cerebellum generates its vast amount of output to the cerebral cortex through the dentate nucleus (DN) that is essential for precise limb movements in primates. Nuclear cells in DN generate burst activity prior to limb movement, and inactivation of DN results in cerebellar ataxia. The question is how DN cells become active under intensive inhibitory(More)
To examine whether mossy fibers (MFs) in the cerebellar hemisphere show delay activity, we recorded MF activity during a wrist movement task with a random instructed delay period in two monkeys. Among 155 task-related MFs, 70 MFs (45%) demonstrated significant delay activity. Those MFs were widely distributed in the cerebellar hemisphere. Some of the(More)
Which brain sites represent the final form of motor commands that encode temporal patterns of muscle activities? Here, we show the possible brain sites which have activity equivalent to the motor commands with functional magnetic resonance imaging (fMRI). We hypothesized that short-temporal patterns of movements or stimuli are reflected in(More)
Anticipating the timing of behaviorally relevant events is crucial for organizing movement. The time to initiate actions based on events (i.e., reaction time (RT)) is a useful measure to quantify states of anticipation. Few studies have examined how anticipation affects the timing of limb movements. We addressed this question behaviorally with two macaque(More)