
Keisuke KushiroKyoto University | Kyodai · Graduate School of Human and Environmental Studies
Keisuke Kushiro
Doctor of Philosophy
About
43
Publications
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Introduction
Skills and Expertise
Publications
Publications (43)
In this study, we investigated how the temporal properties of the preparation phase for upper limb movements are affected by the reaching direction. Twelve right-handed participants performed three motor tasks, two types of reaching movements, and one finger-lifting movement. Reaching movements were performed from the home position to 15 target loc...
Human body movements are based on the intrinsic trade-off between speed and accuracy. Fitts’s law (1954) shows that the time required for movement is represented by a simple logarithmic equation and is applicable to a variety of movements. However, few studies have determined the role of the direction in modulating the performance of upper limb mov...
With the development of measurement technology, data on the movements of actual games in various sports can be obtained and used for planning and evaluating the tactics and strategy. Defense in team sports is generally difficult to be evaluated because of the lack of statistical data. Conventional evaluation methods based on predictions of scores a...
With the development of measurement technology, data on the movements of actual games in various sports are available and are expected to be used for planning and evaluating the tactics and strategy. In particular, defense in team sports is generally difficult to be evaluated because of the lack of statistical data. Conventional evaluation methods...
Concurrent body movements have been shown to enhance the accuracy of spatial judgment, but it remains unclear whether they also contribute to perceptual estimates of gravitational space not involving body movements. To address this, we evaluated the effects of static or dynamic arm movements during prolonged whole-body tilt on the subsequent percep...
With the development of measurement technology, data on the movements of actual games in various sports are available and are expected to be used for planning and evaluating the tactics and strategy. In particular, defense in team sports is generally difficult to be evaluated because of the lack of statistical data. Conventional evaluation methods...
Additional gravitational cues generated by active body movements may play a role in the perception of gravitational space, but no experimental evidence has been shown on this. To investigate this possibility, we evaluated how arm movements made against gravity influenced the perceptual distortion of visual and postural vertical induced by prolonged...
To internally estimate gravitational direction and body orientation, the central nervous system considers several sensory inputs from the periphery and prior knowledge of gravity. It is hypothesized that the modulation of visual inputs, supplying indirect information of gravity, affects the prior knowledge established internally by other sensory in...
The present study utilized induced acceleration analysis to clarify the contributions of muscular and gravitational torques to the kinematics of vertical pointing movements performed by the upper limb. The study included eight healthy men with a mean age of 25 years. The experiment was divided into three blocks with ten trials in each, comprising f...
In our day-to-day life, we can accurately reach for an object in our gravitational environment without any effort. This can be achieved even when the body is tilted relative to gravity. This is accomplished by the central nervous system (CNS) compensation for gravitational forces and torque acting on the upper limbs, based on the magnitude of body...
In the present study, we investigated the kinematics of object-transport movement in a downward direction using a precision grip, to elucidate how the central nervous system (CNS) takes into account object weight when making the movement, even when participants are unable to recognize the weight until they grasp the object. We found that the kinema...
People who stutter (PWS) presumably pay excessive attention to monitoring their speech, possibly exacerbating speech fluency. Using a reading comprehension task, we investigated whether or not PWS devote excessive attention to their speech.
Methods
Eleven PWS and 11 people who do not stutter (PNS) read passages in silent and oral reading condition...
Systemic administration of a gamma-amino butyric acid type B (GABAB) receptor agonist, baclofen, affects various physiological and psychological processes. To date, the effects on oculomotor system have been well characterized in primates, however those in mice have not been explored. In this study, we investigated the effects of baclofen focusing...
Preparatory motion (consciously or unconsciously moving a body part just before performing a task) enhances the motor performance. Repeated body movements are roughly categorized as rhythmic and discrete. However, the most effective mode of preparatory motion remains unclear. The present study utilized both modes of preparatory motion and compared...
The central vestibular system plays an important role in higher neural functions such as self-motion perception and spatial orientation. Its ability to store head angular velocity is called velocity storage mechanism (VSM), which has been thoroughly investigated across a wide range of species. However, little is known about the mouse VSM, because t...
In our daily lives, we can appropriately perform movements on the earth, suggesting that the central nervous system takes into account gravitational forces that act on our bodies during the movements. Recently, gravitational forces have been observed to generate the direction-dependent differences in the spatial properties of the kinematics of preh...
Conclusions:
This study shows that the differences in the waveforms of angular rotation affect the perception and memory of angular displacement.
Objectives:
During daily life, when we turn our head during various activities, our brain calculates how much angular displacement our head has undergone. However, how we obtain an accurate estimation...
Humans sequentially perceive spatial information surrounding them when performing intended motor movements. Precise spatial information is constructed in the brain by integrating sensory information such as visual, vestibular, and somatosensory inputs. Visual input is considered an essential source of stable spatial perception in our daily lives. I...
In the last two decades, we have focused on establishing a reliable technique for focal stimulation of vestibular receptors to evaluate neural connectivity. Here, we summarize the vestibular-related neuronal circuits for the vestibulo-ocular reflex, vestibulocollic reflex, and vestibulospinal reflex arcs. The focal stimulating technique also uncove...
The chewing gum indirectly affects postural control by influencing vestibular function to stabilize posture during upright standing.
This study aimed to evaluate the effect of chewing gum on static posturography in patients.
The subjects were 26 patients with chronic balance disorders. The subjects were instructed to stand as stably as possible on...
The purpose of this study was to investigate the effect of anxiety on the postural stability of a variety of dizzy patients during upright standing. To address this issue, 54 patients complaining of dizziness were enrolled in this study. The degree of anxiety in patients was evaluated on the basis of a routine vestibular examination together with t...
The purpose of this study was to investigate the effect of masticating chewing gum on postural stability during upright standing. To address this issue, 12 healthy subjects performed quiet standing on a force platform for the posturography study. The subjects were instructed to stand as stable as possible on the force platform in order to record th...
We studied the axonal projections of vestibulospinal neurons activated from the posterior semicircular canal. The axonal projection level, axonal pathway, and location of the vestibulospinal neurons originating from the PC were investigated in seven decerebrated cats. Selective electrical stimulation was applied to the PC nerve, and extracellular r...
The visual and vestibular systems begin functioning early in life. However, it is unclear whether young infants perceive the dynamic world based on the retinal coordinate (egocentric reference frame) or the environmental coordinate (allocentric reference frame) when they encounter incongruence between frames of reference due to changes in body posi...
Nystagmus induced by off-vertical axis rotation (OVAR) about a head yaw axis is composed of a yaw bias velocity and modulations in eye position and velocity as the head changes orientation relative to gravity. The bias velocity is dependent on the tilt of the rotational axis relative to gravity and angular head velocity. For axis tilts <15 degrees,...
The morphology of physiologically identified otolith nerve-activated vestibular neurons was investigated using intracellular injections of horseradish peroxidase (HRP). Eleven utricular, 11 saccular and three utricular/saccular nerve-activated vestibular neurons were labeled with HRP. All of these neurons except one were secondary neurons, the exce...
We examined whether otolith-activated second- and third-order vestibular nucleus neurons received commissural inhibition from the contralateral otolithic macula oriented in the same geometric plane. For this purpose we performed intracellular recording in vestibular nucleus neurons after stimulation of the ipsi- and contralateral utricular and sacc...
Properties of otolith inputs to vestibulocerebellar neurons were investigated in 14 adult cats. In the vestibular nuclei, we recorded single-unit activities that responded orthodromically after stimulation of the utricular and/or saccular nerves and antidromically after stimulation of the cerebellum (uvula-nodulus and anterior vermis). Descending a...
The convergence of the posterior semicircular canal (PC) and utricular (UT) inputs in single vestibular nuclei neurons was studied intracellularly in decerebrate cats. A total of 160 vestibular neurons were orthodromically activated by selective stimulation of the PC and the UT nerve and classified according to whether or not they were antidromical...
Saccular and utricular organs are essential for postural stability and gaze control. Although saccular and utricular inputs are known to terminate on vestibular neurons, few previous studies have precisely elucidated the origin of these inputs. We investigated the saccular and utricular inputs to single vestibular neurons in whole vestibular nuclei...
Convergence between posterior canal (PC) and saccular (SAC) inputs in single vestibular nuclei neurons was investigated in decerebrated cats. Postsynaptic potentials were recorded intracellularly after selective stimulation of the SAC and PC nerves. Stimulation of either the SAC or PC nerve orthodromically activated 143 vestibular nuclei neurons. O...
The otolith system contributes to the vestibulo-ocular reflexes (VOR) when the head moves linearly in the horizontal plane or tilts relative to gravity. The saccules are thought to detect predominantly accelerations along the gravity vector. Otolith-induced vertical eye movements following vertical linear accelerations are attributed to the saccule...
The convergence of the posterior semicircular canal (PC) and utricular (UT) inputs in single vestibular nuclei neurons was
studied intracellularly in decerebrate cats. A total of 160 vestibular neurons were orthodromically activated by selective
stimulation of the PC and the UT nerve and classified according to whether or not they were antidromical...
We investigated whether cross-striolar inhibition, which may increase sensitivity to linear acceleration, contributed to utricular (UT) afferent innervation of single vestibular neurons (VNs). Excitatory and inhibitory postsynaptic potentials (EPSPs, IPSPs, respectively) were recorded from VNs after focal stimulation of the UT macula (M). From a to...
Convergence of both afferents from the PC and saccular macula, and those from the PC and utricular macula on single vestibular neurons was noted by use of intercellular recording from vestibular neurons. Vestibular neurons were classified VO neurons (vestibulo-ocular proper neurons), VOS (Vestibulo-oculo-spinal neurons sending axon collaterals both...
Properties of otolith inputs to vestibulocerebellar neurons were investigated in 14 adult cats. In the vestibular nuclei,
we recorded single-unit activities that responded orthodromically after stimulation of the utricular and/or saccular nerves
and antidromically after stimulation of the cerebellum (uvula-nodulus and anterior vermis). Descending a...
Connections from the otolithic organs to sternocleidomastoid (SCM) motoneurons were studied in 20 decerebrate cats. The electrical stimulation was selective for the saccular or the utricular nerves. Postsynaptic potentials were recorded from antidromically identified SCM motoneurons; these muscles participate mainly in neck rotation and flexion. Pa...
Neural connections from the saccular and utricular nerves to the ipsilateral vestibular neurons and the commissural effects were studied by using intracellular recordings of excitatory (E) and inhibitory (I) postsynaptic potentials (PSPs) in vestibular neurons of cats after focal stimulation of the saccular and the utricular maculae. Neural circuit...
Saccular and utricular organs are essential for postural stability and gaze control. Although saccular and utricular inputs are known to terminate on vestibular neurons, few previous studies have precisely elucidated the origin of these inputs. We investigated the saccular and utricular inputs to single vestibular neurons in whole vestibular nuclei...
The convergence of the posterior semicircular canal (PC) and utricular (UT) inputs in single vestibular nuclei neurons was studied intracellularly in decerebrate cats. A total of 160 vestibular neurons were orthodro-mically activated by selective stimulation of the PC and the UT nerve and classified according to whether or not they were antidromica...