Papers by kazuyoshi fukuzawa
Neurocase, 2020
Through cognitive task performance, we examined the functional role of finger writing (kūsho) in ... more Through cognitive task performance, we examined the functional role of finger writing (kūsho) in a Japanese patient with moderate sensory aphasia and reading difficulties. We hypothesized that the visual feedback of kūsho would improve visual language processing, which we tested with a "kanji construction task" using character subparts. Results showed a higher number of correct responses 1) when the patient used kūsho and 2) when visual feedback of finger movements was available. The results suggest that kūsho may not improve the retrieval of phonological information but does aid the visual processing necessary to assemble character subparts.
IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society, 2015
In rehabilitation, a robot is useful and effective for repetitive trainings. However, few rehabil... more In rehabilitation, a robot is useful and effective for repetitive trainings. However, few rehabilitation robots have adaptability to personal difference. Therefore, an index for quantitative assessment of the difference is required to achieve the adaptability. In conventional research, a hand stiffness is used as one of the indeces, and a dynamic hand stiffness is measured only in 2 dimensions. Then, in this paper the dynamic hand stiffness of reaching motions is measured in 3 dimensions by using an arm robot. The experimental results are represented as stiffness ellipsoids. Moreover, the results are compared with the ellipsoids in 2 dimensions. From these results, it is revealed that the characteristics of the dynamic hand stiffness in 3 dimensions is different from that in 2 dimensions. The fact implicits that a human controlls his/her arm stiffness not in work space but in joint space.
Higher Brain Function Research, 2019
PLOS ONE, 2019
Kūsho, which refers to a behavior in which one moves the index finger as a substitute for a pen i... more Kūsho, which refers to a behavior in which one moves the index finger as a substitute for a pen in the air or on a surface, mostly used when trying to recall the shape of a written character or the spelling of a word, has been known to facilitate cognitive task performance among kanji writing-system users. This study investigates whether the facilitative effect of kūsho, the existence of which has been exclusively confirmed in younger adults, is present in old age. Moreover, to further understand the interaction between finger movement and cognitive processing, we analyzed the correlation between the kūsho effect and factors such as age, mini-mental state examination (MMSE) score, and number of years of education. The kūsho effect was assessed by a task where participants mentally assembled a set of kanji subparts to form an actual character. The results showed a significant facilitative effect of kūsho and a strong negative correlation between kūsho effect and education. This study confirms the benefits of finger movement for solving cognitive tasks involving visual processing of written language among older adults and suggests the kūsho effect may be mediated by education.
Neuropsychologia, 2018
The present study investigated the relation between schizotypy and motor control against self-or ... more The present study investigated the relation between schizotypy and motor control against self-or other-produced action. We used an unloading task to focus on the timing component of anticipatory motor control. In the task, a weight was removed from a participants' hand by the participants themselves or by an experimenter (voluntary versus imposed unloading). Postural disturbance at the removal timing was measured as an index of predictive function in motor control. We hypothesized that the postural disturbance in the voluntary unloading would be positively related to schizotypal traits; however, the results did not support this theory. The results showed almost zero correlation between the schizotypy scores and the postural disturbance in the voluntary unloading condition. In contrast, the schizotypy scores positively correlated with the postural disturbance in the imposed unloading condition. These findings were replicated across two participant groups and two schizotypy scales. Further analyses on subscales of the schizotypy questionnaire found moderate levels of positive correlation between each subscale for Cognitive-Perceptual and Disorganization factors and the disturbance. Accordingly, the present study did not support the idea that non-pathological individuals with high schizotypal traits have deficits in prediction of self-produced actions, at least for a temporal domain. Instead, the results suggested that individuals with high schizotypal traits, particularly for the positive and disorganization symptoms, are not good at responding to others-produced actions. The schizophrenic symptoms were discussed in terms of the failure in the processes executed after calculating prediction of sensory consequences and dysfunction in internal models for "other people".
A position reproduction task was performed, in a controlled experimental environment, by seven pa... more A position reproduction task was performed, in a controlled experimental environment, by seven patients with a parietal lobe lesion. We obtained mainly three findings: (a) even for patients who failed a thumb localization test, the accuracy of position reproduction was adequate and did not deviate from the range of error observed in healthy young participants, (b) the patients showed a centralizing tendency in localization, and (c) they initially moved in the wrong direction when reproducing the remembered positions. The study also indicated that patients whose lesion sites included the postcentral gyrus exhibited stronger exploratory movements than those who had no such lesions and lacked smoothness of movement. In patients without the lesion of the postcentral gyrus, a higher-order dysfunction, rather than the pure position sense problem, was suggested to contributed to their task performance. The present study provided fundamental data for sensorimotor skills of patients with par...
PLOS ONE, 2019
The amount of practice and time interval between practice sessions are important factors that inf... more The amount of practice and time interval between practice sessions are important factors that influence motor learning efficiency. Here, we aimed to reveal the relationship between the retention and consolidation of a new internal model, and the amount of practice and time interval between practice sessions. We employed a visuomotor rotation tracking task to test the hypotheses that (1) a new internal model consolidates owing to extensive practice after reaching a task performance plateau and (2) a longer time interval between practice sessions makes it difficult to activate a new internal model. The participants were assigned to one of the four groups that differed in terms of the amount of practice and the time interval between practice sessions. They performed a tracking task in which they experienced 120c lockwise visuomotor rotation and were required to track a moving target on a computer display using a mouse cursor. To evaluate the retention and consolidation of a new internal model, we calculated the aftereffects and savings as measures of motor learning. To the best our knowledge, this is the first study to manipulate both the amount of practice and the time interval between practice sessions simultaneously in one experiment using a visuomotor tracking task. Our results support the previously reported idea that extensive practice is necessary for the consolidation of a new internal model.
Experimental Brain Research, 2018
The present study tested whether remapping of visuomotor correspondence alters automatic motor re... more The present study tested whether remapping of visuomotor correspondence alters automatic motor responses induced by visual stimuli. We hypothesized that the congruency effect, an automatic modulation of motor responses based on stimulusresponse congruency, changes in accordance with a new visuomotor correspondence acquired through an adaptation task. To induce visuomotor adaptation, participants performed a tracking task with 30° or 150° rotation of the visual feedback. The congruency effect was evaluated multiple times by a visual response task where participants moved their finger left or right. We predicted that the congruency effect, as a measure of automatic responses, would be almost reversed after adaptation to the 150° rotation, because a visual stimulus spatially opposite to the participant's own action would become a "congruent" stimulus in a 150°-rotated environment but not in a 30°-rotation environment. The results show that visuomotor adaptation to the 150° rotation did modulate the congruency effect in accordance with the acquired visuomotor correspondence, but did not completely reverse the effect. When the effect was assessed after the manipulation, which was assumed to switch an internal model back to its normal state, there was no change in automatic motor responses. Furthermore, we found that after effects developed as the training proceeded but decreased over time. These findings suggest that the visuomotor system subserving automatic modulation in motor responses is based on the currently active internal model and, therefore, highly adaptive. In addition, the mechanism underlying after effects in a visuomotor task is discussed in terms of a switching function of internal models.
Journal of Motor Behavior, 2017
ABSTRACT This study investigated the influences of task constraint on motor learning for a trajec... more ABSTRACT This study investigated the influences of task constraint on motor learning for a trajectory-based movement considering the speed–accuracy relationship. In the experiment, participants practiced trajectory-based movements for five consecutive days. The participants were engaged in training with time-minimization or time-matching constraints. The results demonstrated that the speed–accuracy tradeoff was not apparent or was weak in the training situation. When the participants practiced the movement with a time-minimization constraint, movement errors did not vary, whereas the movement time decreased. With the time-matching constraint, the errors decreased as a session proceeded. These results were discussed in terms of the combination of signal-dependent noises and exploratory search noises. It is suggested that updating spatial and temporal factors does not appear to occur simultaneously in motor learning.
PLOS ONE, 2017
The present study investigated interactions between cognitive processes and finger actions called... more The present study investigated interactions between cognitive processes and finger actions called "kusho," meaning "air-writing" in Japanese. Kanji-culture individuals often employ kusho behavior in which they move their fingers as a substitute for a pen to write mostly done when they are trying to recall the shape of a Kanji character or the spelling of an English word. To further examine the visualization role of kusho behavior on cognitive processing, we conducted a Kanji construction task in which a stimulus (i.e., sub-parts to be constructed) was simultaneously presented. In addition, we conducted a Kanji vocabulary test to reveal the relation between the kusho benefit and vocabulary size. The experiment provided two sets of novel findings. First, executing kusho behavior improved task performance (correct responses) as long as the participants watched their finger movements while solving the task. This result supports the idea that visual feedback of kusho behavior helps cognitive processing for the task. Second, task performance was positively correlated with the vocabulary score when stimuli were presented for a relatively long time, whereas the kusho benefits and vocabulary score were not correlated regardless of stimulus-presentation time. These results imply that a longer stimulus-presentation could allow participants to utilize their lexical resources for solving the task. The current findings together support the visualization role of kusho behavior, adding experimental evidence supporting the view that there are interactions between cognition and motor behavior.
Higher Brain Function Research, 2013
Higher Brain Function Research, 2006
computational theory minimum torque change model kinematics inverse dynamics inverse ill posed pr... more computational theory minimum torque change model kinematics inverse dynamics inverse ill posed problem 12
Higher Brain Function Research, 1988
PLOS ONE, 2015
The present study investigated the interactions between motor action and cognitive processing wit... more The present study investigated the interactions between motor action and cognitive processing with particular reference to kanji-culture individuals. Kanji-culture individuals often move their finger as if they are writing when they are solving cognitive tasks, for example, when they try to recall the spelling of English words. This behavior is called kusho, meaning air-writing in Japanese. However, its functional role is still unknown. To reveal the role of kusho behavior in cognitive processing, we conducted a series of experiments, employing two different cognitive tasks, a construction task and a stroke count task. To distinguish the effects of the kinetic aspects of kusho behavior, we set three hand conditions in the tasks; participants were instructed to use either kusho, unrelated finger movements or do nothing during the response time. To isolate possible visual effects, two visual conditions in which participants saw their hand and the other in which they did not, were introduced. We used the number of correct responses and response time as measures of the task performance. The results showed that kusho behavior has different functional roles in the two types of cognitive tasks. In the construction task, the visual feedback from finger movement facilitated identifying a character, whereas the kinetic feedback or motor commands for the behavior did not help to solve the task. In the stroke count task, by contrast, the kinetic aspects of the finger movements influenced counting performance depending on the type of the finger movement. Regardless of the visual condition, kusho behavior improved task performance and unrelated finger movements degraded it. These results indicated that motor behavior contributes to cognitive processes. We discussed possible mechanisms of the modality dependent contribution. These findings might lead to better understanding of the complex interaction between action and cognition in daily life.
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Papers by kazuyoshi fukuzawa