ORCID Profile
0000-0003-1024-0051
Current Organisations
University of Pennsylvania
,
University of Tokyo
,
Hospital Clínic de Barcelona
,
Johns Hopkins University
,
Advanced Telecommunications Research Institute International
,
Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)
,
Universitat de Barcelona
,
UCLA
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Publications
Cerebellar activity evoked by common tool-use execution and imagery tasks: an fMRI study.
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/S0010-9452(08)70460-X
Abstract: The purpose of this study is to identify the functional brain networks activated in relation to actual tool-use in humans. Although previous studies have identified brain activity related to tool-use gestures (Moll et al., 2000), they did not investigate the brain activity involved in such tool-use. We investigated brain activity using functional magnetic resonance imaging (fMRI) while human subjects mentally imagined using sixteen common tools and while they actually used them. Brain activity for both actual and imagined tool-use was found in the posterior part of the parietal cortex, in the supplementary motor area, and in the cerebellum. Under imagined tool-use conditions, we found brain activity in the premotor and right pars opercularis. Under actual tool-use conditions, we found it in the primary motor area, in the thalamus, and in the left pars opercularis. Our precise analysis in the cerebellum indicated that activity evoked by imagery was located significantly more lateral to that evoked by actual use. We found a relationship between activity in the tool imagery and execution conditions by comparing their t-value-weighted centroid of activation coordinates. Moreover, for half of the subjects the spatial distribution pattern for each tool was similar, suggesting that neural mechanisms contributing to skillful tool-use are modularly organized in the cerebellum.
Shared neural correlates for language and tool use in Broca's area.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-10-2009
Reorganization of brain activity for multiple internal models after short but intensive training.
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/S0010-9452(08)70459-3
Abstract: Internal models are neural mechanisms that can mimic the input-output properties of controlled objects. Our studies have shown that: 1) an internal model for a novel tool is acquired in the cerebellum (Imamizu et al., 2000) 2) internal models are modularly organized in the cerebellum (Imamizu et al., 2003) 3) their outputs are sent to the premotor regions after learning (Tamada et al., 1999) and 4) the prefrontal and parietal regions contribute to the blending of the outputs (Imamizu et al., 2004). Here, we investigated changes in global neural networks resulting from the acquisition of a new internal model. Human subjects manipulated three types of rotating joystick whose cursor appeared at a position rotated 60 degrees, 110 degrees, or 160 degrees around the screen's center. In a pre-test after long-term training (5 days) for the 60 degrees and 160 degrees joysticks, brain activation was scanned during manipulation of the three joysticks. The subjects were then trained for the 110 degrees for only 25 min. In a post-test, activation was scanned using the same method as the pre-test. Comparisons of the post-test to the pre-test revealed that the volume of activation decreased in most of the regions where activation for the three rotations was observed. However, there was an increase in volume at a marginally significant level (p < .08) only in the inferior-lateral cerebellum and only for the 110 degrees joystick. In the cerebral cortex, activation related to 110 degrees decreased in the prefrontal and parietal regions but increased in the premotor and supplementary motor area (SMA) regions. These results can be explained by a model in which outputs of the 60 degrees and 160 degrees internal models are blended by prefrontal and parietal regions to cope with the novel 110 degrees joystick before the 25-minute training after the acquisition within the cerebellum of an internal model for the 110 degrees, output is directly sent to the premotor and SMA regions, and activation in these regions increases.
Subcortical brain volume differences in participants with attention deficit hyperactivity disorder in children and adults: a cross-sectional mega-analysis
Publisher: Elsevier BV
Date: 04-2017
A computational model of anterior intraparietal (AIP) neurons
Publisher: Elsevier BV
Date: 06-2006
The Effect of Renal Replacement Therapy and Antibiotic Dose on Antibiotic Concentrations in Critically Ill Patients: Data From the Multinational Sampling Antibiotics in Renal Replacement Therapy Study
Publisher: Oxford University Press (OUP)
Date: 09-03-2020
DOI: 10.1093/CID/CIAA224
Abstract: The optimal dosing of antibiotics in critically ill patients receiving renal replacement therapy (RRT) remains unclear. In this study, we describe the variability in RRT techniques and antibiotic dosing in critically ill patients receiving RRT and relate observed trough antibiotic concentrations to optimal targets. We performed a prospective, observational, multinational, pharmacokinetic study in 29 intensive care units from 14 countries. We collected demographic, clinical, and RRT data. We measured trough antibiotic concentrations of meropenem, piperacillin-tazobactam, and vancomycin and related them to high- and low-target trough concentrations. We studied 381 patients and obtained 508 trough antibiotic concentrations. There was wide variability (4–8-fold) in antibiotic dosing regimens, RRT prescription, and estimated endogenous renal function. The overall median estimated total renal clearance (eTRCL) was 50 mL/minute (interquartile range [IQR], 35–65) and higher eTRCL was associated with lower trough concentrations for all antibiotics (P & .05). The median (IQR) trough concentration for meropenem was 12.1 mg/L (7.9–18.8), piperacillin was 78.6 mg/L (49.5–127.3), tazobactam was 9.5 mg/L (6.3–14.2), and vancomycin was 14.3 mg/L (11.6–21.8). Trough concentrations failed to meet optimal higher limits in 26%, 36%, and 72% and optimal lower limits in 4%, 4%, and 55% of patients for meropenem, piperacillin, and vancomycin, respectively. In critically ill patients treated with RRT, antibiotic dosing regimens, RRT prescription, and eTRCL varied markedly and resulted in highly variable antibiotic concentrations that failed to meet therapeutic targets in many patients.
Humanoid Robotics and Neuroscience
Publisher: CRC Press
Date: 19-12-2014
DOI: 10.1201/B17949
Association Between Administration of IL-6 Antagonists and Mortality Among Patients Hospitalized for COVID-19
Publisher: American Medical Association (AMA)
Date: 10-08-2021
Related Organisations
Advanced Telecommunications Research Institute International
Location: Japan
Institut D’Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS)
Location: Spain
University Of Melbourne Faculty Of Veterinary And Agricultural Sciences
Location: Australia
Related Funding Activities
No related grants have been discovered for Hiroshi Imamizu.