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Background and Aim We evaluated whether diffusion kurtosis and tensor imaging (DKI/DTI) could reveal microstructural alterations in the brains of patients with functional gastrointestinal disorders (FGIDs), and whether imaging findings were correlated with health‐related quality of life (HRQOL). Methods Twelve patients with FGIDs fulfilling the Rome IV criteria, and seven healthy controls were examined using a 3 T magnetic resonance (MR) scanner. Tract‐based spatial statistics and regions of interest analyses were performed to compare the mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD) between patients with FGIDs versus controls. HRQOL was assessed in patients with FGIDs using the eight‐item short form of the Medical Outcome Study Questionnaire (SF‐8) and the Gastrointestinal Symptom Rating Scale. Results Patients with FGIDs had extensive, widespread regions of reduced MD in the white matter in comparison with healthy controls, whereas no significant differences were observed in MK and FA. No significant differences in deep gray matter for the MK, FA, and MD values were observed between patients with FGIDs and controls. In patients with FGIDs, the FA values in the globus pallidus had a significant and negative correlation with SF‐8 (a mental component summary) (r = −0.797, P = 0.01 uncorrected for multiple comparisons). Conclusions DKI/DTI can help identify microstructural white matter alterations in patients with FGIDs. The FA values in the globus pallidus may be useful for a severity assessment of FGIDs., We evaluated whether DKI/DTI could reveal microstructural alterations in the brains of patients withFGIDs, and if imaging findings were correlated with HRQOL. Patients with FGIDs had extensive, widespread regions of reduced MD in the white matter in comparison with healthy controls. In FGIDs, the FA values in the globus pallidus had a significant and negative correlation with SF‐8 (a mental component summary). The FA values in the globus pallidus may be useful for a severity assessment of FGIDs.

Several qualitative features distinguish bipedal from quadrupedal locomotion in mammals. In this study we show quantitative differences between quadrupedal and bipedal gait in the Japanese monkey in terms of gait patterns, trunk/hindlimb kinematics, and electromyographic (EMG) activity, obtained from 3 macaques during treadmill walking. We predicted that as a consequence of an almost upright body axis, bipedal gait would show properties consistent with temporal and spatial optimization countering higher trunk/hindlimb loads and a less stable center of mass (CoM). A comparatively larger step width, an ~9% longer duty cycle, and ~20% increased relative duration of the double-support phase were all in line with such a strategy. Bipedal joint kinematics showed the strongest differences in proximal, and least in distal, hindlimb joint excursions compared with quadrupedal gait. Hindlimb joint coordination (cyclograms) revealed more periods of single-joint rotations during bipedal gait and predominance of proximal joints during single support. The CoM described a symmetrical, quasi-sinusoidal left/right path during bipedal gait, with an alternating shift toward the weight-supporting limb during stance. Trunk/hindlimb EMG activity was nonuniformally increased during bipedal gait, most prominently in proximal antigravity muscles during stance (up to 10-fold). Non-antigravity hindlimb EMG showed altered temporal profiles during liftoff or touchdown. Muscle coactivation was more, but muscle synergies less, frequent during bipedal gait. Together, these results show that behavioral and EMG properties of bipedal vs. quadrupedal gait are quantitatively distinct and suggest that the neural control of bipedal primate locomotion underwent specific adaptations to generate these particular behavioral features to counteract increased load and instability. NEW & NOTEWORTHY Bipedal locomotion imposes particular biomechanical constraints on motor control. In a within-species comparative study, we investigated joint kinematics and electromyographic characteristics of bipedal vs. quadrupedal treadmill locomotion in Japanese macaques. Because these features represent (to a large extent) emergent properties of the underlying neural control, they provide a comparative, behavioral, and neurophysiological framework for understanding the neural system dedicated to bipedal locomotion in this nonhuman primate, which constitutes a critical animal model for human bipedalism.

Cerebrovascular reactivity (CVR) to acetazolamide (ACZ) on single-photon emission computed tomography (SPECT) can be used to assess the severity of chronic cerebral ischemia; however, this is an invasive method. We examined whether whole-brain magnetic resonance angiography (MRA) at 7T could non-invasively detect impaired CVR in patients with chronic cerebral ischemia by demonstrating the leptomeningeal collaterals (LMCs).Fifty-seven patients with symptomatic unilateral cervical stenosis underwent whole-brain time-of-flight MRA at 7T and cerebral perfusion SPECT before/after the ACZ challenge. MRA images were visually assessed based on 6-point grading systems to evaluate the development of LMCs toward the middle cerebral artery (MCA) and antegrade flow of MCA. CVR of the affected side was calculated from the SPECT data. Subsequently, we compared the LMC grades on MRA with CVR on SPECT.CVR was significantly lower in grades ≥ 2 of LMCs than in grades 0-1 (P 0.05) when applying LMCs from the anterior cerebral artery (ACA) and/or posterior cerebral artery (PCA). These differences were more evident than those in the grading of the antegrade MCA flow. The LMC grades from ACA/PCA readily detected reduced CVR (18.4%) with a sensitivity/specificity of 0.79/0.82.The development of LMCs on whole-brain MRA at 7T can non-invasively detect reduced CVR with a high sensitivity/specificity in patients with unilateral cervical stenosis.

In stroke patients, muscle tone on the unaffected side is often increased during voluntary tasks. This is known as a mirror movement and might be an impediment to function recovery, but its neural background is still unclear. In this study, we investigated the effect of unilateral muscle hypertonia on ipsilateral cortical activity and contralateral motor function. Fourteen right-handed healthy young subjects lifted a weight of 10% body weight with the right upper limb to increase muscle tone (weight task), while no weight lifting was set as the control 'nonweight' task. We recorded the motor-evoked potential (MEP), resting motor threshold and H-reflex from the left flexor carpi radialis muscle during both tasks. To estimate the functional effect of the weight task, subjects performed the 'Purdue pegboard test', consisting of examination for 30 seconds (peg-30) and assembly for 60 seconds (peg assembly). Left-hand grip strength was also measured. When subjects performed the weight task, the MEP amplitude increased significantly and the MT decreased significantly. There was no significant difference of H-reflex amplitude between the two tasks. No significant difference of the peg-30 score was observed between weight and nonweight tasks, but the peg assembly score was significantly lower during the weight task. Grip strength showed a significant increase during the weight task. These results indicate that the present weight load model may have the potential to advance our understanding of the mechanisms underlying mirror movements after stroke.

The short-term joint immobilization induces a decrease of corticospinal excitability; however, detailed time course of the immobilization-induced central nervous system changes and their extent have not yet been clarified. To evaluate the time course of changes in corticospinal excitability during forearm/hand immobilization for 24 h and investigate the effect on muscle strength, adhesive casting tape was used to immobilize the nondominant forearm/hand. The amplitude of the motor-evoked potential of the flexor pollicis brevis muscle induced by transcranial magnetic stimulation was measured during immobilization and after cast removal. The muscle strength was evaluated after the termination of immobilization. The resting motor-evoked potential recorded from flexor pollicis brevis muscle showed a significant decrease 3 h after initiation of immobilization and gradually declined further until the end of immobilization. It then increased over 2 h after cast removal, but was still significantly below baseline. However, no significant difference from baseline was observed at 3 h. Both pinch power and integrated electromyogram were significantly reduced by immobilization, and then gradually returned to baseline after the cast was removed. These results indicate that short-term forearm/hand immobilization rapidly reduces corticospinal excitability, and this change is rapidly reversed after resumption of movement.

Background and Purpose— The oxygen extraction fraction (OEF) is an effective metric to evaluate metabolic reserve in chronic ischemia. However, OEF is considered to be accurately measured only when using positron emission tomography (PET). Thus, we investigated whether OEF maps generated by magnetic resonance quantitative susceptibility mapping (QSM) at 7 Tesla enabled detection of OEF changes when compared with those obtained with PET. Methods— Forty-one patients with chronic stenosis/occlusion of the unilateral internal carotid artery or middle cerebral artery were examined using 7 Tesla-MRI and PET scanners. QSM images were obtained from 3-dimensional T2*-weighted images, using a multiple dipole-inversion algorithm. OEF maps were generated based on susceptibility differences between venous structures and brain tissues on QSM images. OEF ratios of the ipsilateral middle cerebral artery territory against the contralateral side were calculated on the QSM-OEF and PET-OEF images, using an anatomic template. Results— The OEF ratio in the middle cerebral artery territory showed significant correlations between QSM-OEF and PET-OEF maps ( r =0.69; P r =0.79; P =0.004), although showing significant systematic biases for the agreements. An increased QSM-OEF ratio of >1.09, as determined by receiver operating characteristic analysis, showed a sensitivity and specificity of 0.82 and 0.86, respectively, for the substantial increase in the PET-OEF ratio. Absolute QSM-OEF values were significantly correlated with PET-OEF values in the patients with increased PET-OEF. Conclusions— OEF ratios on QSM-OEF images at 7 Tesla showed a good correlation with those on PET-OEF images in patients with unilateral steno-occlusive internal carotid artery/middle cerebral artery lesions, suggesting that noninvasive OEF measurement by MRI can be a substitute for PET.

Objective To investigate the correlation between changes of contralesional cortical excitability evaluated by transcranial magnetic stimulation (TMS) and functional recovery in patients with hemiparetic stroke. Methods Eight inpatients (mean age: 75.9±13.8 years) with mild to moderate hemiparesis were enrolled. TMS was delivered to the optimal scalp position over the contralesional (ipsilateral to the paresis) primary motor cortex (M1) to activate the unaffected flexor carpi radialis muscle (FCR) while the patient picked up a wooden block with the affected hand. The amplitude of the motor-evoked potential (MEP) was measured and then was divided by the resting MEP amplitude (MEP ratio). For evaluation of motor function, we tested grip strength (GS), performed the upper extremity motor section of the Fugl-Meyer Assessment (FMA-UE), and performed the Purdue Pegboard Test (PPT) when the patients were admitted to our hospital (T1) and 2 months after admission (T2). Results The MEP ratio was significantly decreased at the second examination. The partial correlations between the MEP ratio and FMA-UE at T1, and PPT of an affected hand at T2 were observed while controlling for the period after stroke onset as the confounding variable. Conclusion The reduction of contralesional cortical hyperactivity is related to the functional recovery in part, but not related with the period after stroke onset. This suggests that enhanced reduction of contralesional M1 hyperactivity contributes to functional recovery after stroke.

We compared the time-course of satellite cell (SC) activation between eccentric and concentric contractions in the vastus lateralis (VL) muscle after step exercise. Young adults participated in a 30-min step up/down exercise which mainly involved concentric contractions with the right VL muscle and eccentric contractions with the left VL muscle. The concentric and eccentric contraction phases of the VL muscles were identified by changes in the electromyogram (EMG) and knee joint angle. Biopsy samples were taken from both VL muscles at three time periods: before the exercise and 2 and 5 days after the exercise. We found that the numbers of SCs were significantly increased in the type IIa fibers of the left VL at 2 and 5 days after the exercise. The expression of both hepatocyte growth factor (HGF) and myogenic differentiation 1 (MyoD) mRNA had significantly increased in the left VL at 2 and 5 days after the exercise and in the right VL at 5 days after the exercise. The expression of transient receptor potential canonical (TRPC) 1 mRNA also increased in the left VL at 2 days after exercise. These results indicate that eccentric contraction can effectively activate SC proliferation for up to 5 days after exercise. Similar changes in HGF, MyoD and TRPC1 mRNA expression suggest that HGF/c-Met signal activation through cation influx has a major impact on skeletal muscle SC activation in response to eccentric exercise.

BACKGROUND: Stent placement is thought to obstruct the inflow of blood to an aneurysm. However, we introduced parent artery expansion and demonstrated that this may reduce the blood flow by the stent. In our previous study using idealized shapes, the results showed that flow reduction was greater than 22.2%, even if the expansion rate was only 6%. Furthermore, the parent artery expansion is predominantly caused by the effect of flow reduction as compared to that of flow reduction due to the obstruction of flow under stent placement. However, a realistic shape is complex and the blood flow also becomes complex flow. It is not understood whether the results of flow in the idealized shape are reflective of flow from a realistic 3D model. Therefore, we examined the effect of parent artery expansion using a realistic model. OBJECTIVE: The aim is to clarify the effects of parent artery expansion on inflow rate, wall shear stress, and oscillatory shear index.METHODS: We used a patient-specific geometry of a human internal carotid artery with an aneurysm. The geometry of parent artery expansion due to oversized stent constructed based on the voronoi diagram. We performed calculations in the unsteady-state situations using constructed models. RESULTS: The complexity of the flow in the aneurysm decreases in case of expanded parent artery. The inflow rate decreases by 33.6% immediately after parent artery expansion alone without a stent. The effect of the parent artery expansion on flow reduction is larger than that of the obstruction flow by stent placement. In addition, wall shear stress and oscillatory shear index on the aneurysm wall decrease by change in blood flow due to the parent artery expansion. CONCLUSION: The effects of the parent artery expansion in a realistic aneurysm model with different stent lengths were evaluated on the basis of a numerical simulation. Although the flow was complex, the parent artery expansion with stent reduces the inflow to the aneurysm and wall shear stress and oscillatory shear index on the aneurysm. Therefore, we suggest that changes in the blood flow because of the parent artery expansion may be identified and, sometimes, is more effective than the obstruction flow due to the stent placement.

Background: Infarcts in the lateral striate artery (LSA) territory can be caused by several pathological changes, including lipohyalinosis and microatheroma. However, fluid dynamic effects on these changes remain unknown. Thus, we investigated whether the fluid dynamic metrics of the LSAs were altered in patients with acute ischemic stroke using computational fluid dynamics (CFD) analysis. Methods: Fifty-one patients with acute ischemic stroke confined in the basal ganglia and/or corona radiata underwent high-resolution magnetic resonance angiography (HR-MRA) at 7T. We performed CFD analyses to obtain indices including the wall shear stress (WSS), WSS gradient (WSSG), and flow velocity (FV) and compared these values between the ipsilesional and contralesional sides in the patients with infarcts in the LSA or non-LSA territories. Results: In patients with LSA-territory infarcts, the WSS, WSSG, and FV values were significantly lower in the ipsilesional LSAs than in the contralesional LSAs (P = .01-.03), while these values in the proximal middle cerebral arteries showed no significant lateralities. In contrast, in patients with non-LSA-territory infarcts, there were no significant lateralities in the metrics between the ipsilesional and contralesional sides. Conclusions: The CFD analyses using HR-MRA revealed significantly low WSS and WSSG values of the ipsilesional LSAs compared with that of the contralesional side in patients with LSA-territory infarcts, suggesting that fluid dynamic factors of LSAs can be one of the risk factors for LSA-territory infarctions.

Bipedal (Bp) locomotion is one of the most characteristic motor behaviors in human beings. Innate quadrupedal (Qp) four-legged animals also often walk bipedally. The walking posture, however, is significantly different between the two. This suggests that although both have a potential to walk bipedally, however, the human has a body scheme suitable for Bp locomotion, probably its skeletal system. The skeletal system includes the lumbar lordosis, sacral kyphosis, a round pelvis, a large femur neck angle, short feet, and so on. To verify this hypothesis, we compared kinematic and EMG activities between rats and humans during Qp and Bp locomotion on a treadmill belt. The rat is a representative Qp animal, but it is able to acquire Bp walking capability with motor learning. Although the mobile ranges of the hindlimb joint are different during each locomotor pattern between rats and humans, both showed replicable flexion and extension excursion patterns for each joint depending on the locomotor phase. There are many phase-locked EMG bursts between rats and humans during the same walking task and these are observed in the proximal rather than the distal muscles. This suggests that both rats and humans utilize similar neuronal systems for the elaboration of Qp and Bp locomotion. It was interesting that both subjects showed more muscle activities during non-natural locomotor patterns; Qp < Bp for rats and Bp < Qp for humans. This indicates that rat Bp and human Qp walking need more effort and we may be able to find its reason in their skeletal system.

The purpose of the present study was to establish a rat bipedal walking model to examine the effects of bipedal walking on the central nervous system by training rats to perform bipedal walking over a period of 3 months. The characteristics of bipedal walking were investigated using kinematic and electromyographic methods in established bipedal walking models. Stable bipedal walking was achieved in rats by training them to stand with an upright posture and to walk with the hindlimbs using bipedal-walking training equipment to obtain a water reward. A stable head position in the rat bipedal walking model was attained primarily by closing the swing-phase period with a large angular change in the hip, knee, and ankle joints. The EMG burst pattern of the knee extensor (m. rectus femoris) and the erector muscle of the spine (m. longissimus) during bipedal walking was similar to that during quadrupedal walking in rats. We established two bipedal walking models using normal and forelimb-amputated rats. Comparative studies of these two bipedal walking models are expected to provide the information about the influence of forelimb movements on neuronal control of bipedal walking.

BACKGROUND Stent placement for cerebral aneurysms leads to a decrease in blood flow. This occurs not only through the direct obstruction of flow but also by the expansion of the parent artery. The latter has been observed in several clinical studies. OBJECTIVE The goal of this study was to clarify the effects of parent artery expansion after stent treatment on the following: 1) decrease in blood flow to an aneurysm, 2) wall shear stress (WSS), and 3) oscillatory shear index (OSI). METHODS The parent artery geometry constructed U-shape. The aneurysm location with respect to the U-shaped parent artery was determined according to previous clinical data. We performed calculations in unsteady-state situations using constructed models. RESULTS Parent artery expansion with stent reduces blood inflow to an aneurysm and WSS of the aneurysm wall, in addition to increasing OSI. The aneurysm position affects the decrease of the inflow rate and WSS ratio and increases the OSI ratio. Expansion causes the majority of effects on flow reduction inside an aneurysm model. Thus, the expansion effects of all samples should not be neglected. CONCLUSION These data suggest that parent artery expansion and its effect should be measured and included in the total decrease in blood flow. Parent artery expansion may induce intimal hyperplasia, thus increasing the thickness of the aneurysm wall.

The aging society has rapidly progressed worldwide and the mortality and morbidity rates of aortic diseases are increasing. In particular, aortic aneurysm and aortic dissection are serious disorders. These may be fatal if their diagnosis and treatment are delayed. In 2006, guideline for the diagnosis and treatment of aortic aneurysm and aortic dissection was established in Japan [1]. In 2010, a guideline for the diagnosis and management of patients with thoracic aortic diseasewas established in the United States[2]. These guidelines pay particular attention to the diagnosis and treatment of aortic diseases. We investigated the possibility of estimating timedependent changes in these diseases using Computational Fluid Dynamics (CFD) simulation. This chapter describes the numerical simulations used for ulcer-like projections due to aortic dissections with complete thrombosis. By combining the results of CFD and diagnostic imaging, we can anticipate future improvements in diagnosis.

Percutaneous transluminal coronary angioplasty (PTCA) with stent implantation is widely used for the treatment of coronary stenosis. However, restenosis after stent implantation frequently reported by intravascular ultrasound evaluation. This may occur because of the reduced luminal area after implantation, insufficient stent expansion, or by the elastic recoil of the stent (ERS). Quantitative evaluation of stent expanding should provide further information on how to decrease the incidence of re-stenosis. Many previous studies have observed stent properties in 2D. However, the stent geometry is changed in 3D space, and 3D measurements will provide further information on factors such as the risk for asymmetric ERS. We performed 3D reconstruction using high spatial resolution images obtained with a Micro-CT system to observe the 3D expansion behavior of a test stent and quantitatively evaluate ERS. The expansion behavior of each structural component of the stent varied, as did the ERS and eccentricity. ERS ranged from 2.4% to 9.2% during observation form proximal and distal positions in each component. The greatest difference in ERS between 2D and 3D measurements was 5.2%. 3D measurements provide more information on ERS than 2D measurements. Our result shows the importance of the observation, and the evaluation by three dimensions.

Cerebral aneurysms (CA) are pathological dilations of the cerebral artery walls, which mostly occur at the circle of Willis. The incidence of CA has been estimated to be between 1% and 8 % among western populations. CA has rupture mortality and morbidity rates are exceedingly high. In the medical field, the stent placement in intracranial artery is call as endovascular treatment. Recently, stent placement as a low invasive therapy is paid to attention for treatment of aneurysm. The role of stent is to prevent blood flow into the aneurysm and to decrease the risk of rupture. Moreover, the effect of only stent on the flow reduction in CA has been reported in Computed Fluid Dynamics (CFD), recently. Moreover, the comparable effect is also reported in experiment. Some results suggested that the blood flow into aneurysm can reduce by only stent placement. Moreover, in generally, he stent porosities investigated under physiologically flow conditions were limited to the rage of 60-86%. And the stent of high porosity such as silk stent and pipeline stent is used for treatment of CA. However, the rupture of CA is reported in the case to use silk stent for CA. Although low or high porosity, it is important to understand flow of stent neighborhood and effect to aneurysm in stent placement. We reconstructed idealize cerebral aneurysm geometry to examine flow pattern and effect to aneurysm by stent placement and analyzed without- and with-stent. As results, the flow cannot divert by stent placement. The flow of wall neighborhood flows into aneurysm. Moreover, average and maximum of pressure distribution and wall shear stress distribution with stent is higher than that of without stent. We examine flow pattern and effect to aneurysm. Although treating by stent placement, there is a possibility of increasing the influence on the aneurysm.

Adaptation to the external demands allows us to walk bipedally in the various circumstances. During slanted walking, the control of center of gravity (COG) is crucial for the safe and smooth locomotion. In this study, we tested how the operant-trained bipedal (Bp) Japanese monkey could adapt its locomotor patterns to the changes in the treadmill grades. During uphill vs. level walking, the monkey exhibited: (1) a larger flexion of the hip, a lesser extension of knee and a larger ankle dorsiflexion at around touch-down of the foot, (2) a larger hip and knee extension at the lift-off, (3) a larger extent of forward body axis inclination. In contrast, during downhill vs. level walking, it exhibited: (1) a lesser flexion of the hip, a larger extension of the knee at the touch-down, (2) a lesser extension of the hip, a larger flexion of the knee at the lift-off, (3) a smaller extent of forward body axis inclination. Across all the grades tested, there were linear relationships between treadmill angle and the body axis angle, and between treadmill angle and stride length. These results imply that in order to appropriately transfer the COG forward-upward or forward-downward along the slanted treadmill surface, the monkey utilized both trunk and limb adaptation strategies. The strategies employed were quite similar to those in the human, suggesting that this Bp walking monkey could be a useful animal model that allows us to advance understanding of such adaptive control mechanisms in the human gait.

Background: studies are needed which consider CNS-controlled strategies for accommodating perturbed bipedal (Bp) posture and walking. Objective: to demonstrate the suitability of the Japanese monkey, Macaca fuscata, for the above purpose. Setting and subjects: three adult monkeys were operantly trained to use Bp-walking on a moving treadmill belt. On one side of the belt, a rectangular adjustable-height obstacle confronted the ipsilateral leg every 4–6 steps, as determined by belt speed. Methods: animal posture and walking patterns were captured and digitized by two high-speed video systems. Frame-byframe analyses of side- and back-view kinematics were obtained. Results: the monkeys learned quickly to proactively clear the in-coming obstacles by use of a flexible hip-knee-ankle flexion strategy. This featured an appropriate postural adjustment and leg trajectory. In cases where a monkey failed to clear the obstacle, it promptly adopted a defensive posture to avoid falling. There was then a quick return to a posture that allowed the resumption of a Bp gait. Conclusions: when Bp posture and gait are perturbed in a non-human primate model, the prompt adjustment of a flexible hip-knee-ankle flexion strategy and a defensive postural adjustment act together to prevent a fall and enable the speedy resumption of normal Bp posture and gait.

While the young Japanese monkey, M. fuscata, is growing, it can be trained operantly to maintain an upright posture and use bipedal (Bp) walking on a moving treadmill belt. For Bp locomotion, the animal generates sufficient propulsive force to smoothly and swiftly move the center of body mass (CoM) forward. The monkey can also adapt its gait to meet changing environmental demands. This appears to be accomplished by use of CNS strategies that include reactive and anticipatory control mechanisms. In this chapter, we provide evidence that the Bp walking monkey can select the most appropriate body-leg kinematic parameters to solve a variety of walking tasks. This recently developed non-human primate model has the potential to advance understanding of CNS operating principles that contribute to the elaboration and control of Bp walking in the human.