Generalized inhomogeneity-resilient relaxation along a fictitious field (girRAFF) for improved robustness in rotating frame relaxometry at 3T.

PURPOSE: To optimize Relaxation along a Fictitious Field (RAFF) pulses for rotating frame relaxometry with improved robustness in the presence of B 0 $$ {\mathrm{B}}_0 $$ and B 1 + $$ {\mathrm{B}}_1^{+} $$ field inhomogeneities. METHODS: The resilience of RAFF pulses against B 0 $$ {\mathrm{B}}_0 $$ and B 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneities was studied using Bloch simulations. A parameterized extension of the RAFF formulation was introduced and used to derive a generalized inhomogeneity-resilient RAFF (girRAFF) pulse. RAFF and girRAFF preparation efficiency, defined as the ratio of the longitudinal magnetization before and after the preparation ( M z ( T p ) / M 0 $$ {M}_z\left({T}_p\right)/{M}_0 $$ ), were simulated and validated in phantom experiments. T RAFF $$ {T}_{\mathrm{RAFF}} $$ and T girRAFF $$ {T}_{\mathrm{girRAFF}} $$ parametric maps were acquired at 3T in phantom, the calf muscle, and the knee cartilage of healthy subjects. The relaxation time maps were analyzed for resilience against artificially induced field inhomogeneities and assessed in terms of in vivo reproducibility. RESULTS: Optimized girRAFF preparations yielded improved preparation efficiency (0.95/0.91 simulations/phantom) with respect to RAFF (0.36/0.67 simulations/phantom). T girRAFF $$ {T}_{\mathrm{girRAFF}} $$ preparations showed in phantom/calf 6.0/4.8 times higher resilience to B 0 $$ {\mathrm{B}}_0 $$ inhomogeneities than RAFF, and a 4.7/5.3 improved resilience to B 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneities. In the knee cartilage, T girRAFF $$ {T}_{\mathrm{girRAFF}} $$ (53 ± $$ \pm $$ 14 ms) was higher than T RAFF $$ {T}_{\mathrm{RAFF}} $$ (42 ± $$ \pm $$ 11 ms). Moreover, girRAFF preparations yielded 7.6/4.9 times improved reproducibility across B 0 $$ {\mathrm{B}}_0 $$ / B 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneity conditions, 1.9 times better reproducibility across subjects and 1.2 times across slices compared with RAFF. Dixon-based fat suppression led to a further 15-fold improvement in the robustness of girRAFF to inhomogeneities. CONCLUSIONS: RAFF pulses display residual sensitivity to off-resonance and pronounced sensitivity to B 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneities. Optimized girRAFF pulses provide increased robustness and may be an appealing alternative for applications where resilience against field inhomogeneities is required.

New methods for robust continuous wave T1ρ relaxation preparation.

Measurement of the longitudinal relaxation time in the rotating frame of reference (T1ρ ) is sensitive to the fidelity of the main imaging magnetic field (B0 ) and that of the RF pulse (B1 ). The purpose of this study was to introduce methods for producing continuous wave (CW) T1ρ contrast with improved robustness against field inhomogeneities and to compare the sensitivities of several existing and the novel T1ρ contrast generation methods with the B0 and B1 field inhomogeneities. Four hard-pulse and four adiabatic CW-T1ρ magnetization preparations were investigated. Bloch simulations and experimental measurements at different spin-lock amplitudes under ideal and non-ideal conditions, as well as theoretical analysis of the hard-pulse preparations, were conducted to assess the sensitivity of the methods to field inhomogeneities, at low (ω1 << ΔB0 ) and high (ω1 >> ΔB0 ) spin-locking field strengths. In simulations, previously reported single-refocus and new triple-refocus hard-pulse and double-refocus adiabatic preparation schemes were found to be the most robust. The mean normalized absolute deviation between the experimentally measured relaxation times under ideal and non-ideal conditions was found to be smallest for the refocused preparation schemes and broadly in agreement with the sensitivities observed in simulations. Experimentally, all refocused preparations performed better than those that were non-refocused. The findings promote the use of the previously reported hard-pulse single-refocus ΔB0 and B1 insensitive T1ρ as a robust method with minimal RF energy deposition. The double-refocus adiabatic B1 insensitive rotation-4 CW-T1ρ preparation offers further improved insensitivity to field variations, but because of the extra RF deposition, may be preferred for ex vivo applications.

The interaction between motor simulation and spatial perspective-taking in action language: a cross-cultural study.

Growing evidence has revealed the crucial role of motor simulation and spatial perspective-taking in action language. However, there is still a lack of understanding of how motor and spatial processes interact when there are multiple actors involved, and if embodied processes are consistent across different cultures. To address this gap, we examined the interaction between motor simulation and spatial perspective-taking in action-sentences comprehension, along with the consistency of embodied processes across cultures. We collected data from Italian and US English speakers using an online sentence-picture verification task. The participants completed four conditions: two congruent (i.e., the participant is the agent in the sentence and the photo; the agent is someone else interacting with the participant in both the sentence and the picture) and two incongruent (i.e., the agents of the sentence and the picture do not match). The results show that when the perspective of the picture matched that described in the sentence-processing reaction times (RTs) were faster than in the incongruent conditions. In the congruent conditions where the agent is someone else, RTs were slower compared to the condition where the participant is the agent. This has been interpreted as claiming that motor simulation and perspective-taking are independent processes interacting during sentence comprehension (e.g., motor simulation is always run in the role of the agent, but we can adopt multiple perspectives depending on the pronouns and the contextual cues). Furthermore, Bayesian analysis provided evidence that embodied processing of action language entwines a common mechanism, suggesting cross-cultural consistency of embodied processes.

MEDICAL CONTRACTS WITH CONDITIONS CONTRARY TO PUBLIC POLICY.

OBJECTIVE: The aim: To reveal some features of medical contracts with conditions contrary to public policy. PATIENTS AND METHODS: Materials and methods: The study is based on the statutory acts of countries of European Union. The author also uses acts of international law in the field of medical services, the law and cases court practice of EU. CONCLUSION: Conclusions: The sphere of medical services objectively requires increased control by the state. There are various legal mechanisms for ensuring the rights of the patient and the proper level of medicine. It is important to invalidate the unfair terms of medical contracts, compensation for losses and moral damage. These remedies are obtained through judicial protection and, in some cases, through other jurisdictional means. It is important to implement European standards in national legislation.

Frame of reference training for content analysis with structured teams (FORT-CAST): A framework for content analysis of open-ended survey questions using multidisciplinary coders.

In the context of a global pandemic, the need for reliable analysis of qualitative data in healthcare has never been more pressing. Open-ended questions are a feasible way for both researchers and organizational stakeholders to gain deeper insight into complex situations when timely research is needed. However, the interpretation of brief, textual responses can prove problematic. Both manual and automated/semiautomated methods of coding qualitative data have been associated with errors and costly temporal delays. Data obtained from the qualitative analysis of open-ended questions have been questioned for lacking robust insights. The present article introduces an innovative, manual, team-based method of analyzing responses to open-ended survey questions. This method was developed and implemented at the outset of the COVID-19 pandemic to understand the needs of nurses and their perceptions of organizational strategies that were implemented to address pandemic-related challenges. This framework utilizes a dedicated project management structure, general purpose software for data collection and analysis, frame-of-reference training designed for an interdisciplinary team of coders, and data analysis procedures that align with qualitative content analysis procedures. In concert, these techniques empower researchd team members with varying backgrounds and disparate levels of experience to provide unique human insights to data analysis procedures, refine the coding process, and support the abstraction of meaningful themes that were used to prioritize organizational strategies and further support nurses as the pandemic progressed.

Manually Acquiring Targets From Multiple Viewpoints Using Video Feedback.

OBJECTIVE: The effect of camera viewpoint was studied when performing visually obstructed psychomotor targeting tasks. BACKGROUND: Previous research in laparoscopy and robotic teleoperation found that complex perceptual-motor adaptations associated with misaligned viewpoints corresponded to degraded performance in manipulation. Because optimal camera positioning is often unavailable in restricted environments, alternative viewpoints that might mitigate performance effects are not obvious. METHODS: A virtual keyboard-controlled targeting task was remotely distributed to workers of Amazon Mechanical Turk. The experiment was performed by 192 subjects for a static viewpoint with independent parameters of target direction, Fitts' law index of difficulty, viewpoint azimuthal angle (AA), and viewpoint polar angle (PA). A dynamic viewpoint experiment was also performed by 112 subjects in which the viewpoint AA changed after every trial. RESULTS: AA and target direction had significant effects on performance for the static viewpoint experiment. Movement time and travel distance increased while AA increased until there was a discrete improvement in performance for 180°. Increasing AA from 225° to 315° linearly decreased movement time and distance. There were significant main effects of current AA and magnitude of transition for the dynamic viewpoint experiment. Orthogonal direction and no-change viewpoint transitions least affected performance. CONCLUSIONS: Viewpoint selection should aim to minimize associated rotations within the manipulation plane when performing targeting tasks whether implementing a static or dynamic viewing solution. Because PA rotations had negligible performance effects, PA adjustments may extend the space of viable viewpoints. APPLICATIONS: These results can inform viewpoint selection for visual feedback during psychomotor tasks.

Common and distinct neural trends of allocentric and egocentric spatial coding: An ALE meta-analysis.

The uniqueness of neural processes between allocentric and egocentric spatial coding has been controversial. The distinctive paradigms used in previous studies for manipulating spatial coding could have attributed for the inconsistent results. This study was aimed to generate converging evidence from previous functional brain imaging experiments for collating neural substrates associated with these two types of spatial coding. An additional aim was to test whether test-taking processes would have influenced the results. We obtained coordinate-based functional neuroimaging data for 447 subjects and performed activation likelihood estimation (ALE) meta-analysis. Among the 28 experiments, the results indicate two common clusters of convergence. They were the right precuneus and the right superior frontal gyrus as parts of the parieto-frontal circuit. Between-type differences were in the parieto-occipital circuit, with allocentric showing convergence in the superior occipital gyrus (SOG) cluster compared with egocentric showing convergence in the middle occipital gyrus (MOG) cluster. Task-specific influences were only found in allocentric spatial coding. Spatial judgment-oriented tasks seem to increase the demands on manipulating spatial relationships among the visual objects, while spatial navigation tasks seem to increase the demands on maintaining object representations. Our findings address the theoretical controversies on spatial coding that both the allocentric and egocentric types are common in their processes mediated by the parieto-frontal network, while unique and additional processes in the allocentric type are mediated by the parieto-occipital network. The positive results on possible task-specific confound offer insights into the future design of spatial tasks for eliciting spatial coding processes.

Different mechanisms of magnitude and spatial representation for tactile and auditory modalities.

The human brain creates an external world representation based on magnitude judgments by estimating distance, numerosity, or size. The magnitude and spatial representation are hypothesized to rely on common mechanisms shared by different sensory modalities. We explored the relationship between magnitude and spatial representation using two different sensory systems. We hypothesize that the interaction between space and magnitude is combined differently depending on sensory modalities. Furthermore, we aimed to understand the role of the spatial reference frame in magnitude representation. We used stimulus-response compatibility (SRC) to investigate these processes assuming that performance is improved if stimulus and response share common features. We designed an auditory and tactile SRC task with conflicting spatial and magnitude mapping. Our results showed that sensory modality modulates the relationship between space and magnitude. A larger effect of magnitude over spatial congruency occurred in a tactile task. However, magnitude and space showed similar weight in the auditory task, with neither spatial congruency nor magnitude congruency having a significant effect. Moreover, we observed that the spatial frame activated during tasks was elicited by the sensory inputs. The participants' performance was reversed in the tactile task between uncrossed and crossed hands posture, suggesting an internal coordinate system. In contrast, crossing the hands did not alter performance (i.e., using an allocentric frame of reference). Overall, these results suggest that space and magnitude interaction differ in auditory and tactile modalities, supporting the idea that these sensory modalities use different magnitude and spatial representation mechanisms.

The development of allocentric spatial frame in the auditory system.

The ability to encode space is a crucial aspect of interacting with the external world. Therefore, this ability appears to be fundamental for the correct development of the capacity to integrate different spatial reference frames. The spatial reference frame seems to be present in all the sensory modalities. However, it has been demonstrated that different sensory modalities follow various developmental courses. Nevertheless, to date these courses have been investigated only in people with sensory impairments, where there is a possible bias due to compensatory strategies and it is complicated to assess the exact age when these skills emerge. For these reasons, we investigated the development of the allocentric frame in the auditory domain in a group of typically developing children aged 6-10 years. To do so, we used an auditory Simon task, a paradigm that involves implicit spatial processing, and we asked children to perform the task in both the uncrossed and crossed hands postures. We demonstrated that the crossed hands posture affected the performance only in younger children (6-7 years), whereas at 10 years of age children performed as adults and were not affected by such posture. Moreover, we found that this task's performance correlated with age and developmental differences in spatial abilities. Our results support the hypothesis that auditory spatial cognition's developmental course is similar to the visual modality development as reported in the literature.

Hidden framings and hidden asymmetries in the measurement of personality--A combined lens-model and frame-of-reference perspective.

OBJECTIVE: The symmetry principle and the frame-of-reference perspective have each made contributions to improving the measurement of personality. Although each perspective is valuable in its own right, we argue that even greater improvement can be achieved through the combination of both. Therefore, the goal of the current article was to show the value of a combined lens-model and frame-of-reference perspective. METHOD: We conducted a literature review to summarize relevant research findings that shed light on the interplay of both perspectives and developed an integrative model. RESULTS: Based on the literature review and on theoretical grounds, we argue that a basic premise of the frame-of-reference literature--that personality items are open to interpretation and allow individuals to impose their own contextual framings--should be considered from a symmetry perspective. Unintended context-specificity in items may "spread" to personality facets and domains, and thus, impact the symmetry of personality measures with other criteria. As the individuals´ frames-of-reference and (a)symmetric relationships are not always apparent, we term them as "hidden." CONCLUSIONS: The proposed combination of lens-model and frame-of-reference perspectives provides further insights into current issues in personality research and uncovers important avenues for future research.

Internal Versus External Frame of Reference in Functional Movement Disorders.

OBJECTIVE: The purpose of this study was to determine whether patients with functional movement disorders (FMDs) differ in their internal versus external locus of control (LOC) and whether LOC in these patients affected disease severity, quality of life, and functional impairment compared with control subjects with degenerative (Parkinson's disease) and nondegenerative (focal dystonia) neurological conditions. METHODS: A total of 156 patients with FMD (N=45), Parkinson's disease (N=64), and focal dystonia (N=47) were recruited between June 2015 and August 2017. The authors administered the general Levenson Multidimensional LOC (LOC-G) and health-specific Multidimensional Health LOC (LOC-H) scales. An internal LOC was represented similarly in both scales: the external LOC included "chance" and "powerful others" in the LOC-G measure and chance, "other people," and "doctors" in the LOC-H measure. Quality of life, functional impairment, and FMD severity were assessed. One-way analysis of variance and adjusted logistic regressions were used, as well as ordinary least-squares between and within groups, respectively. RESULTS: Patients with FMD had lower external chance LOC-G scores compared with patients in the Parkinson's disease group (odds ratio=0.90, p=0.03) and higher internal (odds ratio=1.22, p=0.01) and lower external (odds ratio=0.77, p=0.02) doctors LOC-H scores compared with patients in the focal dystonia group. External powerful others LOC-G score was associated with functional impairment (regression coefficient=-0.04, p=0.02). There were no effects of LOC on quality of life or disease severity. CONCLUSIONS: Patients with FMD exhibited high "within our control" internal general and health-specific frame of reference. LOC had no influence on quality of life or disease severity in this patient population.

The differential effect of normal and pathological aging on egocentric and allocentric spatial memory in navigational and reaching space.

BACKGROUND: Topographical disorientation (TD) refers to a particular condition which determines the loss of spatial orientation, both in new and familiar environments. TD and spatial memory impairments occur relatively early as effect of cognitive decline in aging, even in prodromal stages of dementia, namely mild cognitive impairment (MCI). AIMS: (a) To show that components linked to the recall of familiar spatial knowledge are relatively spared with respect to the learning of unfamiliar ones in normal aging, while they are not in MCI, and (b) to investigate gender differences for their impact on egocentric and allocentric frames of reference. METHOD: Forty young participants (YC), 40 healthy elderly participants (HE), 40 elderly participants with subjective memory complaints (SMC), and 40 elderly with probable MCI were administered with egocentric and allocentric familiar tasks, based on the map of their hometown, and with egocentric and allocentric unfamiliar tasks, based on new material to be learned. A series of general linear models were used to analyze data. RESULTS: No group differences were found on egocentric task based on familiar information. MCI performed worse than the other groups on allocentric tasks based on familiar information (YC = HE = SMC > MCI). Significant differences emerged between groups on egocentric and allocentric tasks based on unfamiliar spatial information (YC > HE = SMC > MCI). A gender difference was found, favoring men on allocentric unfamiliar task. CONCLUSION: Familiarity of spatial memory traces can represent a protective factor for retrospective components of TD in normal aging. Conversely, using newly learned information for assessment may lead to overestimating TD severity.

Informational Reinterpretation of the Mechanics Notions and Laws.

The informational re-interpretation of the basic laws of the mechanics exploiting the Landauer principle is suggested. When a physical body is in rest or it moves rectilinearly with the constant speed, zero information is transferred; thus, the informational affinity of the rest state and the rectilinear motion with a constant speed is established. Inertial forces may be involved in the erasure/recording of information. The analysis of the minimal Szilard thermal engine as seen from the noninertial frame of references is carried out. The Szilard single-particle minimal thermal engine undergoes isobaric expansion relative to accelerated frame of references, enabling the erasure of 1 bit of information. The energy ΔQ spent by the inertial force for the erasure of 1 bit of information is estimated as Δ Q ≅ 5 3 k B T ¯ , which is larger than the Landauer bound but qualitatively is close to it. The informational interpretation of the equivalence principle is proposed: the informational content of the inertial and gravitational masses is the same.

Changing the influence of the egocentric reference frame impacts deviations in haptic parallelity matching.

The large systematic deviations in haptic parallelity matching are most likely due to the biasing influence of the hand-centered egocentric reference frame. Previous results showed that eliminating or reducing this bias resulted in smaller deviations, with significantly larger effects observed in female participants. The current study investigated the effect of reducing the egocentric bias in a pure haptic condition. Blind-folded male and female participants had to feel the orientation of a reference bar with their non-dominant hand and to parallel this orientation on a test bar with their dominant hand. In one condition, they were instructed to use their flat-stretched hand to feel and match the bars, while in the other condition (HPF), they were instructed to set the test bar while gripping the bar with the fingers and thumb. It was hypothesized that the latter would reduce the biasing influence of the hand-centered egocentric reference frame. Results showed that this was indeed the case. Deviations were significantly smaller for HPF; however, this effect was the same in both genders. The previously observed gender effect, showing a significantly larger improvement for women when reducing the influence of the egocentric reference frame, was not replicated.

Differential influence of habitual third-person vision of a body part on mental rotation of images of hands and feet.

Left/right judgement (LRJ) tasks involve determining the laterality of presented hand or feet images. Allocentric images (third-person perspective; 3PP) take longer to identify than egocentric images (first-person perspective; 1PP), supporting that implicit motor imagery (IMI)-mentally manoeuvring one's body to match the shown posture-is used. While numerous cognitive processes are involved during LRJs, it remains unclear whether features of the individual (e.g., visual exposure, experience, task-dependent use) influence the type of recognition strategy used during LRJs (IMI versus non-IMI). To investigate whether an individual's routine visual exposure to hands/feet in 3PP disrupts the typical perspective-reaction time (RT) relationship in LRJs, hand therapists, podiatrists, and healthy controls completed online LRJ tasks of hand and feet images. A group-specific reduction in RT for only allocentric images would represent a switch to non-IMI strategies. The results show that routine visual exposure to feet in 3PP (podiatrists) results in quicker RTs only for allocentric images of feet, suggesting a switch from IMI to non-IMI (e.g., visual object-based recognition) strategies. In contrast, routine visual exposure to hands in 3PP (hand therapists) does not alter RT for allocentric images, suggesting maintenance of IMI. However, hand therapists have quicker RTs (vs other groups) for egocentric hand images, supporting enhanced sensorimotor processing for the hand, consistent with task-dependent use (precise hand use). Higher accuracy in health professionals (vs control) on both tasks supports enhanced body schema. Combined, this suggests that 3PP visual exposure to body parts and task-dependent use contribute to LRJ performance/recognition strategy.

Tool use in Goffin's cockatoos: Shape/frame matching.

Nonhuman tool use is no longer questioned; the issues now are whether such use is mostly inflexible and innately specified or involves experience, innovation, adaptation, and cognitive planning, and how many species qualify. Habl and Auersperg (PLoS One, 12(11):e0186859, 2017) have shown that some Goffin's cockatoos (Cacatua goffiniana) respond in novel ways to a tool-use task that nonhuman primates and young children find somewhat challenging.

The choice of intrinsic axis under multi-cue conditions.

In the course of spatial representation, the choice of intrinsic axis depends on various spatial and non-spatial properties. The main purpose of the current study is to investigate how people choose the intrinsic axis in a virtual reality environment with spatial cues from different categories. Sixty-four participants (32 males and 32 females) each took part in one of two experiments. In each experiment, participants learned a layout comprising seven objects and viewed the scene through a head-mounted display from two perspectives. They then completed partial-scene-recognition tasks. Experiment 1 used objects lacking intrinsic orientations, and the directions of the symmetric axis (45°-315°) and the vertical side (0°-180°) of the mat were incongruent. Experiment 2 used avatars whose orientations were all aligned with the vertical mat side. Response patterns showed that the axis which was consistent with the initial learning perspective was chosen as the intrinsic axis in Experiment 1, while in Experiment 2, the 0°-180° axis was chosen. The results indicated that people would choose the intrinsic axis according to their original egocentric experience when there were two conflicting geometric cues of different categories, but if there were three geometric cues, the axis that was consistent with more cues was more likely to be chosen as intrinsic axis.

Constructing representations of spatial location from briefly presented displays.

Spatial memory and reasoning rely heavily on allocentric (often map-like) representations of spatial knowledge. While research has documented many ways in which spatial information can be represented in allocentric form, less is known about how such representations are constructed. For example: Are the very early, pre-attentive parts of the process hard-wired, or can they be altered by experience? We addressed this issue by presenting sub-saccadic (53 ms) masked stimuli consisting of a target among one to three reference features. We then shifted the location of the feature array, and asked participants to identify the target's new relative location. Experience altered feature processing even when the display duration was too short to allow attention re-allocation. The results demonstrate the importance of early perceptual processes in the creation of representations of spatial location, and the malleability of those processes based on experience and expectations.

Influence of the Pixel Sizes of Reference Computed Tomography on Single-photon Emission Computed Tomography Image Reconstruction Using Conjugate-gradient Algorithm.

PURPOSE: The frame-of-reference using computed-tomography (CT) coordinate system on single-photon emission computed tomography (SPECT) reconstruction is one of the advanced characteristics of the xSPECT reconstruction system. The aim of this study was to reveal the influence of the high-resolution frame-of-reference on the xSPECT reconstruction. METHODS: 99mTc line-source phantom and National Electrical Manufacturers Association (NEMA) image quality phantom were scanned using the SPECT/CT system. xSPECT reconstructions were performed with the reference CT images in different sizes of the display field-of-view (DFOV) and pixel. RESULTS: The pixel sizes of the reconstructed xSPECT images were close to 2.4 mm, which is acquired as originally projection data, even if the reference CT resolution was varied. The full width at half maximum (FWHM) of the line-source, absolute recovery coefficient, and background variability of image quality phantom were independent on the sizes of DFOV in the reference CT images. CONCLUSION: The results of this study revealed that the image quality of the reconstructed xSPECT images is not influenced by the resolution of frame-of-reference on SPECT reconstruction.

Bimanual motor coordination controlled by cooperative interactions in intrinsic and extrinsic coordinates.

Although strong motor coordination in intrinsic muscle coordinates has frequently been reported for bimanual movements, coordination in extrinsic visual coordinates is also crucial in various bimanual tasks. To explore the bimanual coordination mechanisms in terms of the frame of reference, here we characterized implicit bilateral interactions in visuomotor tasks. Visual perturbations (finger-cursor gain change) were applied while participants performed a rhythmic tracking task with both index fingers under an in-phase or anti-phase relationship in extrinsic coordinates. When they corrected the right finger's amplitude, the left finger's amplitude unintentionally also changed [motor interference (MI)], despite the instruction to keep its amplitude constant. Notably, we observed two specificities: one was large MI and low relative-phase variability (PV) under the intrinsic in-phase condition, and the other was large MI and high PV under the extrinsic in-phase condition. Additionally, using a multiple-interaction model, we successfully decomposed MI into intrinsic components caused by motor correction and extrinsic components caused by visual-cursor mismatch of the right finger's movements. This analysis revealed that the central nervous system facilitates MI by combining intrinsic and extrinsic components in the condition with in-phases in both intrinsic and extrinsic coordinates, and that under-additivity of the effects is explained by the brain's preference for the intrinsic interaction over extrinsic interaction. In contrast, the PV was significantly correlated with the intrinsic component, suggesting that the intrinsic interaction dominantly contributed to bimanual movement stabilization. The inconsistent features of MI and PV suggest that the central nervous system regulates multiple levels of bilateral interactions for various bimanual tasks.