Single-unit recordings in macaque monkeys have identified effector-specific regions posterior parietal cortex (PPC), but functional neuroimaging the human has yielded controversial results. Here we used on-line repetitive transcranial magnetic stimulation (rTMS) to determine saccade and reach specificity PPC. A short train of three TMS pulses (separated by an interval 100 ms) was delivered superior parieto-occipital (SPOC), a region over midposterior intraparietal sulcus (mIPS), site close...

The location of a remembered reach target can be encoded in egocentric and/or allocentric reference frames. Cortical mechanisms for are relatively well described, but the corresponding representations essentially unknown. Here, we used an event-related fMRI design to distinguish human brain areas involved these two types representation. Our paradigm consisted three tasks with identical stimulus display different instructions: (remember absolute location), relative visual landmark), and...

In this paper, the division-by-zero (DBO) problem in field of nonlinear control, which is traditionally termed control singularity (or specifically, controller problem), investigated by Zhang dynamics (ZD) method and Zhang-gradient (ZG) method. According to impact DBO on state variables controlled system, concepts pseudo-DBO true-DBO are proposed provide a new perspective for researchers problems as well systems. Besides, two classes solved under framework ZG Specific examples shown paper...

Cognition allows for the use of different rule-based sensorimotor strategies, but neural underpinnings such strategies are poorly understood. The purpose this study was to compare activity in superior parietal lobule during a standard (direct interaction) reaching task, with two nonstandard (gaze and reach spatially incongruent) tasks requiring integration information. Specifically, these involved dissociating planes vision or rotating visual feedback by 180°. Single unit activity, gaze,...

The solving of nonlinear equation systems (e.g., complex transcendental dispersion in waveguide systems) is a fundamental topic science and engineering. Davidenko method has been used by electromagnetism researchers to solve time-invariant the aforementioned systems). Meanwhile, Zhang dynamics (ZD), which special class neural dynamics, substantiated as an effective accurate for systems, particularly time-varying systems. In this paper, compared with ZD terms efficiency accuracy Results...

Recurrent neural networks (RNNs) have found a great variety of application areas. As special type RNNs, zeroing network (ZNN), or termed Zhang network, has been reported to powerful abilities address various nonstationary problems. To overcome drawbacks and improve the performance existing ZNN models, several modified models are proposed in this paper, which allow nonconvex activation functions possess accelerated finite-time convergence property. Theoretical analyses suggest that developed...

The frontal eye fields (FEFs) participate in both working memory and sensorimotor transformations for saccades, but their role integrating these functions through time remains unclear. Here, we tracked FEF spatial codes using a novel analytic method applied to the classic memory-delay saccade task. Three-dimensional recordings of head-unrestrained gaze shifts were made two monkeys trained make toward briefly flashed targets after variable delay (450-1500 ms). A preliminary analysis visual...

A fundamental question in sensorimotor control concerns the transformation of spatial signals from retina into eye and head motor commands required for accurate gaze shifts. Here, we investigated these transformations by identifying codes embedded visually evoked movement-related responses frontal fields (FEFs) during head-unrestrained Monkeys made delayed shifts to remembered location briefly presented visual stimuli, with delay serving dissociate movement responses. statistical analysis...

We previously reported that visuomotor activity in the superior colliculus (SC)--a key midbrain structure for generation of rapid eye movements--preferentially encodes target position relative to (Te) during low-latency head-unrestrained gaze shifts (DeSouza et al., 2011). Here, we trained two monkeys perform after a variable post-stimulus delay (400-700 ms), test whether temporally separated SC visual and motor responses show different spatial codes. Target positions, final positions...

Posterior parietal cortex (PPC) has been implicated in the integration of visual and proprioceptive information for planning action. We previously reported that single-pulse transcranial magnetic stimulation (TMS) over dorsal-lateral PPC perturbs early stages spatial processing memory-guided reaching. However, our data did not distinguish whether TMS disrupted reach goal or internal estimate initial hand position needed to calculate vector. To test between these hypotheses, we investigated...

A sensorimotor neuron's receptive field and its frame of reference are easily conflated within the natural variability spatial behavior. Here, we capitalized on such variations in 3-D eye head positions during head-unrestrained gaze shifts to visual targets two monkeys: determine whether intermediate/deep layer superior colliculus (SC) fields code or kinematics, four different frames reference. Visuomotor were either characterized from a central fixation position (32 U) partially each three...

Skillful interaction with the world requires that brain uses a multitude of sensorimotor programs and subroutines, such as for reaching, grasping, coordination two body halves. However, it is unclear how these operate together. Networks bimanual might converge in common areas. For example, Brodmann area 7 (BA7) known to activate disparate tasks involving three types movements separately. Here, we asked whether BA7 plays key role integrating coordinated reach-to-grasp both arms To test this,...

Empirical mode decomposition (EMD) is a widely used adaptive signal processing method, which has shown some shortcomings in engineering practice, such as sifting stop criteria of intrinsic function (IMF), mixing and end effect. In this paper, an improved criterion based on the valid data segment proposed, compared with traditional one. Results show that new avoids influence effects improves correctness EMD. addition, novel AEMD method combining analysis (AMD) EMD developed to solve...

By incorporating the physical constraints in joint space, a different-level simultaneous minimization scheme, which takes both robot kinematics and dynamics into account, is presented investigated for fault-tolerant motion planning of redundant manipulator this paper. The scheme reformulated as quadratic program (QP) with equality bound constraints, then solved by discrete-time recurrent neural network. Simulative verifications based on six-link planar substantiate efficacy accuracy...

Grasping with 2 limbs in opposition to one another is older than the hand, yet neural mechanisms for bimanual grasps remain unclear. Similar unimanual grasping, grasping may require regions parietal cortex that use visual object-feature information find matching stable grasp points on object. The localization of computationally expensive, so it might make sense signals converge a single cortical area. To examine this, we transcranial magnetic stimulation (TMS) probe contribution areas known...

The memory-delay saccade task is often used to separate visual and motor responses in oculomotor structures such as the superior colliculus(SC), with assumption that these same would sum a short delay during immediate 'reactive' saccades stimuli. However, it also possible additional signals (suppression, delay) alter and/or response memory task. Here, we compared spatiotemporal properties of SC neurons recorded both reactive tasks two head-unrestrained monkeys. Comparing tasks, (aligned...

Abstract The visual system is thought to separate egocentric and allocentric representations, but behavioral experiments show that these codes are optimally integrated influence goal-directed movements. To test if frontal cortex participates in this integration, we recorded primate eye field activity during a cue-conflict memory delay saccade task. dissociate coordinates, surreptitiously shifted landmark the period, causing saccades deviate by 37% same direction. assess cellular mechanisms,...

The interstitial nucleus of Cajal (INC) is thought to control torsional and vertical head posture. Unilateral microstimulation the INC evokes rotation positions that are maintained until stimulation offset. inactivation position-holding deficits with tilted in opposite direction. However, underlying muscle synergies for these behavioral effects unknown. Here, we examined neck activity head-unrestrained monkeys before during (50 muA, 200 ms, 300 Hz) (injection 0.3 mul 0.05% muscimol) same...

Humans adopt very different head movement strategies for gaze behaviors, example, when playing sports versus watching on television. Such strategy switching appears to depend both context and expectation of future positions. Here, we explored the neural mechanisms such behaviors by training three monkeys make head-unrestrained shifts toward eccentric radial targets. A randomized color cue provided predictive information about whether that target would be followed either a return shift center...