Finger Configurations Research Articles

Relative finger position influences whether you can localize tactile stimuli

To investigate whether the relative positions of the fingers influence tactile localization, participants were asked to localize tactile stimuli applied to their fingertips. We measured the location and rate of errors for three finger configurations: fingers stretched out and together so that they are touching each other, fingers stretched out and spread apart maximally and fingers stretched out with the two hands on top of each other so that the fingers are interwoven. When the fingers contact each other, it is likely that the error rate to the adjacent fingers will be higher than when the fingers are spread apart. In particular, we reasoned that localization would probably improve when the fingers are spread. We aimed at assessing whether such adjacency was measured in external coordinates (taking proprioception into account) or on the body (in skin coordinates). The results confirmed that the error rate was lower when the fingers were spread. However, there was no decrease in error rate to neighbouring fingertips in the fingers spread condition in comparison with the fingers together condition. In an additional experiment, we showed that the lower error rate when the fingers were spread was not related to the continuous tactile input from the neighbouring fingers when the fingers were together. The current results suggest that information from proprioception is taken into account in perceiving the location of a stimulus on one of the fingertips.

Nonstructural protein 1α subunit-based inhibition of NF-κB activation and suppression of interferon-β production by porcine reproductive and respiratory syndrome virus

Induction of type I interferon (IFN-α/β) is an early antiviral response of the host, and porcine reproductive and respiratory syndrome virus (PRRSV) has been reported to downregulate the IFN response during infection in cells and pigs. We report that the PRRSV nonstructural protein 1α (Nsp1α) subunit of Nsp1 is a nuclear–cytoplasmic protein distributed to the nucleus and contains a strong suppressive activity for IFN-β production that is mediated through the retinoic acid-inducible gene I (RIG-I) signaling pathway. Nsp1α suppressed the activation of nuclear factor (NF)-κB when stimulated with dsRNA or tumor necrosis factor (TNF)-α, and NF-κB suppression was RIG-I-dependent. The suppression of NF-κB activation was associated with the poor production of IFN-β during PRRSV infection. The C-terminal 14 amino acids of the Nsp1α subunit were critical in maintaining immunosuppressive activity of Nsp1α for both IFN-β and NF-κB, suggesting that the newly identified zinc finger configuration comprising of Met180 may be crucial for inhibitory activities. Nsp1α inhibited IκB phosphorylation and as a consequence NF-κB translocation to the nucleus was blocked, leading to the inhibition of NF-κB stimulated gene expression. Our results suggest that PRRSV Nsp1α is a multifunctional nuclear protein participating in the modulation of the host IFN system.

Place and summation coding for canonical and non-canonical finger numeral representations

Fingers can be used to express numerical magnitudes, and cultural habits about the fixed order in which fingers are raised determine which configurations become canonical and which non-canonical. Although both types of configuration carry magnitude information, it has been shown that the canonical ones are recognized faster and directly linked to number semantics. Here we tested whether this difference is a consequence of differences in the qualitative way of processing the two types of configurations. When participants named Arabic digits (Experiment 1) or verbal numerals (Experiment 2) primed by canonical and non-canonical finger configurations, qualitatively different priming patterns were observed for the two types of configurations. Canonical configurations activated a place coding representation, with priming spreading to close smaller and larger magnitudes as a function of the prime–target distance. Conversely, non-canonical configurations activated a summation coding representation priming smaller and equal magnitudes independently of the prime–target distance, and larger targets depending on this distance.

Simulating the Future of Actions in the Human Corticospinal System

Perception of the final position of a moving object or creature is distorted forward along its actual or implied motion path, thus enabling anticipation of its forthcoming position. In a previous research, we demonstrated that viewing static snapshots that imply body actions activates the human motor system. What remains unknown, however, is whether extrapolation of dynamic information and motor activation are higher for upcoming than past action phases. By using single-pulse transcranial magnetic stimulation, we found that observation of start and middle phases of grasp and flick actions engendered a significantly higher motor facilitation than observing their final postures. Differential motor facilitation during start and end postures was independent of finger configuration at the different hand apertures. Subjective ratings showed that modulation of motor facilitation was not due to the amount of implied motion per se but to the forward direction of the motion path toward upcoming phases. Thus, motor facilitation proved maximal for the snapshots evoking ongoing but incomplete actions. The results provide compelling evidence that the frontal component of the observation-execution matching system is preferentially activated by the anticipatory simulation of future action phases and thus plays an important role in the predictive coding of others' motor behaviors.

Absence of Low-Level Visual Difference Between Canonical and Noncanonical Finger-Numeral Configurations

Canonical finger numeral configurations are named faster than less familiar finger configurations and activate a semantic place-coding representation as symbolic stimuli. However, this does not exclude categorically the possibility that mere visuo-perceptual differences between canonical and noncanonical finger configurations may induce differences in processing speed. This study capitalizes on the fact that, in typical visual-detection tasks, participants focus on low-level visuo-perceptual features to detect a target among distractors sharing the same high-level semantic features, producing the so-called pop-out effect. Participants had to decide whether a canonical finger configuration was present among a set of distractors expressing the same numerosity in a noncanonical way. The results showed that the time needed to detect the presence of the target grew linearly with the number of distractors. This indicates that the canonical target enjoyed no perceptual saliency among the noncanonical configurations (i.e., no pop-out effect) excluding visuo-perceptual differences as the source of the better identification of and semantic access of canonical configurations.

Response–effect compatibility of finger–numeral configurations in arithmetical context

The present study aimed at testing, by means of a response-effect compatibility paradigm, whether finger-numeral representations derived from finger counting may underlie simple arithmetic problem solving in adults. Participants were asked to provide a verbal response to simple additions, which triggered the presentation of the correct (Experiment 1) or an incorrect (Experiment 2) response, displayed either as a configuration of fingers or as a series of rods. Answers were faster with finger configurations than with rods, and only when the finger configuration showed the correct result. These findings support the idea that, even in adults, simple arithmetic operations are still unconsciously underlain by finger-numeral representations.

Comments on the generic position of Typton australis Bruce, 1973, and some related taxa (Crustacea: Decapoda: Pontoniinae)

A recent communication by Marin (2008) discussed the generic position of Typton australis Bruce, 1973, with the conclusion that it should be transferred to the genus Onycocaridella Bruce, 1981, with further changes to the generic attributions of Onycocaridella antokha Marin, 2007 and Onycocaridella monodoa (Fujino & Miyake, 1969) and Onycocaridella stenolepis (Holthuis, 1952), both returned to the genus Onycocaris Nobili, 1904. The assessment of the generic situation of T. australis is not helped by the lack of a detailed illustrated description of T. spongicola Costa, 1844, the type species of the genus, which is in the process of rectification. The range of morphological variation found between the 16 species (including T. australis) referred to Typton strongly suggests that that assemblage is artificial and that the genus is in need of revision. Based on the key of Holthuis (1993), the synoptic diagnosis of the genus Typton is: rostrum present, scaphocerite rudimentary, mandibular palp absent, exopods present on all maxillipeds, ambulatory dactyls biunguiculate. The rudimentary scaphocerite distinguishes Typton from Onycocaris and Onycocaridella in which it is well developed. This character is shared with Typtonychus Bruce, 1996, but both genera can be readily distinguished by the presence of filtratory mouthparts in the latter genus. However, an autapomorphic generic character not utilized in the key by Bruce (1995), but included in the diagnosis given for the genus Typton (see Bruce 1995: 144), is the presence of shearing cutting edges on the fingers of the minor second pereiopod. This configuration of the minor cheliped fingers is present in all species currently referred to Typton, including T. australis, and is a character of major significance in the diagnosis of this genus, being absent from species of Onycocaris and Onycocaridella.

Palmar arch dynamics during reach-to-grasp tasks

The relationship between arm transport and grip aperture scaling has traditionally been used to study the control of reaching and grasping. Since the palmar concavity forms a postural base of the hand, intuitively it should play an essential role in hand shape modulation during grasping. This role however has not yet been investigated. This study investigated whether hand shape modulation was initiated at the palmar level or at the level of the finger joints during two types of power grasps (spherical, cylindrical). Hand shape modulation was studied in eight healthy adults and was characterized by the change in palmar arch movement during three phases of the reach-to-grasp tasks, traditionally defined as arm transport, hand preshaping and object contact. Palmar arch kinematics changed significantly during arm transport for both types of grasp (spherical 47.4%, cylindrical 63.7%). Approximately 16% more modulation was observed when grasping the cylindrical as compared to the spherical object. This was counterbalanced by relatively less modulation during the preshaping and object contact phases compared to the spherical grasp. These results showed that the three grasping phases occurred concurrently in a common time window. Furthermore, an increase in the duration of either one of the components impacted the execution of the others. A secondary finding was that hand shape modulation began at the same time or within 125 ms of the initiation of arm transport for both grasp types. In most cases (60%), movement in the palmar arch occurred prior to movement at the metacarpophalangeal joint (MCP) of the index and middle fingers. The same was observed when palmar arch modulation was compared with the time of movement initiation in the proximal interphalangeal (PIP) joints of the index and middle fingers (60-75%). Thus palmar and finger joint movement were initiated almost simultaneously and hand shape modulation began early in the reach-to-grasp task. The findings show that hand shape and arm transport were modulated together and suggest that prehensile movement, including both palmar arch and finger configuration, is planned as early as the intent to grasp.

Acceleration Workspace of Cooperating Multi-Finger Robot Systems

We present a mathematical method for acceleration workspace analysis of cooperating multi-finger robot systems using a model of point-contact with friction. A new unified formulation from dynamic equations of cooperating multi-finger robots is derived considering the force and acceleration relationships between the fingers and the object to be handled. From the dynamic equation, maximum translational and rotational acceleration bounds of an object are calculated under given constraints of contact conditions, configurations of fingers, and bounds on the torques of joint actuators for each finger. Here, the rotational acceleration bounds can be applied as an important manipulability index when the multi-finger robot grasps an object. To verify the proposed method, we used a set of case studies with a simple multi-finger mechanism system. The achievable acceleration boundary in task space can be obtained successfully with the proposed method and the acceleration boundary depends on the configurations of fingers.

Dexterous Manipulation of Origami Cartons With Robotic Fingers Based on the Interactive Configuration Space

This paper investigates the equivalent mechanism structure of origami cartons and for the first time proposes a quantitative model of cartons and the interactive configuration space for folding origami cartons. With an analysis of the equivalent mechanism, gusset vertexes of cartons are investigated based on their equivalent spherical linkages and identified as guiding linkages that determine folding. Having established a kinematics model, a configuration control vector is characterized to control carton manipulation. The information of this configuration control vector is passed to the tip of a robotic finger, and the finger configuration space is hence identified. The paper further introduces configuration transformation and creates a carton interactive configuration space, leading to generating trajectories of all four configuration control vectors and, subsequently, to finger operation trajectories. This results in making use of four robotic fingers for folding origami cartons. The interactive technique is further used for final tucking carton flaps. A novel rig with robotic fingers is then presented to demonstrate the principle and concept.

Masked priming effect with canonical finger numeral configurations

Discrete numerosities can be represented by various finger configurations. The impact of counting strategies on these configurations and their possible semantic status were investigated in young adults. Experiment 1 showed that young adults named numerical finger configurations faster when they conformed to their own canonical finger-counting habits than when they did not. Experiment 2 showed that numeral finger configurations used as unconsciously presented primes speeded up numerical comparative judgements of Arabic numeral targets. Participants responded faster and made fewer errors with numerical than with non-numerical primes, and when primes and targets were congruent (i.e., leading to the same response). Moreover, this priming effect generalised to novel never consciously seen numerosities for canonical configurations but not for non-canonical ones. These results support the idea that canonical finger configurations automatically activate number semantics whereas non-canonical ones do not.

Effect of the Cysteine-Rich Mdm2 Peptide in the Crystal Growth of Hydroxyapatite in Aqueous Solution

The crystal growth of hydroxyapatite (HAP), the most stable calcium phosphate phase at 37 °C, pH 7.40, and ionic strength of 0.15 M NaCl, in the presence of the cysteine-rich Mdm2 peptide (containing 48 aminoacids in ring finger configuration) has been investigated by the constant composition technique. Crystallization took place exclusively on well-characterized HAP crystals in supersaturated solutions only with respect to this calcium phosphate salt. The kinetic results indicated a surface diffusion spiral growth mechanism. The presence of the Mdm2 peptide inhibited the crystal growth of HAP by 59−92% through adsorption onto the active growth sites of the HAP crystal surface. The kinetic results favored a Langmuir-type adsorption model, and the value of the calculated affinity constant was kaff = (258 ± 21) × 104 dm3 mol-1.

The inhibition of calcium carbonate crystal growth by the cysteine-rich Mdm2 peptide

The crystal growth of calcite, the most stable calcium carbonate polymorph, in the presence of the cysteine-rich Mdm2 peptide (containing 48 amino acids in the ring finger configuration), has been investigated by the constant composition technique. Crystallization took place exclusively on well-characterized calcite crystals in solutions supersaturated only with respect to this calcium carbonate salt. The kinetic results indicated a surface diffusion spiral growth mechanism. The presence of the Mdm2 peptide inhibited the crystal growth of calcite by 22–58% in the concentration range tested, through adsorption onto the active growth sites of the calcite crystal surface. The kinetic results favored a Langmuir-type adsorption model, and the value of the calculated affinity constant was k aff = 147 × 10 4 dm 3 mol −1 , a ads = 0.29 .

Parkin Phosphorylation and Modulation of Its E3 Ubiquitin Ligase Activity

Mutations in the PARKIN gene are the most common cause of hereditary parkinsonism. The parkin protein comprises an N-terminal ubiquitin-like domain, a linker region containing caspase cleavage sites, a unique domain in the central portion, and a special zinc finger configuration termed RING-IBR-RING. Parkin has E3 ubiquitin-protein ligase activity and is believed to mediate proteasomal degradation of aggregation-prone proteins. Whereas the effects of mutations on the structure and function of parkin have been intensely studied, post-translational modifications of parkin and the regulation of its enzymatic activity are poorly understood. Here we report that parkin is phosphorylated both in human embryonic kidney HEK293 cells and human neuroblastoma SH-SY5Y cells. The turnover of parkin phosphorylation was rapid, because inhibition of phosphatases with okadaic acid was necessary to stabilize phosphoparkin. Phosphoamino acid analysis revealed that phosphorylation occurred mainly on serine residues under these conditions. At least five phosphorylation sites were identified, including Ser101, Ser131, and Ser136 (located in the linker region) as well as Ser296 and Ser378 (located in the RING-IBR-RING motif). Casein kinase-1, protein kinase A, and protein kinase C phosphorylated parkin in vitro, and inhibition of casein kinase-1 caused a dramatic reduction of parkin phosphorylation in cell lysates. Induction of protein folding stress in cells reduced parkin phosphorylation, and unphosphorylated parkin had slightly but significantly elevated autoubiquitination activity. Thus, complex regulation of the phosphorylation state of parkin may contribute to the unfolded protein response in stressed cells.

Visual Quality Measures for Characterizing Planar Robot Grasps

This paper presents and analyzes 12 quality measures that characterize robotic grips according to their stability and reliability. The measures are designed to assess three-finger grips of two-dimensional parts performed in a real environment, taking into account both theoretical aspects and unavoidable uncertainties of a grasping action. They build on the existing literature and on physical and mechanical considerations. The measures constitute a feature space that pattern recognition methods can use in order to classify robotic grips according to their quality. Six of the measures depend on the actual finger configuration of the gripper, and they have shown to be critical for better characterization. The kinematics of the Barrett Hand have been used. As a validation step, the measures are merged in two global quality values (with different practical applicability) that can be used to rank feasible candidate grips.

A Modular Neural Network Architecture to Learn the Kinematics of Hand Posture During Grasp

The authors propose a modular architecture to learn hand posture kinematics during grasp from little knowledge about the task. The developed model is composed of two parts. The first part is dedicated to the learning of the finger inverse kinematics. This function is fulfilled by a modular architecture (called Fingers Configuration Neural Network, or FCNN) consisting of several neural networks that take into account the discontinuity of the inverse kinematics mapping of the fingers as well as the joint limits. Following the concept of direct associative learning, a second neural network based model is used to optimize the kinematic configuration of the hand according to an evaluative function based on the results of the FCNN. Simulation results show a good learning of grasping postures of various types of objects, with different numbers of fingers and contact sets.

The maize ID1 flowering time regulator is a zinc finger protein with novel DNA binding properties

The INDETERMINATE protein, ID1, plays a key role in regulating the transition to flowering in maize. ID1 is the founding member of a plant-specific zinc finger protein family that is defined by a highly conserved amino sequence called the ID domain. The ID domain includes a cluster of three different types of zinc fingers separated from a fourth C2H2 finger by a long spacer; ID1 is distinct from other ID domain proteins by having a much longer spacer. In vitro DNA selection and amplification binding assays and DNA binding experiments showed that ID1 binds selectively to an 11 bp consensus motif via the ID domain. Unexpectedly, site-directed mutagenesis of the ID1 protein showed that zinc fingers located at each end of the ID domain are not required for binding to the consensus motif despite the fact that one of these zinc fingers is a canonical C2H2 DNA binding domain. In addition, an ID1 in vitro deletion mutant that lacks the extra spacer between zinc fingers binds the same 11 bp motif as normal ID1, suggesting that all ID domain-containing proteins recognize the same DNA target sequence. Our results demonstrate that maize ID1 and ID domain proteins have novel zinc finger configurations with unique DNA binding properties.

Distributing vertical forces between the digits during gripping and lifting: the effects of rotating the hand versus rotating the object

During pinch grip we partition the vertical tangential forces at the digits according to the friction at the grip surfaces, and the mass distribution of the object. However, we cannot predictively partition the vertical forces to adjust to new frictional conditions after viewing a 180-deg rotation of an object with different textures at each grip surface. Hence, the processes that lead to predictive force partitioning may not access object representations, thereby suggesting that these processes are digit-specific. If this is true, then we should fail to predictively partition our fingertip forces when we rotate our hand. We tested this prediction by comparing the effects of object rotation with hand rotation for repeated lifts of an object that had one slippery grip surface and one rough grip surface. Subjects did not predictively redistribute the vertical tangential forces upon grasping the rotated object. Following object rotation, the vertical tangential force trajectories during the first 100 ms after contact indicated that 12/15 subjects failed to anticipate the reversed digit-friction relationships. All subjects appropriately partitioned the vertical tangential forces between the digits by the second lift after object rotation, confirming previous reports that sensory signals update the memory associated with lifting the object. In contrast, after hand rotation, 13/15 subjects anticipated the new digit-friction relationships and upon grasping the object immediately generated a steep rise in the vertical force trajectory at the rough surface. They also delayed the initial rise in vertical tangential force at the digit encountering the low-friction surface by approximately 65 ms. Thus, anticipatory partitioning of vertical fingertip forces is not strictly digit-specific. Internally driven motor plans can access the relevant memories or internal models for predictively partitioning the vertical tangential forces. It is not clear if this process involves rotating internal representations of fingertip force directly, or if the forces are derived after internally rotating a representation of the object. In contrast to the robust effects of vision on reach kinematics, or on wrist and finger configuration, visual signals about object rotation and orientation apparently do not influence vertical tangential fingertip forces.

Focusing of surface-acoustic-wave fields on (100) GaAs surfaces

Focused surface-acoustic waves (SAWs) provide a way to reach intense acoustic fields for electro- and optoacoustic applications on semiconductors. We have investigated the focusing of SAWs by interdigital transducers (IDTs) deposited on (100)-oriented GaAs substrates. The focusing IDTs have curved fingers designed to account for the acoustic anisotropy of the substrate. Different factors that affect focusing, such as the aperture angle and the configuration of the IDT fingers, were systematically addressed. We show that the focusing performance can be considerably improved by appropriate choice of the IDT metal pads, which, under appropriate conditions, create an acoustic waveguide within the IDT. We demonstrate the generation of narrow (full width at half maximum of approx 15 μm), high-frequency (0.5 GHz), continuous SAW beams with vertical displacement as high as 4 nm collimated over distances that exceed 100 μm.

Hemispheric specialisation for imitation of hand–head positions and finger configurations: a controlled study in patients with complete callosotomy

Several studies of patients with unilateral brain damage and a patient with spontaneous callosal disconnection [Journal of Neurology, Neurosurgery, and Psychiatry 61 (1996) 176; Neuropsychologia 37 (1999) 559; Neuropsychologia 39 (2001) 1432] suggest that the imitation of positions of the hand relative to the head is a strongly lateralised left hemispheric function. In contrast, the imitation of finger configurations draws on resources of both hemispheres with a predominance of the right hemisphere. While these findings suggest a specific pattern of imitation impairment in split-brain patients, thus far, no imitation deficits have been reported in split-brain patients. Three patients with complete callosotomy and two control groups, four patients with partial callosotomy and 10 healthy subjects, imitated hand–head positions and finger configurations with non-lateralised and tachistoscopic stimulus presentation. In addition, the influence of visual control on the imitation performance was examined. One split-brain patient showed the predicted dissociation as she had severe right hemispheric deficit in imitating hand–head positions, while finger configuration imitation was preserved. The other two split-brain patients had no impairment in hand–head position imitation. Withdrawal of visual control significantly deteriorated imitation of finger configurations in the split-brain group, but not in the controls, demonstrating that the split-brain patients relied heavily on visual control as a compensatory strategy indicating an imitation deficit in the separate hemispheres. The findings question the previously held belief that in split-brain patients both hemispheres are perfectly capable of imitating gestures and that imitation is not dependent on hemispherically specialised functions.