The role of thumb and index finger placement in manual perineal protection

2014 ◽  
Vol 25 (11) ◽  
pp. 1533-1540 ◽  
Author(s):  
Magdalena Jansova ◽  
Vladimir Kalis ◽  
Libor Lobovsky ◽  
Ludek Hyncik ◽  
Jaroslava Karbanova ◽  
...  
Keyword(s):  
Index Finger ◽  
Manual Perineal Protection

Tactile Recognition of Laterally Inverted Mirror Images by Children: Intermanual Transfer and Rotation of the Palm

Perception ◽  
1986 ◽  
Vol 15 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Gisela Römer ◽  
Heike Gresch ◽  
George Ettlinger ◽  
Josephine V Brown
Keyword(s):  
Special Reference ◽  
Index Finger ◽  
Intermanual Transfer

Intermanual tactile recognition of laterally inverted mirror shapes was studied, with special reference to the role of the thumb. Children were allowed to feel the shapes either with the whole hand, with only four fingers (excluding the thumb), or with only the index finger. Intramanual recognition was also studied after rotation of the hand from the palm down/up to the palm up/down orientation. The thumb was found not to be important for intermanual mirror reversals, and only of limited importance for intramanual reversals. There was no evidence that coding with reference to the hand is of importance for either inter- or intramanual reversals. The explanations for the two kinds of reversals are quite different.

scholarly journals You may point, but do not touch: Impact of gesture-types and cognition on language in typical and atypical development

2020 ◽  
Author(s):  
Mila Vulchanova ◽  
Joana Acha ◽  
Sara Ramos-Cabo ◽  
Valentin Vulchanov
Keyword(s):  
Index Finger ◽  
Longitudinal Design ◽  
Expressive Language ◽  
Children With Autism ◽  
Typically Developing ◽  
Typically Developing Children ◽  
Communicative Development ◽  
Atypical Development ◽  
One Year

We investigated whether two types of pointing hand features (index finger and open palm pointing) and three types of relation with the referent (manipulation, contact, no contact) similarly predict language in children with and without autism, and whether cognition mediates the longitudinal relationship between pointing and language development. Sixteen children with autism, thirteen children at high risk for autism, and eighteen typically developing children participated in an interactive gesture-elicitation task and were tested on standardized cognitive and expressive language batteries in a longitudinal design. Cognition was a significant and direct predictor of language skills in all groups. However, index finger pointing was a direct predictor of language in the autism group above and beyond cognition. In addition, index finger pointing total score and percentage of no contact pointing bids were key predictors of expressive language measured one year apart, once the effect of group, expressive language and cognition at Time 1 were controlled. Findings highlight the role of cognition in communicative development, but suggest a key role of index finder use in the longitudinal relationship between deictic gestures and language atypical development above and beyond cognition.

scholarly journals Challenging the function of motor inhibition: Does it really assist action selection?

2018 ◽  
Author(s):  
Caroline Quoilin ◽  
Fanny Fievez ◽  
Julie Duque
Keyword(s):  
Primary Motor Cortex ◽  
Index Finger ◽  
Motor Evoked Potentials ◽  
Action Selection ◽  
Prime Mover ◽  
Strong Suppression ◽  
Action Preparation ◽  
Contralateral Hand ◽  
Simple Rt

By applying transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) to elicit motor-evoked potentials (MEPs) in muscles of the contralateral hand during reaction time (RT) tasks, many studies have reported a strong suppression of MEPs during action preparation, a phenomenon called preparatory inhibition. Several hypotheses have been put forward regarding the role of this inhibition, with the predominant view suggesting that it would help action selection. However, this assumption is still a matter of debate. Here, we aimed at directly addressing this idea by comparing MEPs in a task that required subjects to select a finger response within a set of predefined options (choice RT task: left or right index finger abduction) or when subjects simply had to provide the same finger response on every trial, in the absence of choice (simple RT task). Moreover, we minimized any effect that could be associated with other forms of inhibition. In both versions of the task, TMS was applied on both M1 (double-coil protocol) at several time points between the go signal and the left or right index finger response, eliciting MEPs bilaterally in the prime mover (index finger agonist) and in an irrelevant muscle (pinky agonist). Overall, MEP suppression was moderate in this study; it was only found for the irrelevant muscle. As such, MEPs in the index agonist were facilitated when elicited in a responding hand (e.g. left MEPs preceding left responses) and remained mostly unchanged in a non-responding hand (e.g. left MEPs preceding right responses). In contrast, MEPs were almost always suppressed in the pinky muscle when elicited in the non-responding hand and sometimes also in the responding hand. Importantly, this effect was more consistent in the choice than in the simple RT task, supporting the view that preparatory inhibition may assist action selection. Moreover, the fact that it sometimes concerned the responding hand is coherent with the idea of a global process, suppressing broadly the motor system.

Congenital adducted thumb: Role of the index transposition flap

1996 ◽  
Vol 4 (2) ◽  
pp. 1-8
Author(s):  
Hugh G Thomson ◽  
Douglas Grace
Keyword(s):  
Functional Assessment ◽  
Index Finger ◽  
White Line ◽  
Transposition Flap ◽  
Radial Side ◽  
Adducted Thumbs ◽  
Term Analysis

This study examines the results of a large length:width ratio transposition flap used for the correction of the congenitally adducted thumb. The flap is elevated from the radial side of the index finger and transposed into the palm parallel to the thenar crease. Long term analysis of flap results included the disappearance of a transverse palmar white line; length:width ratios; angle of abduction of thumb; sensation of flap; and functional assessment of thumb and index finger. There were 49 adducted thumbs operated on and 26 flaps were clinically examined with an average length:width ratio of 3.5:1, with some flaps having ratios of up to 6:1. All adducted thumbs were adequately released with no complications encountered.

scholarly journals The unexpected importance of the fifth digit during stone tool production

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alastair J. M. Key ◽  
Christopher J. Dunmore ◽  
Mary W. Marzke
Keyword(s):  
Index Finger ◽  
Modern Human ◽  
Stone Tool ◽  
Human Hand ◽  
Dominant Hand ◽  
Anatomical Features ◽  
Precision Grips ◽  
Lower Palaeolithic

Abstract Unique anatomical features of the human hand facilitate our ability to proficiently and forcefully perform precision grips and in-hand manipulation of objects. Extensive research has been conducted into the role of digits one to three during these manual behaviours, and the origin of the highly derived first digit anatomy that facilitates these capabilities. Stone tool production has long been thought a key influence in this regard. Despite previous research stressing the unique derived morphology of the human fifth digit little work has investigated why humans alone display these features. Here we examine the recruitment frequency, loading magnitude, and loading distribution of all digits on the non-dominant hand of skilled flintknappers during four technologically distinct types of Lower Palaeolithic stone tool production. Our data reveal the fifth digit to be heavily and frequently recruited during all studied behaviours. It occasionally incurred pressures, and was used in frequencies, greater or equal to those of the thumb, and frequently the same or greater than those of the index finger. The fifth digit therefore appears key to >2 million years of stone tool production activities, a behaviour that likely contributed to the derived anatomy observed in the modern human fifth ray.

scholarly journals Crossed corticospinal facilitation between arm and trunk muscles in humans

2018 ◽  
Vol 120 (5) ◽  
pp. 2595-2602 ◽  
Author(s):  
Shin-Yi Chiou ◽  
Paul H. Strutton ◽  
Monica A. Perez
Keyword(s):  
Primary Motor Cortex ◽  
Index Finger ◽  
Elbow Flexion ◽  
Voluntary Contraction ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Trunk Movements ◽  
Simultaneous Activation ◽  
Voluntary Contractions

A voluntary contraction of muscles with one arm increases the excitability of corticospinal projections to the contralateral resting arm, a phenomenon known as crossed facilitation. Although many motor tasks engage simultaneous activation of the arm and trunk, interactions between corticospinal projections targeting these segments remain largely unknown. Using transcranial magnetic stimulation over the trunk representation of the primary motor cortex, we examined motor-evoked potentials (MEPs) in the resting erector spinae (ES) muscle when the contralateral arm remained at rest or performed 20% of isometric maximal voluntary contraction (MVC) into index finger abduction, thumb abduction, elbow flexion, and elbow extension. We found that MEP size in the ES increased during all voluntary contractions, with greater facilitation occurring during elbow flexion and index finger abduction. To further examine the origin of changes in MEP size, we measured short-interval intracortical inhibition (SICI) and cervicomedullary MEPs (CMEPs) in the ES muscle during elbow flexion and index finger abduction and when the arm remained at rest. Notably, SICI decreased and CMEPs remained unchanged in the ES during both voluntary contractions compared with rest, suggesting a cortical origin for the effects. Our findings reveal crossed facilitatory interactions between trunk extensor and proximal and distal arm muscles, particularly for elbow flexor and index finger muscles, likely involving cortical mechanisms. These interactions might reflect the different role of these muscles during functionally relevant arm and trunk movements. NEW & NOTEWORTHY Many of the tasks of daily life involve simultaneous activation of the arm and trunk. We found that responses in the erector spinae muscles evoked by motor cortical stimulation increased in size during elbow flexion and extension and during index finger abduction and thumb abduction. Crossed facilitation with the trunk was more pronounced during elbow flexion and index finger abduction. These results might reflect the different role of these muscles during arm and trunk movements.

Role of Intracortical Inhibition in Selective Hand Muscle Activation

2003 ◽  
Vol 89 (4) ◽  
pp. 2014-2020 ◽  
Author(s):  
Cathy M. Stinear ◽  
Winston D. Byblow
Keyword(s):  
Muscle Activation ◽  
Primary Motor Cortex ◽  
Index Finger ◽  
Motor Evoked Potential ◽  
Intracortical Inhibition ◽  
Dominant Hand ◽  
Abductor Pollicis Brevis ◽  
Computer Mouse ◽  
Finger Flexion

Previous studies have shown that intracortical inhibition (ICI) plays an important role in shaping the output from primary motor cortex (M1). This study explored the muscle specificity and temporal modulation of ICI during the performance of a phasic index finger flexion task. Fifteen subjects were asked to rest their dominant hand on a computer mouse and depress the mouse button using their index finger in time with a 1-Hz auditory metronome, while keeping the rest of their hand as relaxed as possible. Responses to single- and paired-pulse transcranial magnetic stimulation were recorded from the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles while subjects were at rest and during “on” and “off” phases of the task. For FDI during the on phase, motor evoked potential (MEP) amplitude and pretrigger EMG increased and ICI decreased, as expected. This pattern of modulation was also observed for APB in seven subjects. The remaining eight subjects demonstrated a decrease in MEP amplitude and increase in ICI for APB during the on phase. This was associated with significantly less APB activation during the on phase. These findings suggest that an increase in ICI and decrease in corticospinal excitability can prevent unwanted muscle activation in a muscle-specific, temporally modulated manner.

Proprioceptive sensitivity to imposed finger deflections

2022 ◽  
Author(s):  
Katie H Long ◽  
Kristine R McLellan ◽  
Maria Boyarinova ◽  
Sliman J Bensmaia
Keyword(s):  
Joint Angle ◽  
Index Finger ◽  
Human Subjects ◽  
Hand Function ◽  
Sensory Modality ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Vibratory Stimulus ◽  
Proprioceptive Sensitivity

Hand proprioception - the sense of the posture and movements of the wrist and digits - is critical to dexterous manual behavior and to stereognosis, the ability to sense the three-dimensional structure of objects held in the hand. To better understand this sensory modality and its role in hand function, we sought to characterize the acuity with which the postures and movements of finger joints are sensed. To this end, we measured the ability of human subjects to discriminate changes in posture and speed around the three joints of the index finger. In these experiments, we isolated the sensory component by imposing the postures on an otherwise still hand, to complement other studies, in which subjects made judgments on actively achieved postures. We found that subjects could reliably sense 12-16% changes in joint angle and 18-32% changes in joint speed. Furthermore, the acuity for posture and speed was comparable across the three joints of the finger. Finally, task performance was unaffected by the presence of a vibratory stimulus, calling into question the role of cutaneous cues in hand proprioception.

scholarly journals The Role of Subvocalization in Rehearsal and Maintenance of Rhythmic Patterns

2000 ◽  
Vol 3 ◽  
pp. 63-67 ◽  
Author(s):  
Jordi Pich
Keyword(s):  
Motor Control ◽  
Inner Ear ◽  
Articulatory Suppression ◽  
Index Finger ◽  
Spatial Task ◽  
Rock And Roll ◽  
Inner Voice

This experiment analyzed the influence of subvocal activity in retention of rhythmical auditory patterns. Retention of sixteen percussion sequences was studied. Each sequence (a 4-s “door-knocking” pattern) was followed by one of the following six retention conditions: silence, unattended music (blocking the inner ear, i.e., Gregorian chanting), unattended music (blocking the inner ear, i.e., rock-and-roll), articulatory suppression (blocking the inner voice), tracing circles on the table with index finger (spatial task), and tapping (motor control). After silence, unattended music (chanting), or the spatial task, participants successfully reproduced most patterns. Errors increased with unattended music (rock-and-roll), but significant disruptions only occurred with tapping and articulatory suppression. Whereas the latter case supports the role of an articulatory loop in retention, the production of successive taps or syllables in both interference conditions probably relies on a general rhythm module, which disrupted retention of the patterns.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor
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