Distinctive laterality of neural networks supporting action understanding in left- and right-handed individuals: An EEG coherence study.

PubMed

Kelly, Rachel; Mizelle, J C; Wheaton, Lewis A

2015-08-01

Prior work has demonstrated that perspective and handedness of observed actions can affect action understanding differently in right and left-handed persons, suggesting potential differences in the neural networks underlying action understanding between right and left-handed individuals. We sought to evaluate potential differences in these neural networks using electroencephalography (EEG). Right- and left-handed participants observed images of tool-use actions from egocentric and allocentric perspectives, with right- and left-handed actors performing the actions. Participants judged the outcome of the observed actions, and response accuracy and latency were recorded. Behaviorally, the highest accuracy and shortest latency was found in the egocentric perspective for right- and left-handed observers. Handedness of subject showed an effect on accuracy and latency also, where right-handed observers were faster to respond than left-handed observers, but on average were less accurate. Mu band (8-10 Hz) cortico-cortical coherence analysis indicated that right-handed observers have coherence in the motor dominant left parietal-premotor networks when looking at an egocentric right or allocentric left hands. When looking in an egocentric perspective at a left hand or allocentric right hand, coherence was lateralized to right parietal-premotor areas. In left-handed observers, bilateral parietal-premotor coherence patterns were observed regardless of actor handedness. These findings suggest that the cortical networks involved in understanding action outcomes are dependent on hand dominance, and notably right handed participants seem to utilize motor systems based on the limb seen performing the action. The decreased accuracy for right-handed participants on allocentric images could be due to asymmetrical lateralization of encoding action and motoric dominance, which may interfere with translating allocentric limb action outcomes. Further neurophysiological studies will determine the specific processes of how left- and right-handed participants understand actions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study.

PubMed

Manning, J T; Peters, M

2009-09-01

The ratio of the length of the second to the fourth digit (2D:4D) may be negatively correlated with prenatal testosterone. Hand preference has been linked with prenatal testosterone and 2D:4D. Here we show that 2D:4D is associated with hand preference for writing in a large internet sample (n>170,000) in which participants self-reported their finger lengths. We replicated a significant association between right 2D:4D and writing hand preference (low right 2D:4D associated with left hand preference) as well as a significant correlation between writing hand preference and the difference between left and right 2D:4D or Dr-l (low Dr-l associated with left hand preference). A new significant correlation between left 2D:4D and writing hand preference was also shown (high left 2D:4D associated with left hand preference). There was a clear interaction between writing hand preference and 2D:4D: The left 2D:4D was significantly larger than the right 2D:4D in male and female left-handed writers, and the right hand 2D:4D was significantly larger than the left hand 2D:4D in male and female right-handed writers.

On the evolution of handedness: evidence for feeding biases.

PubMed

Flindall, Jason W; Gonzalez, Claudia L R

2013-01-01

Many theories have been put forward to explain the origins of right-handedness in humans. Here we present evidence that this preference may stem in part from a right hand advantage in grasping for feeding. Thirteen participants were asked to reach-to-grasp food items of 3 different sizes: SMALL (Cheerios®), MEDIUM (Froot Loops®), and LARGE (Oatmeal Squares®). Participants used both their right- and left-hands in separate blocks (50 trials each, starting order counterbalanced) to grasp the items. After each grasp, participants either a) ate the food item, or b) placed it inside a bib worn beneath his/her chin (25 trials each, blocked design, counterbalanced). The conditions were designed such that the outward and inward movement trajectories were similar, differing only in the final step of placing it in the mouth or bib. Participants wore Plato liquid crystal goggles that blocked vision between trials. All trials were conducted in closed-loop with 5000 ms of vision. Hand kinematics were recorded by an Optotrak Certus, which tracked the position of three infrared diodes attached separately to the index finger, thumb, and wrist. We found a task (EAT/PLACE) by hand (LEFT/RIGHT) interaction on maximum grip aperture (MGA; the maximum distance between the index finger and thumb achieved during grasp pre-shaping). MGAs were smaller during right-handed movements, but only when grasping with intent to eat. Follow-up tests show that the RIGHT-HAND/EAT MGA was significantly smaller than all other hand/task conditions. Because smaller grip apertures are typically associated with greater precision, our results demonstrate a right-hand advantage for the grasp-to-eat movement. From an evolutionary perspective, early humans may have preferred the hand that could grasp food with more precision, thereby maximizing the likelihood of retrieval, consumption, and consequently, survival.

Enhancement of specific absorption rate in lossy dielectric objects using a slab of left-handed material.

PubMed

Zhao, Lei; Cui, Tie Jun

2005-12-01

An enhancement of the specific absorption rate (SAR) inside a lossy dielectric object has been investigated theoretically based on a slab of left-handed medium (LHM). In order to make an accurate analysis of SAR distribution, a proper Green's function involved in the LHM slab is proposed, from which an integral equation for the electric field inside the dielectric object is derived. Such an integral equation has been solved accurately and efficiently using the conjugate gradient method and the fast Fourier transform. We have made a lot of numerical experiments on the SAR distributions inside the dielectric object excited by a line source with and without the LHM slab. Numerical experiments show that SAR can be enhanced tremendously when the LHM slab is involved due to the proper usage of strong surface waves, which will be helpful in the potential biomedical applications for hyperthermia. The physical insight for such a phenomenon has also been discussed.

Individual performance and leader's laterality in interactive contests.

PubMed

Mukherjee, Satyam

2017-05-01

Left-handedness is known to provide an intrinsic and tactical advantage at top level in many sports involving interactive contests. Again, most of the renowned leaders of the world are known to have been left-handed. Leadership plays an important role in politics, sports and mentorship. In this paper we show that Cricket captains who bat left-handed have a strategic advantage over the right-handed captains in One Day International (ODI) and Test matches. The present study involving 46 left-handed captains and 148 right-handed captains in ODI matches, reveal a strong relation between leader's laterality and team member performance, demonstrating the critical importance of left-handedness and successful leadership. The odds for superior batting performance in an ODI match under left-handed captains are 89% higher than the odds under right-handed captains. Our study shows that left-handed captains are more successful in extracting superior performance from the batsmen and bowlers in ODI and Test matches; perhaps indicating left-handed leaders are better motivators as leaders when compared to right-handed captains.

Hand movements with a phase structure and gestures that depict action stem from a left hemispheric system of conceptualization.

PubMed

Helmich, I; Lausberg, H

2014-10-01

The present study addresses the previously discussed controversy on the contribution of the right and left cerebral hemispheres to the production and conceptualization of spontaneous hand movements and gestures. Although it has been shown that each hemisphere contains the ability to produce hand movements, results of left hemispherically lateralized motor functions challenge the view of a contralateral hand movement production system. To examine hemispheric specialization in hand movement and gesture production, ten right-handed participants were tachistoscopically presented pictures of everyday life actions. The participants were asked to demonstrate with their hands, but without speaking what they had seen on the drawing. Two independent blind raters evaluated the videotaped hand movements and gestures employing the Neuropsychological Gesture Coding System. The results showed that the overall frequency of right- and left-hand movements is equal independent of stimulus lateralization. When hand movements were analyzed considering their Structure, the presentation of the action stimuli to the left hemisphere resulted in more hand movements with a phase structure than the presentation to the right hemisphere. Furthermore, the presentation to the left hemisphere resulted in more right and left-hand movements with a phase structure, whereas the presentation to the right hemisphere only increased contralateral left-hand movements with a phase structure as compared to hand movements without a phase structure. Gestures that depict action were primarily displayed in response to stimuli presented in the right visual field than in the left one. The present study shows that both hemispheres possess the faculty to produce hand movements in response to action stimuli. However, the left hemisphere dominates the production of hand movements with a phase structure and gestures that depict action. We therefore conclude that hand movements with a phase structure and gestures that represent action stem from a left hemispheric system of conceptualization.

Memorization of Sequences of Movements of the Right or the Left Hand by Right- and Left-Handers: Vector Coding.

PubMed

Bobrova, E V; Bogacheva, I N; Lyakhovetskii, V A; Fabinskaja, A A; Fomina, E V

2017-01-01

In order to test the hypothesis of hemisphere specialization for different types of information coding (the right hemisphere, for positional coding; the left one, for vector coding), we analyzed the errors of right and left-handers during a task involving the memorization of sequences of movements by the left or the right hand, which activates vector coding by changing the order of movements in memorized sequences. The task was first performed by the right or the left hand, then by the opposite hand. It was found that both'right- and left-handers use the information about the previous movements of the dominant hand, but not of the non-dom" inant one. After changing the hand, right-handers use the information about previous movements of the second hand, while left-handers do not. We compared our results with the data of previous experiments, in which positional coding was activated, and concluded that both right- and left-handers use vector coding for memorizing the sequences of their dominant hands and positional coding for memorizing the sequences of non-dominant hand. No similar patterns of errors were found between right- and left-handers after changing the hand, which suggests that in right- and left-handersthe skills are transferred in different ways depending on the type of coding.

Role of hand dominance in mapping preferences for emotional-valence words to keypress responses.

PubMed

Song, Xiaolei; Chen, Jing; Proctor, Robert W

2017-10-01

When a crossed-hands placement (right hand presses left key; left hand presses right key) is used in a two-choice spatial reaction task, the mapping of left stimulus to left key and right stimulus to right key yields faster responses than the opposite mapping. In contrast, de la Vega, Dudschig, De Filippis, Lachmair, and Kaup (2013) reported that when right-handed individuals classified words as having positive or negative affect, there was a benefit for mapping positive affect to the right hand (left key) and negative affect to the left hand (right key). The goal of the present study was to replicate and extend this seemingly distinct finding. Experiment 1 duplicated the design of that study without including nonword "no-go" trials but including a condition in which participants performed with an uncrossed hand placement. Results corroborated the benefit for mapping positive to the right hand and negative to the left hand with the hands crossed, and this benefit was as large as that obtained with the hands uncrossed. Experiment 2 confirmed the importance of the dominant/subordinate hand distinction with left-handed participants, and Experiment 3 showed, with right-handed participants, that it does not depend on which limb is placed over the other. The results verify that the mapping advantage for positive→right/negative→left is indeed due to the distinction between dominant and subordinate hands. Possible reasons for the difference between these results and those obtained with spatial-location stimuli are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

Sensorimotor performance and function in people with osteoarthritis of the hand: A case-control comparison.

PubMed

Magni, Nicoló Edoardo; McNair, Peter John; Rice, David Andrew

2018-04-01

To determine whether hand left/right judgements, tactile acuity, and body perception are impaired in people with hand OA. To examine the relationships between left right judgements, tactile acuity and hand pain. To explore the relationships between sensorimotor measures (left/right judgements and tactile acuity) and measures of hand function in people with hand OA. Twenty patients with symptomatic hand OA and 19 healthy pain-free controls undertook a hand left/right judgment task, a control left/right judgement task, two-point discrimination (TPD) threshold testing (assessing tactile acuity), a neglect-like symptoms questionnaire (assessing body perception) and several established measures of hand function. Neglect-like symptoms were experienced more frequently in the hand OA group (P < 0.05). People with hand OA were slower (P < 0.05) and less accurate (P < 0.05) in the hand left/right judgement task when compared to healthy controls, with no significant difference in the control task. Significant associations were found between hand left/right judgement reaction time and pain intensity (P < 0.05) and accuracy and pain intensity (P < 0.05). TPD was not different between groups, and no correlation was found between TPD and left/right judgement performance. No association was found between left/right judgement performance and measures of hand function (all P > 0.05). However, TPD (tactile acuity) was related to several measures of hand function (all P < 0.05). People with hand OA had more frequent neglect-like symptoms and were slower and less accurate compared to healthy controls at hand left/right judgments, which was indicative of disrupted working body schema. Future studies may wish to examine whether interventions targeting sensorimotor dysfunction are effective at reducing pain and improving hand function and dexterity in people with hand OA. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Comparative analysis of brain EEG signals generated from the right and left hand while writing

NASA Astrophysics Data System (ADS)

Sardesai, Neha; Jamali Mahabadi, S. E.; Meng, Qinglei; Choa, Fow-Sen

2016-05-01

This paper provides a comparative analysis of right handed people and left handed people when they write with both their hands. Two left handed and one right handed subject were asked to write their respective names on a paper using both, their left and right handed, and their brain signals were measured using EEG. Similarly, they were asked to perform simple mathematical calculations using both their hand. The data collected from the EEG from writing with both hands is compared. It is observed that though it is expected that the right brain only would contribute to left handed writing and vice versa, it is not so. When a right handed person writes with his/her left hand, the initial instinct is to go for writing with the right hand. Hence, both parts of the brain are active when a subject writes with the other hand. However, when the activity is repeated, the brain learns to expect to write with the other hand as the activity is repeated and then only the expected part of the brain is active.

Increased functional connectivity between cortical hand areas and praxis network associated with training-related improvements in non-dominant hand precision drawing.

PubMed

Philip, Benjamin A; Frey, Scott H

2016-07-01

Chronic forced use of the non-dominant left hand yields substantial improvements in the precision and quality of writing and drawing. These changes may arise from increased access by the non-dominant (right) hemisphere to dominant (left) hemisphere mechanisms specialized for end-point precision control. To evaluate this prediction, 22 healthy right-handed adults underwent resting state functional connectivity (FC) MRI scans before and after 10 days of training on a left hand precision drawing task. 89% of participants significantly improved left hand speed, accuracy, and smoothness. Smoothness gains were specific to the trained left hand and persistent: 6 months after training, 71% of participants exhibited above-baseline movement smoothness. Contrary to expectations, we found no evidence of increased FC between right and left hemisphere hand areas. Instead, training-related improvements in left hand movement smoothness were associated with increased FC between both sensorimotor hand areas and a left-lateralized parieto-prefrontal network implicated in manual praxis. By contrast, skill retention at 6 months was predicted by changes including decreased FC between the representation of the trained left hand and bilateral sensorimotor, parietal, and premotor cortices, possibly reflecting consolidation and a disengagement of early learning processes. These data indicate that modest amounts of training (<200min total) can induce substantial, persistent improvements the precision and quality of non-dominant hand control in healthy adults, supported by strengthened connectivity between bilateral sensorimotor hand areas and a left-lateralized parieto-prefrontal praxis network. Copyright © 2016 Elsevier Ltd. All rights reserved.

Different distal-proximal movement balances in right- and left-hand writing may hint at differential premotor cortex involvement.

PubMed

Potgieser, A R E; de Jong, B M

2011-12-01

Right-handed people generally write with their right hand. Language expressed in script is thus performed with the hand also preferred for skilled motor tasks. This may suggest an efficient functional interaction between the language area of Broca and the adjacent ventral premotor cortex (PMv) in the left (dominant) hemisphere. Pilot observations suggested that distal movements are particularly implicated in cursive writing with the right hand and proximal movements in left-hand writing, which generated ideas concerning hemisphere-specific roles of PMv and dorsal premotor cortex (PMd). Now we examined upper-limb movements in 30 right-handed participants during right- and left-hand writing, respectively. Quantitative description of distal and proximal movements demonstrated a significant difference between movements in right- and left-hand writing (p<.001, Wilcoxon signed-rank test). A Distal Movement Excess (DME) characterized writing with the right hand, while proximal and distal movements similarly contributed to left-hand writing. Although differences between non-language drawings were not tested, we propose that the DME in right-hand writing may reflect functional dominance of PMv in the left hemisphere. More proximal movements in left-hand writing might be related to PMd dominance in right-hemisphere motor control, logically implicated in spatial visuomotor transformations as seen in reaching. Copyright © 2011 Elsevier B.V. All rights reserved.

Superior Temporal Gyrus Volume Abnormalities and Thought Disorder in Left-Handed Schizophrenic Men

PubMed Central

Holinger, Dorothy P.; Shenton, Martha E.; Wible, Cynthia G.; Donnino, Robert; Kikinis, Ron; Jolesz, Ferenc A.; McCarley, Robert W.

2010-01-01

Objective Studies of schizophrenia have not clearly defined handedness as a differentiating variable. Moreover, the relationship between thought disorder and anatomical anomalies has not been studied extensively in left-handed schizophrenic men. The twofold purpose of this study was to investigate gray matter volumes in the superior temporal gyrus of the temporal lobe (left and right hemispheres) in left-handed schizophrenic men and left-handed comparison men, in order to determine whether thought disorder in the left-handed schizophrenic men correlated with tissue volume abnormalities. Method Left-handed male patients (N=8) with DSM-III-R diagnoses of schizophrenia were compared with left-handed comparison men (N=10) matched for age, socioeconomic status, and IQ. Magnetic resonance imaging (MRI) with a 1.5-T magnet was used to obtain scans, which consisted of contiguous 1.5-mm slices of the whole brain. MRI analyses (as previously defined by the authors) included the anterior, posterior, and total superior temporal gyrus in both the left and right hemispheres. Results There were three significant findings regarding the left-handed schizophrenic men: 1) bilaterally smaller gray matter volumes in the posterior superior temporal gyrus (16% smaller on the right, 15% smaller on the left); 2) a smaller volume on the right side of the total superior temporal gyrus; and 3) a positive correlation between thought disorder and tissue volume in the right anterior superior temporal gyrus. Conclusions These results suggest that expression of brain pathology differs between left-handed and right-handed schizophrenic men and that the pathology is related to cognitive disturbance. PMID:10553736

Cultural and Environmental Pressure against Left-Hand Preference in Urban and Semi-Urban Malawi

ERIC Educational Resources Information Center

Zverev, Y. P.

2006-01-01

The study assessed views of teachers, pupils and their guardians on left-hand preference. Seventy-five percent of the responders indicated that the left hand should not be preferred for habitual activities and 87.6% of them indicated that left-handers should be forced to change the hand. Gender had significant effect on the view on left hand…

Programming of left hand exploits task set but that of right hand depends on recent history.

PubMed

Tang, Rixin; Zhu, Hong

2017-07-01

There are many differences between the left hand and the right hand. But it is not clear if there is a difference in programming between left hand and right hand when the hands perform the same movement. In current study, we carried out two experiments to investigate whether the programming of two hands was equivalent or they exploited different strategies. In the first experiment, participants were required to use one hand to grasp an object with visual feedback or to point to the center of one object without visual feedback on alternate trials, or to grasp an object without visual feedback and to point the center of one object with visual feedback on alternating trials. They then performed the tasks with the other hand. The result was that previous pointing task affected current grasping when it was performed by the left hand, but not the right hand. In experiment 2, we studied if the programming of the left (or right) hand would be affected by the pointing task performed on the previous trial not only by the same hand, but also by the right (or left) hand. Participants pointed and grasped the objects alternately with two hands. The result was similar with Experiment 1, i.e., left-hand grasping was affected by right-hand pointing, whereas right-hand grasping was immune from the interference from left hand. Taken together, the results suggest that when open- and closed-loop trials are interleaved, motor programming of grasping with the right hand was affected by the nature of the online feedback on the previous trial only if it was a grasping trial, suggesting that the trial-to-trial transfer depends on sensorimotor memory and not on task set. In contrast, motor programming of grasping with the left hand can use information about the nature of the online feedback on the previous trial to specify the parameters of the movement, even when the type of movement that occurred was quite different (i.e., pointing) and was performed with the right hand. This suggests that trial-to-trial transfer with the left hand depends on some sort of carry-over of task set for dealing with the availability of visual feedback.

Agraphia of the left hand with dysfunction of the left superior parietal region without callosal lesions.

PubMed

Kinno, Ryuta; Ohashi, Hideaki; Mori, Yukiko; Shiromaru, Azusa; Ono, Kenjiro

2018-03-01

A 28-year-old right-handed man noticed weakness in his legs, three days after an ephedrine overdose. Initial brain magnetic resonance imaging showed lesions in the parietal regions bilaterally. Computed tomography angiography showed segmental and multifocal vasoconstriction of the cerebral arteries. After treatment, clinical and radiological findings resolved, suggesting the patient had reversible cerebral vasoconstriction syndrome with posterior reversible encephalopathy syndrome. However, he had residual agraphia of the left hand. Language testing revealed no difficulties in oral expression, auditory comprehension, understanding of written language, or writing with the right hand. I-123 iodoamphetamine single-photon emission computed tomography showed residual dysfunction in the left superior parietal lobule. There were no apparent signs of other disconnection syndromes or neuroimaging abnormalities in the corpus callosum. We diagnosed left-hand agraphia due to left parietal dysfunction. Our case suggests that left superior parietal dysfunction without callosal lesions is a possible cause of left-hand agraphia. Neural mechanisms for writing with the right or left hand may be separable at the cortical level.

[Memorization of Sequences of Movements of the Right and the Left Hand by Right- and Left-Handers].

PubMed

Bobrova, E V; Bogacheva, I N; Lyakhovetskii, V A; Fabinskaja, A A; Fomina, E V

2015-01-01

We analyzed the errors of right- and left-handers when performing memorized sequences by the left or the right hand during the task which activates positional coding: after 6-10 times the order of movements changed (the positions remained the same during all task). The task was first performed by one ("initial") hand, and then by another one ("continuing"); there were 2 groups of right-handers and 2 groups of left-handers. It was found that the pattern of errors during the task performance by the initial hand is similar in right- and left-handers both for the dominant and non-dominant hand. The information about the previous positions after changing the order of elements is used in the sequences for subdominant hands and not used in the sequences for dominant ones. After changing the hand, right- and left-handers show different patterns of errors ("non-symmetrical"). Thus, the errors of right- and left-handers are "symmetrical" at the early stages of task performance, while the transfer of this motor skill in right-and left-handers occurs in different ways.

Left-right asymmetry of biophoton emission from hemiparesis patients.

PubMed

Jung, Hyun-Hee; Woo, Won-Myung; Yang, Joon-Mo; Choi, Chunho; Lee, Jonghan; Yoon, Gilwon; Yang, Jong S; Lee, Sungmuk; Soh, Kwang-Sup

2003-05-01

Left-right biophoton asymmetry from the palm and the dorsum of hands from 7 Korean hemiparesis patients were studied. There is a strong tendency that the left-hemiparesis patients emit more biophotons from the right than the left hands, while the right-hemiparesis patient emits more from the left hand. Acupuncture treatment reduces dramatically the left-right asymmetry of biophoton emission rates. However there is no systematic difference for the patients in the emission rates from the palm and the dorsum of hands.

Microstructural asymmetry of the corticospinal tracts predicts right-left differences in circle drawing skill in right-handed adolescents.

PubMed

Angstmann, Steffen; Madsen, Kathrine Skak; Skimminge, Arnold; Jernigan, Terry L; Baaré, William F C; Siebner, Hartwig Roman

2016-12-01

Most humans show a strong preference to use their right hand, but strong preference for the right hand does not necessarily imply a strong right-left asymmetry in manual proficiency (i.e., dexterity). Here we tested the hypothesis that intra-individual asymmetry of manual proficiency would be reflected in microstructural differences between the right and left corticospinal tract (CST) in a cohort of 52 right-handed typically-developing adolescents (11-16 years). Participants were asked to fluently draw superimposed circles with their right dominant and left non-dominant hand. Temporal regularity of circle drawing movements was assessed for each hand using a digitizing tablet. Although all participants were right-handed, there was substantial inter-individual variation regarding the relative right-hand advantage for fluent circle drawing. All subjects underwent whole-brain diffusion tensor imaging at 3 Tesla. The right and left CST were defined as regions-of-interest and mean fractional anisotropy (FA) and diffusivity values were calculated for right and left CST. On average, mean FA values were higher in the left CST relative to right CST. The degree of right-left FA asymmetry showed a linear relationship with right-left asymmetry in fluent circle drawing after correction for age and gender. The higher the mean FA values were in the left dominant CST relative to the right non-dominant CST, the stronger was the relative right-hand advantage for regular circle drawing. These findings show that right-left differences in manual proficiency are highly variable in right-handed adolescents and that this variation is associated with a right-left microstructural asymmetry of the CST.

Mirror writing in 5- to 6-year-old children: The preferred hand is not the explanation.

PubMed

Fischer, Jean-Paul; Koch, Anne-Marie

2016-01-01

Non-pathological, spontaneous mirror writing, whether complete or partial, has long been associated with writing with the left hand and attributed to the fact that abductive writing, which most people find easier, is from right to left when people write with their left hand. However, recent research suggests another explanation: children who do not know the orientation of the letters and digits may apply an implicit right-writing rule which causes them to invert mainly left-oriented characters (e.g., J, 3). But would left-hand writers apply such a rule? The present study examines the relationship between these two explanations of mirror writing and asks whether they coexist in children who write with their left hand. Is the abductive writing explanation specific to mirror writing by left-hand writers and the implicit right-writing rule specific to right-hand writers? A comparison of 59 children who wrote with their left hand and 59 children who wrote with their right hand (matched for age and school experience) provided clear evidence against the abductive-writing explanation and in favour of the right-writing rule for both groups. Therefore, spontaneous mirror writing in typical 5- to 6-year-olds does not seem to be a function of preferred writing hand.

[Case of callosal disconnection syndrome with a chief complaint of right-hand disability, despite presence of left-hand diagonistic dyspraxia].

PubMed

Okamoto, Yoko; Saida, Hisako; Yamamoto, Toru

2009-04-01

e report the case of 48-year-old right-handed male patient with an infarction affecting most part of the body and the splenium of the left half of the corpus callosum. Neuropsychological examination revealed typical signs of callosal disconnection including left-sided apraxia, diagonistic dyspraxia, left-sided agraphia, left-hand tactile anomia, left hemialexia, and right-sided constructional disability. Moreover, he complained of impairment in activities involving the right hand disability and agraphia. He could not stop behaving with his right hand when he had a vague idea. For example, he involuntarily picked up a tea bottle with his right hand when he had a desire to drink, although the action was not appropriate to that occasion. The imitation and utilization behavior did not imply this case, because his right hand behaviors were not exaggerated in response to external stimuli, such as the gestures of the examiner or the subjects in front of the patient. Unexpectedly, he complained about impairment of the activity of his right hand and was unaware of left hand apraxia or diagonistic dyspraxia; this trend continued for 6 months, at the time of this writing. We argue that the patient may have been subconsciouly aware of the symptoms of his left hand but had not verbalized them.

Involvement of the primary motor cortex in controlling movements executed with the ipsilateral hand differs between left- and right-handers.

PubMed

van den Berg, Femke E; Swinnen, Stephan P; Wenderoth, Nicole

2011-11-01

Unimanual motor tasks, specifically movements that are complex or require high forces, activate not only the contralateral primary motor cortex (M1) but evoke also ipsilateral M1 activity. This involvement of ipsilateral M1 is asymmetric, such that the left M1 is more involved in motor control with the left hand than the right M1 in movements with the right hand. This suggests that the left hemisphere is specialized for movement control of either hand, although previous experiments tested mostly right-handed participants. In contrast, research on hemispheric asymmetries of ipsilateral M1 involvement in left-handed participants is relatively scarce. In the present study, left- and right-handed participants performed complex unimanual movements, whereas TMS was used to disrupt the activity of ipsilateral M1 in accordance with a "virtual lesion" approach. For right-handed participants, more disruptions were induced when TMS was applied over the dominant (left) M1. For left-handed participants, two subgroups could be distinguished, such that one group showed more disruptions when TMS was applied over the nondominant (left) M1, whereas the other subgroup showed more disruptions when the dominant (right) M1 was stimulated. This indicates that functional asymmetries of M1 involvement during ipsilateral movements are influenced by both hand dominance as well as left hemisphere specialization. We propose that the functional asymmetries in ipsilateral M1 involvement during unimanual movements are primarily attributable to asymmetries in the higher-order areas, although the contribution of transcallosal pathways and ipsilateral projections cannot be completely ruled out.

[Left- or right-handed: the effect of a preferential use of one hand or the other on dental hygiene].

PubMed

Eleveld, C A; Schuller, A A

2016-02-01

A research project investigated the extent to which a preferential use of one hand or the other has an effect on dental hygiene on the left or right side of the mouth. The study made use of epidemiological dental-care data from the Netherlands Organisation for Applied Scientific Research and of data from a dental practice specifically collected for this project. The results revealed that among a population which is 85-90% right-handed, statistically significantly more dental plaque was found on the right side of the mouth than on the left. A separate study revealed the prevalence of statistically significantly more dental plaque on the right side than on the left among right-handed people and, among left-handed people, a non-statistically significant trend of more dental plaque on the left than the right. It is concluded that dental hygiene on the left side and the right side of the mouth is very likely to be dependent on the preferential use of one hand or the other. The differences between the left side of the mouth and right among left- and right-handed people are, however, so small that it is questionable whether these should be taken into consideration in giving instructions about dental hygiene.

Accuracy of Outcome Anticipation, But Not Gaze Behavior, Differs Against Left- and Right-Handed Penalties in Team-Handball Goalkeeping

PubMed Central

Loffing, Florian; Sölter, Florian; Hagemann, Norbert; Strauss, Bernd

2015-01-01

Low perceptual familiarity with relatively rarer left-handed as opposed to more common right-handed individuals may result in athletes' poorer ability to anticipate the former's action intentions. Part of such left-right asymmetry in visual anticipation could be due to an inefficient gaze strategy during confrontation with left-handed individuals. To exemplify, observers may not mirror their gaze when viewing left- vs. right-handed actions but preferentially fixate on an opponent's right body side, irrespective of an opponent's handedness, owing to the predominant exposure to right-handed actions. So far empirical verification of such assumption, however, is lacking. Here we report on an experiment where team-handball goalkeepers' and non-goalkeepers' gaze behavior was recorded while they predicted throw direction of left- and right-handed 7-m penalties shown as videos on a computer monitor. As expected, goalkeepers were considerably more accurate than non-goalkeepers and prediction was better against right- than left-handed penalties. However, there was no indication of differences in gaze measures (i.e., number of fixations, overall and final fixation duration, time-course of horizontal or vertical fixation deviation) as a function of skill group or the penalty-takers' handedness. Findings suggest that inferior anticipation of left-handed compared to right-handed individuals' action intentions may not be associated with misalignment in gaze behavior. Rather, albeit looking similarly, accuracy differences could be due to observers' differential ability of picking up and interpreting the visual information provided by left- vs. right-handed movements. PMID:26648887

Accuracy of Outcome Anticipation, But Not Gaze Behavior, Differs Against Left- and Right-Handed Penalties in Team-Handball Goalkeeping.

PubMed

Loffing, Florian; Sölter, Florian; Hagemann, Norbert; Strauss, Bernd

2015-01-01

Low perceptual familiarity with relatively rarer left-handed as opposed to more common right-handed individuals may result in athletes' poorer ability to anticipate the former's action intentions. Part of such left-right asymmetry in visual anticipation could be due to an inefficient gaze strategy during confrontation with left-handed individuals. To exemplify, observers may not mirror their gaze when viewing left- vs. right-handed actions but preferentially fixate on an opponent's right body side, irrespective of an opponent's handedness, owing to the predominant exposure to right-handed actions. So far empirical verification of such assumption, however, is lacking. Here we report on an experiment where team-handball goalkeepers' and non-goalkeepers' gaze behavior was recorded while they predicted throw direction of left- and right-handed 7-m penalties shown as videos on a computer monitor. As expected, goalkeepers were considerably more accurate than non-goalkeepers and prediction was better against right- than left-handed penalties. However, there was no indication of differences in gaze measures (i.e., number of fixations, overall and final fixation duration, time-course of horizontal or vertical fixation deviation) as a function of skill group or the penalty-takers' handedness. Findings suggest that inferior anticipation of left-handed compared to right-handed individuals' action intentions may not be associated with misalignment in gaze behavior. Rather, albeit looking similarly, accuracy differences could be due to observers' differential ability of picking up and interpreting the visual information provided by left- vs. right-handed movements.

Global and local processing near the left and right hands

PubMed Central

Langerak, Robin M.; La Mantia, Carina L.; Brown, Liana E.

2013-01-01

Visual targets can be processed more quickly and reliably when a hand is placed near the target. Both unimodal and bimodal representations of hands are largely lateralized to the contralateral hemisphere, and since each hemisphere demonstrates specialized cognitive processing, it is possible that targets appearing near the left hand may be processed differently than targets appearing near the right hand. The purpose of this study was to determine whether visual processing near the left and right hands interacts with hemispheric specialization. We presented hierarchical-letter stimuli (e.g., small characters used as local elements to compose large characters at the global level) near the left or right hands separately and instructed participants to discriminate the presence of target letters (X and O) from non-target letters (T and U) at either the global or local levels as quickly as possible. Targets appeared at either the global or local level of the display, at both levels, or were absent from the display; participants made foot-press responses. When discriminating target presence at the global level, participants responded more quickly to stimuli presented near the left hand than near either the right hand or in the no-hand condition. Hand presence did not influence target discrimination at the local level. Our interpretation is that left-hand presence may help participants discriminate global information, a right hemisphere (RH) process, and that the left hand may influence visual processing in a way that is distinct from the right hand. PMID:24194725

Persistent left unilateral mirror writing: A neuropsychological case study.

PubMed

Angelillo, Valentina G; De Lucia, Natascia; Trojano, Luigi; Grossi, Dario

2010-09-01

Mirror writing (MW) is a rare disorder in which a script runs in direction opposite to normal and individual letters are reversed. The disorder generally occurs after left-hemisphere lesions, is transient and is observed on the left hand, whereas usually motor impairments prevent assessment of direction of right handwriting. We describe a left-handed patient with complete left hand mirror writing, still evident 2 years after a hemorrhagic stroke in left nucleo-capsular region. Since the patient could write with his right hand he underwent several writing tasks with either hand, and a thorough assessment to clarify the nature of MW. MW was evident in writing to dictation with left hand only, both in right and left hemispace, but the patient could modify his behavior when a verbal instruction was provided. No mirror errors were found in reading words, in copying geometric figures and in spatial orientation tasks. MW in our patient could be accounted for by a failure in automatic transformation of grapho-motor programs to write with the left hand. A lack of concern (a sort of anosodiaphoria) and a poor cognitive flexibility could contribute to long-term persistence of MW. 2010 Elsevier Inc. All rights reserved.

[Transposition errors during learning to reproduce a sequence by the right- and the left-hand movements: simulation of positional and movement coding].

PubMed

Liakhovetskiĭ, V A; Bobrova, E V; Skopin, G N

2012-01-01

Transposition errors during the reproduction of a hand movement sequence make it possible to receive important information on the internal representation of this sequence in the motor working memory. Analysis of such errors showed that learning to reproduce sequences of the left-hand movements improves the system of positional coding (coding ofpositions), while learning of the right-hand movements improves the system of vector coding (coding of movements). Learning of the right-hand movements after the left-hand performance involved the system of positional coding "imposed" by the left hand. Learning of the left-hand movements after the right-hand performance activated the system of vector coding. Transposition errors during learning to reproduce movement sequences can be explained by neural network using either vector coding or both vector and positional coding.

Left-handedness and language lateralization in children.

PubMed

Szaflarski, Jerzy P; Rajagopal, Akila; Altaye, Mekibib; Byars, Anna W; Jacola, Lisa; Schmithorst, Vincent J; Schapiro, Mark B; Plante, Elena; Holland, Scott K

2012-01-18

This fMRI study investigated the development of language lateralization in left- and righthanded children between 5 and 18 years of age. Twenty-seven left-handed children (17 boys, 10 girls) and 54 age- and gender-matched right-handed children were included. We used functional MRI at 3T and a verb generation task to measure hemispheric language dominance based on either frontal or temporo-parietal regions of interest (ROIs) defined for the entire group and applied on an individual basis. Based on the frontal ROI, in the left-handed group, 23 participants (85%) demonstrated left-hemispheric language lateralization, 3 (11%) demonstrated symmetric activation, and 1 (4%) demonstrated right-hemispheric lateralization. In contrast, 50 (93%) of the right-handed children showed left-hemispheric lateralization and 3 (6%) demonstrated a symmetric activation pattern, while one (2%) demonstrated a right-hemispheric lateralization. The corresponding values for the temporo-parietal ROI for the left-handed children were 18 (67%) left-dominant, 6 (22%) symmetric, 3 (11%) right-dominant and for the right-handed children 49 (91%), 4 (7%), 1 (2%), respectively. Left-hemispheric language lateralization increased with age in both groups but somewhat different lateralization trajectories were observed in girls when compared to boys. The incidence of atypical language lateralization in left-handed children in this study was similar to that reported in adults. We also found similar rates of increase in left-hemispheric language lateralization with age between groups (i.e., independent of handedness) indicating the presence of similar mechanisms for language lateralization in left- and right-handed children. Copyright © 2011 Elsevier B.V. All rights reserved.

Do the hands talk on mind's behalf? Differences in language ability between left- and right-handed children.

PubMed

Natsopoulos, D; Kiosseoglou, G; Xeromeritou, A; Alevriadou, A

1998-09-01

Two hundred seventy children of school age, 135 of whom were left-handed and an equivalent number of whom were right-handed, have been examined in the present study using a test battery of nine language ability measures: Vocabulary, Similarities, Comprehension (WISC-R), Deductive Reasoning, Inductive Reasoning, Sentence Completion, Comprehension of Sentential Semantics, Comprehension of Syntax, and Text Processing. The data analysis has indicated that: (1) One-factor solution applies both to the right- and left-handed population according to Standard Error Scree Method (Zoski & Jurs, 1996) with regard to language ability measures. (2) Handedness discriminates between right-handers (superior) and left-handers (inferior) in language ability. (3) There have been subgroups of left-handed children who differ in language ability distribution compared with right-handed children according to Hierarchical Cluster Analysis. (4) Extreme versus mild bias to hand preference and hand skill do not differentiate performance subgroups neither within the left-handed nor within the right-handed main group. (5) Sex and familial sinistrality do not affect performance. The results are discussed in relation to (a) "human balanced polymorphism" theory advocated by Annett (mainly Annett, 1985, 1993a; Annett & Manning, 1989), (b) potential pathology (mainly Bishop, 1984, 1990a; Coren & Halpern, 1991; Satz, Orsini, Saslow & Henry, 1985) and "developmental instability" (Yeo, Gangestad & Daniel, 1993), and delay of left-hemisphere maturation in left-handed individuals (Geschwind & Galaburda, 1985a,b, 1987), by pointing out the strength and weaknesses of these theoretical approaches in accounting for the present data. Copyright 1998 Academic Press.

Imagining others' handedness: visual and motor processes in the attribution of the dominant hand to an imagined agent.

PubMed

Marzoli, Daniele; Menditto, Silvia; Lucafò, Chiara; Tommasi, Luca

2013-08-01

In a previous study, we found that when required to imagine another person performing an action, participants reported a higher correspondence between their own dominant hand and the hand used by the imagined person when the agent was visualized from the back compared to when the agent was visualized from the front. This suggests a greater involvement of motor representations in the back-view perspective, possibly indicating a greater proneness to put oneself in the agent's shoes in such a condition. In order to assess whether bringing to the foreground the right or left hand of an imagined agent can foster the activation of the corresponding motor representations, we required 384 participants to imagine a person-as seen from the right or left side-performing a single manual action and to indicate the hand used by the imagined person during movement execution. The proportion of right- versus left-handed reported actions was higher in the right-view condition than in the left-view condition, suggesting that a lateral vantage point may activate the corresponding hand motor representations, which is in line with previous research indicating a link between the hemispheric specialization of one's own body and the visual representation of others' bodies. Moreover, in agreement with research on hand laterality judgments, the effect of vantage point was stronger for left-handers (who reported a higher proportion of right- than left-handed actions in the right-view condition and a slightly higher proportion of left- than right-handed actions in the left-view condition) than for right-handers (who reported a higher proportion of right- than left-handed actions in both view conditions), indicating that during the mental simulation of others' actions, right-handers rely on sensorimotor processes more than left-handers, while left-handers rely on visual processes more than right-handers.

Comparison of pressure pain threshold, grip strength,dexterity and touch pressure of dominant and non-dominant hands within and between right-and left-handed subjects.

PubMed

Ozcan, Ayse; Tulum, Zeliha; Pinar, Lamia; Başkurt, Ferdi

2004-12-01

This study was done to evaluate differences in pressure pain threshold, grip strength, manual dexterity and touch pressure threshold in the dominant and non-dominant hands of right- and left-handed subjects, and to compare findings within and between these groups. Thirty-nine right-handed and twenty-one left-handed subjects participated in the study. Pressure pain threshold was assessed using a dolorimeter, grip strength was assessed with a hand-grip dynamometer, manual dexterity was evaluated using the VALPAR Component Work Sample-4 system, and touch pressure threshold was determined using Semmes Weinstein monofilaments. Results for the dominant and non-dominant hands were compared within and between the groups. In the right-handed subjects, the dominant hand was significantly faster with the VALPAR Component Work Sample-4, showed significantly greater grip strength, and had a significantly higher pressure pain threshold than the non-dominant hand. The corresponding results for the two hands were similar in the left-handed subjects. The study revealed asymmetrical manual performance in grip strength, manual dexterity and pressure pain threshold in right-handed subjects, but no such asymmetries in left-handed subjects.

On the Evolution of Handedness: Evidence for Feeding Biases

PubMed Central

Flindall, Jason W.; Gonzalez, Claudia L. R.

2013-01-01

Many theories have been put forward to explain the origins of right-handedness in humans. Here we present evidence that this preference may stem in part from a right hand advantage in grasping for feeding. Thirteen participants were asked to reach-to-grasp food items of 3 different sizes: SMALL (Cheerios®), MEDIUM (Froot Loops®), and LARGE (Oatmeal Squares®). Participants used both their right- and left-hands in separate blocks (50 trials each, starting order counterbalanced) to grasp the items. After each grasp, participants either a) ate the food item, or b) placed it inside a bib worn beneath his/her chin (25 trials each, blocked design, counterbalanced). The conditions were designed such that the outward and inward movement trajectories were similar, differing only in the final step of placing it in the mouth or bib. Participants wore Plato liquid crystal goggles that blocked vision between trials. All trials were conducted in closed-loop with 5000 ms of vision. Hand kinematics were recorded by an Optotrak Certus, which tracked the position of three infrared diodes attached separately to the index finger, thumb, and wrist. We found a task (EAT/PLACE) by hand (LEFT/RIGHT) interaction on maximum grip aperture (MGA; the maximum distance between the index finger and thumb achieved during grasp pre-shaping). MGAs were smaller during right-handed movements, but only when grasping with intent to eat. Follow-up tests show that the RIGHT-HAND/EAT MGA was significantly smaller than all other hand/task conditions. Because smaller grip apertures are typically associated with greater precision, our results demonstrate a right-hand advantage for the grasp-to-eat movement. From an evolutionary perspective, early humans may have preferred the hand that could grasp food with more precision, thereby maximizing the likelihood of retrieval, consumption, and consequently, survival. PMID:24236078

Left-handed Children in Singapore.

ERIC Educational Resources Information Center

Gan, Linda

1998-01-01

Used teacher questionnaires to examine incidence of left-handedness in nearly 2,800 Singaporean children, racial differences in this left-handed population, and educational provisions in preschool and primary school. Findings indicated that 7.5% of preschoolers and 6.3% of primary children were left-handed, with a higher proportion being Chinese…

One hand or the other? Effector selection biases in right and left handers.

PubMed

Main, Julie C; Carey, David P

2014-11-01

Much debate in the handedness literature has centred on the relative merits of questionnaire-based measures assessing hand preference versus simple movement tasks such as peg moving or finger tapping, assessing hand performance. A third paradigm has grown in popularity, which assesses choices by participants when either hand could be used to execute movements. These newer measures may be useful in predicting possible "reversed" asymmetries in proportions of non-right handed ("adextral") people. In the current studies we examine hand choice in large samples of dextral (right handed) and adextral participants. Unlike in some previous experiments on choice, we found that left handers were as biased towards their dominant hand as were right handers, for grasping during a puzzle-making task (study 1). In a second study, participants had to point to either of two suddenly appearing targets with one hand or the other. In study 2, left handers were not significantly less one handed than their right-handed counterparts as in study 1. In a final study, we used random effects meta analysis to summarise the possible differences in hand choice between left handers and right handers across all hand choice studies published to date. The meta analysis suggests that right handers use their dominant hand 12.5% more than left handers favour their dominant hand (with 95% confidence that the real difference lies between 7% and 18%). These last results suggest that our two experiments reported here may represent statistical Type 2 errors. This mean difference may be related to greater left hemispheric language and praxic laterality in right handers. Nevertheless, more data are needed regarding the precise proportions of left and right handers who favour their preferred hands for different tasks. Copyright © 2014 Elsevier Ltd. All rights reserved.

Apraxia in left-handers.

PubMed

Goldenberg, Georg

2013-08-01

In typical right-handed patients both apraxia and aphasia are caused by damage to the left hemisphere, which also controls the dominant right hand. In left-handed subjects the lateralities of language and of control of the dominant hand can dissociate. This permits disentangling the association of apraxia with aphasia from that with handedness. Pantomime of tool use, actual tool use and imitation of meaningless hand and finger postures were examined in 50 consecutive left-handed subjects with unilateral hemisphere lesions. There were three aphasic patients with pervasive apraxia caused by left-sided lesions. As the dominant hand is controlled by the right hemisphere, they constitute dissociations of apraxia from handedness. Conversely there were also three patients with pervasive apraxia caused by right brain lesions without aphasia. They constitute dissociations of apraxia from aphasia. Across the whole group of patients dissociations from handedness and from aphasia were observed for all manifestations of apraxia, but their frequency depended on the type of apraxia. Defective pantomime and defective tool use occurred rarely without aphasia, whereas defective imitation of hand, but not finger, postures was more frequent after right than left brain damage. The higher incidence of defective imitation of hand postures in right brain damage was mainly due to patients who had also hemi-neglect. This interaction alerts to the possibility that the association of right hemisphere damage with apraxia has to do with spatial aptitudes of the right hemisphere rather than with its control of the dominant left hand. Comparison with data from right-handed patients showed no differences between the severity of apraxia for imitation of hand or finger postures, but impairment on pantomime of tool use was milder in apraxic left-handers than in apraxic right-handers. This alleviation of the severity of apraxia corresponded with a similar alleviation of the severity of aphasia as manifested by a lower proportion of left-handed patients with global aphasia.

Mediolateral hoof balance in relation to the handedness of apprentice farriers.

PubMed

Ronchetti, A; Day, P; Weller, R

2011-01-15

Horses that had been trimmed and shod by apprentice farriers were sourced from the Royal School of Military Engineering, Melton Mowbray (37 horses) and from the Household Cavalry, Knightsbridge (54 horses). The lateral and medial hoof wall angles of both forelimbs were measured using a Ruidoso hoof gauge by the same operator. The difference between the lateral and medial hoof wall angles for each horse was calculated and the results were compared between right-handed and left-handed farriers using the Mann-Whitney U test (P<0.05). There was a significant difference in the mediolateral hoof balance obtained between right-handed and left-handed farriers for each forelimb (P<0.001). Right-handed farriers were shown to create an imbalance in 47 per cent of left forelimbs and 46 per cent of right forelimbs assessed, while left-handed farriers created an imbalance in 41 per cent of left forelimbs and 71 per cent of right forelimbs. The tendency was for right-handed farriers to over-trim the medial (inner) aspect of the left forelimb and the lateral (outer) aspect of the right forelimb; the reverse was demonstrated for left-handed farriers. Performing a risk ratio confirmed these findings.

Cerebral lateralization of praxis in right- and left-handedness: same pattern, different strength.

PubMed

Vingerhoets, Guy; Acke, Frederic; Alderweireldt, Ann-Sofie; Nys, Jo; Vandemaele, Pieter; Achten, Eric

2012-04-01

We aimed to investigate the effect of hand effector and handedness on the cerebral lateralization of pantomiming learned movements. Fourteen right-handed and 14 left-handed volunteers performed unimanual and bimanual tool-use pantomimes with their dominant or nondominant hand during fMRI. A left hemispheric lateralization was observed in the right- and left-handed group regardless of which hand(s) performed the task. Asymmetry was most marked in the dorsolateral prefrontal cortex (DLPFC), premotor cortex (PMC), and superior and inferior parietal lobules (SPL and IPL). Unimanual pantomimes did not reveal any significant differences in asymmetric cerebral activation patterns between left- and right-handers. Bimanual pantomimes showed increased left premotor and posterior parietal activation in left- and right-handers. Lateralization indices (LI) of the 10% most active voxels in DLPFC, PMC, SPL, and IPL were calculated for each individual in a contrast that compared all tool versus all control conditions. Left-handers showed a significantly reduced overall LI compared with right-handers. This was mainly due to diminished asymmetry in the IPL and SPL. We conclude that the recollection and pantomiming of learned gestures recruits a similar left lateralized activation pattern in right and left-handed individuals. Handedness only influences the strength (not the side) of the lateralization, with left-handers showing a reduced degree of asymmetry that is most readily observed over the posterior parietal region. Together with similar findings in language and visual processing, these results point to a lesser hemispheric specialization in left-handers that may be considered in the cost/benefit assessment to explain the disproportionate handedness polymorphism in humans. Copyright © 2011 Wiley Periodicals, Inc.

Effects of handedness (left vs right) and cannabis abuse on intermanual coordination and negative symptoms in schizophrenic patients of the paranoid type.

PubMed

Gorynia, Inge; Schwaiger, Markus

2011-09-01

Intermanual coordination as an index of interhemispheric transfer and negative symptoms were investigated in 50 left- and 42 right-handed schizophrenic inpatients of the paranoid type, also including drug abusers. The primary objective was to show that there were higher values in intermanual coordination and fewer manifestations of negative symptoms in the left-handed compared to the right-handed patients. This assumption was based on previous studies. Most importantly, right- and left-handed patients showed a different behaviour in intermanual coordination, when the duration of illness was taken into consideration. Thus, long-term left-handed paranoid patients performed better in intermanual coordination and showed fewer manifestations of negative symptoms than did long-term right-handed patients. These results were true for the large group of all patients, and among them for the subgroup of patients without drug abuse. Consequently, higher scores in intermanual coordination in left-handed patients may be related to a better interhemispheric crosstalk resulting in less pronounced negative symptoms. Secondary objectives assessed by explorative data analysis included the effects of cannabis abuse. While cannabis abuse may be more prevalent in left-handed patients, its effects may be more pronounced in right-handed patients, scoring higher in intermanual coordination and lower in manifestations of negative symptoms.

Bimanual proprioceptive performance differs for right- and left-handed individuals.

PubMed

Han, Jia; Waddington, Gordon; Adams, Roger; Anson, Judith

2013-05-10

It has been proposed that asymmetry between the upper limbs in the utilization of proprioceptive feedback arises from functional differences in the roles of the preferred and non-preferred hands during bimanual tasks. The present study investigated unimanual and bimanual proprioceptive performance in right- and left-handed young adults with an active finger pinch movement discrimination task. With visual information removed, participants were required to make absolute judgments about the extent of pinch movements made to physical stops, either by one hand, or by both hands concurrently, with the sequence of presented movement extents varied randomly. Discrimination accuracy scores were derived from participants' responses using non-parametric signal detection analysis. Consistent with previous findings, a non-dominant hand/hemisphere superiority effect was observed, where the non-dominant hands of right- and left-handed individuals performed overall significantly better than their dominant hands. For all participants, bimanual movement discrimination scores were significantly lower than scores obtained in the unimanual task. However, the magnitude of the performance reduction, from the unimanual to the bimanual task, was significantly greater for left-handed individuals. The effect whereby bimanual proprioception was disproportionately affected in left-handed individuals could be due to enhanced neural communication between hemispheres in left-handed individuals leading to less distinctive separation of information obtained from the two hands in the cerebral cortex. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Medical student hand preference, perceived dexterity, and impact of handedness on training.

PubMed

Callahan, Devon; de Virgilio, Christian; Tillou, Areti; DeUgarte, Daniel A

2016-07-01

The ubiquity of right-handed instruments and a predominance of right-handed surgical faculty present a challenge to left-handed trainees. Little is known about hand preference and its impact on specialty selection. We sought to evaluate hand preference, perceived dexterity, and impact of handedness on training among medical students. A survey was distributed to third and fourth year medical students. Hand preference was queried for various activities. A Likert scale was used to assess perceived dexterity and impact of handedness on training. Fisher's exact test was used to compare groups. Of those queried, 131 (37%) responded. Handedness was defined by writing preference: right (80%), left (18%), other (2%). Left-handed students were more likely to perceive themselves to be ambidextrous (50% versus 15%; P < 0.001) and prefer their contralateral hand for at least one other activity (50% versus 4%; P < 0.001). Left-handed students were significantly more likely to report that handedness affected their specialty selection (33% versus 10%; P < 0.01) and training (58% versus 6%; P < 0.001). In addition, they reported that they would benefit from additional training with right-handed instruments (61% versus 31%; P < 0.01), availability of left-handed instruments (63% versus 8%; P < 0.001), and trainers who adapted to their handedness (70% versus 14%; P < 0.001). Left-handed medical students reported greater ambidexterity and adverse impact of handedness on training. These results provide a contemporary snapshot of hand preference in medical students and an argument for improving and adapting surgical training for left-handed individuals. Copyright © 2016 Elsevier Inc. All rights reserved.

Behavioral evidence for left-hemisphere specialization of motor planning

PubMed Central

Meulenbroek, Ruud G. J.; Steenbergen, Bert

2010-01-01

Recent studies suggest that the left hemisphere is dominant for the planning of motor actions. This left-hemisphere specialization hypothesis was proposed in various lines of research, including patient studies, motor imagery studies, and studies involving neurophysiological techniques. However, most of these studies are primarily based on experiments involving right-hand-dominant participants. Here, we present the results of a behavioral study with left-hand-dominant participants, which follows up previous work in right-hand-dominant participants. In our experiment, participants grasped CD casings and replaced them in a different, pre-cued orientation. Task performance was measured by the end-state comfort effect, i.e., the anticipated degree of physical comfort associated with the posture that is planned to be adopted at movement completion. Both left- and right-handed participants showed stronger end-state comfort effects for their right hand compared to their left hand. These results lend behavioral support to the left-hemisphere-dominance motion-planning hypothesis. PMID:21184219

49 CFR 571.123 - Standard No. 123; Motorcycle controls and displays.

Code of Federal Regulations, 2013 CFR

2013-10-01

...'s right hand from the throttle. Each control located on a left handlebar shall be operable by the operator's left hand throughout its full range without removal of the operator's left hand from the... rear brake control, the control shall be located on the left handlebar. If a scooter with an automatic...

49 CFR 571.123 - Standard No. 123; Motorcycle controls and displays.

Code of Federal Regulations, 2011 CFR

2011-10-01

...'s right hand from the throttle. Each control located on a left handlebar shall be operable by the operator's left hand throughout its full range without removal of the operator's left hand from the... rear brake control, the control shall be located on the left handlebar. If a scooter with an automatic...

49 CFR 571.123 - Standard No. 123; Motorcycle controls and displays.

Code of Federal Regulations, 2012 CFR

2012-10-01

...'s right hand from the throttle. Each control located on a left handlebar shall be operable by the operator's left hand throughout its full range without removal of the operator's left hand from the... rear brake control, the control shall be located on the left handlebar. If a scooter with an automatic...

49 CFR 571.123 - Standard No. 123; Motorcycle controls and displays.

Code of Federal Regulations, 2014 CFR

2014-10-01

...'s right hand from the throttle. Each control located on a left handlebar shall be operable by the operator's left hand throughout its full range without removal of the operator's left hand from the... rear brake control, the control shall be located on the left handlebar. If a scooter with an automatic...

The Left-Handed: "Their Sinister" History.

ERIC Educational Resources Information Center

Costas, Elaine Fowler

The history of left-handedness can provide teachers and parents a better understanding of left-handed children and give those children more pride in their difference. No child should be made to feel that he or she is abnormal because of using the left hand, although some specific instruction for these students is necessary in handwriting. Many…

Enhanced left-finger deftness following dominant upper- and lower-limb amputation.

PubMed

Swanberg, Kelley M; Clark, Abigail M; Kline, Julia E; Yurkiewicz, Ilana R; Chan, Brenda L; Pasquina, Paul F; Heilman, Kenneth M; Tsao, Jack W

2011-09-01

After amputation, the sensorimotor cortex reorganizes, and these alterations might influence motor functions of the remaining extremities. The authors examined how amputation of the dominant or nondominant upper or lower extremity alters deftness in the intact limbs. The participants were 32 unilateral upper- or lower-extremity amputees and 6 controls. Upper-extremity deftness was tested by coin rotation (finger deftness) and pegboard (arm, hand, and finger deftness) tasks. Following right-upper- or right-lower-extremity amputation, the left hand's finger movements were defter than the left-hand fingers of controls. In contrast, with left-upper- or left-lower-extremity amputation, the right hand's finger performance was the same as that of the controls. Although this improvement might be related to increased use (practice), the finding that right-lower-extremity amputation also improved the left hand's finger deftness suggests an alternative mechanism. Perhaps in right-handed persons the left motor cortex inhibits the right side of the body more than the right motor cortex inhibits the left side, and the physiological changes induced by right-sided amputation reduced this inhibition.

Specialization of the left supramarginal gyrus for hand-independent praxis representation is not related to hand dominance.

PubMed

Króliczak, Gregory; Piper, Brian J; Frey, Scott H

2016-12-01

Data from focal brain injury and functional neuroimaging studies implicate a distributed network of parieto-fronto-temporal areas in the human left cerebral hemisphere as playing distinct roles in the representation of meaningful actions (praxis). Because these data come primarily from right-handed individuals, the relationship between left cerebral specialization for praxis representation and hand dominance remains unclear. We used functional magnetic resonance imaging (fMRI) to evaluate the hypothesis that strongly left-handed (right hemisphere motor dominant) adults also exhibit this left cerebral specialization. Participants planned familiar actions for subsequent performance with the left or right hand in response to transitive (e.g., "pounding") or intransitive (e.g. "waving") action words. In linguistic control trials, cues denoted non-physical actions (e.g., "believing"). Action planning was associated with significant, exclusively left-lateralized and extensive increases of activity in the supramarginal gyrus (SMg), and more focal modulations in the left caudal middle temporal gyrus (cMTg). This activity was hand- and gesture-independent, i.e., unaffected by the hand involved in subsequent action performance, and the type of gesture (i.e., transitive or intransitive). Compared directly with right-handers, left-handers exhibited greater involvement of the right angular gyrus (ANg) and dorsal premotor cortex (dPMC), which is indicative of a less asymmetric functional architecture for praxis representation. We therefore conclude that the organization of mechanisms involved in planning familiar actions is influenced by one's motor dominance. However, independent of hand dominance, the left SMg and cMTg are specialized for ideomotor transformations-the integration of conceptual knowledge and motor representations into meaningful actions. These findings support the view that higher-order praxis representation and lower-level motor dominance rely on dissociable mechanisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

Specialization of the left supramarginal gyrus for hand-independent praxis representation is not related to hand dominance

PubMed Central

Króliczak, Gregory; Piper, Brian J.; Frey, Scott H.

2016-01-01

Data from focal brain injury and functional neuroimaging studies implicate a distributed network of parieto-fronto-temporal areas in the human left cerebral hemisphere as playing distinct roles in the representation of meaningful actions (praxis). Because these data come primarily from right-handed individuals, the relationship between left cerebral specialization for praxis representation and hand dominance remains unclear. We used functional magnetic resonance imaging (fMRI) to evaluate the hypothesis that strongly left-handed (right hemisphere motor dominant) adults also exhibit this left cerebral specialization. Participants planned familiar actions for subsequent performance with the left or right hand in response to transitive (e.g., “pounding”) or intransitive (e.g. “waving”) action words. In linguistic control trials, cues denoted non-physical actions (e.g., “believing”). Action planning was associated with significant, exclusively left-lateralized and extensive increases of activity in the supramarginal gyrus (SMg), and more focal modulations in the left caudal middle temporal gyrus (cMTg). This activity was hand- and gesture-independent, i.e., unaffected by the hand involved in subsequent action performance, and the type of gesture (i.e., transitive or intransitive). Compared directly with right-handers, left-handers exhibited greater involvement of the right angular gyrus (ANg) and dorsal premotor cortex (dPMC), which is indicative of a less asymmetric functional architecture for praxis representation. We therefore conclude that the organization of mechanisms involved in planning familiar actions is influenced by one’s motor dominance. However, independent of hand dominance, the left SMg and cMTg are specialized for ideomotor transformations—the integration of conceptual knowledge and motor representations into meaningful actions. These findings support the view that higher-order praxis representation and lower-level motor dominance rely on dissociable mechanisms. PMID:27020138

Switching handedness: fMRI study of hand motor control in right-handers, left-handers and converted left-handers.

PubMed

Grabowska, Anna; Gut, Malgorzata; Binder, Marek; Forsberg, Lars; Rymarczyk, Krystyna; Urbanik, Andrzej

2012-01-01

The purpose of this study was to investigate the differences in the brain organization of motor control in left- and right-handers and to study whether early left-to-right handwriting switch changes the cortical representation of finger movements in the left and right hemispheres. Echo-planar MR imaging was performed in 52 subjects: consistent right-handers (RH), consistent left-handers (LH), and subjects who had been forced at an early age to switch their left-hand preferences toward the right side. The scanning was performed during simple (flexion/extension of the index finger) and complex (successive finger-thumb opposition) tasks. Subjects performed the tasks using both the preferred and non-preferred hand. In right-handers, there was a general predominance of left-hemisphere activation relative to right hemisphere activation. In lefthanders this pattern was reversed. The switched subjects showed no such volumetric asymmetry. Increasing levels of complexity of motor activity resulted in an increase in the volume of consistently activated areas and the involvement of the ipsilateral in addition to contralateral activations. In both right- and left-handers, movements of the preferred hand activated mainly the contralateral hemisphere, whereas movements of the non-preferred hand resulted in a more balanced pattern of activation in the two hemispheres, indicating greater involvement of the ipsilateral activations. Overall, this study shows that in both left- and right-handed subjects, the preferred hand is controlled mainly by the hemisphere contralateral to that hand, whereas the non-preferred hand is controlled by both hemispheres. The switched individuals share features of both lefthanders and right-handers regarding their motor control architectures.

On the Gender Effects of Handedness in Professional Tennis

PubMed Central

Breznik, Kristijan

2013-01-01

The aim of this study was to explore the effects of the gender variable in relation to other player and match characteristics on the advantage possessed by left-handed professional tennis players over their right-handed rivals. The data include 16 732 male tennis players and 16 432 female tennis players who played 438 937 and 415 346 matches, respectively, in the period from 1968 to the end of 2011. The results revealed that the advantage of left-handed professional tennis players is higher in males compared to females. The inverse impact of player and match quality on the left- handers’ advantage was clearly confirmed. On the contrary, it seems that the type of court surface does not directly imply this advantage. To obtain an overview on the individual level, directed and weighted networks of tennis matches in both gender categories were constructed. Applying network analytic methods and the PageRank algorithm, the best left and right-handed players in the Open Era of tennis were identified. The top three ranked left-handed players in the male and female categories were found to be far more consistent in their ranks achieved against left and right-handed opponents compared to their right-handed counterparts. Key Points The advantage of left-handed professional tennis players over their right-handed opponents is higher in males compared to females. The quality of player and match is inversely proportional to the advantage of left-handers against their right-handed counterparts. On the contrary, it seems that the type of court surface does not directly imply this advantage. When the tennis talent appears in left-handers it is likely to be an outstanding one, particularly in the female category. PMID:24149815

Keep your hands crossed: the valence-by-left/right interaction is related to hand, not side, in an incongruent hand-response key assignment.

PubMed

de la Vega, Irmgard; Dudschig, Carolin; De Filippis, Mónica; Lachmair, Martin; Kaup, Barbara

2013-02-01

The body-specificity hypothesis (Casasanto, 2009) associates positive emotional valence and the space surrounding the dominant hand, and negative valence and the space surrounding the non-dominant hand. This effect has not only been found for manual responses, but also for the left and right side. In the present study, we investigated whether this compatibility effect still shows when hand and side carry incongruent information, and whether it is then related to hand or to side. We conducted two experiments which used an incongruent hand-response key assignment, that is, participants had their hands crossed. Participants were instructed to respond with their right vs. left hand (Experiment 1) or with the right vs. left key (Experiment 2). In both experiments, a compatibility effect related to hand emerged, indicating that the association between hand and valence overrides the one between side and valence when hand and side carry contradicting information. Copyright © 2013 Elsevier B.V. All rights reserved.

Lateralized dual task interference in left-handers: initial value differences do not affect the outcome.

PubMed

McBride, D M; Cherry, B J; Kee, D W; Neale, P L

1995-07-01

The study was conducted to clarify factors involved in dual-task finger-tapping interference. Left-handers, as assessed by hand-writing preference and left-hand baseline tapping advantage, tapped both alone and while solving anagrams. Even though the left-hand baseline tapping advantage was experimentally removed on some (adjusted) trials, greater left- than right-hand tapping interference was observed during concurrent task performance. This result coupled with previous findings for right-handed subjects [Kee and Cherry, Neuropsychologia, Vol. 28, pp. 313-316, 1990] indicates that lateralized interference effects are not merely due to initial baseline tapping differences as proposed by Willis and Goodwin [Neuropsychologia, Vol. 25, pp. 719-724, 1987].

The effect of hand position on perceived finger orientation in left- and right-handers.

PubMed

Fraser, Lindsey E; Harris, Laurence R

2017-12-01

In the absence of visual feedback, the perceived orientation of the fingers is systematically biased. In right-handers these biases are asymmetrical between the left and right hands in the horizontal plane and may reflect common functional postures for the two hands. Here we compared finger orientation perception in right- and left-handed participants for both hands, across various hand positions in the horizontal plane. Participants rotated a white line on a screen optically superimposed over their hand to indicate the perceived position of the finger that was rotated to one of seven orientations with the hand either aligned with the body midline, aligned with the shoulder, or displaced by twice the shoulder-to-midline distance from the midline. We replicated the asymmetric pattern of biases previously reported in right-handed participants (left hand biased towards an orientation ~30° inward, right hand ~10° inward). However, no such asymmetry was found for left-handers, suggesting left-handers may use different strategies when mapping proprioception to body or space coordinates and/or have less specialization of function between the hands. Both groups' responses rotated further outward as distance of the hand from the body midline increased, consistent with other research showing spatial orientation estimates diverge outward in the periphery. Finally, for right-handers, precision of responses was best when the hand was aligned with the shoulder compared to the other two conditions. These results highlight the unique role of hand dominance and hand position in perception of finger orientation, and provide insight into the proprioceptive position sense of the upper limbs.

Left-handedness and neurotic disturbances in adult urban population.

PubMed

Milenković, Sanja; Brkić, Milica; Belojević, Goran

2013-01-01

Controversial results on the relationship between the left-handedness and neurotic disturbances have been obtained in so far investigations. The aim of this study was to investigate the link between the left-handedness and neurotic disturbances in an adult urban population. A cross-sectional study was performed on 1,202 adult residents of the Stari Grad municipality in Belgrade, out of which 401 were males (33.4%) and 801 were females (66.6%). A questionnaire was used as an investigation instrument, with questions concerning age, gender, writing hand and neurotic disturbances: tension, agressiveness, anger, nervousness, weepiness and seclusion. Left-handedness was found in 60 subjects (5%) and it was statistically more frequent in males (7.7%) compared to females (3.6%) (p = 0.003). A decreasing trend of proportion of left-handed males was found in relation to aging. In the age group 18 to 39 years, agressiveness, as a specific neurotic disturbance, was significantly more frequent in left-handed males in comparison to right-handers (p = 0.035). In the age group 40 to 59 years, neurotic disturbances were more common among left-handed males compared to right-handers (p = 0.030).There were no significant diferences in the proportion of neurotic disturbances between the left-handed and the right-handed females. From a public health point of view, left-handed men may be regarded as a relatively vulnerable population category concerning mental health.

Knee-laxity measurements examined by a left-hand- and a right-hand-dominant physiotherapist, in patients with anterior cruciate ligament injuries and healthy controls.

PubMed

Sernert, Ninni; Helmers, Janett; Kartus, Catarina; Ejerhed, Lars; Kartus, Jüri

2007-10-01

The purpose of the study was to analyse and compare KT-1000 knee laxity as examined by a left-hand- and a right-hand-dominant physiotherapist in a group of patients with an anterior cruciate ligament (ACL) injury and a group of patients, 2 years after ACL reconstruction. The other aim was to measure and analyse knee laxity in a group of persons without any known knee problems. A cross-sectional examination of two groups of patients pre-operatively and post-operatively after ACL reconstruction and examination of healthy controls on two different occasions was performed. Fifty-three patients who were scheduled for ACL reconstruction and 39 patients who attended a 2-year follow-up examination were included in the study. In the ACL-deficient group, 32 patients had a right-sided ACL injury and 21 patients a left-sided ACL injury. The corresponding figures in the post-operative group were 21 patients with a right-sided ACL injury and 18 patients with a left-sided ACL injury. Twenty-eight healthy persons without any known knee problems served as controls. One left-hand- and one right-hand-dominant experienced physiotherapist performed all the examinations. To be able to evaluate the intra and inter-reliability of the examiners the controls were examined at two occasions. The left-hand-dominant physiotherapist measured significantly higher absolute laxity values in the left knee, both injured and non-injured ones, compared with the right-hand-dominant physiotherapist. This was found irrespectively of whether the patients belonged to the ACL deficient or the post-operative group. In the healthy control group, the right-hand-dominant physiotherapist measured significantly higher knee-laxity values in the right knee compared with the left-hand-dominant physiotherapist. Correspondingly, the left-hand-dominant physiotherapist measured significantly higher knee laxity values in the left knee. We conclude that KT-1000 arthrometer laxity measurements can be affected by the hand dominance of the examiner. This might affect the reliability of KT-1000 arthrometer measurements. Level of evidence is II.

Postural Effects on the Mental Rotation of Body-Related Pictures: An fMRI Study.

PubMed

Qu, Fangbing; Wang, Jianping; Zhong, Yuan; Ye, Haosheng

2018-01-01

This study investigated the embodied effects involved in the mental rotation of pictures of body parts (hands and feet). Blood oxygen level-dependent (BOLD) signals were collected from 18 healthy volunteers who performed mental rotation tasks of rotated drawings of hands under different arm postures. Congruent drawings of hands (those congruent with left-hand posture) evoked stronger activation in the left supplementary motor area (SMA), left precentral gyrus, and left superior parietal lobule (SPL) than did incongruent drawings of hands. Congruent drawings of hands (those congruent with right-hand posture) evoked significant activation in the left inferior parietal lobule (IPL), right SMA, bilateral middle frontal gyrus (MFG), left inferior frontal gyrus (IFG), and bilateral superior frontal gyrus (SFG) compared to that evoked by the incongruent drawings of hands. Similar methodology was implemented with drawings of feet. However, no significant differences in brain activation were observed between congruent and incongruent drawings of feet. This finding suggests that body posture influences body part-related mental rotation in an effector-specific manner. A direct comparison between the medially and laterally rotated drawings revealed activation in the right IPL, left precentral gyrus, bilateral IFG, and bilateral SFG. These results suggest that biomechanical constraints affect the cognitive process of mental rotation.

[A case of left hand agraphia without callosal apraxia].

PubMed

Tsuzuki, S; Indo, T; Takahashi, A

1989-01-01

A 65-year-old male who had agraphia confined to the left hand was reported. The patient was admitted to the neurological department of Kasugai city Hospital because of suddenly-developed mild right-sided hemiparesis with central facial palsy. Computerized tomography of the brain was performed 2 and 14 days after admission. As a result, low-density regions were found in the left cingulate and medial frontal gyri and the trunk of the corpus callosum. Magnetic resonance imaging of the saggital plane more clearly visualized a localized infarction affecting both the trunk of the corpus callosum and its leftward outflow. Neuropsychological findings of the patient were summarized as follows. 1) He had no difficulty in any of the actual use of object, copying the manipulation of objects, and proper use of objects according to verbal commands. 2) With the eyes closed, he could correctly name the objects handed over to the right hand, while he could do only 15 out of 20 objects handed over to the left hand. However, whichever hand an object was handed to, he could explain how to use the object. 3) He could write Hiragana, Katakana, and Kanji correctly with his right hand in accordance with verbal commands, whereas with his left hand he could do only for 20% of Hiragana, 20% of Katakana, and 90% of Kanji. 4) He could copy Kanji, Hiragana, and figures with either right or left hand. 5) He could point out verbally-presented letters using letter cards whether with the right hand or with the left hand, and could also select the letter card corresponding to the letter visually-presented.(ABSTRACT TRUNCATED AT 250 WORDS)

Are Canadian-born Major League Baseball players more likely to bat left-handed? A partial test of the hockey-influence on batting hypothesis.

PubMed

Cairney, John; Chirico, Daniele; Li, Yao-Chuen; Bremer, Emily; Graham, Jeffrey D

2018-01-01

It has been suggested that Canadian-born Major League Baseball (MLB) players are more likely to bat left-handed, possibly owing to the fact that they learn to play ice hockey before baseball, and that there is no clear hand-preference when shooting with a hockey stick; approximately half of all ice hockey players shoot left. We constructed a database on active (i.e., October, 2016) MLB players from four countries/regions based on place of birth (Canada, United States of America [USA], Dominican Republic and South Asia [i.e., Japan, Taiwan and South Korea]), including information on which hand they use to bat and throw. We also extracted information on all Canadian-born MLB players, dating back to 1917. Our results confirm that the proportion of left-handed batters born in Canada is higher when compared to the other countries selected; also, since 1917, the proportion of Canadian MLB players who bat left has been consistently higher than the league average. We also compared the proportion of left-handed batters in Canada with players born in states in the USA grouped into high, average and low based on hockey participation. The proportion of MLB players born in states with a high level of hockey participation were more likely to bat left, although the differences were significant at trend level only (p < .10). Lastly, we found that while Canadians were more likely to bat left-handed, this did not correspond with a greater left-hand dominance, as determined by throwing hand. In conclusion, the present study confirms that Canadian-born MLB players are more likely to bat left-handed when compared to American, Dominican Republic and South Asian-born MLB players, providing partial support for the hockey influence on batting hypothesis.

Why are some people left-handed? An evolutionary perspective

PubMed Central

Llaurens, V.; Raymond, M.; Faurie, C.

2008-01-01

Since prehistoric times, left-handed individuals have been ubiquitous in human populations, exhibiting geographical frequency variations. Evolutionary explanations have been proposed for the persistence of the handedness polymorphism. Left-handedness could be favoured by negative frequency-dependent selection. Data have suggested that left-handedness, as the rare hand preference, could represent an important strategic advantage in fighting interactions. However, the fact that left-handedness occurs at a low frequency indicates that some evolutionary costs could be associated with left-handedness. Overall, the evolutionary dynamics of this polymorphism are not fully understood. Here, we review the abundant literature available regarding the possible mechanisms and consequences of left-handedness. We point out that hand preference is heritable, and report how hand preference is influenced by genetic, hormonal, developmental and cultural factors. We review the available information on potential fitness costs and benefits acting as selective forces on the proportion of left-handers. Thus, evolutionary perspectives on the persistence of this polymorphism in humans are gathered for the first time, highlighting the necessity for an assessment of fitness differences between right- and left-handers. PMID:19064347

Pantomime to visual presentation of objects: left hand dyspraxia in patients with complete callosotomy.

PubMed

Lausberg, Hedda; Cruz, Robyn F; Kita, Sotaro; Zaidel, Eran; Ptito, Alain

2003-02-01

Investigations of left hand praxis in imitation and object use in patients with callosal disconnection have yielded divergent results, inducing a debate between two theoretical positions. Whereas Liepmann suggested that the left hemisphere is motor dominant, others maintain that both hemispheres have equal motor competences and propose that left hand apraxia in patients with callosal disconnection is secondary to left hemispheric specialization for language or other task modalities. The present study aims to gain further insight into the motor competence of the right hemisphere by investigating pantomime of object use in split-brain patients. Three patients with complete callosotomy and, as control groups, five patients with partial callosotomy and nine healthy subjects were examined for their ability to pantomime object use to visual object presentation and demonstrate object manipulation. In each condition, 11 objects were presented to the subjects who pantomimed or demonstrated the object use with either hand. In addition, six object pairs were presented to test bimanual coordination. Two independent raters evaluated the videotaped movement demonstrations. While object use demonstrations were perfect in all three groups, the split-brain patients displayed apraxic errors only with their left hands in the pantomime condition. The movement analysis of concept and execution errors included the examination of ipsilateral versus contralateral motor control. As the right hand/left hemisphere performances demonstrated retrieval of the correct movement concepts, concept errors by the left hand were taken as evidence for right hemisphere control. Several types of execution errors reflected a lack of distal motor control indicating the use of ipsilateral pathways. While one split-brain patient controlled his left hand predominantly by ipsilateral pathways in the pantomime condition, the error profile in the other two split-brain patients suggested that the right hemisphere controlled their left hands. In the object use condition, in all three split-brain patients fine-graded distal movements in the left hand indicated right hemispheric control. Our data show left hand apraxia in split-brain patients is not limited to verbal commands, but also occurs in pantomime to visual presentation of objects. As the demonstration with object in hand was unimpaired in either hand, both hemispheres must contain movement concepts for object use. However, the disconnected right hemisphere is impaired in retrieving the movement concept in response to visual object presentation, presumably because of a deficit in associating perceptual object representation with the movement concepts.

Enhanced visuo-haptic integration for the non-dominant hand.

PubMed

Yalachkov, Yavor; Kaiser, Jochen; Doehrmann, Oliver; Naumer, Marcus J

2015-07-21

Visuo-haptic integration contributes essentially to object shape recognition. Although there has been a considerable advance in elucidating the neural underpinnings of multisensory perception, it is still unclear whether seeing an object and exploring it with the dominant hand elicits the same brain response as compared to the non-dominant hand. Using fMRI to measure brain activation in right-handed participants, we found that for both left- and right-hand stimulation the left lateral occipital complex (LOC) and anterior cerebellum (aCER) were involved in visuo-haptic integration of familiar objects. These two brain regions were then further investigated in another study, where unfamiliar, novel objects were presented to a different group of right-handers. Here the left LOC and aCER were more strongly activated by bimodal than unimodal stimuli only when the left but not the right hand was used. A direct comparison indicated that the multisensory gain of the fMRI activation was significantly higher for the left than the right hand. These findings are in line with the principle of "inverse effectiveness", implying that processing of bimodally presented stimuli is particularly enhanced when the unimodal stimuli are weak. This applies also when right-handed subjects see and simultaneously touch unfamiliar objects with their non-dominant left hand. Thus, the fMRI signal in the left LOC and aCER induced by visuo-haptic stimulation is dependent on which hand was employed for haptic exploration. Copyright © 2015 Elsevier B.V. All rights reserved.

Upper Limb Asymmetry in the Sense of Effort Is Dependent on Force Level

PubMed Central

Mitchell, Mark; Martin, Bernard J.; Adamo, Diane E.

2017-01-01

Previous studies have shown that asymmetries in upper limb sensorimotor function are dependent on the source of sensory and motor information, hand preference and differences in hand strength. Further, the utilization of sensory and motor information and the mode of control of force may differ between the right hand/left hemisphere and left hand/right hemisphere systems. To more clearly understand the unique contribution of hand strength and intrinsic differences to the control of grasp force, we investigated hand/hemisphere differences when the source of force information was encoded at two different force levels corresponding to a 20 and 70% maximum voluntary contraction or the right and left hand of each participant. Eleven, adult males who demonstrated a stronger right than left maximum grasp force were requested to match a right or left hand 20 or 70% maximal voluntary contraction reference force with the opposite hand. During the matching task, visual feedback corresponding to the production of the reference force was available and then removed when the contralateral hand performed the match. The matching relative force error was significantly different between hands for the 70% MVC reference force but not for the 20% MVC reference force. Directional asymmetries, quantified as the matching force constant error, showed right hand overshoots and left undershoots were force dependent and primarily due to greater undershoots when matching with the left hand the right hand reference force. Findings further suggest that the interaction between internal sources of information, such as efferent copy and proprioception, as well as hand strength differences appear to be hand/hemisphere system dependent. Investigations of force matching tasks under conditions whereby force level is varied and visual feedback of the reference force is available provides critical baseline information for building effective interventions for asymmetric (stroke-related, Parkinson’s Disease) and symmetric (Amyotrophic Lateral Sclerosis) upper limb recovery of neurological conditions where the various sources of sensory – motor information have been significantly altered by the disease process. PMID:28491047

Upper Limb Asymmetry in the Sense of Effort Is Dependent on Force Level.

PubMed

Mitchell, Mark; Martin, Bernard J; Adamo, Diane E

2017-01-01

Previous studies have shown that asymmetries in upper limb sensorimotor function are dependent on the source of sensory and motor information, hand preference and differences in hand strength. Further, the utilization of sensory and motor information and the mode of control of force may differ between the right hand/left hemisphere and left hand/right hemisphere systems. To more clearly understand the unique contribution of hand strength and intrinsic differences to the control of grasp force, we investigated hand/hemisphere differences when the source of force information was encoded at two different force levels corresponding to a 20 and 70% maximum voluntary contraction or the right and left hand of each participant. Eleven, adult males who demonstrated a stronger right than left maximum grasp force were requested to match a right or left hand 20 or 70% maximal voluntary contraction reference force with the opposite hand. During the matching task, visual feedback corresponding to the production of the reference force was available and then removed when the contralateral hand performed the match. The matching relative force error was significantly different between hands for the 70% MVC reference force but not for the 20% MVC reference force. Directional asymmetries, quantified as the matching force constant error, showed right hand overshoots and left undershoots were force dependent and primarily due to greater undershoots when matching with the left hand the right hand reference force. Findings further suggest that the interaction between internal sources of information, such as efferent copy and proprioception, as well as hand strength differences appear to be hand/hemisphere system dependent. Investigations of force matching tasks under conditions whereby force level is varied and visual feedback of the reference force is available provides critical baseline information for building effective interventions for asymmetric (stroke-related, Parkinson's Disease) and symmetric (Amyotrophic Lateral Sclerosis) upper limb recovery of neurological conditions where the various sources of sensory - motor information have been significantly altered by the disease process.

Semantic processing in the left versus right cerebral hemispheres following unilateral hand contractions.

PubMed

Turner, Casey E; Hahn, Michael E; Kellogg, Ronald T

2017-03-01

Unilateral hand contractions increase activation in the motor cortex of the contralateral hemisphere, providing a means to alter the relative degree of activation in the right hemisphere versus the left hemisphere through spreading activation. Prior research reported enhanced verbal creativity as measured by performance on remote associate problems in Hebrew from left-hand contractions (right-hemisphere activation). We sought to extend the previous findings to English problems and to homograph interpretation. In Experiment 1, unilateral hand contractions in fact altered performance on the English remote associates, but in the direction of improved performance following right-hand contractions and left-hemisphere activation. In Experiment 2, the probability of retrieving atypical interpretations of homographs with multiple meanings was least likely for left-hemisphere dominant strong right handers, but the hand contraction manipulation had no effect.

Brain oxygenation patterns during the execution of tool use demonstration, tool use pantomime, and body-part-as-object tool use.

PubMed

Helmich, Ingo; Holle, Henning; Rein, Robert; Lausberg, Hedda

2015-04-01

Divergent findings exist whether left and right hemispheric pre- and postcentral cortices contribute to the production of tool use related hand movements. In order to clarify the neural substrates of tool use demonstrations with tool in hand, tool use pantomimes without tool in hand, and body-part-as-object presentations of tool use (BPO) in a naturalistic mode of execution, we applied functional Near InfraRed Spectroscopy (fNIRS) in twenty-three right-handed participants. Functional NIRS techniques allow for the investigation of brain oxygenation during the execution of complex hand movements with an unlimited movement range. Brain oxygenation patterns were retrieved from 16 channels of measurement above pre- and postcentral cortices of each hemisphere. The results showed that tool use demonstration with tool in hand leads to increased oxygenation as compared to tool use pantomimes in the left hemispheric somatosensory gyrus. Left hand executions of the demonstration of tool use, pantomime of tool use, and BPO of tool use led to increased oxygenation in the premotor and somatosensory cortices of the left hemisphere as compared to right hand executions of either condition. The results indicate that the premotor and somatosensory cortices of the left hemisphere constitute relevant brain structures for tool related hand movement production when using the left hand, whereas the somatosensory cortex of the left hemisphere seems to provide specific mental representations when performing tool use demonstrations with the tool in hand. Copyright © 2015 Elsevier B.V. All rights reserved.

The role of handedness-dependent sensorimotor experience in the development of mirroring.

PubMed

Mori, Hirotaka; Yamamoto, Shinji; Aihara, Tsuyoshi; Uehara, Shintaro

2015-01-01

In daily life, we often try to learn motor actions by imitating others' actions. Motor imitation requires us to simultaneously map an observed action onto a motor program used to perform that action. This sensorimotor associative experience can plastically modulate the mirror property of the human mirror system, which has a role in matching observed actions directly with the observer's motor programs, to enhance the association between observed and performed actions. In the present study, we investigated the effects of handedness on the mirror property. Healthy left- and right-handed individuals performed a motor imitation task. They were required to imitate hand actions with their dominant hand as quickly and accurately as possible in response to pictures of a left and right hand. Reaction times (RTs) for imitating the hand actions were evaluated. Under the condition where the hand pictures were presented as if facing the participant, we found that, in left-handed participants, RTs for imitating right-handed actions were significantly shorter than those for imitating left-handed actions. Under the same conditions in right-handers, similar differences in RTs when presented left- and right-handed actions were not observed. These findings demonstrate that the imitative responses for left- and right-handed actions are differently facilitated depending on the handedness of the observer, indicating an effect of handedness on the development of mirror systems. The mirror property in left- and right-handers is likely modulated in a different manner by different sensorimotor associative experiences throughout their daily lives. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Stent Implantation for Malignant Pulmonary Artery Stenosis in a Metastasizing Non-Small Cell Bronchial Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutzeit, A., E-mail: andreas.gutzeit@ksw.c; Koch, S.; Meier, U. R.

2008-07-15

A 58-year-old patient with recently diagnosed non-small cell bronchial carcinoma was referred to us with increasing shortness of breath and orthopnea by her family practitioner. To exclude the possibility of a pulmonary embolism, contrast medium-enhanced angio-CT of the thorax was performed. This showed a large mediastinal tumor, which, on the one hand, infiltrated and occluded the left upper lobe bronchus and, on the other, constricted the left pulmonary artery over a considerable part of its length. In view of the palliative situation and massively increasing dyspnea, balloon dilatation of the obstructed left pulmonary artery followed by stent placement was performed.more » This resulted in an immediate improvement of the symptoms. The originally strongly oxygen-dependent and heavily dyspneic patient could be relieved of the external supply of oxygen and was able to sleep normally without additional medication within 24 h. The patient was able ambulate freely within 2 days, with a markedly improved quality of life.« less

Quasi-phase-matching of the dual-band nonlinear left-handed metamaterial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yahong, E-mail: yhliu@nwpu.edu.cn; Song, Kun; Gu, Shuai

2014-11-17

We demonstrate a type of nonlinear meta-atom creating a dual-band nonlinear left-handed metamaterial (DNLHM). The DNLHM operates at two distinct left-handed frequency bands where there is an interval of one octave between the two center frequencies. Under the illumination of a high-power signal at the first left-handed frequency band corresponding to fundamental frequency (FF), second-harmonic generation (SHG) is observed at the second left-handed band. This means that our DNLHM supports backward-propagating waves both at FF and second-harmonic (SH) frequency. We also experimentally demonstrate quasi-phase-matching configurations for the backward SHG. This fancy parametric process can significantly transmits the SH generated bymore » an incident FF wave.« less

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2012 CFR

2012-10-01

...,” “Original page 1,” “Original page 2,” etc. (1) All such pages must show, in the upper left-hand corner the... designation directly below; in the lower left-hand corner the issued date; in the lower right-hand corner the... and check sheet only. (2) As an alternative, the issuing carrier may show in the upper left-hand...

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2014 CFR

2014-10-01

...,” “Original page 1,” “Original page 2,” etc. (1) All such pages must show, in the upper left-hand corner the... designation directly below; in the lower left-hand corner the issued date; in the lower right-hand corner the... and check sheet only. (2) As an alternative, the issuing carrier may show in the upper left-hand...

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2013 CFR

2013-10-01

...,” “Original page 1,” “Original page 2,” etc. (1) All such pages must show, in the upper left-hand corner the... designation directly below; in the lower left-hand corner the issued date; in the lower right-hand corner the... and check sheet only. (2) As an alternative, the issuing carrier may show in the upper left-hand...

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2011 CFR

2011-10-01

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Left, right, left, right, eyes to the front! Müller-Lyer bias in grasping is not a function of hand used, hand preferred or visual hemifield, but foveation does matter.

PubMed

van der Kamp, John; de Wit, Matthieu M; Masters, Rich S W

2012-04-01

We investigated whether the control of movement of the left hand is more likely to involve the use of allocentric information than movements performed with the right hand. Previous studies (Gonzalez et al. in J Neurophys 95:3496-3501, 2006; De Grave et al. in Exp Br Res 193:421-427, 2009) have reported contradictory findings in this respect. In the present study, right-handed participants (N = 12) and left-handed participants (N = 12) made right- and left-handed grasps to foveated objects and peripheral, non-foveated objects that were located in the right or left visual hemifield and embedded within a Müller-Lyer illusion. They were also asked to judge the size of the object by matching their hand aperture to its length. Hand apertures did not show significant differences in illusory bias as a function of hand used, handedness or visual hemifield. However, the illusory effect was significantly larger for perception than for action, and for the non-foveated compared to foveated objects. No significant illusory biases were found for reach movement times. These findings are consistent with the two-visual system model that holds that the use of allocentric information is more prominent in perception than in movement control. We propose that the increased involvement of allocentric information in movements toward peripheral, non-foveated objects may be a consequence of more awkward, less automatized grasps of nonfoveated than foveated objects. The current study does not support the conjecture that the control of left-handed and right-handed grasps is predicated on different sources of information.

Kinematic and kinetic differences between left-and right-handed professional baseball pitchers.

PubMed

Diffendaffer, Alek Z; Fleisig, Glenn S; Ivey, Brett; Aune, Kyle T

2018-03-21

While 10% of the general population is left-handed, 27% of professional baseball pitchers are left-handed. Biomechanical differences between left- and right-handed college pitchers have been previously reported, but these differences have yet to be examined at the professional level. Therefore, the purpose of this study was to compare pitching biomechanics between left- and right-handed professional pitchers. It was hypothesised that there would be significant kinematic and kinetic differences between these two groups. Pitching biomechanics were collected on 96 left-handed pitchers and a group of 96 right-handed pitchers matched for age, height, mass and ball velocity. Student t-tests were used to identify kinematic and kinetic differences (p < 0.05). Of the 31 variables tested, only four were found to be significantly different between the groups. Landing position of the stride foot, trunk separation at foot contact, maximum shoulder external rotation and trunk forward tilt at ball release were all significantly greater in right-handed pitchers. The magnitude of the statistical differences found were small and not consistent with differences in the two previous, smaller studies. Thus, the differences found may be of minimal practical significance and mechanics can be taught the same to all pitchers, regardless of throwing hand.

Functional asymmetries in early learning during right, left, and bimanual performance in right-handed subjects.

PubMed

Aznárez-Sanado, Maite; Fernández-Seara, Maria A; Loayza, Francis R; Pastor, Maria A

2013-03-01

To elucidate differences in activity and connectivity during early learning due to the performing hand. Twenty right-handed subjects were recruited. The neural correlates of explicit visuospatial learning executed with the right, the left hand, and bimanually were investigated using functional magnetic resonance imaging. Connectivity analyses were carried out using the psychophysiological interactions model, considering right and left anterior putamen as index regions. A common neural network was found for the three tasks during learning. Main activity increases were located in posterior cingulate cortex, supplementary motor area, parietal cortex, anterior putamen, and cerebellum (IV-V), whereas activity decrements were observed in prefrontal regions. However, the left hand task showed a greater recruitment of left hippocampal areas when compared with the other tasks. In addition, enhanced connectivity between the right anterior putamen and motor cortical and cerebellar regions was found for the left hand when compared with the right hand task. An additional recruitment of brain regions and increased striato-cortical and striato-cerebellar functional connections is needed when early learning is performed with the nondominant hand. In addition, access to brain resources during learning may be directed by the dominant hand in the bimanual task. Copyright © 2012 Wiley Periodicals, Inc.

[Agraphia of the left hand--its characteristics and mechanism of development].

PubMed

Ohigashi, Y; Hamanaka, T; Asano, K; Morimune, S

1983-11-01

We observed 62 y.o. right-handed woman, whose truncus of corps callosum was damaged by infarction of left anterior cerebral artery, that was verified by coronal CT scan finding. She was apraxic and agraphic only with left hand. We examined the characteristics of her unilateral left agraphia from the point of quantitative and qualitative views. These analysis seemed to reveal three main characteristics of unilateral left agraphia of this patient. These were as follows; 1) productive, 2) neographic and 3) iterative. Another important feature of this patient was the mute state during her left-hand writing. Her left agraphia could not explained by apraxic factor, because her copying capacity was remarkably preserved in comparison with her dictation or written naming ability. Furthermore, this agraphia was not aphasic because her right-hand writing was almost intact. We agreed with Yamadori who insisted that this type of agraphia was neither apraxic nor aphasic, but the particular third agraphia which was named as "disconnection agraphia". We considered that the mute state during her left-hand writing might some kind of transient aphasia, which may reflect the functional disturbance of left hemisphere, and the reduced energy in the left hemisphere could increase the activity of right hemisphere. Partial interhemispheric disconnection might induce transient "linguistic anosognosia" in this patient. We believe that these transient hyperactivity and transient linguistic anosognosia could generate above mentioned characteristics of her left agraphia; productive, neographic and iterative.

Chiral Symmetry Breaking and Complete Chiral Purity by Thermodynamic-Kinetic Feedback Near Equilibrium: Implications for the Origin of Biochirality

NASA Astrophysics Data System (ADS)

Viedma, Cristobal

2007-05-01

Chiral symmetry breaking occurs when a physical or chemical process spontaneously generates a large excess of one of the two enantiomers-left-handed (L) or right-handed (D)--with no preference as to which of the two enantiomers is produced. From the viewpoint of energy, these two enantiomers can exist with an equal probability, and inorganic processes that involve chiral products commonly yield a racemic mixture of both. The fact that biologically relevant molecules exist only as one of the two enantiomers is a fascinating example of complete symmetry breaking in chirality and has long intrigued the science community. The origin of this selective chirality has remained a fundamental enigma with regard to the origin of life since the time of Pasteur, some 140 years ago. Here, it is shown that two populations of chiral crystals of left and right hand cannot coexist in solution: one of the chiral populations disappears in an irreversible autocatalytic process that nurtures the other one. Final and complete chiral purity seems to be an inexorable fate in the course of the common process of growth-dissolution. This unexpected chiral symmetry breaking can be explained by the feedback between the thermodynamic control of dissolution and the kinetics of the growth process near equilibrium. This ``thermodynamic-kinetic feedback near equilibrium'' is established as a mechanism to achieve complete chiral purity in solid state from a previously solid racemic medium. The way in which this mechanism could operate in solutions of chiral biomolecules is described. Finally, based on this mechanism, experiments designed to search for chiral purity in a new way are proposed: chiral purity of amino acids or biopolymers is predicted in solid phase from a previously solid racemic medium. This process may have played a key role in the origin of biochirality.

Hand-independent representation of tool-use pantomimes in the left anterior intraparietal cortex.

PubMed

Ogawa, Kenji; Imai, Fumihito

2016-12-01

Previous neuropsychological studies of ideomotor apraxia (IMA) indicated impairments in pantomime actions for tool use for both right and left hands following lesions of parieto-premotor cortices in the left hemisphere. Using functional magnetic resonance imaging (fMRI) with multi-voxel pattern analysis (MVPA), we tested the hypothesis that the left parieto-premotor cortices are involved in the storage or retrieval of hand-independent representation of tool-use actions. In the fMRI scanner, one of three kinds of tools was displayed in pictures or letters, and the participants made pantomimes of the use of these tools using the right hand for the picture stimuli or with the left hand for the letters. We then used MVPA to classify which kind of tool the subjects were pantomiming. Whole-brain searchlight analysis revealed successful decoding using the activities largely in the contralateral primary sensorimotor region, ipsilateral cerebellum, and bilateral early visual area, which may reflect differences in low-level sensorimotor components for three types of pantomimes. Furthermore, a successful cross-classification between the right and left hands was possible using the activities of the left inferior parietal lobule (IPL) near the junction of the anterior intraparietal sulcus. Our finding indicates that the left anterior intraparietal cortex plays an important role in the production of tool-use pantomimes in a hand-independent manner, and independent of stimuli modality.

Mid-infrared metasurface made of composite right/left-handed transmission-line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Yi; Ying, Xiangxiao; Pu, Yang

2016-06-06

We report on the realization of a mid-infrared metasurface based on the concept of composite right/left-handed transmission-line. The metasurface consists of a three-layer metal-insulator-metal structure patterned into transmission-lines by electron-beam lithography. Angle-variable reflection spectroscopy measurements reveal resonant absorption features corresponding to both right- and left-handed propagations in the leaky-wave guided mode region. Material loss is shown to dominate the quality factor of the left-handed modes, while the radiative loss dominates the right-handed ones. The experimental results are in good agreement with full-wave numerical simulations and are explained with an equivalent circuit model.

Kinematics of reaching and implications for handedness in rhesus monkey infants

PubMed Central

Nelson, Eliza L.; Konidaris, George D.; Berthier, Neil E.; Braun, Maurine C.; Novak, Matthew F.S.X.; Suomi, Stephen J.; Novak, Melinda A.

2014-01-01

Kinematic studies of reaching in human infants using two-dimensional (2-D) and three-dimensional (3-D) recordings have complemented behavioral studies of infant handedness by providing additional evidence of early right asymmetries. Right hand reaches have been reported to be straighter and smoother than left hand reaches during the first year. Although reaching has been a popular measure of handedness in primates, there has been no systematic comparison of left and right hand reach kinematics. We investigated reaching in infant rhesus monkeys using the 2-D motion analysis software MaxTRAQ Lite+ (Innovision Systems). Linear mixed-effects models revealed that left hand reaches were smoother, but not straighter, than right hand reaches. An early left bias matches previous findings of a left hand preference for reaching in adult rhesus monkeys. Additional work using this kind of kinematic approach will extend our understanding of primate handedness beyond traditional studies measuring only frequency or bouts of hand use. PMID:22031459

Auditory middle latency responses differ in right- and left-handed subjects: an evaluation through topographic brain mapping.

PubMed

Mohebbi, Mehrnaz; Mahmoudian, Saeid; Alborzi, Marzieh Sharifian; Najafi-Koopaie, Mojtaba; Farahani, Ehsan Darestani; Farhadi, Mohammad

2014-09-01

To investigate the association of handedness with auditory middle latency responses (AMLRs) using topographic brain mapping by comparing amplitudes and latencies in frontocentral and hemispheric regions of interest (ROIs). The study included 44 healthy subjects with normal hearing (22 left handed and 22 right handed). AMLRs were recorded from 29 scalp electrodes in response to binaural 4-kHz tone bursts. Frontocentral ROI comparisons revealed that Pa and Pb amplitudes were significantly larger in the left-handed than the right-handed group. Topographic brain maps showed different distributions in AMLR components between the two groups. In hemispheric comparisons, Pa amplitude differed significantly across groups. A left-hemisphere emphasis of Pa was found in the right-handed group but not in the left-handed group. This study provides evidence that handedness is associated with AMLR components in frontocentral and hemispheric ROI. Handedness should be considered an essential factor in the clinical or experimental use of AMLRs.

Relative age effect and left-handedness in world class water polo male and female players.

PubMed

Barrenetxea-Garcia, Josu; Torres-Unda, Jon; Esain, Izaro; Gil, Susana M

2018-06-01

Most studies of the relative age effect (RAE) refer to popular sports. In contrast, we examined to what extent the RAE is present in elite water polo players, as well as the association between handedness and RAE. For these purposes, laterality, anthropometry, month of birth, performance and playing position of participants in the 2011, 2013 and 2015 World Championships (623 women, 622 men) were analised. No RAE was observed in the total sample. However, the proportion of male left-handed field players born in the first quarter (11%) was lower than those born in the second (35.3%) and fourth quarter (29.4%). Regarding the overall laterality, the amount of left handed players was similar to the general population (10%). Nevertheless, there was a larger amount of left-handed wings than expected both in men (23.7%) and women (34.4%). Left-handed male players performed more shots, shots/minute and also scored more goals than right-handed players. Women left-handed players were younger and they performed more shots/minute. There is no RAE in elite male and female water polo players. However, laterality could be a possible moderator of the RAE particularly in left handed players, which should be taken into account in future studies.

Asymmetries in motor attention during a cued bimanual reaching task: left and right handers compared.

PubMed

Buckingham, Gavin; Main, Julie C; Carey, David P

2011-04-01

Several studies have indicated that right handers have attention biased toward their right hand during bimanual coordination (Buckingham and Carey, 2009; Peters, 1981). To determine if this behavioral asymmetry was linked to cerebral lateralization, we examined this bias in left and right handers by combining a discontinuous double-step reaching task with a Posner-style hand cueing paradigm. Left and right handed participants received a tactile cue (valid on 80% of trials) prior to a bimanual reach to target pairs. Right handers took longer to inhibit their right hand and made more right hand errors, suggesting that their dominant hand was more readily primed to move than their non-dominant hand, likely due to the aforementioned attentional bias. Left handers, however, showed neither of these asymmetries, suggesting that they lack an equivalent dominant hand attentional bias. The findings are discussed in relation to recent unimanual handedness tasks in right and left handers, and the lateralization of systems for speech, language and motor attention. Copyright © 2009. Published by Elsevier Srl.

Hand Matters: Left-Hand Gestures Enhance Metaphor Explanation

ERIC Educational Resources Information Center

Argyriou, Paraskevi; Mohr, Christine; Kita, Sotaro

2017-01-01

Research suggests that speech-accompanying gestures influence cognitive processes, but it is not clear whether the gestural benefit is specific to the gesturing hand. Two experiments tested the "(right/left) hand-specificity" hypothesis for self-oriented functions of gestures: gestures with a particular hand enhance cognitive processes…

Problem of image superresolution with a negative-refractive-index slab.

PubMed

Nieto-Vesperinas, Manuel

2004-04-01

By means of the angular spectrum representation of wave fields, a discussion is given on the propagation and restoration of the wave-front structure in a slab of a left-handed medium (or negative-index medium) whose surface impedance matches that of vacuum, namely, one whose effective optical parameters are n = epsilon = mu = -1. This restoration was previously discussed [Phys. Rev. Lett. 85, 3866 (2000)] in regard to whether it may yield superresolved images. The divergence of the wave field in the slab, and its equivalence with that of the inverse diffraction propagator in free space, is addressed. Further, the existence of absorption, its regularization of this divergence, and the trade-off of a resulting limited superresolution are analyzed in detail in terms of its effect on the evanescent components of the wave field and hence on the transfer function width.

Functional Outcomes 18 Months After Total and Midarm Transplantation: A Case Report.

PubMed

Iglesias, M; Ramírez-Berumen, M; Butrón, P; Alberú-Gómez, J; Salazar-Hernández, F; Macias-Gallardo, J; Leal-Villalpando, R P; Zamudio-Bautista, J; Acosta, V; Jauregui, L; Hernández-Campos, A; Espinosa-Cruz, V; Vázquez-Lamadrid, J; González-Sánchez, J; Cuellar-Rodriguez, J; Sierra-Madero, J G; Gaytan-Cervantes, R; Contreras-Barbosa, S; Navarro-Lara, A; Guzman-Gonzalez, J; Domínguez-Cherit, J; Vilatoba, M; Toussaint-Caire, S; Vega-Boada, F; Gómez-Pérez, F J; Mayorquin-Ruiz, M

2018-04-01

The function reported after arm transplantation is deemed beneficial relative to the marked disability that upper arm amputation causes. We report a 51-year-old man with a Disabilities of the Arm, Shoulder and Hand (DASH) score of 75.83 who underwent bilateral arm transplantation in October 2015. The right arm was transplanted at the glenohumeral joint level, including transplantation of the humeral head, joint capsule, and rotator cuff ligaments and tendons. Additionally, neurorrhaphies were performed at the origin of the terminal branches of the brachial plexus, including the axillary and musculocutaneous nerves. Therefore, this was considered a total arm transplantation. The left arm was transplanted at the transhumeral level, with complete transplantation of the biceps and triceps brachii, and terminolateral neurorrhaphy of the donor musculocutaneous nerve to the receptor radial nerve. A maintenance triple immunosuppression scheme was administered, with tacrolimus levels kept at 10 ng/mL. At 18 months post-transplantation, the intrinsic musculature in the left hand showed electrical registry, DASH score was 67.5, Carroll test score was 28 in both extremities, Hand Transplant Score System was 67.5 in the right extremity and 77.5 in the left extremity, and Short Form-36 score was 96.1. The patient was healthy, with restored body integrity. He could lift medium-sized weightless objects, eat and go to the bathroom by himself, drink liquids with bimanual grasp, swim, dress almost independently, and drive. The functional evolution of the patient was similar to previously reported transplanted arms, even though the right arm transplant involved the glenohumeral joint and axillary and musculocutaneous nerve repair. Copyright © 2017 Elsevier Inc. All rights reserved.

Visuokinesthetic Perception of Hand Movement is Mediated by Cerebro–Cerebellar Interaction between the Left Cerebellum and Right Parietal Cortex

PubMed Central

Hagura, Nobuhiro; Oouchida, Yutaka; Aramaki, Yu; Okada, Tomohisa; Matsumura, Michikazu; Sadato, Norihiro

2009-01-01

Combination of visual and kinesthetic information is essential to perceive bodily movements. We conducted behavioral and functional magnetic resonance imaging experiments to investigate the neuronal correlates of visuokinesthetic combination in perception of hand movement. Participants experienced illusory flexion movement of their hand elicited by tendon vibration while they viewed video-recorded flexion (congruent: CONG) or extension (incongruent: INCONG) motions of their hand. The amount of illusory experience was graded by the visual velocities only when visual information regarding hand motion was concordant with kinesthetic information (CONG). The left posterolateral cerebellum was specifically recruited under the CONG, and this left cerebellar activation was consistent for both left and right hands. The left cerebellar activity reflected the participants' intensity of illusory hand movement under the CONG, and we further showed that coupling of activity between the left cerebellum and the “right” parietal cortex emerges during this visuokinesthetic combination/perception. The “left” cerebellum, working with the anatomically connected high-order bodily region of the “right” parietal cortex, participates in online combination of exteroceptive (vision) and interoceptive (kinesthesia) information to perceive hand movement. The cerebro–cerebellar interaction may underlie updating of one's “body image,” when perceiving bodily movement from visual and kinesthetic information. PMID:18453537

On the advantage of being left-handed in volleyball: further evidence of the specificity of skilled visual perception.

PubMed

Loffing, Florian; Schorer, Jörg; Hagemann, Norbert; Baker, Joseph

2012-02-01

High ball speeds and close distances between competitors require athletes in interactive sports to correctly anticipate an opponent's intentions in order to render appropriate reactions. Although it is considered crucial for successful performance, such skill appears impaired when athletes are confronted with a left-handed opponent, possibly because of athletes' reduced perceptual familiarity with rarely encountered left-handed actions. To test this negative perceptual frequency effect hypothesis, we invited 18 skilled and 18 novice volleyball players to predict shot directions of left- and right-handed attacks in a video-based visual anticipation task. In accordance with our predictions, and with recent reports on laterality differences in visual perception, the outcome of left-handed actions was significantly less accurately predicted than the outcome of right-handed attacks. In addition, this left-right bias was most distinct when predictions had to be based on preimpact (i.e., before hand-ball contact) kinematic cues, and skilled players were generally more affected by the opponents' handedness than were novices. The study's findings corroborate the assumption that skilled visual perception is attuned to more frequently encountered actions.

Lateralization of motor excitability during observation of bimanual signs.

PubMed

Möttönen, Riikka; Farmer, Harry; Watkins, Kate E

2010-08-01

Viewing another person's hand actions enhances excitability in an observer's left and right primary motor (M1) cortex. We aimed to determine whether viewing communicative hand actions alters this bilateral sensorimotor resonance. Using single-pulse transcranial magnetic stimulation (TMS), we measured excitability in the left and right M1 while right-handed non-signing participants observed bimanual communicative hand actions, i.e., meaningful signs in British Sign Language. TMS-induced motor evoked potentials were recorded from hand muscles during sign observation before and after teaching the participants to associate meanings with half of the signs. Before this teaching, when participants did not know that the presented hand actions were signs, excitability of left and right M1 was modulated equally. After learning the meanings of half the signs, excitability of the left, but not right, M1 was significantly enhanced. This left-lateralized enhancement of M1 excitability occurred during observation of signs with known and unknown meanings. The findings suggest that awareness of the communicative nature of another person's hand actions strengthens sensorimotor resonance in the left M1 cortex and alters hemispheric balance during action observation. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Functional Anatomy of Writing with the Dominant Hand

PubMed Central

Najee-ullah, Muslimah ‘Ali; Hallett, Mark

2013-01-01

While writing performed by any body part is similar in style, indicating a common program, writing with the dominant hand is particularly skilled. We hypothesized that this skill utilizes a special motor network supplementing the motor equivalence areas. Using functional magnetic resonance imaging in 13 normal subjects, we studied nine conditions: writing, zigzagging and tapping, each with the right hand, left hand and right foot. We identified brain regions activated with the right (dominant) hand writing task, exceeding the activation common to right-hand use and the writing program, both identified without right-hand writing itself. Right-hand writing significantly differed from the other tasks. First, we observed stronger activations in the left dorsal prefrontal cortex, left intraparietal sulcus and right cerebellum. Second, the left anterior putamen was required to initiate all the tested tasks, but only showed sustained activation during the right-hand writing condition. Lastly, an exploratory analysis showed clusters in the left ventral premotor cortex and inferior and superior parietal cortices were only significantly active for right-hand writing. The increased activation with right-hand writing cannot be ascribed to increased effort, since this is a well-practiced task much easier to perform than some of the other tasks studied. Because parietal-premotor connections code for particular skills, it would seem that the parietal and premotor regions, together with basal ganglia-sustained activation likely underlie the special skill of handwriting with the dominant hand. PMID:23844132

Functional anatomy of writing with the dominant hand.

PubMed

Horovitz, Silvina G; Gallea, Cecile; Najee-Ullah, Muslimah 'ali; Hallett, Mark

2013-01-01

While writing performed by any body part is similar in style, indicating a common program, writing with the dominant hand is particularly skilled. We hypothesized that this skill utilizes a special motor network supplementing the motor equivalence areas. Using functional magnetic resonance imaging in 13 normal subjects, we studied nine conditions: writing, zigzagging and tapping, each with the right hand, left hand and right foot. We identified brain regions activated with the right (dominant) hand writing task, exceeding the activation common to right-hand use and the writing program, both identified without right-hand writing itself. Right-hand writing significantly differed from the other tasks. First, we observed stronger activations in the left dorsal prefrontal cortex, left intraparietal sulcus and right cerebellum. Second, the left anterior putamen was required to initiate all the tested tasks, but only showed sustained activation during the right-hand writing condition. Lastly, an exploratory analysis showed clusters in the left ventral premotor cortex and inferior and superior parietal cortices were only significantly active for right-hand writing. The increased activation with right-hand writing cannot be ascribed to increased effort, since this is a well-practiced task much easier to perform than some of the other tasks studied. Because parietal-premotor connections code for particular skills, it would seem that the parietal and premotor regions, together with basal ganglia-sustained activation likely underlie the special skill of handwriting with the dominant hand.

Focal dystonia of right hand with mirror movements upon use of left arm.

PubMed

Rana, Abdul Qayyum; Athar, Aysha

2013-05-01

Dystonia is a movement disorder characterized by sustained muscle contractions, causing twisting and repetitive movements or abnormal postures of affected body parts. Here, we present a novel case of focal dystonia of a 51 years old right-handed woman who had developed difficulty in writing and performing fine motor tasks. Due to a discomfort in her right hand at use, she started using her left hand instead and noticed inconsistent mirror movements in her right hand upon use of left hand. She was treated with trihexyphenidyl which allowed her right hand to function better, though writing still remained a problem.

Going beyond the reflectance limit of cholesteric liquid crystals

NASA Astrophysics Data System (ADS)

Mitov, Michel; Dessaud, Nathalie

2006-05-01

Cholesteric liquid-crystalline states of matter are abundant in nature: atherosclerosis, arthropod cuticles, condensed phases of DNA, plant cell walls, human compact bone osteon, and chiral biopolymers. The self-organized helical structure produces unique optical properties. Light is reflected when the wavelength matches the pitch (twice periodicity); cholesteric liquid crystals are not only coloured filters, but also reflectors and polarizers. But, in theory, the reflectance is limited to 50% of the ambient (unpolarized) light because circularly polarized light of the same handedness as the helix is reflected. Here we give details of a cholesteric medium for which the reflectance limit is exceeded. Photopolymerizable monomers are introduced into a cholesteric medium exhibiting a thermally induced helicity inversion, and the blend is then cured with ultraviolet light when the helix is right-handed. Because of memory effects attributable to the polymer network, the reflectance exceeds 50% when measured at the temperature assigned for a cholesteric helix with the same pitch but a left-handed sense before the reaction. As cholesteric materials are used as tunable bandpass filters, reflectors or polarizers and temperature or pressure sensors, novel opportunities to modulate the reflection over the whole light flux range, instead of only 50%, are offered.

Evidence for right-hand feeding biases in a left-handed population.

PubMed

Flindall, Jason W; Stone, Kayla D; Gonzalez, Claudia L R

2015-05-01

We have recently shown that actions with similar kinematic requirements, but different end-state goals may be supported by distinct neural networks. Specifically, we demonstrated that when right-handed individuals reach-to-grasp food items with intent to eat, they produce smaller maximum grip apertures (MGAs) than when they grasp the same item with intent to place it in a location near the mouth. This effect was restricted to right-handed movements; left-handed movements showed no difference between tasks. The current study investigates whether (and to which side) the effect may be lateralized in left-handed individuals. Twenty-one self-identified left-handed participants grasped food items of three different sizes while grasp kinematics were captured via an Optotrak Certus motion capture array. A main effect of task was identified wherein the grasp-to-eat action generated significantly smaller MGAs than did the grasp-to-place action. Further analysis revealed that similar to the findings in right-handed individuals, this effect was significant only during right-handed movements. Upon further inspection however, we found individual differences in the magnitude and direction of the observed lateralization. These results underscore the evolutionary significance of the grasp-to-eat movement in producing population-level right-handedness in humans as well as highlighting the heterogeneity of the left-handed population.

Do Right- and Left-Handed Monkeys Differ on Cognitive Measures?

NASA Technical Reports Server (NTRS)

Hopkins, William D.; Washburn, David A.

1994-01-01

Twelve left- and 14 right-handed monkeys were compared on 6 measures of cognitive performance (2 maze-solving tasks, matching-to-sample, delayed matching-to-sample, delayed response using spatial cues, and delayed response using form cues). The dependent variable was trials-to-training criterion for each of the 6 tasks. Significant differences were found between left- and right-handed monkeys on the 2 versions of the delayed response task. Right-handed monkeys reached criterion significantly faster on the form cue version of the task, whereas left-handed monkeys reached criterion significantly faster on delayed response for spatial position (p less than .05). The results suggest that sensitive hand preference measures of laterality can reveal differences in cognitive performance, which in turn may reflect underlying laterality in functional organization of the nervous system.

Task-specific motor performance and musculoskeletal response in self-classified right handers.

PubMed

Kumar, Sameer; Mandal, Manas K

2003-11-01

We examined the difference between the left and right hand motor performance (in terms of erg produced) of self-classified right handers (15 men, 15 women) for power (task involving muscle force) and skilled (task involving precision and eye hand coordination) tasks. Musculoskeletal response during task performance was measured by electromyogram to test the hypothesis that performance with the nondominant hand would trigger more generalized muscle tension. The difference between the left and right hand performance of men was nonsignificant for power task; for women, right hand performance was significantly superior than left for such task. Men excelled in power and women excelled in skilled tasks relative to their counterparts. Generalized muscle tension was significantly more during the left than the right hand performance for power but not for skilled tasks.

[Left-handedness and health].

PubMed

Milenković, Sanja; Belojević, Goran; Kocijancić, Radojka

2010-01-01

Hand dominance is defined as a proneness to use one hand rather than another in performing the majority of activities and this is the most obvious example of cerebral lateralization and an exclusive human characteristic. Left-handed people comprise 6-14% of the total population, while in Serbia, this percentage is 5-10%, moving from undeveloped to developed environments, where a socio-cultural pressure is less present. There is no agreement between investigators who in fact may be considered a left-handed person, about the percentage of left-handers in the population and about the etiology of left-handedness. In the scientific literature left-handedness has been related to health disorders (spine deformities, immunological disorders, migraine, neurosis, depressive psychosis, schizophrenia, insomnia, homosexuality, diabetes mellitus, arterial hypertension, sleep apnea, enuresis nocturna and Down Syndrome), developmental disorders (autism, dislexia and sttutering) and traumatism. The most reliable scientific evidences have been published about the relationship between left-handedness and spinal deformities in school children in puberty and with traumatism in general population. The controversy of other results in up-to-now investigations of health aspects of left-handedness may partly be explained by a scientific disagreement whether writing with the left hand is a sufficient criterium for left-handedness, or is it necessary to investigate other parameters for laterality assessment. Explanation of health aspects of left-handedness is dominantly based on Geschwind-Galaburda model about "anomalous" cerebral domination, as a consequence of hormonal disbalance.

Hand preference and magnetic resonance imaging asymmetries of the central sulcus.

PubMed

Foundas, A L; Hong, K; Leonard, C M; Heilman, K M

1998-04-01

Hand preference is perhaps the most evident behavioral asymmetry observed in humans. Anatomic brain asymmetries that may be associated with hand preference have not been extensively studied, and no clear relationship between asymmetries of the motor system and hand preference have been established. Therefore, using volumetric magnetic resonance imaging methodologies, the surface area of the hand representation was measured along the length of the central sulcus in 15 consistent right- and 15 left-handers matched for age and gender. There was a significant leftward asymmetry of the motor hand area of the precentral gyrus in the right-handers, but no directional asymmetry was found in the left-handers. When asymmetry quotients were computed to determine the distribution of interhemispheric asymmetries, the left motor bank was greater than the right motor bank in 9 of 15 right-handers, the right motor bank was greater than the left motor bank in 3 of 15 right-handers, and the motor banks were equal in 3 of 15 right-handers. In contrast, among left-handers, the left motor bank was greater than the right motor bank in 5 of 15, the right motor bank was greater than the left motor bank in 5 of 15, and the motor banks were equal in 5 of 15. Although no direct measure of motor dexterity and skill was performed, these data suggest that anatomic asymmetries of the motor hand area may be related to hand preference because of the differences in right-handers and left-handers. Furthermore, the predominant leftward asymmetry in right-handers and the random distribution of asymmetries in the left-handers support Annett's right-shift theory. It is unclear, however, whether these asymmetries are the result of preferential hand use or are a reflection of a biologic preference to use one limb over the other.

Maturation of the Middle Phalanx of the Third Finger: A Comparative Study between Right and Left Hand.

PubMed

Gracco, Antonio; Bruno, Giovanni; De Stefani, Alberto; Siviero, Laura; Perri, Alessandro; Stellini, Edoardo

Recently a classification of patient's skeletal age based on the phalanx maturation, The Middle Phalanx Maturation of the third finger (MPM) method, was suggested. The aim of this study is to evaluate if there is a difference in MPM between the right and left hand. Two hundred fifty-four patients were obtained from the Complex Operating Unit of Orthodontics of Padua University Hospital. The total sample size has been selected by appropriate statistical calculations resulting in 130 patients. It was decided to further double the sample size of a previous study to ensure a robust statistical analysis. Radiographs of the right and left were obtained using the MPM method. Stages were compared using the right hand as a reference. The statistical analysis (Fisher exact test) was performed for the entire sample and related to gender in order to compare the right and the left hand stages. In MPS2, 6 out 49 (12.2%) males and 7 out 27 females (25.9%) showed MPS3 in the left hand (p-value < 0.05). In all other stages, a total agreement (100%) was found. The authors confirm the use of the right hand as reference. In patients with MPS2 an additional radiograph on the left hand can be taken in order to increase the diagnostic accuracy. In all other stages other radiographs are not needed as a total agreement between the right and left hand was found.

Effect of familial sinistrality on planum temporale surface and brain tissue asymmetries.

PubMed

Tzourio-Mazoyer, Nathalie; Simon, Gregory; Crivello, Fabrice; Jobard, Gael; Zago, Laure; Perchey, Guy; Hervé, Pierre-Yves; Joliot, Marc; Petit, Laurent; Mellet, Emmanuel; Mazoyer, Bernard

2010-06-01

The impact of having left-handers (LHs) among one's close relatives, called familial sinistrality (FS), on neuroanatomical markers of left-hemisphere language specialization was studied in 274 normal adults, including 199 men and 75 women, among whom 77 men and 27 women were positive for FS. Measurements of the surface of a phonological cortical area, the "planum temporale" (PT), and gray and white matter hemispheric volumes and asymmetries were made using brain magnetic resonance images. The size of the left PT of subjects with left-handed close relatives (FS+) was reduced by 10%, decreasing with the number of left-handed relatives, and lowest when the subject's mother was left-handed. Such findings had no counterparts in the right hemisphere, and the subject's handedness and sex were found to have no significant effect or interaction with FS on the left PT size. The FS+ subjects also exhibited increased gray matter volume, reduced hemispheric gray matter leftward asymmetry, and, in LHs, reduced strength of hand preference. These results add to the increasing body of evidence suggesting multiple and somewhat independent mechanisms for the inheritance of hand and language lateralization.

Motor planning and execution in left- and right-handed individuals during a bimanual grasping and placing task.

PubMed

Hughes, Charmayne M L; Reissig, Paola; Seegelke, Christian

2011-09-01

The issue of handedness has been the topic of great interest for researchers in a number of scientific domains. It is typically observed that the dominant hand yields numerous behavioral advantages over the non-dominant hand during unimanual tasks, which provides evidence of hemispheric specialization. In contrast to advantages for the dominant hand during motor execution, recent research has demonstrated that the right hand has advantages during motor planning (regardless of handedness), indicating that motor planning is a specialized function of the left hemisphere. In the present study we explored hemispheric advantages in motor planning and execution in left- and right-handed individuals during a bimanual grasping and placing task. Replicating previous findings, both motor planning and execution was influenced by object end-orientation congruency. In addition, although motor planning (i.e., end-state comfort) was not influenced by hand or handedness, motor execution differed between left and right hand, with shorter object transport times observed for the left hand, regardless of handedness. These results demonstrate that the hemispheric advantages often observed in unimanual tasks do not extend to discrete bimanual tasks. We propose that the differences in object transport time between the two hands arise from overt shifting visual fixation between the two hands/objects. Copyright © 2011 Elsevier B.V. All rights reserved.

Actigraphic investigations on the activity-rest behavior of right- and left-handed students.

PubMed

Lehnkering, Hanna; Strauss, Andreas; Wegner, Brigitte; Siegmund, Renate

2006-01-01

The aim of this study was to explore differences between left-and right-handed subjects in sleep duration. Sleep and activity patterns were continuously registered for 12 days using actometers on 20 left-handed and 20 right-handed medical students in Berlin. Handedness was determined by a modified version of the Edinburgh handedness inventory. Each participant wore one actometer on each wrist. Actiwatch Sleep Analysis Software (CNT, UK) was used to evaluate the data, and statistical calculations were performed with a non-parametric variance analysis. A significant difference in mean sleep duration between left-handers (7.9 h) and right-handers (7.3 h) was determined (p=0.025 for measurement made on the dominant hand and p=0.013 for ones made on the non-dominant hand). In contrast, the maximal phase of daily activity (acrophase) did not show any difference between the two groups. The difference in sleep duration might be caused by either the greater effort required for left-handers to cope in a right-handed world or by structural brain differences.

LEFT-RIGHT DIFFERENCES ON TIMED MOTOR EXAMINATION IN CHILDREN

PubMed Central

Roeder, Megan B.; Mahone, E. Mark; Larson, J. Gidley; Mostofsky, S. H.; Cutting, Laurie E.; Goldberg, Melissa C.; Denckla, Martha B.

2008-01-01

Age-related change in the difference between left- and right-side speed on motor examination may be an important indicator of maturation. Cortical maturation and myelination of the corpus callosum are considered to be related to increased bilateral skill and speed on timed motor tasks. We compared left minus right foot, hand, and finger speed differences using the Revised Physical and Neurological Assessment for Subtle Signs (PANESS; Denckla, 1985); examining 130 typically developing right-handed children (65 boys, 65 girls) ages 7−14. Timed tasks included right and left sets of 20 toe taps, 10 toe-heel alternation sequences, 20 hand pats, 10 hand pronate-supinate sets, 20 finger taps, and 5 sequences of each finger-to-thumb apposition. For each individual, six difference scores between left- and right-sided speeded performances of timed motor tasks were analyzed. Left-right differences decreased significantly with age on toe tapping, heel-toe alternations, hand pronation-supination, finger repetition, and finger sequencing. There were significant gender effects for heel-toe sequences (boys showing a greater left-right difference than girls), and a significant interaction between age and gender for hand pronation-supination, such that the magnitude of the left-right difference was similar for younger, compared with older girls, while the difference was significantly larger for younger, compared to older boys. Speed of performing right and left timed motor tasks equalizes with development; for some tasks, the equalization occurs earlier in girls than in boys. PMID:17852124

Mixed handedness and achievement test scores of middle school boys.

PubMed

Sarma, P S B

2008-10-01

The purpose of the study was to replicate findings of an earlier study of fourth grade boys manifesting mixed handedness with a sample. Among 32 mixed-handed boys in Grades 6 to 8, the right-handed writer, left-handed thrower group obtained low spelling scores (Normal Curve Equivalent Scores) on the California Achievement Test significantly more frequently than the left-handed writer, right-handed thrower group. These findings are consistent with data for Grade 4 boys in the earlier study. Findings strengthen the hypotheses that mixed handedness is not a unitary neuropsychological entity and that boys who write with the right hand and throw with the left hand might be at risk for certain academic deficits.

Transferability of different classical force fields for right and left handed α-helices constructed from enantiomeric amino acids.

PubMed

Biswas, Santu; Sarkar, Sujit; Pandey, Prithvi Raj; Roy, Sudip

2016-02-21

Amino acids can form d and l enantiomers, of which the l enantiomer is abundant in nature. The naturally occurring l enantiomer has a greater preference for a right handed helical conformation, and the d enantiomer for a left handed helical conformation. The other conformations, that is, left handed helical conformations of the l enantiomers and right handed helical conformations of the d enantiomers, are not common. The energetic differences between left and right handed alpha helical peptide chains constructed from enantiomeric amino acids are investigated using quantum chemical calculations (using the M06/6-311g(d,p) level of theory). Further, the performances of commonly used biomolecular force fields (OPLS/AA, CHARMM27/CMAP and AMBER) to represent the different helical conformations (left and right handed) constructed from enantiomeric (D and L) amino acids are evaluated. 5- and 10-mer chains from d and l enantiomers of alanine, leucine, lysine, and glutamic acid, in right and left handed helical conformations, are considered in the study. Thus, in total, 32 α-helical polypeptides (4 amino acids × 4 conformations of 5-mer and 10-mer) are studied. Conclusions, with regards to the performance of the force fields, are derived keeping the quantum optimized geometry as the benchmark, and on the basis of phi and psi angle calculations, hydrogen bond analysis, and different long range helical order parameters.

Patterns of hand preference for pairs of actions and the classification of handedness.

PubMed

Annett, Marian

2009-08-01

Pairs of actions such as write x throw and throw x racquet were examined for items of the Annett hand preference questionnaire (AHPQ). Right (R) and left (L) responses were described for frequencies of RR, RL, LR, and LL pairings (write x throw etc.) in a large representative combined sample with the aim of discovering the distribution over the population as a whole. The frequencies of RL pairings varied significantly over the different item pairs but the frequencies of LR pairings were fairly constant. An important difference was found between primary actions (originally write, throw, racquet, match, toothbrush, hammer with the later addition of scissors for right-handers) and non-primary actions (needle and thread, broom, spade, dealing playing cards, and unscrewing the lid of a jar). For primary actions, there were similar numbers of right and left writers using the 'other' hand. For non-primary actions more right-handers used the left hand than for primary actions but more left-handers did not use the right hand. That is, different frequencies of response to primary versus non-primary actions were found for right-handers but not for left-handers. The pattern of findings was repeated for a corresponding analysis of left-handed throwing x AHPQ actions. The findings have implications for the classification of hand preferences and for analyses of the nature of hand skill.

[Amplitude Changes of Low Frequency Fluctuation in Brain Spontaneous Nervous Activities Induced by Needling at Hand Taiyin Lung Channel].

PubMed

Zhou, You-long; Su, Cheng-guo; Liu, Shou-fang; Jin, Xiang-yu; Duan, Yan-li; Chen, Xiao-yan; Zhao, Shu-hua; Wang, Quan-liang; Dang, Chang-lin

2016-05-01

To observe amplitude changes of low frequency fluctuation in brain spontaneous nervous activities induced by needling at Hand Taiyin Lung Channel, and to preliminarily explore the possible brain function network of Hand Taiyin Lung Channel. By using functional magnetic resonance imaging (fMRI), 16 healthy volunteers underwent resting-state scanning (R1) and scanning with retained acupuncture at Hand Taiyin Lung Channel (acupuncture, AP). Data of fMRI collected were statistically calculated using amplitude of low frequency fluctuations (ALFF). Under R1 significantly enhanced ALFF occurred in right precuneus, left inferior parietal lobule, bilateral superior temporal gyrus, bilateral middle frontal gyrus, left superior frontal gyrus, left inferior frontal gyrus, left medial frontal gyrus. Under AP significantly enhanced ALFF occurred in right precuneus, bilateral superior frontal gyrus, cerebellum, bilateral middle frontal gyrus, right medial frontal gyrus, and so on. Compared with R1, needing at Hand Taiyin Lung Channel could significantly enhance ALFF in right gyrus subcallosum and right inferior frontal gyrus. Significant decreased ALFF appeared in right postcentral gyrus, left precuneus, left superior temporal gyrus, left middle temporal gyrus, and so on. Needing at Hand Taiyin Lung Channel could significantly change fixed activities of cerebral cortex, especially in right subcallosal gyrus, right inferior frontal gyrus, and so on.

Improving ideomotor limb apraxia by electrical stimulation of the left posterior parietal cortex.

PubMed

Bolognini, Nadia; Convento, Silvia; Banco, Elisabetta; Mattioli, Flavia; Tesio, Luigi; Vallar, Giuseppe

2015-02-01

Limb apraxia, a deficit of planning voluntary gestures, is most frequently caused by damage to the left hemisphere, where, according to an influential neurofunctional model, gestures are planned, before being executed through the motor cortex of the hemisphere contralateral to the acting hand. We used anodal transcranial direct current stimulation delivered to the left posterior parietal cortex (PPC), the right motor cortex (M1), and a sham stimulation condition, to modulate the ability of six left-brain-damaged patients with ideomotor apraxia, and six healthy control subjects, to imitate hand gestures, and to perform skilled hand movements using the left hand. Transcranial direct current stimulation delivered to the left PPC reduced the time required to perform skilled movements, and planning, but not execution, times in imitating gestures, in both patients and controls. In patients, the amount of decrease of planning times brought about by left PPC transcranial direct current stimulation was influenced by the size of the parietal lobe damage, with a larger parietal damage being associated with a smaller improvement. Of interest from a clinical perspective, left PPC stimulation also ameliorated accuracy in imitating hand gestures in patients. Instead, transcranial direct current stimulation to the right M1 diminished execution, but not planning, times in both patients and healthy controls. In conclusion, by using a transcranial stimulation approach, we temporarily improved ideomotor apraxia in the left hand of left-brain-damaged patients, showing a role of the left PPC in planning gestures. This evidence opens up novel perspectives for the use of transcranial direct current stimulation in the rehabilitation of limb apraxia. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Left hemisphere specialization for the control of voluntary movement rate.

PubMed

Agnew, John A; Zeffiro, Thomas A; Eden, Guinevere F

2004-05-01

Although persuasive behavioral evidence demonstrates the superior dexterity of the right hand in most people under a variety of conditions, little is known about the neural mechanisms responsible for this phenomenon. As this lateralized superiority is most evident during the performance of repetitive, speeded movement, we used parametric rate variations to compare visually paced movement of the right and left hands. Twelve strongly right-handed subjects participated in a functional magnetic resonance imaging (fMRI) experiment involving variable rate thumb movements. For movements of the right hand, contralateral rate-related activity changes were identified in the precentral gyrus, thalamus, and posterior putamen. For left-hand movements, activity was seen only in the contralateral precentral gyrus, consistent with the existence of a rate-sensitive motor control subsystem involving the left, but not the right, medial premotor corticostriatal loop in right-handed individuals. We hypothesize that the right hemisphere system is less skilled at controlling variable-rate movements and becomes maximally engaged at a lower movement rate without further modulation. These findings demonstrate that right- and left-hand movements engage different neural systems to control movement, even during a relatively simple thumb flexion task. Specialization of the left hemisphere corticostriatal system for dexterity is reflected in asymmetric mechanisms for movement rate control.

TMS stimulus-response asymmetry in left- and right-handed individuals.

PubMed

Daligadu, Julian; Murphy, Bernadette; Brown, Jeff; Rae, Brendan; Yielder, Paul

2013-02-01

There have been inconsistencies in the literature regarding asymmetrical neural control and results of experiments using TMS techniques. Therefore, the aim of this study was to further our understanding of the neural relationships that may underlie performance asymmetry with respect to the distal muscles of the hand using a TMS stimulus-response curve technique. Twenty-four male subjects (12 right handed, 12 left handed) participated in a TMS stimulus-response (S-R) curve trial. Focal TMS was applied over the motor cortex to find the optimal position for the first dorsal interossei muscle and to determine rest threshold (RTh). Seven TMS intensities ranging from 90 to 150 % of RTh were delivered in 10 % increments. One single TMS block consisted of 16 stimuli at each intensity. Peak-to-peak amplitudes were measured and the S-R curve generated. In right-handed subjects, the mean difference in slopes between the right and left hand was -0.011 ± 0.03, while the mean difference between hands in left-handed subjects was -0.049 ± 0.08. Left-handed normalized data in right handers displayed a mean of 1.616 ± 1.019 (two-tailed t test p < 0.05). The left-handed group showed a significant change in the normalized slope as indicated by a mean of 1.693 ± 0.149 (two-tailed t test p < 0.00006). The results found in this study reinforce previous work which suggests that there is an asymmetry in neural drive that exists in both left- and right-handed individuals. However, the results show that the non-dominant motor hemisphere displays a greater amount of excitability than the dominant, which goes against the conventional dogma. This asymmetry indicates that the non-dominant hemisphere may have a higher level of excitation or a lower level of inhibition for both groups of participants.

Toddler hand preference trajectories predict 3-year language outcome.

PubMed

Nelson, Eliza L; Gonzalez, Sandy L; Coxe, Stefany; Campbell, Julie M; Marcinowski, Emily C; Michel, George F

2017-11-01

A growing body of work suggests that early motor experience affects development in unexpected domains. In the current study, children's hand preference for role-differentiated bimanual manipulation (RDBM) was measured at monthly intervals from 18 to 24 months of age (N = 90). At 3 years of age, children's language ability was assessed using the Preschool Language Scales 5th edition (PLS™-5). Three distinct RDBM hand preference trajectories were identified using latent class growth analysis: (1) children with a left hand preference but a moderate amount of right hand use; (2) children with a right hand preference but a moderate amount of left hand use; and (3) children with a right hand preference and only a mild amount of left hand use. Stability over time within all three trajectories indicated that children did not change hand use patterns from 18 to 24 months. Children with the greatest amount of preferred (i.e., right) hand use demonstrated higher expressive language scores compared to children in both trajectories with moderate levels of non-preferred hand use. Children with the greatest amount of right hand use also had higher scores for receptive language compared to children with a right hand preference but moderate left hand use. Results support that consistency in handedness as measured by the amount of preferred hand use is related to distal language outcomes in development. © 2017 Wiley Periodicals, Inc.

Hemispheric Dominance for Stereognosis in a Patient With an Infarct of the Left Postcentral Sensory Hand Area.

PubMed

Moll, Jorge; de Oliveira-Souza, Ricardo

2017-09-01

The concept of left hemispheric dominance for praxis, speech, and language has been one of the pillars of neurology since the mid-19th century. In 1906, Hermann Oppenheim reported a patient with bilateral stereoagnosia (astereognosis) caused by a left parietal lobe tumor and proposed that the left hemisphere was also dominant for stereognosis. Surprisingly, few cases of bilateral stereoagnosia caused by a unilateral cerebral lesion have been documented in the literature since then. Here we report a 75-year-old right-handed man who developed bilateral stereoagnosia after suffering a small infarct in the crown of the left postcentral gyrus. He could not recognize objects with either hand, but retained the ability to localize stimuli applied to the palm of his left (ipsilesional) hand. He was severely disabled in ordinary activities requiring the use of his hands. The lesion corresponded to Brodmann area 1, where probabilistic anatomic, functional, and electrophysiologic studies have located one of the multiple somatosensory representations of the hand. The lesion was in a strategic position to interrupt both the processing of afferent tactile information issuing from the primary somatosensory cortex (areas 3a and 3b) and the forward higher-order processing in area 2, the secondary sensory cortex, and the contralateral area 1. The lesion also deprived the motor hand area of its afferent regulation from the sensory hand area (grasping), while leaving intact the visuomotor projections from the occipital cortex (reaching). Our patient supports Oppenheim's proposal that the left postcentral gyrus of some individuals is dominant for stereognosis.

Right and left in the Korean (Qur'an).

PubMed

Tan, U

1998-06-01

Right and left were mentioned in 11 chapters in the Koran, Right was mentioned in 23 sentences and left in 11 sentences which did not deal with handedness. Rather, the right hand refers to the right side or place of honor and goodness; the left hand refers to the bad side and badness. They were only a few sentences indicating the use of the right hand in writing and throwing. The Koran is thus not an exception of the ancient thought in this respect.

Atypical handedness in mesial temporal lobe epilepsy.

PubMed

Doležalová, Irena; Schachter, Steven; Chrastina, Jan; Hemza, Jan; Hermanová, Markéta; Rektor, Ivan; Pažourková, Marta; Brázdil, Milan

2017-07-01

The main aim of our study was to investigate the handedness of patients with mesial temporal lobe epilepsy (MTLE). We also sought to identify clinical variables that correlated with left-handedness in this population. Handedness (laterality quotient) was assessed in 73 consecutive patients with MTLE associated with unilateral hippocampal sclerosis (HS) using the Edinburgh Handedness Inventory. Associations between right- and left-handedness and clinical variables were investigated. We found that 54 (74.0%) patients were right-handed, and 19 (26%) patients were left-handed. There were 15 (36.6%) left-handed patients with left-sided seizure onset compared to 4 (12.5%) left-handed patients with right-sided seizure onset (p=0.030). Among patients with left-sided MTLE, age at epilepsy onset was significantly correlated with handedness (8years of age [median; min-max 0.5-17] in left-handers versus 15years of age [median; min-max 3-30] in right-handers (p<0.001). Left-sided MTLE is associated with atypical handedness, especially when seizure onset occurs during an active period of brain development, suggesting a bi-hemispheric neuroplastic process for establishing motor dominance in patients with early-onset left-sided MTLE. Copyright © 2017 Elsevier Inc. All rights reserved.

Hand specific representations in language comprehension.

PubMed

Moody-Triantis, Claire; Humphreys, Gina F; Gennari, Silvia P

2014-01-01

Theories of embodied cognition argue that language comprehension involves sensory-motor re-enactments of the actions described. However, the degree of specificity of these re-enactments as well as the relationship between action and language remains a matter of debate. Here we investigate these issues by examining how hand-specific information (left or right hand) is recruited in language comprehension and action execution. An fMRI study tested self-reported right-handed participants in two separate tasks that were designed to be as similar as possible to increase sensitivity of the comparison across task: an action execution go/no-go task where participants performed right or left hand actions, and a language task where participants read sentences describing the same left or right handed actions as in the execution task. We found that language-induced activity did not match the hand-specific patterns of activity found for action execution in primary somatosensory and motor cortex, but it overlapped with pre-motor and parietal regions associated with action planning. Within these pre-motor regions, both right hand actions and sentences elicited stronger activity than left hand actions and sentences-a dominant hand effect. Importantly, both dorsal and ventral sections of the left pre-central gyrus were recruited by both tasks, suggesting different action features being recruited. These results suggest that (a) language comprehension elicits motor representations that are hand-specific and akin to multimodal action plans, rather than full action re-enactments; and (b) language comprehension and action execution share schematic hand-specific representations that are richer for the dominant hand, and thus linked to previous motor experience.

78 FR 41280 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-10

... Transportation (DOT). ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for certain... left-hand and right-hand sides of the continuity fittings at the front windshield lower framing on a... cracking on the left- hand and right-hand sides of the windshield central lower node continuity fittings...

Sequential effects after practice with the dominant and non-dominant hand on the acquisition of a sliding task in schoolchildren.

PubMed

Senff, Oliver; Weigelt, Matthias

2011-03-01

This study was designed to investigate sequential effects after practice with the dominant and non-dominant hand on the acquisition of a new motor task. A total of 64 middle school children were asked to practise a cent-slide task, which required them to slide coins from one side of a cardboard into a circular target on the opposite side. Four groups practised this task within different practice schedules: (1) participants practised only with their dominant hand (right-only group); (2) participants used only their non-dominant hand (left-only group); (3) participants started to practise the skill with their dominant hand and then switched to their non-dominant hand (right-to-left group); or (4) participants started to practise the skill with their non-dominant hand and then switched to their dominant hand (left-to-right group). The acquisition of the task was facilitated after initial practice with the non-dominant hand. This was reflected in a better retention of the task and a stronger performance under a modified testing situation of the left-to-right group when compared to all other groups. Also, the left-only group showed larger interlimb transfer effects to the untrained hand than the right-only group. It is concluded that the sequence in which the dominant and non-dominant hands are used to practise influences the acquisition of new motor tasks.

Hand effects on mentally simulated reaching.

PubMed

Gabbard, Carl; Ammar, Diala; Rodrigues, Luis

2005-08-01

Within the area of simulated (imagined) versus actual movement research, investigators have discovered that mentally simulated movements, like real actions, are controlled primarily by the hemispheres contralateral to the simulated limb. Furthermore, evidence points to a left-brain advantage for accuracy of simulated movements. With this information it could be suggested that, compared to left-handers, most right-handers would have an advantage. To test this hypothesis, strong right- and left-handers were compared on judgments of perceived reachability to visual targets lasting 150 ms in multiple locations of midline, right- and left-visual field (RVF/LVF). In reference to within group responses, we found no hemispheric or hand use advantage for right-handers. Although left-handers revealed no hemispheric advantage, there was a significant hand effect, favoring the non-dominant limb, most notably in LVF. This finding is explained in regard to a possible interference effect for left-handers, not shown for right-handers. Overall, left-handers displayed significantly more errors across hemispace. Therefore, it appears that when comparing hand groups, a left-hemisphere advantage favoring right-handers is plausible.

The cortical activation pattern by a rehabilitation robotic hand: a functional NIRS study

PubMed Central

Chang, Pyung-Hun; Lee, Seung-Hee; Gu, Gwang Min; Lee, Seung-Hyun; Jin, Sang-Hyun; Yeo, Sang Seok; Seo, Jeong Pyo; Jang, Sung Ho

2014-01-01

Introduction: Clarification of the relationship between external stimuli and brain response has been an important topic in neuroscience and brain rehabilitation. In the current study, using functional near infrared spectroscopy (fNIRS), we attempted to investigate cortical activation patterns generated during execution of a rehabilitation robotic hand. Methods: Ten normal subjects were recruited for this study. Passive movements of the right fingers were performed using a rehabilitation robotic hand at a frequency of 0.5 Hz. We measured values of oxy-hemoglobin (HbO), deoxy-hemoglobin (HbR) and total-hemoglobin (HbT) in five regions of interest: the primary sensory-motor cortex (SM1), hand somatotopy of the contralateral SM1, supplementary motor area (SMA), premotor cortex (PMC), and prefrontal cortex (PFC). Results: HbO and HbT values indicated significant activation in the left SM1, left SMA, left PMC, and left PFC during execution of the rehabilitation robotic hand (uncorrected, p < 0.01). By contrast, HbR value indicated significant activation only in the hand somatotopic area of the left SM1 (uncorrected, p < 0.01). Conclusions: Our results appear to indicate that execution of the rehabilitation robotic hand could induce cortical activation. PMID:24570660

Hesitations in continuous tracking induced by a concurrent discrete task

NASA Technical Reports Server (NTRS)

Klapp, S. T.; Kelly, P. A.; Netick, A.

1985-01-01

Subjects performed a continuous visually-guided pursuit tracking task with the right hand. From time to time (intervals averaging 30 sec) an auditory tone appeared signaling the subjects to perform a discrete response with the left hand. The presence of this tone was frequently associated with a hesitation in right-hand tracking which lasted 1/3 sec or longer. The rate of occurrence of these hesitations was about the same when the left-hand response involved a choice between competing responses as when the left hand responded in a predetermined direction. Hesitations occurred for three different mechanical tracking manipulanda using different controlling muscles, and appeared to be due to freezing rather than to relaxation of muscular action. The rate of occurrence of hesitations declined with practice, and this improvement in right-hand performance was accompanied by an improvement in performance of the concurrent left-hand response. The presence of hesitations, and their reduction with practice, can be interpreted within several viewpoints.

Right- and left-handed three-helix proteins. II. Similarity and differences in mechanical unfolding of proteins.

PubMed

Glyakina, Anna V; Likhachev, Ilya V; Balabaev, Nikolay K; Galzitskaya, Oxana V

2014-01-01

Here, we study mechanical properties of eight 3-helix proteins (four right-handed and four left-handed ones), which are similar in size under stretching at a constant speed and at a constant force on the atomic level using molecular dynamics simulations. The analysis of 256 trajectories from molecular dynamics simulations with explicit water showed that the right-handed three-helix domains are more mechanically resistant than the left-handed domains. Such results are observed at different extension velocities studied (192 trajectories obtained at the following conditions: v = 0.1, 0.05, and 0.01 Å ps(-1) , T = 300 K) and under constant stretching force (64 trajectories, F = 800 pN, T = 300 K). We can explain this by the fact, at least in part, that the right-handed domains have a larger number of contacts per residue and the radius of cross section than the left-handed domains. Copyright © 2013 Wiley Periodicals, Inc.

Hemispheric dominance and cell phone use.

PubMed

Seidman, Michael D; Siegel, Bianca; Shah, Priyanka; Bowyer, Susan M

2013-05-01

A thorough understanding of why we hold a cell phone to a particular ear may be of importance when studying the impact of cell phone safety. To determine if there is an obvious association between sidedness of cell phone use and auditory hemispheric dominance (AHD) or language hemispheric dominance (LHD). It is known that 70% to 95% of the population are right-handed, and of these, 96% have left-brain LHD. We have observed that most people use their cell phones in their right ear. An Internet survey was e-mailed to individuals through surveymonkey.com. The survey used a modified Edinburgh Handedness Inventory protocol. Sample questions surveyed which hand was used to write with, whether the right or left ear was used for phone conversations, as well as whether a brain tumor was present. General community. An Internet survey was randomly e-mailed to 5000 individuals selected from an otology online group, patients undergoing Wada testing and functional magnetic resonance imaging, as well as persons on the university listserv, of which 717 surveys were completed. Determination of hemispheric dominance based on preferred ear for cell phone use. A total of 717 surveys were returned. Ninety percent of the respondents were right handed, and 9% were left handed. Sixty-eight percent of the right-handed people used the cell phone in their right ear, 25% in the left ear, and 7% had no preference. Seventy-two of the left-handed respondents used their left ear, 23% used their right ear, and 5% had no preference. Cell phone use averaged 540 minutes per month over the past 9 years. An association exists between hand dominance laterality of cell phone use (73%) and our ability to predict hemispheric dominance. Most right-handed people have left-brain LHD and use their cell phone in their right ear. Similarly, most left-handed people use their cell phone in their left ear. Our study suggests that AHD may differ from LHD owing to the difference in handedness and cell phone ear use. Literature suggests a possible relationship between cell phone use and cancer. The fact that few tumors were identified in this population does not rule out an association.

The da vinci robot system eliminates multispecialty surgical trainees' hand dominance in open and robotic surgical settings.

PubMed

Badalato, Gina M; Shapiro, Edan; Rothberg, Michael B; Bergman, Ari; RoyChoudhury, Arindam; Korets, Ruslan; Patel, Trushar; Badani, Ketan K

2014-01-01

Handedness, or the inherent dominance of one hand's dexterity over the other's, is a factor in open surgery but has an unknown importance in robot-assisted surgery. We sought to examine whether the robotic surgery platform could eliminate the effect of inherent hand preference. Residents from the Urology and Obstetrics/Gynecology departments were enrolled. Ambidextrous and left-handed subjects were excluded. After completing a questionnaire, subjects performed three tasks modified from the Fundamentals of Laparoscopic Surgery curriculum. Tasks were performed by hand and then with the da Vinci robotic surgical system (Intuitive Surgical, Sunnyvale, California). Participants were randomized to begin with using either the left or the right hand, and then switch. Left:right ratios were calculated from scores based on time to task completion. Linear regression analysis was used to determine the significance of the impact of surgical technique on hand dominance. Ten subjects were enrolled. The mean difference in raw score performance between the right and left hands was 12.5 seconds for open tasks and 8 seconds for robotic tasks (P<.05). Overall left-right ratios were found to be 1.45 versus 1.12 for the open and robot tasks, respectively (P<.05). Handedness significantly differed between robotic and open approaches for raw time scores (P<.0001) and left-right ratio (P=.03) when controlling for the prior tasks completed, starting hand, prior robotic experience, and comfort level. These findings remain to be validated in larger cohorts. The robotic technique reduces hand dominance in surgical trainees across all task domains. This finding contributes to the known advantages of robotic surgery.

Right- and left-handed three-helix proteins. I. Experimental and simulation analysis of differences in folding and structure.

PubMed

Glyakina, Anna V; Pereyaslavets, Leonid B; Galzitskaya, Oxana V

2013-09-01

Despite the large number of publications on three-helix protein folding, there is no study devoted to the influence of handedness on the rate of three-helix protein folding. From the experimental studies, we make a conclusion that the left-handed three-helix proteins fold faster than the right-handed ones. What may explain this difference? An important question arising in this paper is whether the modeling of protein folding can catch the difference between the protein folding rates of proteins with similar structures but with different folding mechanisms. To answer this question, the folding of eight three-helix proteins (four right-handed and four left-handed), which are similar in size, was modeled using the Monte Carlo and dynamic programming methods. The studies allowed us to determine the orders of folding of the secondary-structure elements in these domains and amino acid residues which are important for the folding. The obtained data are in good correlation with each other and with the experimental data. Structural analysis of these proteins demonstrated that the left-handed domains have a lesser number of contacts per residue and a smaller radius of cross section than the right-handed domains. This may be one of the explanations of the observed fact. The same tendency is observed for the large dataset consisting of 332 three-helix proteins (238 right- and 94 left-handed). From our analysis, we found that the left-handed three-helix proteins have some less-dense packing that should result in faster folding for some proteins as compared to the case of right-handed proteins. Copyright © 2013 Wiley Periodicals, Inc.

Left-handers show no self-advantage in detecting a delay in visual feedback concerning an active movement.

PubMed

Hoover, Adria E N; Elzein, Yasmeenah; Harris, Laurence R

2016-07-01

Right-handed people show an advantage in detecting a delay in visual feedback concerning an active movement of their right hand when it is viewed in a natural perspective compared to when it is seen as if viewing another person's hand (Hoover and Harris in Exp Brain Res 233:1053-1060, 2012. doi: 10.1007/s00221-014-4181-9 ; Exp Brain Res 222:389-397, 2015a. doi: 10.1007/s00221-012-3224-3 ). This self-advantage is unique to their dominant hand and may reflect an enhanced sense of ownership which contributes to how right-handed people relate to the world. Here we asked whether left-handers show the same pattern of performance for their dominant hand. We measured the minimum delay that could be detected by 29 left-handers when viewing either their dominant or non-dominant hand from 'self' or 'other' perspectives and compared their thresholds to an age-matched sample of 22 right-handers. Right-handers showed a significant signature self-advantage of 19 ms when viewing their dominant hand in an expected 'self' perspective compared to 'other' perspectives. Left-handers, however, showed no such advantage for either their dominant or non-dominant hand. This lack of self-advantage in detecting delayed visual feedback might indicate a less secure sense of body ownership amongst left-handers.

Cued Dichotic Listening with Right-Handed, Left-Handed, Bilingual and Learning-Disabled Children.

ERIC Educational Resources Information Center

Obrzut, John E.; And Others

This study used cued dichotic listening to investigate differences in language lateralization among right-handed (control), left handed, bilingual, and learning disabled children. Subjects (N=60) ranging in age from 7-13 years were administered a consonant-vowel-consonant dichotic paradigm with three experimental conditions (free recall, directed…

Artificial dexterous hand

NASA Technical Reports Server (NTRS)

Lee, Sukhan (Inventor)

1990-01-01

An artificial dexterous hand is provided for grasping and manipulating objects. The hand includes left and right thumbs that are operatively connected to an engagement assembly which causes movement of the left and right thumbs. The left thumb has a left thumb base and is movable about three separate first left thumb axes which run through the left thumb base. Correspondingly, the right thumb has a right thumb base and is movable about three separate first right thumb axes which run through the right thumb base. The engagement assembly has a gear assembly which is operatively connected to a motor assembly. Upon actuation by the motor assembly, the gear assembly causes movement of the left and right thumbs about the first left thumb axes and first right thumb axes respectively. The hand can also have a center finger which is operatively connected to the engagement assembly and which is interposed between the left and right thumbs. The finger has a finger base and is movable about two separate first finger axes running through the finger base. Therefore, upon actuation by the motor assembly, the gear assembly will also cause movement of the finger about the first finger axes.

Cognitive bias, hand preference and welfare of common marmosets.

PubMed

Gordon, Dianne J; Rogers, Lesley J

2015-01-01

Common marmosets (Callithrix jacchus) have hand preferences for grasping pieces of food and holding them while eating and these are stable throughout adult life. We report here that left-handed marmosets have negative cognitive bias compared to right-handed marmosets. Twelve marmosets were trained to expect a food reward from a bowl with a black lid and not from one with a white lid, or vice versa. In probe tests with ambiguous, grey-lidded bowls a left-handed group (N=7) were less likely to remove the lid to inspect the bowl than a right-handed group (N=5). This difference between left- and right-handed marmosets was not dependent on rate of learning, sex or age. In fact, hand-preference was not associated with rate of learning the task. Furthermore, retrospective examination of colony records of 39 marmosets revealed that more aggression was directed towards left- than right-handed marmosets. Hence, hand preference, which can be measured easily, could serve as an indicator of cognitive bias and may signal a need for particular care in laboratory environments. We explain the results by arguing that hand preference reflects more frequent (or dominant) use of the opposite hemisphere and this predisposes individuals to behave differently. Copyright © 2015 Elsevier B.V. All rights reserved.

Can the chirality of the ISM be measured

NASA Technical Reports Server (NTRS)

Pendleton, Y.; Sandford, S. A.; Werner, Michael W.; Lauer, J.; Chang, Sherwood

1990-01-01

Many moderately complex carbon-based molecules of the type associated with biological systems can exist in one of two mirror-image forms (left-handed and right-handed), which can be distinguished on the basis of their influence on the state of polarization of a light beam. Both forms are possible in nature; yet in living organisms it is invariably the rule that one of these two species predominates. This gives rise to a net chirality. One possible explanation for the net chirality is that the early earth was somehow seeded from the ISM with an excess of chiral organic compounds which led to the development of life forms which are based on left-handed amino acids and right-handed sugars. Molecular spectroscopy of the interstellar medium (ISM) has revealed a complex variety of molecular species similar to those thought to have been available in the oceans and atmospheres of the earth at the time life formed. The detection of such molecules demonstrates the generality of the chemical processes occurring in both environments. If this generality extends to the processes which produce chirality, it may be possible to detect a net chirality in the ISM. This is of particular interest because determining whether or not net chirality exists elsewhere in the universe is an essential aspect of understanding how life developed on earth and how widely distributed it might be. Researchers report preliminary results of a feasibility study to determine whether or not a net chirality in the ISM can be measured. If laboratory results identify candidate chiral molecules that might exist in the ISM, the next step in this feasibility study will be to estimate the detectability of the chiral signature in astrophysical environments.

An Investigation of the Differences and Similarities between Generated Small-World Networks for Right- and Left-Hand Motor Imageries.

PubMed

Zhang, Jiang; Li, Yuyao; Chen, Huafu; Ding, Jurong; Yuan, Zhen

2016-11-04

In this study, small-world network analysis was performed to identify the similarities and differences between functional brain networks for right- and left-hand motor imageries (MIs). First, Pearson correlation coefficients among the nodes within the functional brain networks from healthy subjects were calculated. Then, small-world network indicators, including the clustering coefficient, the average path length, the global efficiency, the local efficiency, the average node degree, and the small-world index, were generated for the functional brain networks during both right- and left-hand MIs. We identified large differences in the small-world network indicators between the functional networks during MI and in the random networks. More importantly, the functional brain networks underlying the right- and left-hand MIs exhibited similar small-world properties in terms of the clustering coefficient, the average path length, the global efficiency, and the local efficiency. By contrast, the right- and left-hand MI brain networks showed differences in small-world characteristics, including indicators such as the average node degree and the small-world index. Interestingly, our findings also suggested that the differences in the activity intensity and range, the average node degree, and the small-world index of brain networks between the right- and left-hand MIs were associated with the asymmetry of brain functions.

Dark localized structures in a cavity filled with a left-handed material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tlidi, Mustapha; Kockaert, Pascal; Gelens, Lendert

2011-07-15

We consider a nonlinear passive optical cavity filled with left-handed and right-handed materials and driven by a coherent injected beam. We assume that both left-handed and right-handed materials possess a Kerr focusing type of nonlinearity. We show that close to the zero-diffraction regime, high-order diffraction allows us to stabilize dark localized structures in this device. These structures consist of dips in the transverse profile of the intracavity field and do not exist without high-order diffraction. We analyze the snaking bifurcation diagram associated with these structures. Finally, a realistic estimation of the model parameters is provided.

[Influence of "prehistory" of sequential movements of the right and the left hand on reproduction: coding of positions, movements and sequence structure].

PubMed

Bobrova, E V; Liakhovetskiĭ, V A; Borshchevskaia, E R

2011-01-01

The dependence of errors during reproduction of a sequence of hand movements without visual feedback on the previous right- and left-hand performance ("prehistory") and on positions in space of sequence elements (random or ordered by the explicit rule) was analyzed. It was shown that the preceding information about the ordered positions of the sequence elements was used during right-hand movements, whereas left-hand movements were performed with involvement of the information about the random sequence. The data testify to a central mechanism of the analysis of spatial structure of sequence elements. This mechanism activates movement coding specific for the left hemisphere (vector coding) in case of an ordered sequence structure and positional coding specific for the right hemisphere in case of a random sequence structure.

Cerebral activations related to writing and drawing with each hand.

PubMed

Potgieser, Adriaan R E; van der Hoorn, Anouk; de Jong, Bauke M

2015-01-01

Writing is a sequential motor action based on sensorimotor integration in visuospatial and linguistic functional domains. To test the hypothesis of lateralized circuitry concerning spatial and language components involved in such action, we employed an fMRI paradigm including writing and drawing with each hand. In this way, writing-related contributions of dorsal and ventral premotor regions in each hemisphere were assessed, together with effects in wider distributed circuitry. Given a right-hemisphere dominance for spatial action, right dorsal premotor cortex dominance was expected in left-hand writing while dominance of the left ventral premotor cortex was expected during right-hand writing. Sixteen healthy right-handed subjects were scanned during audition-guided writing of short sentences and simple figure drawing without visual feedback. Tapping with a pencil served as a basic control task for the two higher-order motor conditions. Activation differences were assessed with Statistical Parametric Mapping (SPM). Writing and drawing showed parietal-premotor and posterior inferior temporal activations in both hemispheres when compared to tapping. Drawing activations were rather symmetrical for each hand. Activations in left- and right-hand writing were left-hemisphere dominant, while right dorsal premotor activation only occurred in left-hand writing, supporting a spatial motor contribution of particularly the right hemisphere. Writing contrasted to drawing revealed left-sided activations in the dorsal and ventral premotor cortex, Broca's area, pre-Supplementary Motor Area and posterior middle and inferior temporal gyri, without parietal activation. The audition-driven postero-inferior temporal activations indicated retrieval of virtual visual form characteristics in writing and drawing, with additional activation concerning word form in the left hemisphere. Similar parietal processing in writing and drawing pointed at a common mechanism by which such visually formatted information is used for subsequent sensorimotor integration along a dorsal visuomotor pathway. In this, the left posterior middle temporal gyrus subserves phonological-orthographical conversion, dissociating dorsal parietal-premotor circuitry from perisylvian circuitry including Broca's area.

Cerebral Activations Related to Writing and Drawing with Each Hand

PubMed Central

Potgieser, Adriaan R. E.; van der Hoorn, Anouk; de Jong, Bauke M.

2015-01-01

Background Writing is a sequential motor action based on sensorimotor integration in visuospatial and linguistic functional domains. To test the hypothesis of lateralized circuitry concerning spatial and language components involved in such action, we employed an fMRI paradigm including writing and drawing with each hand. In this way, writing-related contributions of dorsal and ventral premotor regions in each hemisphere were assessed, together with effects in wider distributed circuitry. Given a right-hemisphere dominance for spatial action, right dorsal premotor cortex dominance was expected in left-hand writing while dominance of the left ventral premotor cortex was expected during right-hand writing. Methods Sixteen healthy right-handed subjects were scanned during audition-guided writing of short sentences and simple figure drawing without visual feedback. Tapping with a pencil served as a basic control task for the two higher-order motor conditions. Activation differences were assessed with Statistical Parametric Mapping (SPM). Results Writing and drawing showed parietal-premotor and posterior inferior temporal activations in both hemispheres when compared to tapping. Drawing activations were rather symmetrical for each hand. Activations in left- and right-hand writing were left-hemisphere dominant, while right dorsal premotor activation only occurred in left-hand writing, supporting a spatial motor contribution of particularly the right hemisphere. Writing contrasted to drawing revealed left-sided activations in the dorsal and ventral premotor cortex, Broca’s area, pre-Supplementary Motor Area and posterior middle and inferior temporal gyri, without parietal activation. Discussion The audition-driven postero-inferior temporal activations indicated retrieval of virtual visual form characteristics in writing and drawing, with additional activation concerning word form in the left hemisphere. Similar parietal processing in writing and drawing pointed at a common mechanism by which such visually formatted information is used for subsequent sensorimotor integration along a dorsal visuomotor pathway. In this, the left posterior middle temporal gyrus subserves phonological-orthographical conversion, dissociating dorsal parietal-premotor circuitry from perisylvian circuitry including Broca's area. PMID:25955655

Quantitative biomechanical analysis of wrist motion in bone-trimming jobs in the meat packing industry.

PubMed

Marklin, R W; Monroe, J F

1998-02-01

This study was motivated by the serious impact that cumulative trauma disorders (CTDs) of the upper extremities have on the meat packing industry. To date, no quantitative data have been gathered on the kinematics of hand and wrist motion required in bone-trimming jobs in the red-meat packing industry and how these motions are related to the risk of CTDs. The wrist motion of bone-trimming workers from a medium-sized plant was measured, and the kinematic data were compared to manufacturing industry's preliminary wrist motion benchmarks from industrial workers who performed hand-intensive, repetitive work in jobs that were of low and high risk of hand/wrist CTDs. Results of this comparison show that numerous wrist motion variables in both the left and right hands of bone-trimming workers are in the high-risk category. This quantitative analysis provides biomechanical support for the high incidence of CTDs in the meat packing industry. The research reported in this paper established a preliminary database of wrist and hand kinematics required in bone-trimming jobs in the red-meat packing industry. This kinematic database could augment the industry's efforts to reduce the severity and cost of CTDs. Ergonomics practitioners in the industry could use the kinematic methods employed in this research to assess the CTD risk of jobs that require repetitious, hand-intensive work.

Anarchic-Hand Syndrome: ERP Reflections of Lost Control over the Right Hemisphere

ERIC Educational Resources Information Center

Verleger, Rolf; Binkofski, Ferdinand; Friedrich, Monique; Sedlmeier, Peter; Kompf, Detlef

2011-01-01

In patients with the callosal type of anarchic-hand syndrome, the left hand often does not act as intended and counteracts the right hand. Reports are scarce about the underlying neurophysiological mechanisms. We report the case G.H. who developed the syndrome after infarction of the left arteria pericallosa. It has been suggested that the…

Unimanual SNARC Effect: Hand Matters.

PubMed

Riello, Marianna; Rusconi, Elena

2011-01-01

A structural representation of the hand embedding information about the identity and relative position of fingers is necessary to counting routines. It may also support associations between numbers and allocentric spatial codes that predictably interact with other known numerical spatial representations, such as the mental number line (MNL). In this study, 48 Western participants whose typical counting routine proceeded from thumb-to-little on both hands performed magnitude and parity binary judgments. Response keys were pressed either with the right index and middle fingers or with the left index and middle fingers in separate blocks. 24 participants responded with either hands in prone posture (i.e., palm down) and 24 participants responded with either hands in supine (i.e., palm up) posture. When hands were in prone posture, the counting direction of the left hand conflicted with the direction of the left-right MNL, whereas the counting direction of the right hand was consistent with it. When hands were in supine posture, the opposite was true. If systematic associations existed between relative number magnitude and an allocentric spatial representation of the finger series within each hand, as predicted on the basis of counting habits, interactions would be expected between hand posture and a unimanual version of the spatial-numerical association of response codes (SNARC) effect. Data revealed that with hands in prone posture a unimanual SNARC effect was present for the right hand, and with hands in supine posture a unimanual SNARC effect was present for the left hand. We propose that a posture-invariant body structural representation of the finger series provides a relevant frame of reference, a within-hand directional vector, that is associated to simple number processing. Such frame of reference can significantly interact with stimulus-response correspondence effects, like the SNARC, that have been typically attributed to the mapping of numbers on a left-to-right mental line.

Probing for hemispheric specialization for motor skill learning: a transcranial direct current stimulation study

PubMed Central

Schambra, Heidi M.; Abe, Mitsunari; Luckenbaugh, David A.; Reis, Janine; Krakauer, John W.

2011-01-01

Convergent findings point to a left-sided specialization for the representation of learned actions in right-handed humans, but it is unknown whether analogous hemispheric specialization exists for motor skill learning. In the present study, we explored this question by comparing the effects of anodal transcranial direct current stimulation (tDCS) over either left or right motor cortex (M1) on motor skill learning in either hand, using a tDCS montage to better isolate stimulation to one hemisphere. Results were compared with those previously found with a montage more commonly used in the field. Six groups trained for three sessions on a visually guided sequential pinch force modulation task with their right or left hand and received right M1, left M1, or sham tDCS. A linear mixed-model analysis for motor skill showed a significant main effect for stimulation group (left M1, right M1, sham) but not for hand (right, left) or their interaction. Left M1 tDCS induced significantly greater skill learning than sham when hand data were combined, a result consistent not only with the hypothesized left hemisphere specialization for motor skill learning but also with possible increased left M1 responsiveness to tDCS. The unihemispheric montage effect size was one-half that of the more common montage, and subsequent power analysis indicated that 75 subjects per group would be needed to detect differences seen with only 12 subjects with the customary bihemispheric montage. PMID:21613597

Corticospinal tract asymmetry and handedness in right- and left-handers by diffusion tensor tractography.

PubMed

Seizeur, Romuald; Magro, Elsa; Prima, Sylvain; Wiest-Daesslé, Nicolas; Maumet, Camille; Morandi, Xavier

2014-03-01

Cerebral hemispheres represent both structural and functional asymmetry, which differs among right- and left-handers. The left hemisphere is specialised for language and task execution of the right hand in right-handers. We studied the corticospinal tract in right- and left-handers by diffusion tensor imaging and tractography. The present study aimed at revealing a morphological difference resulting from a region of interest (ROI) obtained by functional MRI (fMRI). Twenty-five healthy participants (right-handed: 15, left-handed: 10) were enrolled in our assessment of morphological, functional and diffusion tensor MRI. Assessment of brain fibre reconstruction (tractography) was done using a deterministic algorithm. Fractional anisotropy (FA) and mean diffusivity (MD) were studied on the tractography traces of the reference slices. We observed a significant difference in number of leftward fibres based on laterality. The significant difference in regard to FA and MD was based on the slices obtained at different levels and the laterality index. We found left-hand asymmetry and right-hand asymmetry, respectively, for the MD and FA. Our study showed the presence of hemispheric asymmetry based on laterality index in right- and left-handers. These results are inconsistent with some studies and consistent with others. The reported difference in hemispheric asymmetry could be related to dexterity (manual skill).

Proprioceptive recalibration in the right and left hands following abrupt visuomotor adaptation.

PubMed

Salomonczyk, Danielle; Henriques, Denise Y P; Cressman, Erin K

2012-03-01

Previous studies have demonstrated that after reaching with misaligned visual feedback of the hand, one adapts his or her reaches and partially recalibrates proprioception, such that sense of felt hand position is shifted to match the seen hand position. However, to date, this has only been demonstrated in the right (dominant) hand following reach training with a visuomotor distortion in which the rotated cursor distortion was introduced gradually. As reach adaptation has been shown to differ depending on how the distortion is introduced (gradual vs. abrupt), we sought to examine proprioceptive recalibration following reach training with a cursor that was abruptly rotated 30° clockwise relative to hand motion. Furthermore, because the left and right arms have demonstrated selective advantages when matching visual and proprioceptive targets, respectively, we assessed proprioceptive recalibration in right-handed subjects following training with either the right or the left hand. On average, we observed shifts in felt hand position of approximately 7.6° following training with misaligned visual feedback of the hand, which is consistent with our previous findings in which the distortion was introduced gradually. Moreover, no difference was observed in proprioceptive recalibration across the left and right hands. These findings suggest that proprioceptive recalibration is a robust process that arises symmetrically in the two hands following visuomotor adaptation regardless of the initial magnitude of the error signal.

Impact of body posture on laterality judgement and explicit recognition tasks performed on self and others' hands.

PubMed

Conson, Massimiliano; Errico, Domenico; Mazzarella, Elisabetta; De Bellis, Francesco; Grossi, Dario; Trojano, Luigi

2015-04-01

Judgments on laterality of hand stimuli are faster and more accurate when dealing with one's own than others' hand, i.e. the self-advantage. This advantage seems to be related to activation of a sensorimotor mechanism while implicitly processing one's own hands, but not during explicit one's own hand recognition. Here, we specifically tested the influence of proprioceptive information on the self-hand advantage by manipulating participants' body posture during self and others' hand processing. In Experiment 1, right-handed healthy participants judged laterality of either self or others' hands, whereas in Experiment 2, an explicit recognition of one's own hands was required. In both experiments, the participants performed the task while holding their left or right arm flexed with their hand in direct contact with their chest ("flexed self-touch posture") or with their hand placed on a wooden smooth surface in correspondence with their chest ("flexed proprioceptive-only posture"). In an "extended control posture", both arms were extended and in contact with thighs. In Experiment 1 (hand laterality judgment), we confirmed the self-advantage and demonstrated that it was enhanced when the subjects judged left-hand stimuli at 270° orientation while keeping their left arm in the flexed proprioceptive-only posture. In Experiment 2 (explicit self-hand recognition), instead, we found an advantage for others' hand ("self-disadvantage") independently from posture manipulation. Thus, position-related proprioceptive information from left non-dominant arm can enhance sensorimotor one's own body representation selectively favouring implicit self-hands processing.

Is there any relationship between right and left hand dominance and right and left nasal airflow dominance?

PubMed

Price, A; Eccles, R

2017-10-01

Left- or right-handedness is a common human trait, and it has been previously reported that human nasal airflow dominance correlates with hand dominance. Any relationship between hand dominance and nasal airflow dominance would be unusual. This study aimed to measure nasal airflow and look for any relationship to handedness. The modified Glatzel mirror was used to record the dominant nasal passage at 15-minute intervals over a 6-hour period in 29 healthy participants consisting of 15 left-handers and 14 right-handers. In left-handers, the percentage of time that the left nasal passage was dominant ranged from 0 to 100 per cent. In right-handers, the percentage of time that the right nasal passage was dominant ranged from 4.2 to 95.8 per cent. No correlation between nasal airflow dominance and hand dominance was identified. The results do not support the hypothesis that nasal airflow and handedness are related.

It’s Out of My Hands! Grasping Capacity May Not Influence Perceived Object Size

PubMed Central

2017-01-01

Linkenauger, Witt, and Proffitt (2011) found that the perceived size of graspable objects was scaled by perceived grasping capacity. However, it is possible that this effect occurred because object size was estimated on the same trial as grasping capacity. This may have led to a conflation of estimates of perceived action capacity and spatial properties. In 5 experiments, we tested Linkenauger et al.’s claim that right-handed observers overestimate the grasping capacity of their right hand relative to their left hand, and that this, in turn, leads them to underestimate the size of objects to-be-grasped in their right hand relative to their left hand. We replicated the finding that right handers overestimate the size and grasping capacity of their right hand relative to their left hand. However, when estimates of object size and grasping capacity were made in separate tasks, objects grasped in the right hand were not underestimated relative to those grasped in the left hand. Further, when grasping capacity was physically restricted, observers appropriately recalibrated their perception of their maximum grasp but estimates of object size were unaffected. Our results suggest that changes in action capacity may not influence perceived object size if sources of conflation are controlled for. PMID:28191987

Explicit knowledge about the availability of visual feedback affects grasping with the left but not the right hand.

PubMed

Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

2014-01-01

Previous research (Whitwell et al. in Exp Brain Res 188:603-611, 2008; Whitwell and Goodale in Exp Brain Res 194:619-629, 2009) has shown that trial history, but not anticipatory knowledge about the presence or absence of visual feedback on an upcoming trial, plays a vital role in determining how that feedback is exploited when grasping with the right hand. Nothing is known about how the non-dominant left hand behaves under the same feedback regimens. In present study, therefore, we compared peak grip aperture (PGA) for left- and right-hand grasps executed with and without visual feedback (i.e., closed- vs. open-loop conditions) in right-handed individuals under three different trial schedules: the feedback conditions were blocked separately, they were randomly interleaved, or they were alternated. When feedback conditions were blocked, the PGA was much larger for open-loop trials as compared to closed-loop trials, although this difference was more pronounced for right-hand grasps than left-hand grasps. Like Whitwell et al., we found that mixing open- and closed-loop trials together, compared to blocking them separately, homogenized the PGA for open- and closed-loop grasping in the right hand (i.e., the PGAs became smaller on open-loop trials and larger on closed-loop trials). In addition, the PGAs for right-hand grasps were entirely determined by trial history and not by knowledge of whether or not visual feedback would be available on an upcoming trial. In contrast to grasps made with the right hand, grasps made by the left hand were affected both by trial history and by anticipatory knowledge of the upcoming visual feedback condition. But these effects were observed only on closed-loop trials, i.e., the PGAs of grasps made with the left hand on closed-loop trials were smaller when participants could anticipate the availability of feedback on an upcoming trial (alternating trials) than when they could not (randomized trials). In contrast, grasps made with the left hand on open-loop trials exhibited the same large PGAs under all feedback schedules: blocked, random, or alternating. In other words, there was no evidence for homogenization. Taken together, these results suggest that in addition to the real-time demands of the task, such as the target's size and position and the availability of visual feedback, the initial (i.e., pre-movement) programming of right-hand grasping relies on what happened on the previous trial, whereas the programming of left-hand grasping is more cognitively supervised and exploits explicit information about trial order to prepare for an upcoming trial.

Compensatory changes accompanying chronic forced use of the nondominant hand by unilateral amputees.

PubMed

Philip, Benjamin A; Frey, Scott H

2014-03-05

Amputation of the dominant hand forces patients to use the nondominant hand exclusively, including for tasks (e.g., writing and drawing) that were formerly the sole domain of the dominant hand. The behavioral and neurological effects of this chronic forced use of the nondominant hand remain largely unknown. Yet, these effects may shed light on the potential to compensate for degradation or loss of dominant hand function, as well as the mechanisms that support motor learning under conditions of very long-term training. We used a novel precision drawing task and fMRI to investigate 8 adult human amputees with chronic (mean 33 years) unilateral dominant (right) hand absence, and right-handed matched controls (8 for fMRI, 19 for behavior). Amputees' precision drawing performances with their left hands reached levels of smoothness (associated with left hemisphere control), acceleration time (associated with right hemisphere control), and speed equivalent to controls' right hands, whereas accuracy maintained a level comparable with controls' left hands. This compensation is supported by an experience-dependent shift from heavy reliance on the dorsodorsal parietofrontal pathway (feedback control) to the ventrodorsal pathway and prefrontal regions involved in the cognitive control of goal-directed actions. Relative to controls, amputees also showed increased activity within the former cortical sensorimotor hand territory in the left (ipsilateral) hemisphere. These data demonstrate that, with chronic and exclusive forced use, the speed and quality of nondominant hand precision endpoint control in drawing can achieve levels nearly comparable with the dominant hand.

Left and right in the Bible from a neuropsychological perspective.

PubMed

Fabbro, F

1994-03-01

Although in several neuropsychological works dealing with hemispheric specializations a few passages of the Bible referring to the left and the right have been mentioned now and then, a systematical study with a neuropsychological approach to this topic was still a missing link. By using concordance texts from the Bible books of the Hebrew Canon (Old Testament, OT) and from the New Testament (NT), all the verses containing any reference to the left and the right (OT = 151, NT = 49 verses) have been identified and classified into 10 groups: (1) references to space, (2) symmetric sayings, (3) the right hand is the favorite hand, (4) right eye preference, (5) God's right hand, (6) the right side is more prestigious, (7) the right side in liturgy, (8) left hand preference, (9) fatal left-hand shots, and (10) on the left side. Some statistical considerations have been put forward and a neuropsychological, anthropological approach has been suggested for the purpose of interpreting the most interesting verses. According to the author of the present paper, it would be worthwhile commenting on some texts of ancient and modern literature not only from a linguistic, historical, religious and theological point of view, but also by means of a neuropsychological approach.

Side of symptom onset affects motor dysfunction in Parkinson's disease.

PubMed

Haaxma, C A; Helmich, R C G; Borm, G F; Kappelle, A C; Horstink, M W I M; Bloem, B R

2010-11-10

The healthy brain appears to have an asymmetric dopamine distribution, with higher levels of dopamine in the left than in the right striatum. Here, we test the hypothesis that this neurochemical asymmetry renders the right striatum relatively more vulnerable to the effects of dopaminergic denervation in Parkinson's disease (PD). Using the pegboard dexterity test, we compared motor performance of both hands between healthy subjects (n=48), PD patients with predominantly right-hemispheric dopamine depletion (PD-RIGHT; n=83) and PD patients with more severe left-hemispheric dopamine depletion (PD-LEFT; n=103). All subjects were right-handed. After adjusting for hand-dominance effects, we found that PD-RIGHT patients exhibited a 55% larger difference between right and left dexterity scores than PD-LEFT patients. This effect could be attributed to greater motor dysfunction of the more-affected hand in PD-RIGHT patients, while the less-affected hand performed similarly in both groups. We conclude that the side of symptom onset affects motor dysfunction in PD, and suggest that the non-dominant right hemisphere may be more susceptible to dopaminergic denervation than the dominant left hemisphere. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Polymorphism complexity and handedness inversion in serum albumin amyloid fibrils.

PubMed

Usov, Ivan; Adamcik, Jozef; Mezzenga, Raffaele

2013-12-23

Protein-based amyloid fibrils can show a great variety of polymorphic structures within the same protein precursor, although the origins of these structural homologues remain poorly understood. In this work we investigate the fibrillation of bovine serum albumin--a model globular protein--and we follow the polymorphic evolution by a statistical analysis of high-resolution atomic force microscopy images, complemented, at larger length scales, by concepts based on polymer physics formalism. We identify six distinct classes of coexisting amyloid fibrils, including flexible left-handed twisted ribbons, rigid right-handed helical ribbons and nanotubes. We show that the rigid fibrils originate from flexible fibrils through two diverse polymorphic transitions, first, via a single-fibril transformation when the flexible left-handed twisted ribbons turn into the helical left-handed ribbons, to finally evolve into nanotube-like structures, and second, via a double-fibril transformation when two flexible left-handed twisted ribbons wind together resulting in a right-handed twisted ribbon, followed by a rigid right-handed helical ribbon polymorphic conformation. Hence, the change in handedness occurs with an increase in the level of the fibril's structural organization.

Handedness influences intermanual transfer in chimpanzees (Pan troglodytes) but not rhesus monkeys (Macaca mulatta).

PubMed

Boeving, Emily R; Lacreuse, Agnès; Hopkins, William D; Phillips, Kimberley A; Novak, Melinda A; Nelson, Eliza L

2015-03-01

Intermanual transfer refers to an effect, whereby training one hand to perform a motor task improves performance in the opposite untrained hand. We tested the hypothesis that handedness facilitates intermanual transfer in two nonhuman primate species: rhesus monkeys (N = 13) and chimpanzees (N = 52). Subjects were grouped into one of four conditions: (1) left-handers trained with the left (dominant) hand; (2) left-handers trained with the right (nondominant) hand; (3) right-handers trained with the left (nondominant) hand; and (4) right-handers trained with the right (dominant) hand. Intermanual transfer was measured using a task where subjects removed a Life Savers(®) candy (monkeys) or a washer (chimpanzees) from metal shapes. Transfer was measured with latency by comparing the average time taken to solve the task in the first session with the trained hand compared to the first session with the untrained hand. Hypotheses and predictions were derived from three models of transfer: access: benefit training with nondominant hand; proficiency: benefit training with dominant hand; and cross-activation: benefit irrespective of trained hand. Intermanual transfer (i.e., shorter latency in untrained hand) occurred regardless of whether monkeys trained with the dominant hand or nondominant hand, supporting the cross-activation model. However, transfer was only observed in chimpanzees that trained with the dominant hand. When handedness groups were examined separately, the transfer effect was only significant for right-handed chimpanzees, partially supporting the proficiency model. Findings may be related to neurophysiological differences in motor control as well as differences in handedness patterning between rhesus monkeys and chimpanzees.

Handedness influences intermanual transfer in chimpanzees (Pan troglodytes) but not rhesus monkeys (Macaca mulatta)

PubMed Central

Boeving, Emily R.; Lacreuse, Agnès; Hopkins, William D.; Phillips, Kimberley A.; Novak, Melinda A.; Nelson, Eliza L.

2015-01-01

Intermanual transfer refers to an effect whereby training one hand to perform a motor task improves performance in the opposite untrained hand. We tested the hypothesis that handedness facilitates intermanual transfer in two nonhuman primate species: rhesus monkeys (N = 13) and chimpanzees (N = 52). Subjects were grouped into one of four conditions: (1) left-handers trained with the left (dominant) hand; (2) left-handers trained with the right (non-dominant) hand; (3) right-handers trained with the left (non-dominant) hand; and (4) right-handers trained with the right (dominant) hand. Intermanual transfer was measured using a task where subjects removed a Life Savers® candy (monkeys) or a washer (chimpanzees) from metal shapes. Transfer was measured with latency by comparing the average time taken to solve the task in the first session with the trained hand compared to the first session with the untrained hand. Hypotheses and predictions were derived from three models of transfer: access: benefit training with non-dominant hand; proficiency: benefit training with dominant hand; and cross-activation: benefit irrespective of trained hand. Intermanual transfer (i.e., shorter latency in untrained hand) occurred regardless of whether monkeys trained with the dominant hand or non-dominant hand, supporting the cross-activation model. However, transfer was only observed in chimpanzees that trained with the dominant hand. When handedness groups were examined separately, the transfer effect was only significant for right-handed chimpanzees, partially supporting the proficiency model. Findings may be related to neurophysiological differences in motor control as well as differences in handedness patterning between rhesus monkeys and chimpanzees. PMID:25466868

Role of Corticospinal Suppression during Motor Preparation

PubMed Central

Ivry, Richard B.

2009-01-01

Behavior arises from a constant competition between potential actions. For example, movements performed unimanually require selecting one hand rather than the other. Corticospinal (CS) excitability of the nonselected hand is typically decreased prior to movement initiation, suggesting that response selection may involve mechanisms that inhibit nonselected candidate movements. To examine this hypothesis, participants performed a reaction time task, responding with the left, right, or both indexes. Transcranial magnetic stimulation was applied over the right primary motor cortex (M1) to induce motor-evoked potentials (MEPs) in a left hand muscle at various stages during response preparation. To vary the time of response selection, an imperative signal was preceded by a preparatory cue that was either informative or uninformative. Left MEPs decreased following the cue. Surprisingly, this decrease was greater when an informative cue indicated that the response might require the left hand than when it indicated a right hand response. In the uninformative condition, we did not observe additional attenuation of left MEP after an imperative indicating a right hand response. These results argue against the “deselection” hypothesis. Rather, CS suppression seems to arise from “impulse control” mechanisms that ensure that responses associated with potentially selected actions are not initiated prematurely. PMID:19126798

Birefringence in a chiral medium, via temporal cloaking

NASA Astrophysics Data System (ADS)

Khan, Humayun; Haneef, Muhammad

2017-05-01

This paper reports theoretical investigation of birefringence in a chiral medium for the creation of temporal cloaking. The chiral medium splits the input probe beam into left/right circular polarized beams. These left/right circular polarized beams are then controlled and modified within the chiral medium. The left circular polarized beam delays by 24 ns whereas the right circular polarized beam advances by  -23 ns at a control field of rabbi frequency 6γ . This opens a 47 ns time gap for temporal cloaking to hide information without noise corruption and energy loss. The results have potential applications in communication devices for secure propagation of light pulse.

An Electrophysiological Contribution to the Study of Language Lateralization and Prognosis of Aphasia

ERIC Educational Resources Information Center

Cobianchi, Andrea

2010-01-01

The study is aimed at identifying hemispheric language dominance in both the right-handed and left-handed participants. Eighteen right-handed and 18 left-handed young volunteers were invited to listen for 80 times to a 720 ms duration Italian word. Signals from 16 electrodes were averaged and displayed both as traces and maps. When the word was…

Right unilateral agraphia following callosal infarction in a left-hander.

PubMed

Tei, H; Soma, Y; Maruyama, S

1994-01-01

A left-handed Japanese man is reported who presented right-hand agraphia and tactile anomia following callosal infarction. Magnetic resonance imaging revealed an ischemic lesion extending from the posterior half of the trunk to the splenium of the corpus callosum. In his right handwriting, the 'Kana' (phonogram) was more severely impaired than the 'Kanji' (ideogram), and the most frequent typewriting error was morphological followed by neographism. His visuoconstructional ability was also more impaired in the right hand than in the left. Right-hand agraphia in our case is readily explained by the right hemisphere dominance both for language and visuoconstructional ability.

Left hand tactile agnosia after posterior callosal lesion.

PubMed

Balsamo, Maddalena; Trojano, Luigi; Giamundo, Arcangelo; Grossi, Dario

2008-09-01

We report a patient with a hemorrhagic lesion encroaching upon the posterior third of the corpus callosum but sparing the splenium. She showed marked difficulties in recognizing objects and shapes perceived through her left hand, while she could appreciate elementary sensorial features of items tactually presented to the same hand flawlessly. This picture, corresponding to classical descriptions of unilateral associative tactile agnosia, was associated with finger agnosia of the left hand. This very unusual case report can be interpreted as an instance of disconnection syndrome, and allows a discussion of mechanisms involved in tactile object recognition.

Relationships between intestinal parasitosis and handedness.

PubMed

Uslu, Hakan; Dane, Senol; Uyanik, M Hamidullah; Ayyildiz, Ahmet

2010-07-01

The aim of the study was to investigate if there is a possible relation between intestinal parasitosis and handedness in patients with suspected intestinal parasitosis. Hand preference was assessed on the Edinburgh Handedness Inventory. Stool samples were examined microscopically for the presence of parasite. In the present study right-handers had many more helminth infections and left-handers had many more protozoon infections. Lower rate of helminth infections in the present study, and higher asthma incidences in the left-handed population in literature, may be associated with different immune machinery in left-handed people than in right-handed ones.

The effect of hand dominance on martial arts strikes.

PubMed

Neto, Osmar Pinto; Silva, Jansen Henrique; Marzullo, Ana Carolina de Miranda; Bolander, Richard P; Bir, Cynthia A

2012-08-01

The main goal of this study was to compare dominant and non-dominant martial arts palm strikes under different circumstances that usually happen during martial arts and combative sports applications. Seven highly experienced (10±5 years) right hand dominant Kung Fu practitioners performed strikes with both hands, stances with left or right lead legs, and with the possibility or not of stepping towards the target (moving stance). Peak force was greater for the dominant hand strikes (1593.76±703.45 N vs. 1042.28±374.16 N; p<.001), whereas no difference was found in accuracy between the hands (p=.141). Additionally, peak force was greater for the strikes with moving stance (1448.75±686.01 N vs. 1201.80±547.98 N; p=.002) and left lead leg stance (1378.06±705.48 N vs. 1269.96±547.08 N). Furthermore, the difference in peak force between strikes with moving and stationary stances was statistically significant only for the strikes performed with a left lead leg stance (p=.007). Hand speed was higher for the dominant hand strikes (5.82±1.08 m/s vs. 5.24±0.78 m/s; p=.001) and for the strikes with moving stance (5.79±1.01 m/s vs. 5.29±0.90 m/s; p<.001). The difference in hand speed between right and left hand strikes was only significant for strikes with moving stance. In summary, our results suggest that the stronger palm strike for a right-handed practitioner is a right hand strike on a left lead leg stance moving towards the target. Copyright © 2011 Elsevier B.V. All rights reserved.

THE EFFECT OF HAND DOMINANCE ON MARTIAL ARTS STRIKES

PubMed Central

Neto, Osmar Pinto; Silva, Jansen Henrique; de Miranda Marzullo, Ana Carolina; Bolander, Richard P.; Bir, Cynthia A.

2011-01-01

The main goal of this study was to compare dominant and non-dominant martial arts palm strikes under different circumstances that usually happen during martial arts and combative sports applications. Seven highly experienced (10 ± 5 years) right hand dominant Kung Fu practitioners performed strikes with both hands, stances with left or right lead legs, and with the possibility or not of stepping towards the target (moving stance). Peak force was greater for the dominant hand strikes (1593.76 ± 703.45 N vs. 1042.28 ± 374.16 N; p < .001), whereas no difference was found in accuracy between the hands (p = .141). Additionally, peak force was greater for the strikes with moving stance (1448.75 ± 686.01 N vs. 1201.80 ± 547.98 N; p = .002) and left lead leg stance (1378.06 ± 705.48 N vs.1269.96 ± 547.08 N). Furthermore, the difference in peak force between strikes with moving and stationary stances was statistically significant only for the strikes performed with a left lead leg stance (p = .007). Hand speed was higher for the dominant hand strikes (5.82 ± 1.08 m/s vs. 5.24 ± 0.78 m/s; p = 0.001) and for the strikes with moving stance (5.79 ± 1.01 m/s vs. 5.29 ± 0.90 m/s; p < .001). The difference in hand speed between right and left hand strikes was only significant for strikes with moving stance. In summary, our results suggest that the stronger palm strike for a right-handed practitioner is a right hand strike on a left lead leg stance moving towards the target. PMID:22047701

Motivation and motor control: hemispheric specialization for approach motivation reverses with handedness.

PubMed

Brookshire, Geoffrey; Casasanto, Daniel

2012-01-01

According to decades of research on affective motivation in the human brain, approach motivational states are supported primarily by the left hemisphere and avoidance states by the right hemisphere. The underlying cause of this specialization, however, has remained unknown. Here we conducted a first test of the Sword and Shield Hypothesis (SSH), according to which the hemispheric laterality of affective motivation depends on the laterality of motor control for the dominant hand (i.e., the "sword hand," used preferentially to perform approach actions) and the nondominant hand (i.e., the "shield hand," used preferentially to perform avoidance actions). To determine whether the laterality of approach motivation varies with handedness, we measured alpha-band power (an inverse index of neural activity) in right- and left-handers during resting-state electroencephalography and analyzed hemispheric alpha-power asymmetries as a function of the participants' trait approach motivational tendencies. Stronger approach motivation was associated with more left-hemisphere activity in right-handers, but with more right-hemisphere activity in left-handers. The hemispheric correlates of approach motivation reversed between right- and left-handers, consistent with the way they typically use their dominant and nondominant hands to perform approach and avoidance actions. In both right- and left-handers, approach motivation was lateralized to the same hemisphere that controls the dominant hand. This covariation between neural systems for action and emotion provides initial support for the SSH.

49 CFR 572.15 - General description.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Assembly SA 103C 030 Torso Assembly SA 103C 041 Upper Arm Assembly Left SA 103C 042 Upper Arm Assembly Right SA 103C 051 Forearm Hand Assembly Left SA 103C 052 Forearm Hand Assembly Right SA 103C 061Upper Leg Assembly Left SA 103C 062 Upper Leg Assembly Right SA 103C 071 Lower Leg Assembly Left SA 103C 072...

49 CFR 572.15 - General description.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Assembly SA 103C 030 Torso Assembly SA 103C 041 Upper Arm Assembly Left SA 103C 042 Upper Arm Assembly Right SA 103C 051 Forearm Hand Assembly Left SA 103C 052 Forearm Hand Assembly Right SA 103C 061Upper Leg Assembly Left SA 103C 062 Upper Leg Assembly Right SA 103C 071 Lower Leg Assembly Left SA 103C 072...

49 CFR 572.15 - General description.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Assembly SA 103C 030 Torso Assembly SA 103C 041 Upper Arm Assembly Left SA 103C 042 Upper Arm Assembly Right SA 103C 051 Forearm Hand Assembly Left SA 103C 052 Forearm Hand Assembly Right SA 103C 061Upper Leg Assembly Left SA 103C 062 Upper Leg Assembly Right SA 103C 071 Lower Leg Assembly Left SA 103C 072...

49 CFR 572.15 - General description.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Assembly SA 103C 030 Torso Assembly SA 103C 041 Upper Arm Assembly Left SA 103C 042 Upper Arm Assembly Right SA 103C 051 Forearm Hand Assembly Left SA 103C 052 Forearm Hand Assembly Right SA 103C 061Upper Leg Assembly Left SA 103C 062 Upper Leg Assembly Right SA 103C 071 Lower Leg Assembly Left SA 103C 072...

The Handedness of Leonardo da Vinci: A Tale of the Complexities of Lateralisation

ERIC Educational Resources Information Center

McManus, I. C.; Drury, Helena

2004-01-01

The handedness of Leonardo da Vinci is controversial. Although there is little doubt that many of his well-attributed drawings were drawn with the left hand, the hatch marks of the shading going downwards from left to right, it is not clear that he was a natural left-hander, there being some suggestion that he may have become left-handed as the…

The Neural Correlates of Grasping in Left-Handers: When Handedness Does Not Matter.

PubMed

Begliomini, Chiara; Sartori, Luisa; Di Bono, Maria G; Budisavljević, Sanja; Castiello, Umberto

2018-01-01

Neurophysiological studies showed that in macaques, grasp-related visuomotor transformations are supported by a circuit involving the anterior part of the intraparietal sulcus, the ventral and the dorsal region of the premotor area. In humans, a similar grasp-related circuit has been revealed by means of neuroimaging techniques. However, the majority of "human" studies considered movements performed by right-handers only, leaving open the question of whether the dynamics underlying motor control during grasping is simply reversed in left-handers with respect to right-handers or not. To address this question, a group of left-handed participants has been scanned with functional magnetic resonance imaging while performing a precision grasping task with the left or the right hand. Dynamic causal modeling was used to assess how brain regions of the two hemispheres contribute to grasping execution and whether the intra- and inter-hemispheric connectivity is modulated by the choice of the performing hand. Results showed enhanced inter-hemispheric connectivity between anterior intraparietal and dorsal premotor cortices during grasping execution with the left dominant hand (LDH) (e.g., right hemisphere) compared to the right (e.g., left hemisphere). These findings suggest that that the left hand, although dominant and theoretically more skilled in left handers, might need additional resources in terms of the visuomotor control and on-line monitoring to accomplish a precision grasping movement. The results are discussed in light of theories on the modulation of parieto-frontal networks during the execution of prehensile movements, providing novel evidence supporting the hypothesis of a handedness-independent specialization of the left hemisphere in visuomotor control.

Reduced asymmetry in motor skill learning in left-handed compared to right-handed individuals.

PubMed

McGrath, Robert L; Kantak, Shailesh S

2016-02-01

Hemispheric specialization for motor control influences how individuals perform and adapt to goal-directed movements. In contrast to adaptation, motor skill learning involves a process wherein one learns to synthesize novel movement capabilities in absence of perturbation such that they are performed with greater accuracy, consistency and efficiency. Here, we investigated manual asymmetry in acquisition and retention of a complex motor skill that requires speed and accuracy for optimal performance in right-handed and left-handed individuals. We further determined if degree of handedness influences motor skill learning. Ten right-handed (RH) and 10 left-handed (LH) adults practiced two distinct motor skills with their dominant or nondominant arms during separate sessions two-four weeks apart. Learning was quantified by changes in the speed-accuracy tradeoff function measured at baseline and one-day retention. Manual asymmetry was evident in the RH group but not the LH group. RH group demonstrated significantly greater skill improvement for their dominant-right hand than their nondominant-left hand. In contrast, for the LH group, both dominant and nondominant hands demonstrated comparable learning. Less strongly-LH individuals (lower EHI scores) exhibited more learning of their dominant hand. These results suggest that while hemispheric specialization influences motor skill learning, these effects may be influenced by handedness. Copyright © 2015 Elsevier B.V. All rights reserved.

Are there right hemisphere contributions to visually-guided movement? Manipulating left hand reaction time advantages in dextrals.

PubMed

Carey, David P; Otto-de Haart, E Grace; Buckingham, Gavin; Dijkerman, H Chris; Hargreaves, Eric L; Goodale, Melvyn A

2015-01-01

Many studies have argued for distinct but complementary contributions from each hemisphere in the control of movements to visual targets. Investigators have attempted to extend observations from patients with unilateral left- and right-hemisphere damage, to those using neurologically-intact participants, by assuming that each hand has privileged access to the contralateral hemisphere. Previous attempts to illustrate right hemispheric contributions to the control of aiming have focussed on increasing the spatial demands of an aiming task, to attenuate the typical right hand advantages, to try to enhance a left hand reaction time advantage in right-handed participants. These early attempts have not been successful. The present study circumnavigates some of the theoretical and methodological difficulties of some of the earlier experiments, by using three different tasks linked directly to specialized functions of the right hemisphere: bisecting, the gap effect, and visuospatial localization. None of these tasks were effective in reducing the magnitude of left hand reaction time advantages in right handers. Results are discussed in terms of alternatives to right hemispheric functional explanations of the effect, the one-dimensional nature of our target arrays, power and precision given the size of the left hand RT effect, and the utility of examining the proportions of participants who show these effects, rather than exclusive reliance on measures of central tendency and their associated null hypothesis significance tests.

Are there right hemisphere contributions to visually-guided movement? Manipulating left hand reaction time advantages in dextrals

PubMed Central

Carey, David P.; Otto-de Haart, E. Grace; Buckingham, Gavin; Dijkerman, H. Chris; Hargreaves, Eric L.; Goodale, Melvyn A.

2015-01-01

Many studies have argued for distinct but complementary contributions from each hemisphere in the control of movements to visual targets. Investigators have attempted to extend observations from patients with unilateral left- and right-hemisphere damage, to those using neurologically-intact participants, by assuming that each hand has privileged access to the contralateral hemisphere. Previous attempts to illustrate right hemispheric contributions to the control of aiming have focussed on increasing the spatial demands of an aiming task, to attenuate the typical right hand advantages, to try to enhance a left hand reaction time advantage in right-handed participants. These early attempts have not been successful. The present study circumnavigates some of the theoretical and methodological difficulties of some of the earlier experiments, by using three different tasks linked directly to specialized functions of the right hemisphere: bisecting, the gap effect, and visuospatial localization. None of these tasks were effective in reducing the magnitude of left hand reaction time advantages in right handers. Results are discussed in terms of alternatives to right hemispheric functional explanations of the effect, the one-dimensional nature of our target arrays, power and precision given the size of the left hand RT effect, and the utility of examining the proportions of participants who show these effects, rather than exclusive reliance on measures of central tendency and their associated null hypothesis significance tests. PMID:26379572

Chameleon's behavior of modulable nonlinear electrical transmission line

NASA Astrophysics Data System (ADS)

Togueu Motcheyo, A. B.; Tchinang Tchameu, J. D.; Fewo, S. I.; Tchawoua, C.; Kofane, T. C.

2017-12-01

We show that modulable discrete nonlinear transmission line can adopt Chameleon's behavior due to the fact that, without changing its appearance structure, it can become alternatively purely right or left handed line which is different to the composite one. Using a quasidiscrete approximation, we derive a nonlinear Schrödinger equation, that predicts accurately the carrier frequency threshold from the linear analysis. It appears that the increasing of the linear capacitor in parallel in the series branch induced the selectivity of the filter in the right-handed region while it increases band pass filter in the left-handed region. Numerical simulations of the nonlinear model confirm the forward wave in the right handed line and the backward wave in the left handed one.

Comparison of Muscle Activation during Dominant Hand Wrist Flexion when Writing.

PubMed

Park, Soohee

2013-12-01

[Purpose] This study investigated the difference in muscle activation of the dominant upper extremity in right-handed and left-handed persons during writing. [Subjects] There were 36 subjects (16 left- handers/ 20 right- handers), and the study was conducted from 03/01/2012 to 30/3/2012. [Methods] Six electrodes were attached to the FCU (flexor carpi ulnaris), FCR (flexor carpi radialis), ECU (extensor carpi ulnaris), ECR (extensor carpi radialis), and both UT (upper trapezius) muscles. [Results] FCU muscle activation was 16.77±9.12% in left-handers and 10.29±4.13% (%MVIC) in right-handers. FCR muscle activation was 19.09±9.43% in left-handers and 10.64±5.03% in right-handers. In addition, the UT muscle activation on the writing hand side was 11.91±5.79% in left-handers and 1.66±1.19% in right-handers. [Conclusion] As a result of this study, it was discovered that left-handers used more wrist flexion in performance of the writing task with the dominant upper extremity than right-handers, and that the left-handers activated the wrist and shoulder muscles more than the right-handers. These results indicate a potential danger of musculoskeletal disease in left-hander.

Left-handers look before they leap: handedness influences reactivity to novel Tower of Hanoi tasks

PubMed Central

Wright, Lynn; Hardie, Scott M.

2015-01-01

A sample of 203 task naïve left- and right-handed participants were asked to complete a combination of the 3- and 4-disk Towers of Hanoi (ToH), manipulating novelty and complexity. Self-reported state anxiety and latency to respond (initiation time) were recorded before each ToH. Novelty had a major effect on initiation time, particularly for left-handers. Left-handers had a longer latency to start and this was significantly longer on the first trial. Irrespective of hand-preference, initiation time reduced on the second trial, however, this was greatest for left-handers. Condition of task did not systematically influence initiation time for right handers, but did for left-handers. State anxiety was influenced by task novelty and complexity in a more complicated way. During the first trial, there was a significant handedness × number of disks interaction with left-handers having significantly higher state anxiety levels before the 3-disk ToH. This suggests that the initial reaction to this task for left-handers was not simply due to perceived difficulty. On their second trial, participants completing a novel ToH had higher state anxiety scores than those completing a repeated version. Overall, left-handers had a larger reduction in their state anxiety across trials. Relating to this, the expected strong positive correlation between state and trait anxiety was absent for left-handed females in their first tower presentation, but appeared on their second. This was driven by low trait anxiety individuals showing a higher state anxiety response in the first (novel) trial, supporting the idea that left-handed females respond to novelty in a way that is not directly a consequence of their trait anxiety. A possible explanation may be stereotype threat influencing the behavior of left-handed females. PMID:25691878

Generation of co-speech gestures based on spatial imagery from the right-hemisphere: evidence from split-brain patients.

PubMed

Kita, Sotaro; Lausberg, Hedda

2008-02-01

It has been claimed that the linguistically dominant (left) hemisphere is obligatorily involved in production of spontaneous speech-accompanying gestures (Kimura, 1973a, 1973b; Lavergne and Kimura, 1987). We examined this claim for the gestures that are based on spatial imagery: iconic gestures with observer viewpoint (McNeill, 1992) and abstract deictic gestures (McNeill, et al. 1993). We observed gesture production in three patients with complete section of the corpus callosum in commissurotomy or callosotomy (two with left-hemisphere language, and one with bilaterally represented language) and nine healthy control participants. All three patients produced spatial-imagery gestures with the left-hand as well as with the right-hand. However, unlike healthy controls and the split-brain patient with bilaterally represented language, the two patients with left-hemispheric language dominance coordinated speech and spatial-imagery gestures more poorly in the left-hand than in the right-hand. It is concluded that the linguistically non-dominant (right) hemisphere alone can generate co-speech gestures based on spatial imagery, just as the left-hemisphere can.

Lateral comparisons using Fishman's skeletal maturation assessment.

PubMed

Safer, Abraham N; Homel, Peter; Chung, David D

2015-05-01

To assess lateral differences between ossification events and stages of bone development in the hands and wrists utilizing Fishman's skeletal maturation indicators (SMIs). The skeletal ages of 125 subjects, aged 8 to 20 years, were determined with left and right hand-wrist radiographs using Fishman's SMI assessment. Each subject was also given the Edinburgh Handedness Questionnaire to assess handedness. The skeletal ages of both hand-wrist radiographs were analyzed against each other, handedness, chronologic age, and gender. There were no significant differences overall in right and left SMI scores (P  =  .70); 79% of all patients showed no difference in right and left SMI scores, regardless of handedness, gender, or age. However, when patients were categorized based on clinical levels of SMI score for the right hand-wrist, there was a significant difference (P  =  .01) between the SMI 1-3 group and the SMI 11 group. Subjects in the SMI 1-3 group were more likely to show a left > right SMI score, while subjects in the SMI 11 group were likely to show a right > left SMI score. Although no significant overall lateral differences in SMI scores were noted, it may be advisable to obtain a left hand-wrist radiograph and/or additional diagnostic information to estimate completion of growth in young surgical patients.

The handedness of Leonardo da Vinci: a tale of the complexities of lateralisation.

PubMed

McManus, I C; Drury, Helena

2004-07-01

The handedness of Leonardo da Vinci is controversial. Although there is little doubt that many of his well-attributed drawings were drawn with the left hand, the hatch marks of the shading going downwards from left to right, it is not clear that he was a natural left-hander, there being some suggestion that he may have become left-handed as the result of an injury to his right hand in early adulthood. Leonardo's lateralisation may be illuminated by an obscure passage in his notebooks in which he describes crouching down to look into a dark cave, putting his left hand on his knee, and shading his eyes with his right hand. We carried out a questionnaire survey, using 33 written and photographic items, to find whether this behaviour was typical of right handers or left handers. In fact the 'Leonardo task' showed almost no direct association with handedness, meaning that it contributes little to the immediate problem of elucidating Leonardo's handedness. However, the lateralisation of the task did relate to other aspects of behavioural laterality in surprisingly complex ways. This suggests that individual differences in handedness, and behavioural laterality in general, have a structural complexity which is not fully encompassed by simple measures of direction or degree of handedness.

Left-handed helical preference in an achiral peptide chain is induced by an L-amino acid in an N-terminal type II β-turn.

PubMed

De Poli, Matteo; De Zotti, Marta; Raftery, James; Aguilar, Juan A; Morris, Gareth A; Clayden, Jonathan

2013-03-15

Oligomers of the achiral amino acid Aib adopt helical conformations in which the screw-sense may be controlled by a single N-terminal residue. Using crystallographic and NMR techniques, we show that the left- or right-handed sense of helical induction arises from the nature of the β-turn at the N terminus: the tertiary amino acid L-Val induces a left-handed type II β-turn in both the solid state and in solution, while the corresponding quaternary amino acid L-α-methylvaline induces a right-handed type III β-turn.

Molecular analogs of the hemihelix: A computational study of chain molecules containing left- and right-handed helices

NASA Astrophysics Data System (ADS)

Pichierri, Fabio

2014-08-01

Using density functional theory (DFT) we design two novel chain molecules containing a left-handed (thia)helicene unit connected to a right-handed (thia)helicene unit via a phosphoroussbnd phosphorous (Psbnd P) bond. These chains represent the molecular analogs of the novel hemihelix structure recently discovered by a group of Harvard University scientists. The HOMO and LUMO levels of the heterochiral chains, termed hemihelicenes, are localized on the left- and right-handed blocks, respectively. In contrast, the frontier orbitals of the chains containing homochiral (thia)helicenes connected by a Psbnd P bond are delocalized all over the chain.

Exploring laterality and memory effects in the haptic discrimination of verbal and non-verbal shapes.

PubMed

Stoycheva, Polina; Tiippana, Kaisa

2018-03-14

The brain's left hemisphere often displays advantages in processing verbal information, while the right hemisphere favours processing non-verbal information. In the haptic domain due to contra-lateral innervations, this functional lateralization is reflected in a hand advantage during certain functions. Findings regarding the hand-hemisphere advantage for haptic information remain contradictory, however. This study addressed these laterality effects and their interaction with memory retention times in the haptic modality. Participants performed haptic discrimination of letters, geometric shapes and nonsense shapes at memory retention times of 5, 15 and 30 s with the left and right hand separately, and we measured the discriminability index d'. The d' values were significantly higher for letters and geometric shapes than for nonsense shapes. This might result from dual coding (naming + spatial) or/and from a low stimulus complexity. There was no stimulus-specific laterality effect. However, we found a time-dependent laterality effect, which revealed that the performance of the left hand-right hemisphere was sustained up to 15 s, while the performance of the right-hand-left hemisphere decreased progressively throughout all retention times. This suggests that haptic memory traces are more robust to decay when they are processed by the left hand-right hemisphere.

Individual left-hand and right-hand intra-digit representations in human primary somatosensory cortex.

PubMed

Schweisfurth, Meike A; Frahm, Jens; Schweizer, Renate

2015-09-01

Individual intra-digit somatotopy of all phalanges of the middle and little finger of the right and left hand was studied by functional magnetic resonance imaging in 12 healthy subjects. Phalanges were tactilely stimulated and activation in BA 3b of the human primary somatosensory cortex could be observed for each individual phalanx. Activation peaks were further analysed using the Direction/Order (DiOr) method, which identifies somatotopy, if a significantly high number of subjects exhibit ordered distal-to-proximal phalanx representions along a similar direction. Based on DiOr, ordered and similar-direction-aligned intra-digit maps across subjects were found at the left hand for the little and middle finger and at the right hand for the little finger. In these digits the proximal phalanges were represented more medially along the course of the central sulcus than the distal phalanges. This is contrasted by the intra-digit maps for the middle finger of the right hand, which showed larger inter-subject variations of phalanx alignments without a similar within-digit representation across subjects. As all subjects were right-handed and as the middle finger of the dominant hand probably plays a more individual role in everyday tactile performance than the little finger of the right hand and all left-hand digits, the observed variation might reflect a functional somatotopy based on individual use of that particular digit at the dominant hand. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

The Time Course for Language Acquisition in Biologically Distinct Populations: Evidence from Deaf Individuals

ERIC Educational Resources Information Center

Ross, Danielle S.; Bever, Thomas G.

2004-01-01

The present study provides evidence that individuals who have different patterns of cerebral lateralization and who develop along different maturational time courses can attain comparable levels of language proficiency. Right-handed individuals with left-handed family members (left-handed familials, LHFs) showed a shorter sensitive period for…

Brain Activation Associated with Practiced Left Hand Mirror Writing

ERIC Educational Resources Information Center

Kushnir, T.; Arzouan, Y.; Karni, A.; Manor, D.

2013-01-01

Mirror writing occurs in healthy children, in various pathologies and occasionally in healthy adults. There are only scant experimental data on the underlying brain processes. Eight, right-handed, healthy young adults were scanned (BOLD-fMRI) before and after practicing left-hand mirror-writing (lh-MW) over seven sessions. They wrote dictated…

77 FR 60658 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-04

...: We propose to adopt a new airworthiness directive (AD) for certain Airbus Model A319-112, -113, and... airplanes. This proposed AD was prompted by a report of two fatigue cracks on the left-hand and right-hand... proposed AD would require a high frequency eddy current (HFEC) inspection for any cracking on the left-hand...

Hand grip strength in the adult Malaysian population.

PubMed

Kamarul, T; Ahmad, T S; Loh, W Y C

2006-08-01

To measure the hand grip strength of Malaysians aged 18 to 65 years. Between January and April 2003, 412 subjects (200 women and 212 men) were recruited from staff, students, and visitors of the University of Malaya Medical Centre. Socioeconomic, general health, and lifestyle data were collected from each subject using a standard questionnaire. Weight and height were measured prior to testing. Standardised positioning and instructions based on several hand grip protocols were used. Data were collected using the LIDO kinetic work set. 93% of the subjects were right-hand dominant and 7% were left-hand dominant. Hand grip strength was significantly correlated with hand dominance, gender, occupation, height, and weight, but not body mass index. No significant differences in grip strength were noted with regard to race or level of income. Men were stronger than women in all age-groups, with a ratio of 1.75:1. In both right- and left-hand dominant groups, the dominant hand was consistently stronger than the non-dominant side, with a ratio of 1.12:1 in the right-hand dominant group and 1.05:1 in the left-hand dominant group. The strongest hand grip strength in the right-hand dominant group occurred in the age-group of 25 to 34 years; in the left-hand dominant group it was in the age-group of 18 to 24 years. In western populations, the mean grip strength can be as much as 1.5 times greater than in the Malaysian population. Data derived from western populations cannot be applied to a comparable Malaysian population. Gender, hand dominance, age, occupation, weight, and height must be considered when establishing normal values for grip strength.

Pantomiming tool use with an imaginary tool in hand as compared to demonstration with tool in hand specifically modulates the left middle and superior temporal gyri.

PubMed

Lausberg, Hedda; Kazzer, Philipp; Heekeren, Hauke R; Wartenburger, Isabell

2015-10-01

Neuropsychological lesion studies evidence the necessity to differentiate between various forms of tool-related actions such as real tool use, tool use demonstration with tool in hand and without physical target object, and pantomime without tool in hand. However, thus far, neuroimaging studies have primarily focused only on investigating tool use pantomimes. The present fMRI study investigates pantomime without tool in hand as compared to tool use demonstration with tool in hand in order to explore patterns of cerebral signal modulation associated with acting with imaginary tools in hand. Fifteen participants performed with either hand (i) tool use pantomime with an imaginary tool in hand in response to visual tool presentation and (ii) tool use demonstration with tool in hand in response to visual-tactile tool presentation. In both conditions, no physical target object was present. The conjunction analysis of the right and left hands executions of tool use pantomime relative to tool use demonstration yielded significant activity in the left middle and superior temporal lobe. In contrast, demonstration relative to pantomime revealed large bihemispherically distributed homologous areas of activity. Thus far, fMRI studies have demonstrated the relevance of the left middle and superior temporal gyri in viewing, naming, and matching tools and related actions and contexts. Since in our study all these factors were equally (ir)relevant both in the tool use pantomime and the tool use demonstration conditions, the present findings enhance the knowledge about the function of these brain regions in tool-related cognitive processes. The two contrasted conditions only differ regarding the fact that the pantomime condition requires the individual to act with an imaginary tool in hand. Therefore, we suggest that the left middle and superior temporal gyri are specifically involved in integrating the projected mental image of a tool in the execution of a tool-specific movement concept. Copyright © 2015 Elsevier Ltd. All rights reserved.

Left-handed transmission in a simple cut-wire pair structure

NASA Astrophysics Data System (ADS)

Tung, Nguyen Thanh; Thuy, Vu Tran Thanh; Park, Jin Woo; Rhee, Joo Yull; Lee, YoungPak

2010-01-01

It is well known that, together with the plasma behavior of continuous wires, the use of cut-wire pair as a metamagnetic component is to drive the negative permeability in the left-handed combined structure. In this study, we have investigated a strange left-handed transmission in a metamaterial consisting of only conventional cut-wire pair structure without additional adjustment. It is shown that the observed left-handed behavior, which occurs at a frequency three times higher than that for the combined structure, originates from the fundamental negative permittivity provided by the symmetric resonant mode and a negative permeability by the third-order asymmetric resonance. Our results would simplify extremely the fabricating procedure, especially, for terahertz regime as well as reveal many possibilities to design optical devices based on the electromagnetic responses of cut-wire structure.

Involuntary masturbation and hemiballismus after bilateral anterior cerebral artery infarction.

PubMed

Bejot, Yannick; Caillier, Marie; Osseby, Guy-Victor; Didi, Roy; Ben Salem, Douraied; Moreau, Thibault; Giroud, Maurice

2008-02-01

Ischemia of the areas supplied by the anterior cerebral artery is relatively uncommon. In addition, combined hemiballismus and masturbation have rarely been reported in patients with cerebrovascular disease. We describe herein a 62-year-old right-handed man simultaneously exhibiting right side hemiballismus and involuntary masturbation with the left hand after bilateral infarction of the anterior cerebral artery territory. Right side hemiballismus was related to the disruption of afferent fibers from the left frontal lobe to the left subthalamic nucleus. Involuntary masturbation using the left hand was exclusively linked to a callosal type of alien hand syndrome secondary to infarction of the right side of the anterior corpus callosum. After 2 weeks, these abnormal behaviours were completely extinguished. This report stresses the wide diversity of clinical manifestations observed after infarction of the anterior cerebral artery territory.

Optical vortex generation from a diode-pumped alexandrite laser

NASA Astrophysics Data System (ADS)

Thomas, G. M.; Minassian, A.; Damzen, M. J.

2018-04-01

We present the demonstration of an optical vortex mode directly generated from a diode-pumped alexandrite slab laser, operating in the bounce geometry. This is the first demonstration of an optical vortex mode generated from an alexandrite laser or from any other vibronic laser. An output power of 2 W for a vortex mode with a ‘topological charge’ of 1 was achieved and the laser was made to oscillate with both left- and right-handed vorticity. The laser operated at two distinct wavelengths simultaneously, 755 and 759 nm, due to birefringent filtering in the alexandrite gain medium. The result offers the prospect of broadly wavelength tunable vortex generation directly from a laser.

Effect of ambient temperature on the thermal profile of the human forearm, hand, and fingers

NASA Technical Reports Server (NTRS)

Montgomery, L. D.; Williams, B. A.

1976-01-01

Forearm, hand, and finger skin temperatures were measured on the right and left sides of seven resting men. The purpose was to determine the bilateral symmetry of these segmental temperature profiles at ambient temperatures from 10 to 45 C. Thermistors placed on the right and left forearms, hands, and index fingers were used to monitor the subjects until equilibration was reached at each ambient temperature. Additionally, thermal profiles of both hands were measured with copper-constantan thermocouples. During one experimental condition (23 C ambient), rectal, ear canal, and 24 skin temperatures were measured on each subject. Average body and average skin temperatures are given for each subject at the 23 C ambient condition. Detailed thermal profiles are also presented for the dorsal, ventral, and circumferential left forearm, hand, and finger skin temperatures at 23 C ambient. No significant differences were found between the mean skin temperatures of the right and left contralateral segments at any of the selected ambient temperatures.

Where are my hands? Influence of limb posture on tactile extinction.

PubMed

Auclair, Laurent; Barra, Julien; Raibaut, Patrick

2012-05-01

Tactile localization on the skin involves both a somatotopic and a postural schema (body-schema) representation. The present study determines the extent to which body posture influences tactile perception in right-brain-damaged patients. In a first set of experiments, patients were asked to detect single tactile stimulation delivered to their left or right hands or to both hands simultaneously (double stimulation) in different arm postures. Only patients who had no difficulty localizing single and double tactile stimulations when their hands were placed in anatomic position were tested. Participant's hands were crossed, one over the other, and the tactile stimuli were delivered either to the hand (beyond the crossing point, Experiment 1) or to the forearm (before the crossing point, Experiment 2). In Experiment 3, the left hand was placed in the right hemispace and the right hand in the left hemispace without crossing over (opposite condition). In a second set of experiments, patients were asked to detect stimulation delivered to the forefinger. The fingers were crossed, one over the other at the level of the middle phalanx, and stimuli were delivered either beyond or before the crossing point. In all experimental conditions, control participants performed at ceiling. We observed a left-hand tactile extinction on double stimulation in the crossed condition. These results suggest that tactile stimuli can be encoded based on multiple specific body-part representations rather than on an integrated body-schema representation.

Inverse design of an ultra-compact broadband optical diode based on asymmetric spatial mode conversion

PubMed Central

Callewaert, Francois; Butun, Serkan; Li, Zhongyang; Aydin, Koray

2016-01-01

The objective-first inverse-design algorithm is used to design an ultra-compact optical diode. Based on silicon and air only, this optical diode relies on asymmetric spatial mode conversion between the left and right ports. The first even mode incident from the left port is transmitted to the right port after being converted into an odd mode. On the other hand, same mode incident from the right port is reflected back by the optical diode dielectric structure. The convergence and performance of the algorithm are studied, along with a transform method that converts continuous permittivity medium into a binary material design. The optimal device is studied with full-wave electromagnetic simulations to compare its behavior under right and left incidences, in 2D and 3D settings as well. A parametric study is designed to understand the impact of the design space size and initial conditions on the optimized devices performance. A broadband optical diode behavior is observed after optimization, with a large rejection ratio between the two transmission directions. This illustrates the potential of the objective-first inverse-design method to design ultra-compact broadband photonic devices. PMID:27586852

An eastward propagating compressional Pc 5 wave observed by AMPTE/CCE in the postmidnight sector. [Active Magnetospheric Particle Tracer Explorers

NASA Technical Reports Server (NTRS)

Takahashi, K.; Mcentire, R. W.; Zanetti, L. J.; Lopez, R. E.; Kistler, L. M.

1987-01-01

This paper presents a detailed analysis of a compressional Pc 5 wave observed in the postmidnight sector on July 21, 1986, using data from the magnetometer, the charge-energy-mass spectrometer, and the medium-energy particle analyzer aboard the AMPTE/Charge Composition Explorer (CCE) spacecraft. The Pc 5 wave exhibited harmonically related transverse and compressional magnetic oscillations, modulation of the flux of medium energy protons, and a large azimuthal wave number, i.e., properties that are similar to those of compressional Pc5 waves observed previously at geostationary orbit. The unique observations recorded by the AMPTE/CCE included the occurrence of the wave in the postmidnight sector, its sunward propagation with respect to the spacecraft, and the left-handed polarization of the perturbed magnetic field. In spite of the morphological uniqueness observed, the excitation of the July 21 event is considered to be due to the same type of instability as operates at geostationary orbit.

An eastward propagating compressional Pc 5 wave observed by AMPTE/CCE in the postmidnight sector

NASA Astrophysics Data System (ADS)

Takahashi, K.; Lopez, R. E.; McEntire, R. W.; Zanetti, L. J.; Kistler, L. M.; Ipavich, F. M.

1987-12-01

This paper presents a detailed analysis of a compressional Pc 5 wave observed in the postmidnight sector on July 21, 1986, using data from the magnetometer, the charge-energy-mass spectrometer, and the medium-energy particle analyzer aboard the AMPTE/Charge Composition Explorer (CCE) spacecraft. The Pc 5 wave exhibited harmonically related transverse and compressional magnetic oscillations, modulation of the flux of medium energy protons, and a large azimuthal wave number, i.e., properties that are similar to those of compressional Pc5 waves observed previously at geostationary orbit. The unique observations recorded by the AMPTE/CCE included the occurrence of the wave in the postmidnight sector, its sunward propagation with respect to the spacecraft, and the left-handed polarization of the perturbed magnetic field. In spite of the morphological uniqueness observed, the excitation of the July 21 event is considered to be due to the same type of instability as operates at geostationary orbit.

Effect of gender and hand laterality on pain processing in human neonates.

PubMed

Ozawa, Mio; Kanda, Katsuya; Hirata, Michio; Kusakawa, Isao; Suzuki, Chieko

2011-01-01

Previous studies in adults have reported that handedness and gender can affect pain perception. However, it is currently unclear when these differences emerge in human development. Therefore, we examined prefrontal responses to pain stimulation among newborns during their first acute pain experience after birth. Forty newborns at 4-6 days postnatal age were observed during clinically required blood sampling while prefrontal activation was measured with near infrared spectroscopy. Blood sampling in this study was the first experience of a procedure involving skin breaking for these infants. We divided subjects into a right-hand stimulation group (n=21) and a left-hand stimulation group (n=19), depending on whether blood was sampled from the right or the left hand. A three-way analysis of variance (ANOVA) was conducted to examine the effects of several variables on the magnitude of the oxy-Hb value in response to pain stimulus, including stimulus side (right hand or left hand), gender (male or female), recording side (right prefrontal area or left prefrontal area) and interactions between these variables. The data revealed a significant effect of stimulus side (F (1, 72)=9.892, P=0.002), showing that the right-hand stimulation induced a greater prefrontal activation than the left-hand stimulation. No significant gender difference or interactions were found. Our findings suggest that hand laterality affects pain perception even in neonates. However, gender differences in pain perception did not appear to occur during the neonatal period. Further investigations using brain-imaging techniques are required to identify laterality- or gender-related differences in pain processing in humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Motor Experience Influences Object Knowledge

PubMed Central

Chrysikou, Evangelia G.; Casasanto, Daniel; Thompson-Schill, Sharon L.

2016-01-01

An object’s perceived readiness-for-action (e.g., its size, the degree of rotation from its canonical position, or the user’s viewpoint) can influence semantic knowledge retrieval. Yet, the organization of object knowledge may also be affected by body-specific sensorimotor experiences. Here, we investigated whether people’s history of performing motor actions with their hands influences the knowledge they store and retrieve about graspable objects. We compared object representations between healthy right- and left-handers (Experiment 1), and between unilateral stroke patients, whose motor experience was changed by impairment of either their right or left hand (Experiment 2). Participants saw pictures of graspable everyday items with the handles oriented toward either the left or right hand, and they generated the type of grasp they would employ (i.e., clench or pinch) when using each object, responding orally. In both experiments, hand dominance and object orientation interacted to predict response times. In Experiment 1, judgments were fastest when objects were oriented toward the right hand in right-handers, but not in left-handers. In Experiment 2, judgments were fastest when objects were oriented toward the left hand in patients who had lost the use of their right hand, even though these patients were right-handed prior to brain injury. Results suggest that at least some aspects of object knowledge are determined by motor experience, and can be changed by new patterns of motor experience. People with different bodily characteristics, who interact with objects in systematically different ways, form correspondingly different neurocognitive representations of the same common objects. PMID:28253009

Motor experience influences object knowledge.

PubMed

Chrysikou, Evangelia G; Casasanto, Daniel; Thompson-Schill, Sharon L

2017-03-01

An object's perceived readiness-for-action (e.g., its size, the degree of rotation from its canonical position, the user's viewpoint) can influence semantic knowledge retrieval. Yet, the organization of object knowledge may also be affected by body-specific sensorimotor experiences. Here, we investigated whether people's history of performing motor actions with their hands influences the knowledge they store and retrieve about graspable objects. We compared object representations between healthy right- and left-handers (Experiment 1), and between unilateral stroke patients, whose motor experience was changed by impairment of either their right or left hand (Experiment 2). Participants saw pictures of graspable everyday items with the handles oriented toward either the left or right hand, and they generated the type of grasp they would employ (i.e., clench or pinch) when using each object, responding orally. In both experiments, hand dominance and object orientation interacted to predict response times. In Experiment 1, judgments were fastest when objects were oriented toward the right hand in right-handers, but not in left-handers. In Experiment 2, judgments were fastest when objects were oriented toward the left hand in patients who had lost the use of their right hand, even though these patients were right-handed prior to brain injury. Results suggest that at least some aspects of object knowledge are determined by motor experience, and can be changed by new patterns of motor experience. People with different bodily characteristics, who interact with objects in systematically different ways, form correspondingly different neurocognitive representations of the same common objects. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Lateralization in motor facilitation during action observation: a TMS study.

PubMed

Aziz-Zadeh, Lisa; Maeda, Fumiko; Zaidel, Eran; Mazziotta, John; Iacoboni, Marco

2002-05-01

Action observation facilitates corticospinal excitability. This is presumably due to a premotor neural system that is active when we perform actions and when we observe actions performed by others. It has been speculated that this neural system is a precursor of neural systems subserving language. If this theory is true, we may expect hemispheric differences in the motor facilitation produced by action observation, with the language-dominant left hemisphere showing stronger facilitation than the right hemisphere. Furthermore, it has been suggested that body parts are recognized via cortical regions controlling sensory and motor processing associated with that body part. If this is true, then corticospinal facilitation during action observation should be modulated by the laterality of the observed body part. The present study addressed these two issues using TMS for each motor cortex separately as participants observed actions being performed by a left hand, a right hand, or a control stimulus on the computer screen. We found no overall difference between the right and left hemisphere for motor-evoked potential (MEP) size during action observation. However, when TMS was applied to the left motor cortex, MEPs were larger while observing right hand actions. Likewise, when TMS was applied to the right motor cortex, MEPs were larger while observing left hand actions. Our data do not suggest left hemisphere superiority in the facilitating effects of action observation on the motor system. However, they do support the notion of a sensory-motor loop according to which sensory stimulus properties (for example, the image of a left hand or a right hand) directly affect motor cortex activity, even when no motor output is required. The pattern of this effect is congruent with the pattern of motor representation in each hemisphere.

Commentary: Left Hand, Right Hand and on the Other Hand

ERIC Educational Resources Information Center

Parslow, Graham R.

2011-01-01

It was deeply ingrained in the author from his undergraduate studies of psychology and courses in learning theory that people have a rational left brain and a creative right brain. Learning theory suggested that activities needed to be tailored to develop both hemispheres. Handedness in relation to abilities has been commented on from the 1800s by…

Ratio Tables to Promote Proportional Reasonings in the Primary Classroom

ERIC Educational Resources Information Center

Dole, Shelley

2008-01-01

There are many classroom activities that can be implemented with primary students that introduce and immerse them in ratio investigations. Some enjoyable tasks include finding the ratio of tongue rollers to non-tongue rollers in the classroom; left-hand dominant to right-hand dominant; right-thumb over left-thumb when clasping the hands to…

Short-lived brain state after cued motor imagery in naive subjects.

PubMed

Pfurtscheller, G; Scherer, R; Müller-Putz, G R; Lopes da Silva, F H

2008-10-01

Multi-channel electroencephalography recordings have shown that a visual cue, indicating right hand, left hand or foot motor imagery, can induce a short-lived brain state in the order of about 500 ms. In the present study, 10 able-bodied subjects without any motor imagery experience (naive subjects) were asked to imagine the indicated limb movement for some seconds. Common spatial filtering and linear single-trial classification was applied to discriminate between two conditions (two brain states: right hand vs. left hand, left hand vs. foot and right hand vs. foot). The corresponding classification accuracies (mean +/- SD) were 80.0 +/- 10.6%, 83.3 +/- 10.2% and 83.6 +/- 8.8%, respectively. Inspection of central mu and beta rhythms revealed a short-lasting somatotopically specific event-related desynchronization (ERD) in the upper mu and/or beta bands starting approximately 300 ms after the cue onset and lasting for less than 1 s.

Cerebral specialization for spatial processing in adults with Down syndrome.

PubMed

Elliott, D; Pollock, B J; Chua, R; Weeks, D J

1995-05-01

Cerebral specialization for spatial processing in adults with Down syndrome was examined. In the first experiment, both control and right-handed subjects with Down syndrome exhibited no lateral advantage in a dihaptic shape-matching task, whereas left-handed subjects with Down syndrome displayed an expected left-hand advantage. In a visual field dot enumeration task in the second experiment, all groups exhibited left-field superiority. Thus, atypical cerebral organization of function in adults with Down syndrome appears to be confined to speech perception (Elliott & Weeks, 1993).

Handedness and dominant side of symptoms in Parkinson's disease.

PubMed

Shi, Jie; Liu, Jie; Qu, Qiumin

2014-02-20

To investigate the association between handedness and the side of symptom dominance in Parkinson's disease (PD). One hundred and forty-six PD patients with symmetric symptoms (92 males and 54 females), aged 64.3 ± 9.1 years old, from a series of 247 PD patients were assessed for handedness and clinical features. The severity of PD was scored by unified Parkinson's disease rating scale (UPDRS) and Hoehn-Yahr staging on the "ON" state. Of 134 right-handed patients (91.8%), 83 (61.7%) had an initial onset on the right side (P=0.008), while of 12 left-handed patients (8.2%), 9 (75.0%) had an initial onset on the left side (P=0.013). Out of right-handed patients, 103 (76.9%) had the right-side dominance of PD symptoms (P<0.001). Among the left-handed subjects, 7 patients (58.3%) had left-sided and 5 patients (41.7%) had right-sided symptom dominance (P=0.564). In general, dominant side of symptoms was in accordance with handedness (P=0.008). In right-handed patients, rest tremor was the most common initial symptom (P<0.001), while rest tremor and rigidity-bradykinesia were initial symptoms in left-handed patients (P=0.366). PD symptoms emerge more often on the dominant hand-side, and the dominant side of symptoms is in accordance with handedness. Copyright © 2012 Elsevier España, S.L. All rights reserved.

The content of the message influences the hand choice in co-speech gestures and in gesturing without speaking.

PubMed

Lausberg, Hedda; Kita, Sotaro

2003-07-01

The present study investigates the hand choice in iconic gestures that accompany speech. In 10 right-handed subjects gestures were elicited by verbal narration and by silent gestural demonstrations of animations with two moving objects. In both conditions, the left-hand was used as often as the right-hand to display iconic gestures. The choice of the right- or left-hands was determined by semantic aspects of the message. The influence of hemispheric language lateralization on the hand choice in co-speech gestures appeared to be minor. Instead, speaking seemed to induce a sequential organization of the iconic gestures.

A second Leonardo da Vinci?

PubMed

Nakano, Mitsuko; Endo, Toshitaka; Tanaka, Shigeki

2003-10-01

We describe a young woman who suddenly began mirror writing with her right hand and has not reverted to normal writing for more than 6 years, although she writes normally with her left hand. She is ambidextrous, although she had previously used only her right hand for writing and drawing. Since it is much easier for her to use right-handed mirror writing, she uses her left hand only for writing meant to be read by others and her right hand for all other writing. Her hobbies are sculpture and painting, and her chief complaint is migraine accompanied by sensory and perceptive disturbances.

Multifocal sensory demyelinating neuropathy: Report of a case.

PubMed

Oh, Shin J

2017-10-01

Multifocal sensory demyelinating neuropathy has not been adequately reported in the literature. A 42-year-old man with numbness of the left hand for 3 years and of the right hand for 6 months had a pure multifocal sensory neuropathy involving both hands, most prominently affecting 2-point discrimination, number writing, and object recognition of the left hand. Near-nerve needle sensory and mixed nerve conduction studies were performed on the left ulnar nerve. Studies of the left ulnar nerve documented a demyelinating neuropathy characterized by temporal dispersion and marked decrease in the amplitudes of the sensory and mixed compound nerve potentials in the above-elbow-axilla segment. With intravenous immunoglobulin treatment, there was improvement in his neuropathic condition. In this study I describe a case of multifocal sensory demyelinating neuropathy as a counterpart of multifocal motor neuropathy. Muscle Nerve 56: 825-828, 2017. © 2016 Wiley Periodicals, Inc.

Evidence for two concurrent inhibitory mechanisms during response preparation

PubMed Central

Duque, Julie; Lew, David; Mazzocchio, Riccardo; Olivier, Etienne; Ivry, Richard B.

2010-01-01

Inhibitory mechanisms are critically involved in goal-directed behaviors. To gain further insight into how such mechanisms shape motor representations during response preparation, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and H-reflexes were recorded from left hand muscles during choice reaction time tasks. The imperative signal, which indicated the required response, was always preceded by a preparatory cue. During the post-cue delay period, left MEPs were suppressed when the left hand had been cued for the forthcoming response, suggestive of a form of inhibition specifically directed at selected response representations. H-reflexes were also suppressed on these trials, indicating that the effects of this inhibition extend to spinal circuits. In addition, left MEPs were suppressed when the right hand was cued, but only when left hand movements were a possible response option before the onset of the cue. Notably, left hand H-reflexes were not modulated on these trials, consistent with a cortical locus of inhibition that lowers the activation of task-relevant, but non-selected responses. These results suggest the concurrent operation of two inhibitory mechanisms during response preparation: one decreases the activation of selected responses at the spinal level, helping to control when selected movements should be initiated by preventing their premature release; a second, upstream mechanism helps to determine what response to make during a competitive selection process. PMID:20220014

Left-handers' struggle in a rightward wor(l)d: The relation between horizontal spatial bias and effort in directed movements.

PubMed

Suitner, Caterina; Maass, Anne; Bettinsoli, Maria Laura; Carraro, Luciana; Kumar, Serena

2017-01-01

Five studies investigated the role of handedness and effort in horizontal spatial bias related to agency (Spatial Agency Bias, SAB). A Pilot Study (n = 33) confirmed the basic assumption that rightward writing requires greater effort from left- than from right-handers. In three studies, Italian students (n = 591 right-handed, n = 115 left-handed) were found to start drawings on the left, proceeding rightward (Study 1a, 1b), and to draw moving objects with a rightward orientation in line with script direction (Study 1c). These spatial asymmetries were displayed stronger by left- than by right-handed primacy school children, arguably due to the greater effort involved in learning how to write in a rightward fashion. Once writing has become fully automatic (high school) right- and left-handed students showed comparable spatial bias (Study 1c). The hypothesized role of effort was tested explicitly in Study 2 in which 99 right-handed adults learned a new (leftward) spatial trajectory through an easy or difficult motor exercise. The habitual rightward bias was reliably reduced, especially among those who performed a difficult task requiring greater effort. Together, findings are largely in line with the body specificity hypothesis (Casasanto, 2011 ) and suggest that spatial asymmetries are learned and unlearned most efficiently through effortful motor exercises.

Dominant use of the left hand by athetotic cerebral palsied children.

PubMed

Yokochi, K; Shimabukuro, S; Kodama, M; Hosoe, A

1990-01-01

Hand preference was studied in 57 children with athetotic cerebral palsy. A left-sided preference was seen in 61% of the subjects. In more severely affected children for whom the possible cause was asphyxia, the left-sided preference was especially common. The perinatal brain damage causing athetosis may affect a motor system controlling movement on the right side more severely.

40 CFR Appendix I to Part 60 - Removable Label and Owner's Manual

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES (CONTINUED) Pt. 60, App. I Appendix I to Part... label): • Manufacturer name (upper left hand corner, • Model name/number (upper left hand corner, • The... equipped wood heaters the 3.0 inch line shall be labeled “0” on the left end of the line (centered below...

40 CFR Appendix I to Part 60 - Removable Label and Owner's Manual

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES (CONTINUED) Pt. 60, App. I Appendix I to Part... label): • Manufacturer name (upper left hand corner, • Model name/number (upper left hand corner, • The... equipped wood heaters the 3.0 inch line shall be labeled “0” on the left end of the line (centered below...

Right sided weakness with right subdural hematoma: motor deafferentation of left hemisphere resulted in paralysis of the right side.

PubMed

Derakhshan, Iraj

2009-08-01

A right handed man with trauma to the head was admitted with headache and seizures. A severe right sided weakness was noted after a blunt trauma to the right side of his head. MRI of brain revealed a right-sided subdural hematoma and a normal left hemisphere and downstream motor pathways. Bimanual simultaneous drawing and manual reaction times indicated that the patient was right hemispheric in laterality of his major hemisphere. The right sided weakness in this patient was due to temporary transcallosal disconnection (diaschisis) of the minor hemisphere (left, in this case) from the excitatory signals arising from those structures of his major hemisphere devoted to movements occurring on nondominant side, transmitted via the corpus callosum to his left hemisphere. This case draws attention to disparity between neural and behavioral handedness (laterality of major hemisphere versus that of the preferred hand). Drawing longer lines by the left hand in simultaneous bimanual tasks and a slower simple reaction time to central visual stimuli by the ostensible dominant hand permitted lateralization of the major hemisphere to the right. Thus, the neurally nondominant side (right) lagged behind the dominant (left) by an interval equal to interhemispheric transfer time.

Cerebral laterality and verbal processes.

PubMed

Sherman, J L; Kulhavy, R W; Burns, K

1976-11-01

Research suggests that we process information by way of two distinct and functionallly separate coding systems. The localization of these two processing systems appears to be somewhat dependent on cerebral laterality, which has been shown to vary in right-handed and left-handed persons. To test the dual coding model, right-handed and left-handed subjects learned lists of abstract and concrete words under various conditions of visual and tactile interference. Right-handed subjects showed a significant superiority in the remembering of highly concrete items, while total recall did not differ reliably between groups.

Finger Length Ratios in Serbian Transsexuals

PubMed Central

Vujović, Svetlana; Popović, Srdjan; Mrvošević Marojević, Ljiljana; Ivović, Miomira; Tančić-Gajić, Milina; Stojanović, Miloš; Marina, Ljiljana V.; Barać, Marija; Barać, Branko; Kovačević, Milena; Duišin, Dragana; Barišić, Jasmina; Djordjević, Miroslav L.; Micić, Dragan

2014-01-01

Atypical prenatal hormone exposure could be a factor in the development of transsexualism. There is evidence that the 2nd and 4th digit ratio (2D : 4D) associates negatively with prenatal testosterone and positively with estrogens. The aim was to assess the difference in 2D : 4D between female to male transsexuals (FMT) and male to female transsexuals (MFT) and controls. We examined 42 MFT, 38 FMT, and 45 control males and 48 control females. Precise measurements were made by X-rays at the ventral surface of both hands from the basal crease of the digit to the tip using vernier calliper. Control male and female patients had larger 2D : 4D of the right hand when compared to the left hand. Control male's left hand ratio was lower than in control female's left hand. There was no difference in 2D : 4D between MFT and control males. MFT showed similar 2D : 4D of the right hand with control women indicating possible influencing factor in embryogenesis and consequently finger length changes. FMT showed the lowest 2D : 4D of the left hand when compared to the control males and females. Results of our study go in favour of the biological aetiology of transsexualism. PMID:24982993

How right is left? Handedness modulates neural responses during morphosyntactic processing.

PubMed

Grey, Sarah; Tanner, Darren; van Hell, Janet G

2017-08-15

Most neurocognitive models of language processing generally assume population-wide homogeneity in the neural mechanisms used during language comprehension, yet individual differences are known to influence these neural mechanisms. In this study, we focus on handedness as an individual difference hypothesized to affect language comprehension. Left-handers and right-handers with a left-handed blood relative, or familial sinistrals, are hypothesized to process language differently than right-handers with no left-handed relatives (Hancock and Bever, 2013; Ullman, 2004). Yet, left-handers are often excluded from neurocognitive language research, and familial sinistrality in right-handers is often not taken into account. In the current study we used event-related potentials to test morphosyntactic processing in three groups that differed in their handedness profiles: left-handers (LH), right-handers with a left-handed blood relative (RH FS+), and right-handers with no reported left-handed blood relative (RH FS-; both right-handed groups were previously tested by Tanner and Van Hell, 2014). Results indicated that the RH FS- group showed only P600 responses during morphosyntactic processing whereas the LH and RH FS+ groups showed biphasic N400-P600 patterns. N400s in LH and RH FS+ groups are consistent with theories that associate left-handedness (self or familial) with increased reliance on lexical/semantic mechanisms during language processing. Inspection of individual-level results illustrated that variability in RH FS- individuals' morphosyntactic processing was remarkably low: most individuals were P600-dominant. In contrast, LH and RH FS+ individuals showed marked variability in brain responses, which was similar for both groups: half of individuals were N400-dominant and half were P600-dominant. Our findings have implications for neurocognitive models of language that have been largely formulated around data from only right-handers without accounting for familial sinistrality or including left-handers, and moreover highlight that there is systematic - and often ignored - variability in language processing outcomes in neurologically healthy populations. Copyright © 2017 Elsevier B.V. All rights reserved.

The Effect of Morphemic Homophony on the Processing of Japanese Two-kanji Compound Words

ERIC Educational Resources Information Center

Tamaoka, Katsuo

2005-01-01

Two experiments investigated the effect of kanji morphemic homophony on lexical decision and naming. Effects were examined from both the left-hand and right-hand positions of Japanese two-kanji compound words. The number of homophones affected the processing of compound words in the same way for both tasks. For left-hand kanji, fewer morphemic…

Moving Events in Time: Time-Referent Hand-Arm Movements Influence Perceived Temporal Distance to Past Events

ERIC Educational Resources Information Center

Blom, Stephanie S. A. H.; Semin, Gun R.

2013-01-01

We examine and find support for the hypothesis that time-referent hand-arm movements influence temporal judgments. In line with the concept of "left is associated with earlier times, and right is associated with later times," we show that performing left (right) hand-arm movements while thinking about a past event increases (decreases) the…

Analysis of EEG signal by flicker-noise spectroscopy: identification of right-/left-hand movement imagination.

PubMed

Broniec, A

2016-12-01

Flicker-noise spectroscopy (FNS) is a general phenomenological approach to analyzing dynamics of complex nonlinear systems by extracting information contained in chaotic signals. The main idea of FNS is to describe an information hidden in correlation links, which are present in the chaotic component of the signal, by a set of parameters. In the paper, FNS is used for the analysis of electroencephalography signal related to the hand movement imagination. The signal has been parametrized in accordance with the FNS method, and significant changes in the FNS parameters have been observed, at the time when the subject imagines the movement. For the right-hand movement imagination, abrupt changes (visible as a peak) of the parameters, calculated for the data recorded from the left hemisphere, appear at the time corresponding to the initial moment of the imagination. In contrary, for the left-hand movement imagination, the meaningful changes in the parameters are observed for the data recorded from the right hemisphere. As the motor cortex is activated mainly contralaterally to the hand, the analysis of the FNS parameters allows to distinguish between the imagination of the right- and left-hand movement. This opens its potential application in the brain-computer interface.

Lateralized ultradian rhythms: evidence from tactile discrimination of either hand.

PubMed

Meier-Koll, A

1998-12-01

Endogenous ultradian rhythms with periods of one or a few hours affect not only on physiological and behavioural functions but also perception and cognition. In particular, lateralized ultradian rhythms which seem to operate separately in the right and left hemispheres of the brain can be monitored by testing the tactile discrimination of the contralateral hand. The present paper is based on two subsequent studies: First, ultradian rhythms in tactile discrimination of either hand were examined in German subjects under laboratory conditions. Considerably different ultradian periods of right and left-handed tactile error rate were found in men but not in women. In a second study, a group of Kenyan Masai shepherds were tested while the subjects were leading herds on daily feeding routes through a savanna habitat. They showed ultradian periods of about 2 hours in tactile discrimination of either hand. Since the right hemisphere is specialized for visuospatial, the left for verbal processing lateralized ultradian rhythms may serve for a long-scale timing of neural processes underlying spatial and semantic mapping of the environment. Sex difference in German subjects and lateral differences found in left-handed (right-hemispheric) ultradian rhythms of German and Masai subjects are discussed from this point of view.

A Left-Hand Rule for Faraday's Law

ERIC Educational Resources Information Center

Salu, Yehuda

2014-01-01

A left-hand rule for Faraday's law is presented here. This rule provides a simple and quick way of finding directional relationships between variables of Faraday's law without using Lenz's rule.

Relevance of grasp types to assess functionality for personal autonomy.

PubMed

Gracia-Ibáñez, Verónica; Sancho-Bru, Joaquin L; Vergara, Margarita

Cross-sectional research design. Current assessment of hand function is not focused on evaluating the real abilities required for autonomy. To quantify the relevance of grasp types for autonomy to guide hand recovery and its assessment. Representative tasks of the International Classification of Functioning, Disability and Health activities in which the hands are directly involved were recorded. The videos were analyzed to identify the grasps used with each hand, and their relevance for autonomy was determined by weighting time with the frequency of appearance of each activity in disability and dependency scales. Relevance is provided globally and distinguished by hand (right-left) and bimanual function. Significant differences in relevance are also checked. The most relevant grasps are pad-to-pad pinch (31.9%), lumbrical (15.4%), cylindrical (12%), and special pinch (7.3%) together with the nonprehensile (18.6%) use of the hand. Lumbrical grasp has higher relevance for the left hand (19.9% vs 12%) while cylindrical grasp for the right hand (15.3% vs 7.7%). Relevancies are also different depending on bimanual function. Different relative importance was obtained when considering dependency vs disability scales. Pad-to-pad pinch and nonprehensile grasp are the most relevant grasps for both hands, whereas lumbrical grasp is more relevant for the left hand and cylindrical grasp for the right one. The most significant difference in bimanual function refers to pad-to-pad pinch (more relevant for unimanual actions of the left hand and bimanual actions of the right). The relative importance of each grasp type for autonomy and the differences observed between hand and bimanual action should be used in medical and physical decision-making. N/A. Copyright © 2017 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Hand preference for writing and associations with selected demographic and behavioral variables in 255,100 subjects: the BBC internet study.

PubMed

Peters, Michael; Reimers, Stian; Manning, John T

2006-11-01

In an Internet study unrelated to handedness, 134,317 female and 120,783 male participants answered a graded question as to which hand they preferred for writing. This allowed determination of hand preference patterns across 7 ethnic groups. Sex differences in left-handedness were found in 4 ethnic groups, favoring males, while no significant sex differences were found in three of the groups. Prevalence of left-handedness in the largest of the ethnic groups (self-labelled as "White") was comparable to contemporary hand preference data for this group [Gilbert, A. N., & Wysocki, C. J. (1992). Hand preference and age in the United states. Neuropsychologia, 30, 601-608] but the prevalence of left-handedness in individuals >70 years of age was considerably higher in the present study. Individuals who indicated "either" hand for writing preference had significantly lower spatial performance (mental rotation task) and significantly higher prevalence of hyperactivity, dyslexia, asthma than individuals who had clear left or right hand preferences, in support of Crow et al. [Crow, T., Crow, L., Done, D., & Leask, S. (1998). Relative hand skill predicts academic ability: global deficits at the point of hemispheric indecision. Neuropsychologia, 36, 1275-1282]. Similarly, an association of writing hand preference and non-heterosexual orientation was clearest for individuals with "either" writing hand responses. We conclude that contradictions in the literature as to whether or not these variables are linked to handedness stem largely from different definitions of hand preference. Due to a lack of statistical power in most studies in the literature, the "either" hand writing preference group that yielded the most salient results in this study is not normally available for analysis.

Astronauts Garriott and Merbold monitoring experiemnts in Spacelab

NASA Image and Video Library

1983-11-28

STS009-123-340 (28 Nov 1983) --- Astronaut Owen K. Garriott, STS-9 mission specialist, left, and Ulf Merbold, payload specialist, take a break from monitoring experimentation aboard Spacelab to be photographed. Dr. Garriott, holds in his left hand a data/log book for the solar spectrum experiment. Dr. Merbold, holds a map in his left hand for the monitoring of ground objectives of the metric camera.

Numbers and space: associations and dissociations.

PubMed

Nathan, Merav Ben; Shaki, Samuel; Salti, Moti; Algom, Daniel

2009-06-01

A cornerstone of contemporary research in numerical cognition is the surprising link found between numbers and space. In particular, people react faster and more accurately to small numbers with a left-hand key and to large numbers with a right-hand key. Because this contingency is found in a variety of tasks, it has been taken to support the automatic activation of magnitude as well as the notion of a mental number line arranged from left to right. The present study challenges the presence of a link between left-right location, on the one hand, and small-large number, on the other hand. We show that a link exists between space and relative magnitude, a relationship that might or might not be unique to numbers.

The contributions of vision and haptics to reaching and grasping

PubMed Central

Stone, Kayla D.; Gonzalez, Claudia L. R.

2015-01-01

This review aims to provide a comprehensive outlook on the sensory (visual and haptic) contributions to reaching and grasping. The focus is on studies in developing children, normal, and neuropsychological populations, and in sensory-deprived individuals. Studies have suggested a right-hand/left-hemisphere specialization for visually guided grasping and a left-hand/right-hemisphere specialization for haptically guided object recognition. This poses the interesting possibility that when vision is not available and grasping relies heavily on the haptic system, there is an advantage to use the left hand. We review the evidence for this possibility and dissect the unique contributions of the visual and haptic systems to grasping. We ultimately discuss how the integration of these two sensory modalities shape hand preference. PMID:26441777

A natural approach to convey numerical digits using hand activity recognition based on hand shape features

NASA Astrophysics Data System (ADS)

Chidananda, H.; Reddy, T. Hanumantha

2017-06-01

This paper presents a natural representation of numerical digit(s) using hand activity analysis based on number of fingers out stretched for each numerical digit in sequence extracted from a video. The analysis is based on determining a set of six features from a hand image. The most important features used from each frame in a video are the first fingertip from top, palm-line, palm-center, valley points between the fingers exists above the palm-line. Using this work user can convey any number of numerical digits using right or left or both the hands naturally in a video. Each numerical digit ranges from 0 to9. Hands (right/left/both) used to convey digits can be recognized accurately using the valley points and with this recognition whether the user is a right / left handed person in practice can be analyzed. In this work, first the hand(s) and face parts are detected by using YCbCr color space and face part is removed by using ellipse based method. Then, the hand(s) are analyzed to recognize the activity that represents a series of numerical digits in a video. This work uses pixel continuity algorithm using 2D coordinate geometry system and does not use regular use of calculus, contours, convex hull and datasets.

Left-handed compact MIMO antenna array based on wire spiral resonator for 5-GHz wireless applications

NASA Astrophysics Data System (ADS)

Alqadami, Abdulrahman Shueai Mohsen; Jamlos, Mohd Faizal; Soh, Ping Jack; Rahim, Sharul Kamal Abdul; Narbudowicz, Adam

2017-01-01

A compact coplanar waveguide-fed multiple-input multiple-output antenna array based on the left-handed wire loaded spiral resonators (SR) is presented. The proposed antenna consists of a 2 × 2 wire SR with two symmetrical microstrip feed lines, each line exciting a 1 × 2 wire SR. Left-handed metamaterial unit cells are placed on its reverse side and arranged in a 2 × 3 array. A reflection coefficient of less than -16 dB and mutual coupling of less than -28 dB are achieved at 5.15 GHz WLAN band.

Behavioral asymmetries of psychomotor performance in rhesus monkeys (Macaca mulatta) - A dissociation between hand preference and skill

NASA Technical Reports Server (NTRS)

Hopkins, William D.; Washburn, David A.; Berke, Leslie; Williams, Mary

1992-01-01

Hand preferences were recorded for 35 rhesus monkeys (Macaca mulatta) as they manipulated a joystick in response to 2 computerized tasks. These preferences were then used to contrast 8 left- and 10 right-handed subjects on performance measures of hand skill. Individual hand preferences were found, but no significant population asymmetry was observed across the sample. However, the performance data reveal substantial benefits of right-handedness for joystick manipulation, as this group of monkeys mastered the 2 psychomotor tasks significantly faster than did their left-handed counterparts. The data support earlier reports of a right-hand advantage for joystick manipulation and also support the importance of distinguishing between hand preference and manual performance in research on functional asymmetries.

Note on the helicity decomposition of spin and orbital optical currents

NASA Astrophysics Data System (ADS)

Aiello, Andrea; Berry, M. V.

2015-06-01

In the helicity representation, the Poynting vector (current) for a monochromatic optical field, when calculated using either the electric or the magnetic field, separates into right-handed and left-handed contributions, with no cross-helicity contributions. Cross-helicity terms do appear in the orbital and spin contributions to the current. But when the electric and magnetic formulas are averaged (‘electric-magnetic democracy’), these terms cancel, restoring the separation into right-handed and left-handed currents for orbital and spin separately.

Mirrors in the PDB: left-handed alpha-turns guide design with D-amino acids.

PubMed

Annavarapu, Srinivas; Nanda, Vikas

2009-09-22

Incorporating variable amino acid stereochemistry in molecular design has the potential to improve existing protein stability and create new topologies inaccessible to homochiral molecules. The Protein Data Bank has been a reliable, rich source of information on molecular interactions and their role in protein stability and structure. D-amino acids rarely occur naturally, making it difficult to infer general rules for how they would be tolerated in proteins through an analysis of existing protein structures. However, protein elements containing short left-handed turns and helices turn out to contain useful information. Molecular mechanisms used in proteins to stabilize left-handed elements by L-amino acids are structurally enantiomeric to potential synthetic strategies for stabilizing right-handed elements with D-amino acids. Propensities for amino acids to occur in contiguous alpha(L) helices correlate with published thermodynamic scales for incorporation of D-amino acids into alpha(R) helices. Two backbone rules for terminating a left-handed helix are found: an alpha(R) conformation is disfavored at the amino terminus, and a beta(R) conformation is disfavored at the carboxy terminus. Helix capping sidechain-backbone interactions are found which are unique to alpha(L) helices including an elevated propensity for L-Asn, and L-Thr at the amino terminus and L-Gln, L-Thr and L-Ser at the carboxy terminus. By examining left-handed alpha-turns containing L-amino acids, new interaction motifs for incorporating D-amino acids into right-handed alpha-helices are identified. These will provide a basis for de novo design of novel heterochiral protein folds.

Mirrors in the PDB: left-handed α-turns guide design with D-amino acids

PubMed Central

Annavarapu, Srinivas; Nanda, Vikas

2009-01-01

Background Incorporating variable amino acid stereochemistry in molecular design has the potential to improve existing protein stability and create new topologies inaccessible to homochiral molecules. The Protein Data Bank has been a reliable, rich source of information on molecular interactions and their role in protein stability and structure. D-amino acids rarely occur naturally, making it difficult to infer general rules for how they would be tolerated in proteins through an analysis of existing protein structures. However, protein elements containing short left-handed turns and helices turn out to contain useful information. Molecular mechanisms used in proteins to stabilize left-handed elements by L-amino acids are structurally enantiomeric to potential synthetic strategies for stabilizing right-handed elements with D-amino acids. Results Propensities for amino acids to occur in contiguous αL helices correlate with published thermodynamic scales for incorporation of D-amino acids into αR helices. Two backbone rules for terminating a left-handed helix are found: an αR conformation is disfavored at the amino terminus, and a βR conformation is disfavored at the carboxy terminus. Helix capping sidechain-backbone interactions are found which are unique to αL helices including an elevated propensity for L-Asn, and L-Thr at the amino terminus and L-Gln, L-Thr and L-Ser at the carboxy terminus. Conclusion By examining left-handed α-turns containing L-amino acids, new interaction motifs for incorporating D-amino acids into right-handed α-helices are identified. These will provide a basis for de novo design of novel heterochiral protein folds. PMID:19772623

Quantification of the power changes in BOLD signals using Welch spectrum method during different single-hand motor imageries.

PubMed

Zhang, Jiang; Yuan, Zhen; Huang, Jin; Yang, Qin; Chen, Huafu

2014-12-01

Motor imagery is an experimental paradigm implemented in cognitive neuroscience and cognitive psychology. To investigate the asymmetry of the strength of cortical functional activity due to different single-hand motor imageries, functional magnetic resonance imaging (fMRI) data from right handed normal subjects were recorded and analyzed during both left-hand and right-hand motor imagery processes. Then the average power of blood oxygenation level-dependent (BOLD) signals in temporal domain was calculated using the developed tool that combines Welch power spectrum and the integral of power spectrum approach of BOLD signal changes during motor imagery. Power change analysis results indicated that cortical activity exhibited a stronger power in the precentral gyrus and medial frontal gyrus with left-hand motor imagery tasks compared with that from right-hand motor imagery tasks. These observations suggest that right handed normal subjects mobilize more cortical nerve cells for left-hand motor imagery. Our findings also suggest that the approach based on power differences of BOLD signals is a suitable quantitative analysis tool for quantification of asymmetry of brain activity intensity during motor imagery tasks. Copyright © 2014 Elsevier Inc. All rights reserved.

Individuated finger control in focal hand dystonia: an fMRI study

PubMed Central

Moore, Ryan D; Gallea, Cecile; Horovitz, Silvina G; Hallett, Mark

2012-01-01

Objectives To better understand deficient selective motor control in focal hand dystonia by determining changes in striatal activation and connectivity in patients performing individuated finger control. Methods Functional imaging with a 3-Tesla magnetic resonance scanner was performed on 18 patients and 17 controls during non-symptom producing tasks requiring right-handed individuated or coupled finger control. A global linear model and psychophysiologic interactions model compared individuated to coupled tasks for patients and controls separately, and the results were submitted to a group analysis. The sensorimotor (posterior) and associative (anterior) putamen were considered as seed regions for the connectivity analysis. Results Compared to controls, patients had significant differences in activations and connectivity during individuated compared to coupled tasks: (i) decreased activations in the bilateral postcentral gyri, right associative posterior parietal areas, right cerebellum and left posterior putamen, while activations in the left anterior putamen were not different; (ii) increased connectivity of the left posterior putamen with the left cerebellum and left sensorimotor cortex; (iii) increased connectivity of the left anterior putamen with bilateral supplementary motor areas, the left premotor cortex, and left cerebellum. Interpretation Decreased activations in the sensorimotor putamen and cerebellum controlling the affected hand might underlie low levels of surround inhibition during individuated tasks. For identical motor performance in both groups, increased connectivity of sensorimotor and associative striato-cortical circuits in FHD suggests that both affected and unaffected territories of the striatum participate in compensatory processes. PMID:22484405

Individuated finger control in focal hand dystonia: an fMRI study.

PubMed

Moore, Ryan D; Gallea, Cecile; Horovitz, Silvina G; Hallett, Mark

2012-07-16

To better understand deficient selective motor control in focal hand dystonia by determining changes in striatal activation and connectivity in patients performing individuated finger control. Functional imaging with a 3-Tesla magnetic resonance scanner was performed on 18 patients and 17 controls during non-symptom producing tasks requiring right-handed individuated or coupled finger control. A global linear model and psychophysiologic interaction model compared individuated to coupled tasks for patients and controls separately, and the results were submitted to a group analysis. The sensorimotor (posterior) and associative (anterior) parts of the putamen were considered as seed regions for the connectivity analysis. Compared to controls, patients had significant differences in activations and connectivity during individuated compared to coupled tasks: (i) decreased activations in the bilateral postcentral gyri, right associative posterior parietal areas, right cerebellum and left posterior putamen, while activations in the left anterior putamen were not different; (ii) increased connectivity of the left posterior putamen with the left cerebellum and left sensorimotor cortex; and (iii) increased connectivity of the left anterior putamen with bilateral supplementary motor areas, the left premotor cortex, and left cerebellum. Decreased activations in the sensorimotor putamen and cerebellum controlling the affected hand might underlie low levels of surround inhibition during individuated tasks. For identical motor performance in both groups, increased connectivity of sensorimotor and associative striato-cortical circuits in FHD suggests that both affected and unaffected territories of the striatum participate in compensatory processes. Published by Elsevier Inc.

Both hand position and movement direction modulate visual attention

PubMed Central

Festman, Yariv; Adam, Jos J.; Pratt, Jay; Fischer, Martin H.

2013-01-01

The current study explored effects of continuous hand motion on the allocation of visual attention. A concurrent paradigm was used to combine visually concealed continuous hand movements with an attentionally demanding letter discrimination task. The letter probe appeared contingent upon the moving right hand passing through one of six positions. Discrimination responses were then collected via a keyboard press with the static left hand. Both the right hand's position and its movement direction systematically contributed to participants' visual sensitivity. Discrimination performance increased substantially when the right hand was distant from, but moving toward the visual probe location (replicating the far-hand effect, Festman et al., 2013). However, this effect disappeared when the probe appeared close to the static left hand, supporting the view that static and dynamic features of both hands combine in modulating pragmatic maps of attention. PMID:24098288

Dissociable neural responses to hands and non-hand body parts in human left extrastriate visual cortex.

PubMed

Bracci, Stefania; Ietswaart, Magdalena; Peelen, Marius V; Cavina-Pratesi, Cristiana

2010-06-01

Accumulating evidence points to a map of visual regions encoding specific categories of objects. For example, a region in the human extrastriate visual cortex, the extrastriate body area (EBA), has been implicated in the visual processing of bodies and body parts. Although in the monkey, neurons selective for hands have been reported, in humans it is unclear whether areas selective for individual body parts such as the hand exist. Here, we conducted two functional MRI experiments to test for hand-preferring responses in the human extrastriate visual cortex. We found evidence for a hand-preferring region in left lateral occipitotemporal cortex in all 14 participants. This region, located in the lateral occipital sulcus, partially overlapped with left EBA, but could be functionally and anatomically dissociated from it. In experiment 2, we further investigated the functional profile of hand- and body-preferring regions by measuring responses to hands, fingers, feet, assorted body parts (arms, legs, torsos), and non-biological handlike stimuli such as robotic hands. The hand-preferring region responded most strongly to hands, followed by robotic hands, fingers, and feet, whereas its response to assorted body parts did not significantly differ from baseline. By contrast, EBA responded most strongly to body parts, followed by hands and feet, and did not significantly respond to robotic hands or fingers. Together, these results provide evidence for a representation of the hand in extrastriate visual cortex that is distinct from the representation of other body parts.

Dissociable Neural Responses to Hands and Non-Hand Body Parts in Human Left Extrastriate Visual Cortex

PubMed Central

Ietswaart, Magdalena; Peelen, Marius V.; Cavina-Pratesi, Cristiana

2010-01-01

Accumulating evidence points to a map of visual regions encoding specific categories of objects. For example, a region in the human extrastriate visual cortex, the extrastriate body area (EBA), has been implicated in the visual processing of bodies and body parts. Although in the monkey, neurons selective for hands have been reported, in humans it is unclear whether areas selective for individual body parts such as the hand exist. Here, we conducted two functional MRI experiments to test for hand-preferring responses in the human extrastriate visual cortex. We found evidence for a hand-preferring region in left lateral occipitotemporal cortex in all 14 participants. This region, located in the lateral occipital sulcus, partially overlapped with left EBA, but could be functionally and anatomically dissociated from it. In experiment 2, we further investigated the functional profile of hand- and body-preferring regions by measuring responses to hands, fingers, feet, assorted body parts (arms, legs, torsos), and non-biological handlike stimuli such as robotic hands. The hand-preferring region responded most strongly to hands, followed by robotic hands, fingers, and feet, whereas its response to assorted body parts did not significantly differ from baseline. By contrast, EBA responded most strongly to body parts, followed by hands and feet, and did not significantly respond to robotic hands or fingers. Together, these results provide evidence for a representation of the hand in extrastriate visual cortex that is distinct from the representation of other body parts. PMID:20393066

Long-term results after left ventricular aneurysmectomy.

PubMed Central

Otterstad, J E; Christensen, O; Levorstad, K; Nitter-Hauge, S

1981-01-01

Twenty-six patients (21 men and five women) with a mean age of 54.8 years have been reinvestigated nine to 62 months (mean 29.7) after left ventricular aneurysmectomy. Preoperatively left ventricular angiography disclosed an anterior aneurysm in all cases, which was large in 15 (57%) and small to medium in 11 (42%). At follow-up a large residual aneurysm was found in five (19%), a small to medium one in 13 (50%), and akinesia without aneurysm in eight (31%). The sum of ST elevation (sigma ST) in praecordial leads in the electrocardiogram was reduced from a mean value of 11.2 mm to 7.7 mm. In no patient did ST segments return to normal after operation. Preoperatively, mean sigma ST was identical in patients with large and with small to medium aneurysms. At reinvestigation mean sigma ST was identical in patients with large and with small to medium residual aneurysms as well as in patients with akinesia. Left ventricular end-diastolic pressure before angiography was reduced from a mean value of 21.5 mm to 15.1 mmHg and after angiography from 26.7 mm to 21.1 mmHg. Progression of coronary artery stenoses was a characteristic finding in patients whose left ventricular end-diastolic pressures did not return to normal. These patients had a longer follow-up time than those with no progression of coronary disease, who all showed an improvement in left ventricular end-diastolic pressure. Six patients who had coronary bypass grafting performed had unchanged left ventricular end-diastolic pressures at follow-up. The results indicate that progression of coronary artery disease may be responsible for an eventual further deterioration in left ventricular function after aneurysmectomy. Additional bypass grafting did not result in improved left ventricular function. PMID:6971647

General structure of fermion two-point function and its spectral representation in a hot magnetized medium

NASA Astrophysics Data System (ADS)

Das, Aritra; Bandyopadhyay, Aritra; Roy, Pradip K.; Mustafa, Munshi G.

2018-02-01

We have systematically constructed the general structure of the fermion self-energy and the effective quark propagator in the presence of a nontrivial background such as a hot magnetized medium. This is applicable to both QED and QCD. The hard thermal loop approximation has been used for the heat bath. We have also examined transformation properties of the effective fermion propagator under some of the discrete symmetries of the system. Using the effective fermion propagator we have analyzed the fermion dispersion spectra in a hot magnetized medium along with the spinor for each fermion mode obtained by solving the modified Dirac equation. The fermion spectra is found to reflect the discrete symmetries of the two-point functions. We note that for a chirally symmetric theory the degenerate left- and right-handed chiral modes in vacuum or in a heat bath get separated and become asymmetric in the presence of a magnetic field without disturbing the chiral invariance. The obtained general structure of the two-point functions is verified by computing the three-point function, which agrees with the existing results in one-loop order. Finally, we have computed explicitly the spectral representation of the two-point functions which would be very important to study the spectral properties of the hot magnetized medium corresponding to QED and QCD with background magnetic field.

CRLH-TL Sensors for Flow Inhomogeneties Detection of Pneumatic Conveyed Pulverized Solids

NASA Astrophysics Data System (ADS)

Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf

2011-08-01

This paper presents an application of a Composite Right/Left-Handed (CRLH) Transmission Line resonator for a compact mass flow detector which is able to detect inhomogeneous flows. In this concept, series capacitors and shunt inductors are used to synthesize a medium with simultaneously negative permeability and permittivity - the so called metamaterial. The helix shape of the cylindrical CRLH-TL sensor offers the possibility to detect flow inhomogeneities within the pipeline which can be used to correct the detected massflow rate. A combination of two CRLH-TL structures within the same cross-section of the pipeline can improve the angular sensitivity of the sensor. A prototype was realized and tested in a dedicated measurement setup to prove the concept.

Goal-Directed Movement Enhances Body Representation Updating

PubMed Central

Wen, Wen; Muramatsu, Katsutoshi; Hamasaki, Shunsuke; An, Qi; Yamakawa, Hiroshi; Tamura, Yusuke; Yamashita, Atsushi; Asama, Hajime

2016-01-01

Body representation refers to perception, memory, and cognition related to the body and is updated continuously by sensory input. The present study examined the influence of goals on body representation updating with two experiments of the rubber hand paradigm. In the experiments, participants moved their hidden left hands forward and backward either in response to instruction to touch a virtual object or without any specific goal, while a virtual left hand was presented 250 mm above the real hand and moved in synchrony with the real hand. Participants then provided information concerning the perceived heights of their real left hands and rated their sense of agency and ownership of the virtual hand. Results of Experiment 1 showed that when participants moved their hands with the goal of touching a virtual object and received feedback indicating goal attainment, the perceived positions of their real hands shifted more toward that of the virtual hand relative to that in the condition without a goal, indicating that their body representations underwent greater modification. Furthermore, results of Experiment 2 showed that the effect of goal-directed movement occurred in the active condition, in which participants moved their own hands, but did not occur in the passive condition, in which participants’ hands were moved by the experimenter. Therefore, we concluded that the sense of agency probably contributed to the updating of body representation involving goal-directed movement. PMID:27445766

Bilateral Forearm Transplantation in Mexico: 2-Year Outcomes.

PubMed

Iglesias, Martin; Butron, Patricia; Moran-Romero, Mario; Cruz-Reyes, Angel; Alberu-Gomez, Josefina; Leal-Villalpando, Paulino; Bautista-Zamudio, Jorge; Ramirez-Berumen, Maria; Lara-Hinojosa, Euridice; Espinosa-Cruz, Veronica; Gaytan-Cervantes, Rocio; Bravo-Ruiz, Leonardo; Rodriguez-Rojas, Elizabeth; Ramos-Peek, Jaime; Garcia-Alvarez, Miriam; Vega-Boada, Felipe; Sierra-Madero, Juan; Gamboa-Dominguez, Armando; Gonzalez-Sanchez, Judith; Contreras-Barbosa, Sarai; Navarro-Lara, Africa; Vazquez-Lamadrid, Jorge; Guzman-Gonzalez, Juan

2016-01-01

Patients with proximal forearm and arm transplantation have obtained and/or maintained function of the elbow joint and full active range of motion of the extrinsic muscles of the hand, but with diminished protective sensibility and a lack of good function of the intrinsic muscles. These patients have improved function, as measured by the Disabilities of the Arm, Shoulder and Hand questionnaire. We report the case of a 52-year-old man who suffered a high-voltage electrical burn requiring amputation of his upper limbs. He underwent bilateral proximal forearm transplantation in Mexico City in May 2012. At 2-year follow-up, immunosuppressive treatment has not led to metabolic, oncologic, or infectious complications. Keloid scars developed at the graft-recipient interface. There have been 4 acute rejections: the fourth was treated with methylprednisolone, rituximab, and immunoglobulin. Chronic rejection has not been detected. The extrinsic muscles of the wrist and digits have good function. Although the intrinsic muscles demonstrated electrical activity 15 months postoperatively, clinically, they are nonuseful. After 2 years, hand function is sufficient to allow the patient to grasp lightweight and medium-sized objects. The patient's Disabilities of the Arm, Shoulder and Hand questionnaire score improved from 50.00 points to 30.83 points, and his Hand Transplantation Score System rating is good, at 69/73 (right/left) of 100. The patient and his family are very satisfied with the functional and aesthetic outcomes. Upper arm or proximal forearm transplantation is a reconstructive option for patients who have experienced amputation because of trauma.

Eye-hand preference in schizophrenia: sex differences and significance for hand function.

PubMed

Liu, Yi-Chia; Yang, Yen Kuang; Lee, I Hui; Lin, Keh-Chung; Jeffries, Keith J; Lee, Li-Ching

2004-06-01

Hand preference and eye dominance were investigated in 73 (30 women, 43 men) schizophrenic patients and 71 (30 women, 41 men) healthy controls. There were significantly more schizophrenic patients and normal controls who were significantly right-hand dominant. However, schizophrenic patients showed a significant excess of left-eye dominance relative to controls (65.8% vs 29.6%; Odds Ratio= 4.75, p< .001). In addition, female schizophrenic patients showed a higher rate of nonright (either left or inconsistent) eye dominance (80%) than male schizophrenic patients (55.8%) and controls (33.3%). Analysis of hand performance on the Purdue Pegboard Test indicated that schizophrenic patients who showed crossed eye-hand dominance scored higher than did patients without crossed eye-hand dominance.

Relative effectiveness of dominant versus non-dominant hand position for rescuer's side of approach during chest compressions between right-handed and left-handed novice rescuers.

PubMed

You, Je Sung; Kim, Hoon; Park, Jung Soo; Baek, Kyung Min; Jang, Mun Sun; Lee, Hye Sun; Chung, Sung Phil; Kim, SeungWhan

2015-03-01

The major components affecting high quality cardiopulmonary resuscitation (CPR) have been defined as the ability of the rescuer, hand position, position of the rescuer and victim, depth and rate of chest compressions, and fatigue. Until now, there have been no studies on dominant versus non-dominant hand position and the rescuer's side of approach. This study was designed to evaluate the effectiveness of hand position and approach side on the quality of CPR between right-handed (RH) and left-handed (LH) novice rescuers. 44 health science university students with no previous experience of basic life support (BLS) volunteered for the study. We divided volunteers into two groups by handedness. Adult BLS was performed on a manikin for 2 min in each session. The sequences were randomly performed on the manikin's left side of approach (Lap) with the rescuer's left hand in contact with the sternum (Lst), Lap/Rst, Rap/Lst and Rap/Rst. We compared the quality of chest compressions between the RH and LH groups according to predetermined positions. A significant decrease in mean compression depth between the two groups was only observed when rescuers performed in the Rap/Lst scenario, regardless of hand dominance. The frequency of correct hand placement also significantly decreased in the Lap/Rst position for the LH group. The performance of novice rescuers during chest compressions is influenced by the position of the dominant hand and the rescuer's side of approach. In CPR training and real world situations, a novice rescuer, regardless of handedness, should consider hand positions for contacting the sternum identical to the side of approach after approaching from the nearest and most accessible side, for optimal CPR performance. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Science in the Making: Right Hand, Left Hand. III: Estimating historical rates of left-handedness.

PubMed

McManus, I C; Moore, James; Freegard, Matthew; Rawles, Richard

2010-01-01

The BBC television programme Right Hand, Left Hand, broadcast in August 1953, used a postal questionnaire to ask viewers about their handedness. Respondents were born between 1864 and 1948, and in principle therefore the study provides information on rates of left-handedness in those born in the nineteenth century, a group for which few data are otherwise available. A total of 6,549 responses were received, with an overall rate of left-handedness of 15.2%, which is substantially above that expected for a cohort born in the nineteenth and early twentieth centuries. Left-handers are likely to respond preferentially to surveys about handedness, and the extent of over-response can be estimated in modern control data obtained from a handedness website, from the 1953 BBC data, and from Crichton-Browne's 1907 survey, in which there was also a response bias. Response bias appears to have been growing, being relatively greater in the most modern studies. In the 1953 data there is also evidence that left-handers were more common among later rather than early responders, suggesting that left-handers may have been specifically recruited into the study, perhaps by other left-handers who had responded earlier. In the present study the estimated rate of bias was used to correct the nineteenth-century BBC data, which was then combined with other available data as a mixture of two constrained Weibull functions, to obtain an overall estimate of handedness rates in the nineteenth century. The best estimates are that left-handedness was at its nadir of about 3% for those born between about 1880 and 1900. Extrapolating backwards, the rate of left-handedness in the eighteenth century was probably about 10%, with the decline beginning in about 1780, and reaching around 7% in about 1830, although inevitably there are many uncertainties in those estimates. What does seem indisputable is that rates of left-handedness fell during most of the nineteenth century, only subsequently to rise in the twentieth century.

Dynamic dominance varies with handedness: reduced interlimb asymmetries in left-handers

PubMed Central

Przybyla, Andrzej; Good, David C.; Sainburg, Robert L.

2013-01-01

Our previous studies of interlimb asymmetries during reaching movements have given rise to the dynamic-dominance hypothesis of motor lateralization. This hypothesis proposes that dominant arm control has become optimized for efficient intersegmental coordination, which is often associated with straight and smooth hand-paths, while non-dominant arm control has become optimized for controlling steady-state posture, which has been associated with greater final position accuracy when movements are mechanically perturbed, and often during movements made in the absence of visual feedback. The basis for this model of motor lateralization was derived from studies conducted in right-handed subjects. We now ask whether left-handers show similar proficiencies in coordinating reaching movements. We recruited right- and left-handers (20 per group) to perform reaching movements to three targets, in which intersegmental coordination requirements varied systematically. Our results showed that the dominant arm of both left- and right-handers were well coordinated, as reflected by fairly straight hand-paths and low errors in initial direction. Consistent with our previous studies, the non-dominant arm of right-handers showed substantially greater curvature and large errors in initial direction, most notably to targets that elicited higher intersegmental interactions. While the right, non-dominant, hand-paths of left-handers were slightly more curved than those of the dominant arm, they were also substantially more accurate and better coordinated than the non-dominant arm of right-handers. Our results indicate a similar pattern, but reduced lateralization for intersegmental coordination in left-handers. These findings suggest that left-handers develop more coordinated control of their non-dominant arms than right-handers, possibly due to environmental pressure for right-handed manipulations. PMID:22113487

Dynamic dominance varies with handedness: reduced interlimb asymmetries in left-handers.

PubMed

Przybyla, Andrzej; Good, David C; Sainburg, Robert L

2012-02-01

Our previous studies of interlimb asymmetries during reaching movements have given rise to the dynamic-dominance hypothesis of motor lateralization. This hypothesis proposes that dominant arm control has become optimized for efficient intersegmental coordination, which is often associated with straight and smooth hand-paths, while non-dominant arm control has become optimized for controlling steady-state posture, which has been associated with greater final position accuracy when movements are mechanically perturbed, and often during movements made in the absence of visual feedback. The basis for this model of motor lateralization was derived from studies conducted in right-handed subjects. We now ask whether left-handers show similar proficiencies in coordinating reaching movements. We recruited right- and left-handers (20 per group) to perform reaching movements to three targets, in which intersegmental coordination requirements varied systematically. Our results showed that the dominant arm of both left- and right-handers were well coordinated, as reflected by fairly straight hand-paths and low errors in initial direction. Consistent with our previous studies, the non-dominant arm of right-handers showed substantially greater curvature and large errors in initial direction, most notably to targets that elicited higher intersegmental interactions. While the right, non-dominant, hand-paths of left-handers were slightly more curved than those of the dominant arm, they were also substantially more accurate and better coordinated than the non-dominant arm of right-handers. Our results indicate a similar pattern, but reduced lateralization for intersegmental coordination in left-handers. These findings suggest that left-handers develop more coordinated control of their non-dominant arms than right-handers, possibly due to environmental pressure for right-handed manipulations.

Dissociating the Influence of Response Selection and Task Anticipation on Corticospinal Suppression During Response Preparation

PubMed Central

Duque, Julie; Labruna, Ludovica; Cazares, Christian; Ivry, Richard B.

2014-01-01

Motor behavior requires selecting between potential actions. The role of inhibition in response selection has frequently been examined in tasks in which participants are engaged in some advance preparation prior to the presentation of an imperative signal. Under such conditions, inhibition could be related to processes associated with response selection, or to more general inhibitory processes that are engaged in high states of anticipation. In Experiment 1, we manipulated the degree of anticipatory preparation. Participants performed a choice reaction time task that required choosing between a movement of the left or right index finger, and used transcranial magnetic stimulation (TMS) to elicit motor evoked potentials (MEPs) in the left hand agonist. In high anticipation blocks, a non-informative cue (e.g., fixation marker) preceded the imperative; in low anticipation blocks, there was no cue and participants were required to divide their attention between two tasks to further reduce anticipation. MEPs were substantially reduced before the imperative signal in high anticipation blocks. In contrast, in low anticipation blocks, MEPs remained unchanged before the imperative signal but showed a marked suppression right after the onset of the imperative. This effect occurred regardless of whether the imperative had signaled a left or right hand response. After this initial inhibition, left MEPs increased when the left hand was selected and remained suppressed when the right hand was selected. We obtained similar results in Experiment 2 except that the persistent left MEP suppression when the left hand was not selected was attenuated when the alternative response involved a non-homologous effector (right foot). These results indicate that, even in the absence of an anticipatory period, inhibitory mechanisms are engaged during response selection, possibly to prevent the occurrence of premature and inappropriate responses during a competitive selection process. PMID:25128431

Hand preference, magical thinking and left-right confusion.

PubMed

Jaspers-Fayer, Fern; Peters, Michael

2005-03-01

Several reports suggest a significant correlation between hand preference quotients and Magical Ideation Scale (MIS) scores, such that individuals with mixed preferences have higher MIS scores. In a sample of 156 male and 257 female undergraduate university students no significant correlation was found between MIS scores and hand preference; hand preference being defined in numerous ways, and using short and long hand preference questionnaires to assess handedness. An index of left-right confusion was significantly related to MIS score, but only in females. We suggest that the role of subjects' response style and general approach to filling out questionnaires should be fully explored before "neurological" causes of links between hand preference and other questionnaire-assessed behavioural variables are invoked.

78 FR 17073 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-20

... of Transportation (DOT). ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive..., and CL-604 Variants) airplanes. This AD was prompted by reports of jamming/malfunctioning of the left-hand engine thrust control mechanism. This AD requires modifying the left-hand engine upper core-cowl...

Note on hand use in the manipulation of joysticks by rhesus monkeys (Macaca mulatta) and chimpanzees (Pan troglodytes)

NASA Technical Reports Server (NTRS)

Hopkins, William D.; Washburn, David A.; Rumbaugh, Duane M.

1989-01-01

MacNeilage et al. (1987) have proposed that nonhuman primate handedness may be contingent on the specific task requirements, with visual-spatial tasks yielding left-hand preferences and fine-motor tasks producing right-hand preferences. This study reports hand preferences in the manipulation of joysticks by 2 rhesus monkeys and 3 chimpanzees. Reach data were also collected for comparison with preference data for manipulation of the joystick. The data indicated that all 5 subjects demonstrated significant right-hand preferences in manipulating the joystick. In contrast, no significant hand preferences were found for the reach data. Reaction-time data also indicated that the right hand could perform a perceptual-motor task better than the left hand in all 5 subjects. Overall, the data indicate that reach tasks may not be sensitive enough measures to produce reliable hand preferences, whereas tasks that assess fine-motor control produce significant hand preferences.

Neural correlates for the suppression of habitual behavior: a functional MRI study.

PubMed

Matsubara, Miwa; Yamaguchi, Shuhei; Xu, Jiang; Kobayashi, Shotai

2004-01-01

It has been suggested that inhibitory executive control of behavior is directed by the frontal lobes. We used functional magnetic resonance imaging to explore the brain regions that are involved in the inhibition of habitual manual responses. Fifteen right-handed subjects performed the rock-scissors-paper game against computer-simulated pictures of hands during the scanning procedure. The subjects were required to win, lose, or draw against the presented picture in a separate block. We considered that the situation in which subjects intentionally lost the game required the suppression of habitual behavior, because it is natural behavior for people to attempt to win the game. Compared with the WIN and DRAW conditions, the left premotor and sensorimotor areas were activated for both hand sessions with a positive correlation with error rates. Importantly, the LOSE condition in the case of the right hand yielded brain activation exclusively in the anterior part of the left inferior frontal gyrus, the activity which showed a negative correlation with error rates. Overall brain activations were predominant in the left hemisphere, irrespective of the hand used for the response. The results suggest that the anterior part of the left inferior frontal gyrus plays a critical role in the inhibition of habitual manual behavior, and that the left hemisphere is dominant for the selection of well-learned manual behavior.

Minimal left-right symmetric intersecting D-brane model

NASA Astrophysics Data System (ADS)

Anchordoqui, Luis A.; Antoniadis, Ignatios; Goldberg, Haim; Huang, Xing; Lüst, Dieter; Taylor, Tomasz R.

2017-01-01

We investigate left-right symmetric extensions of the standard model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. The left-handed and right-handed fermions transform as doublets under S p (1 )L and S p (1 )R, and so their masses must be generated by the introduction of Higgs fields in a bifundamental (2 ,2 ) representation under the two S p (1 ) gauge groups. For such D-brane configurations the left-right symmetry must be broken by Higgs fields in the doublet representation of S p (1 )R and therefore Majorana mass terms are suppressed by some higher physics scale. The left-handed and right-handed neutrinos pair up to form Dirac fermions which control the decay widths of the right-handed W' boson to yield comparable branching fractions into dilepton and dijet channels. Using the most recent searches at LHC13 Run II with 2016 data we constrain the (gR,mW') parameter space. Our analysis indicates that independent of the coupling strength gR, gauge bosons with masses mW'≳3.5 TeV are not ruled out. As the LHC is just beginning to probe the TeV scale, significant room for W' discovery remains.

Age-related shifts in hemispheric dominance for syntactic processing.

PubMed

Leckey, Michelle; Federmeier, Kara D

2017-12-01

Recent ERP data from young adults have revealed that simple syntactic anomalies elicit different patterns of lateralization in right-handed participants depending upon their familial sinistrality profile (whether or not they have left-handed biological relatives). Right-handed participants who do not have left-handed relatives showed a strongly lateralized response pattern, with P600 responses following left-hemisphere-biased presentations and N400 responses following right-hemisphere-biased presentations. Given that the literature on aging has documented a tendency to change across adulthood from asymmetry of function to a more bilateral pattern, we tested the stability of this asymmetric response to syntactic violations by recording ERPs as 24 older adults (age 60+) with no history of familial sinistrality made grammaticality judgments on simple two-word phrases. Results showed that the asymmetric pattern observed in right-handed adults without familial sinistrality indeed changes with age, such that P600 responses come to be elicited not only with left-hemisphere-biased but also with right-hemisphere-biased presentations in older adults. These findings suggest that, as with many other cognitive functions, syntactic processing becomes more bilateral with age. © 2017 Society for Psychophysiological Research.

Brief Communication: Latent toxoplasmosis and salivary testosterone concentration--important confounding factors in second to fourth digit ratio studies.

PubMed

Flegr, Jaroslav; Lindová, Jitka; Pivoñková, Vera; Havlícek, Jan

2008-12-01

A sexually dimorphic characteristic, the second to fourth digit ratio (2D:4D ratio), has been shown to reflect the prenatal concentration of sex steroid hormones and to correlate with many personality, physiological, and life history traits. The correlations are usually stronger for the right than the left hand. Most studies have shown that the 2D:4D ratio does not vary with age or postnatal concentration of sex steroid hormones. Recently, a strong association between left hand 2D:4D ratio and infection with a common human parasite Toxoplasma has been reported. We hypothesized that the confounding effect of Toxoplasma infection on left hand 2D:4D ratio could be responsible for the stronger association between different traits and right hand rather than left hand 2D:4D ratio. This confounding effect of toxoplasmosis could also be responsible for the difficulty in finding an association between 2D:4D ratio and age or postnatal steroid hormone concentration. To test this hypothesis, we analyzed the association between sex and age and 2D:4D ratio in a population of 194 female and 106 male students with and without controlling for the confounding variables of Toxoplasma infection and testosterone concentration. Our results showed that the relationship between age and sex and 2D:4D ratio increased sharply when Toxoplasma infection and testosterone concentration were controlled. These results suggest that left hand 2D:4D ratio is more susceptible to postnatal influences and that the confounding factors of Toxoplasma infection, testosterone concentration and possibly also age, should be controlled in future 2D:4D ratio studies. Because of a stronger 2D:4D dimorphism in Toxoplasma-infected than Toxoplasma-free subjects, we predict that 2D:4D ratio dimorphism as well as right hand/left hand 2D:4D ratio dimorphism will be higher in countries with a high prevalence of Toxoplasma infection than in those with a low prevalence. (c) 2008 Wiley-Liss, Inc.

Interindividual uniformity and variety of the "Writing center": a functional MRI study.

PubMed

Sugihara, Genichi; Kaminaga, Tatsuro; Sugishita, Morihiro

2006-10-01

Our aim is to investigate the neural substrates for writing using fMRI (twenty right-handed subjects). We assumed that common areas involved in both writing with right and left hands are crucial to the central process of writing. We employed Japanese phonograms (Kana), in which phoneme-grapheme conversion would be extremely simple. Brain activation was examined under three conditions: (1) written naming with the right hand (WR), (2) written naming with the left hand (WL), and (3) naming silently (NA). While the comparison of WR to NA (WR>NA) exhibited activation only in the left frontoparietal area, the WL>NA comparison exhibited broader activation than the WR>NA comparison, i.e., the left frontoparietal area except the motor and sensory areas and the right frontoparietal area. A conjunction analysis in SPM2 revealed common areas of activation across the WR>NA and WL>NA comparisons, which are assumed to be crucial to writing. In the group analysis, three areas were found to be activated: the posterior end of the left superior frontal gyrus, which is superior and posterior to Exner's center; the anterior part of the left superior parietal lobule; and the lower part of the anterior limb of the left supramarginal gyrus. In the single-subject analysis, whereas the first two of the above three areas were found to be crucial for writing in all individuals, an interindividual inconsistency of involvement with writing was observed in three areas: the lower part of the anterior limb of the left supramarginal gyrus (60% involved); the right frontal region (47%); and the right intraparietal sulcus (47%).

Split-brain patients neglect left personal space during right-handed gestures.

PubMed

Lausberg, Hedda; Kita, Sotaro; Zaidel, Eran; Ptito, Alain

2003-01-01

Since some patients with right hemisphere damage or with spontaneous callosal disconnection neglect the left half of space, it has been suggested that the left cerebral hemisphere predominantly attends to the right half of space. However, clinical investigations of patients having undergone surgical callosal section have not shown neglect when the hemispheres are tested separately. These observations question the validity of theoretical models that propose a left hemispheric specialisation for attending to the right half of space. The present study aims to investigate neglect and the use of space by either hand in gestural demonstrations in three split-brain patients as compared to five patients with partial callosotomy and 11 healthy subjects. Subjects were asked to demonstrate with precise gestures and without speaking the content of animated scenes with two moving objects. The results show that in the absence of primary perceptual or representational neglect, split-brain patients neglect left personal space in right-handed gestural demonstrations. Since this neglect of left personal space cannot be explained by directional or spatial akinesia, it is suggested that it originates at the conceptual level, where the spatial coordinates for right-hand gestures are planned. The present findings are at odds with the position that the separate left hemisphere possesses adequate mechanisms for acting in both halves of space and neglect results from right hemisphere suppression of this potential. Rather, the results provide support for theoretical models that consider the left hemisphere as specialised for processing the right half of space during the execution of descriptive gestures.

Left-handed and right-handed U(1) gauge symmetry

NASA Astrophysics Data System (ADS)

Nomura, Takaaki; Okada, Hiroshi

2018-01-01

We propose a model with the left-handed and right-handed continuous Abelian gauge symmetry; U(1) L × U(1) R . Then three right-handed neutrinos are naturally required to achieve U(1) R anomaly cancellations, while several mirror fermions are also needed to do U(1) L anomaly cancellations. Then we formulate the model, and discuss its testability of the new gauge interactions at collider physics such as the large hadron collider (LHC) and the international linear collider (ILC). In particular, we can investigate chiral structure of the interactions by the analysis of forward-backward asymmetry based on polarized beam at the ILC.

Bimanual tapping of a syncopated rhythm reveals hemispheric preferences for relative movement frequencies.

PubMed

Pflug, Anja; Gompf, Florian; Kell, Christian Alexander

2017-08-01

In bimanual multifrequency tapping, right-handers commonly use the right hand to tap the relatively higher rate and the left hand to tap the relatively lower rate. This could be due to hemispheric specializations for the processing of relative frequencies. An extension of the double-filtering-by-frequency theory to motor control proposes a left hemispheric specialization for the control of relatively high and a right hemispheric specialization for the control of relatively low tapping rates. We investigated timing variability and rhythmic accentuation in right handers tapping mono- and multifrequent bimanual rhythms to test the predictions of the double-filtering-by-frequency theory. Yet, hemispheric specializations for the processing of relative tapping rates could be masked by a left hemispheric dominance for the control of known sequences. Tapping was thus either performed in an overlearned quadruple meter (tap of the slow rhythm on the first auditory beat) or in a syncopated quadruple meter (tap of the slow rhythm on the fourth auditory beat). Independent of syncopation, the right hand outperformed the left hand in timing accuracy for fast tapping. A left hand timing benefit for slow tapping rates as predicted by the double-filtering-by-frequency theory was only found in the syncopated tapping group. This suggests a right hemisphere preference for the control of slow tapping rates when rhythms are not overlearned. Error rates indicate that overlearned rhythms represent hierarchically structured meters that are controlled by a single timer that could potentially reside in the left hemisphere. Copyright © 2017 Elsevier B.V. All rights reserved.

The handedness of Michelangelo Buonarroti.

PubMed

Lazzeri, Davide

2018-05-07

The handedness of Michelangelo Buonarroti (1475-1564), one of the greatest artists of all time, is still controversial. Although there is no doubt that almost all of his well-attributed drawings were drawn with the right hand, the hatch marks of the shading going downward from right to left; it has been often neglected in the literature that he was an innate left-hander. An unfairly unknown autobiography of Raffaello da Montelupo stated that Michelangelo, a natural left-hander, trained himself from a young age to become right-handed. The same biography also underlined that Michelangelo restricted the use of his left hand only to works requiring force such as hammering, carving, and chiseling marble. The sign of the wooden crucifix donated to Santo Spirito in 1492 and two autographic sketches by Michelangelo-one left alongside a poem in 1509, and the other in the dress of the Vittoria Colonna sketch in 1525-are useful tools for analyzing the artist's evolution from left to right handedness when drawing, writing, and painting. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Sulcal morphology and volume of Broca's area linked to handedness and sex.

PubMed

Powell, Joanne L; Kemp, Graham J; Roberts, Neil; García-Finaña, Marta

2012-06-01

We investigated the effect of handedness and sex on: (i) sulcal contours defining PO and PTR and (ii) volume estimates of PO and PTR subfields in 40 left- and 42 right-handers. Results show an effect of handedness on discontinuity of the inferior frontal sulcus (IFS: P<0.01). Discontinuity of IFS was observed in: 43% left- and 62% right hemispheres in right-handers and in 65% left- and 48% right-hemispheres in left-handers. PO volume asymmetry was rightward in left-handed males (P=0.007) and females (P=0.02), showed a leftward trend in right-handed males (P=0.06), and was non-asymmetrical in right-handed females (P=0.96, i.e. left- and right-hemisphere PO volumes did not differ significantly). PO volume asymmetry in males differed significantly between handedness groups (P=0.001). Findings indicate a high degree of variability in the sulcal contours of PO and PTR and volume asymmetry of PO: the factors sex and handedness can explain some of this variability. Copyright © 2012 Elsevier Inc. All rights reserved.

Implications of Being Left-Handed as Related To Being Right-Handed.

ERIC Educational Resources Information Center

Thomas, Jana H.

Research indicates that there are physical and social, and possibly cognitive, differences between left-handers and right-handers. The three substantive sections of this colloquium paper cover brain functions, theories pertaining to the genesis of handedness, and cognitive development as related to handedness. Section 1 provides a brief…

Lateralization of Motor Excitability during Observation of Bimanual Signs

ERIC Educational Resources Information Center

Mottonen, Riikka; Farmer, Harry; Watkins, Kate E.

2010-01-01

Viewing another person's hand actions enhances excitability in an observer's left and right primary motor (M1) cortex. We aimed to determine whether viewing communicative hand actions alters this bilateral sensorimotor resonance. Using single-pulse transcranial magnetic stimulation (TMS), we measured excitability in the left and right M1 while…

FRONT ELEVATION, WITH DRIVEWAY ON LEFT HAND SIDE, AND STREET ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FRONT ELEVATION, WITH DRIVEWAY ON LEFT HAND SIDE, AND STREET IN FOREGROUND. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Four-Bedroom, Single-Family Type 10, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

77 FR 57484 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-18

... certain cowl assemblies of the left- and right-hand thrust reversers. This new AD requires removing certain C- duct assemblies of the left- and right-hand thrust reversers from service at certain designated life limits, and also adds airplanes to the applicability. This AD was prompted by new life limits on...

77 FR 15636 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-16

... proposed rulemaking (NPRM). SUMMARY: We propose to adopt a new airworthiness directive (AD) for all Airbus... cables on the left- and right- hand sides to determine whether a certain part number is installed, and replacement if necessary. We are proposing this AD to prevent non- availability of left- or right-hand off...

77 FR 20746 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-06

...). SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600.../ malfunctioning of the left-hand engine thrust control mechanism. This proposed AD would require modifying the left-hand engine upper core- cowl. We are proposing this AD to prevent jamming/malfunctioning of the...

77 FR 41886 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-17

... Transportation (DOT). ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for all... the left- and right-hand sides to determine whether a certain part number is installed, and replacement if necessary. We are issuing this AD to prevent non-availability of left- or right-hand off-wing...

77 FR 37342 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-21

...). SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600... was prompted by reports of jamming/malfunctioning of the left-hand engine thrust control mechanism. This proposed AD would require modifying the left-hand engine upper core-cowl. We are proposing this AD...

77 FR 37829 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-25

... assemblies of the left- and right-hand thrust reversers. Since we issued that AD, the manufacturer has issued new life limits on certain thrust reverser C-duct assemblies. This proposed AD would require removing certain C-duct assemblies of the left- and right-hand thrust reversers from service at certain designated...

Timing variability of reach trajectories in left versus right hemisphere stroke.

PubMed

Freitas, Sandra Maria Sbeghen Ferreira; Gera, Geetanjali; Scholz, John Peter

2011-10-24

This study investigated trajectory timing variability in right and left stroke survivors and healthy controls when reaching to a centrally located target under a fixed target condition or when the target could suddenly change position after reach onset. Trajectory timing variability was investigated with a novel method based on dynamic programming that identifies the steps required to time warp one trial's acceleration time series to match that of a reference trial. Greater trajectory timing variability of both hand and joint motions was found for the paretic arm of stroke survivors compared to their non-paretic arm or either arm of controls. Overall, the non-paretic left arm of the LCVA group and the left arm of controls had higher timing variability than the non-paretic right arm of the RCVA group and right arm of controls. The shoulder and elbow joint warping costs were consistent predictors of the hand's warping cost for both left and right arms only in the LCVA group, whereas the relationship between joint and hand warping costs was relatively weak in control subjects and less consistent across arms in the RCVA group. These results suggest that the left hemisphere may be more involved in trajectory timing, although the results may be confounded by skill differences between the arms in these right hand dominant participants. On the other hand, arm differences did not appear to be related to differences in targeting error. The paretic left arm of the RCVA exhibited greater trajectory timing variability than the paretic right arm of the LCVA group. This difference was highly correlated with the level of impairment of the arms. Generally, the effect of target uncertainty resulted in slightly greater trajectory timing variability for all participants. The results are discussed in light of previous studies of hemispheric differences in the control of reaching, in particular, left hemisphere specialization for temporal control of reaching movements. Copyright © 2011 Elsevier B.V. All rights reserved.

The neural correlates of biomechanical constraints in hand laterality judgment task performed from other person's perspective: A near-infrared spectroscopy study.

PubMed

Meng, Shuang; Oi, Misato; Saito, Godai; Saito, Hirofumi

2017-01-01

Previous studies, mainly using a first-person perspective (1PP), have shown that the judgments of the hand laterality judgment (HLJ) task are dependent on biomechanical constraints (BC). Specifically, differing reaction times (RT) for hand pictures rotated medially or laterally around the mid sagittal plane are attributed to the BC effect on motor imagery. In contrast, we investigated whether the HLJ task is also subject to BC when performed from a third-person perspective (3PP) as well as 1PP using near-infrared spectroscopy (NIRS) to measure the brain activity of prefrontal cortex (PFC) in right-handed participants assigned to 1PP or 3PP groups. The 1PP group judged whether a presented hand was their own left or right hand, and the 3PP group whether it was the other's left or right hand. Using their HLJ task error rates, the 1PP and 3PP groups were subdivided into an Error Group (EG) and No Error Group (NEG). For the 1PP group, both EG and NEG showed a significant Hand Laterality × Orientation interaction for RT, indicating the BC effect on motor imagery. For the 3PP group, however, neither EG nor NEG showed the interaction, even though EG showed a significantly longer RT than NEG. These results suggest that the 3PP EG appropriately followed the 3PP task instruction, while the NEG might have taken 1PP. However, the 3PP EG NIRS profile of left PFC showed a significant Hand Laterality × Orientation interaction, while the 1PP EG did not. More noteworthy is that the left PFC activation of EG showed an interaction between the 1PP and 3PP groups when the left hand was presented. Furthermore, in the NEG, the PFC activation was not influenced by the BC in either the 1PP or 3PP condition. These results indicate that BC interferes with the HLJ task performed from the 1PP and 3PP.

Three-dimensional movement analysis of handwriting in subjects with mild hemiparesis.

PubMed

Harada, Takako; Okajima, Yasutomo; Takahashi, Hidetoshi

2010-08-01

To investigate the effects of hemiparesis on handwriting using a 3-dimensional movement analyzer. Comparative case study. Ambulatory care clinic. Right-handed patients (n=25; mean age +/- SD, 62.3+/-10y) with mild right hemiparesis secondary to subcortical stroke, and age-matched (n=10; 65.6+/-13y) and age-unmatched (n=15; 32.4+/-10y) control subjects. Not applicable. Time required to write a Japanese character of 2 different sizes and average speed of handwriting at the pen tip. Average radii of tracks of the moving pen tip, metacarpal head of the index finger, and distal end of the forearm during writing. Correlation coefficients of the instantaneous speed-time graph of the pen tip with that of the index finger and with that of the distal forearm during writing. Time for writing with the hemiparetic right hand was longer than that with the unaffected left hand (P=.05 approximately .03), while it was shorter in healthy control subjects (P=.07 approximately .05). In contrast with the left-hand writing, the track radius of the pen tip of the right-hand writing in patients with hemiparesis with normal joint position sense was significantly larger than that of the finger or distal forearm (P=.01). The finding was the same as in the young and elderly control subjects. This right-left difference disappeared in the patients with hemiparesis with position sense impairment. The correlation coefficient of speed between the pen tip and the finger was larger in right-hand than left-hand writing in the control and sensory-normative patients with hemiparesis even though the difference was significant only in the healthy elderly subjects (P=.03). Irrespective of the right or left hand use, the correlation coefficient between the pen tip and the finger or distal forearm significantly increased as the character size increased (P=.03 approximately 6 x10(-6)) in all subjects and patients. However, this size-related difference was less significant in the patients with sensory impairment. The characteristics of handwriting movement by the dominant hand were preserved in patients with mild dominant-hand hemiparesis when joint position sense was normative but were lost in those with position sense impairment.

Individual variation in hemispheric asymmetry: multitask study of effects related to handedness and sex.

PubMed

Hellige, J B; Bloch, M I; Cowin, E L; Eng, T L; Eviatar, Z; Sergent, V

1994-09-01

Functional hemispheric asymmetries were examined for right- or left-handed men and women. Tasks involved (a) auditory processing of verbal material, (b) processing of emotions shown on faces, (c) processing of visual categorical and coordinate spatial relations, and (d) visual processing of verbal material. Similar performance asymmetries were found for the right-handed and left-handed groups, but the average asymmetries tended to be smaller for the left-handed group. For the most part, measures of performance asymmetry obtained from the different tasks did not correlate with each other, suggesting that individual subjects cannot be simply characterized as strongly or weakly lateralized. However, ear differences obtained in Task 1 did correlate significantly with certain visual field differences obtained in Task 4, suggesting that both tasks are sensitive to hemispheric asymmetry in similar phonetic or language-related processes.

Effect of the amyloid β hairpin's structure on the handedness of helices formed by its aggregates

DOE PAGES

GhattyVenkataKrishna, Pavan K.; Uberbacher, Edward C.; Cheng, Xiaolin

2013-07-08

Various structural models for amyloid β fibrils have been derived from a variety of experimental techniques. However, these models cannot differentiate between the relative position of the two arms of the β hairpin called the stagger. Amyloid fibrils of various hierarchical levels form left-handed helices composed of β sheets. However it is unclear if positive, negative and zero staggers all form the macroscopic left-handed helices. To address this issue we have conducted extensive molecular dynamics simulations of amyloid β sheets of various staggers and shown that only negative staggers lead to the experimentally observed left-handed helices while positive staggers generatemore » the incorrect right-handed helices. In conclusion, this result suggests that the negative staggers are physiologically relevant structure of the amyloid β fibrils.« less

Visual cortex activation in kinesthetic guidance of reaching.

PubMed

Darling, W G; Seitz, R J; Peltier, S; Tellmann, L; Butler, A J

2007-06-01

The purpose of this research was to determine the cortical circuit involved in encoding and controlling kinesthetically guided reaching movements. We used (15)O-butanol positron emission tomography in ten blindfolded able-bodied volunteers in a factorial experiment in which arm (left/right) used to encode target location and to reach back to the remembered location and hemispace of target location (left/right side of midsagittal plane) varied systematically. During encoding of a target the experimenter guided the hand to touch the index fingertip to an external target and then returned the hand to the start location. After a short delay the subject voluntarily moved the same hand back to the remembered target location. SPM99 analysis of the PET data contrasting left versus right hand reaching showed increased (P < 0.05, corrected) neural activity in the sensorimotor cortex, premotor cortex and posterior parietal lobule (PPL) contralateral to the moving hand. Additional neural activation was observed in prefrontal cortex and visual association areas of occipital and parietal lobes contralateral and ipsilateral to the reaching hand. There was no statistically significant effect of target location in left versus right hemispace nor was there an interaction of hand and hemispace effects. Structural equation modeling showed that parietal lobe visual association areas contributed to kinesthetic processing by both hands but occipital lobe visual areas contributed only during dominant hand kinesthetic processing. This visual processing may also involve visualization of kinesthetically guided target location and use of the same network employed to guide reaches to visual targets when reaching to kinesthetic targets. The present work clearly demonstrates a network for kinesthetic processing that includes higher visual processing areas in the PPL for both upper limbs and processing in occipital lobe visual areas for the dominant limb.

The Ratio of 2nd to 4th Digit Length in Korean Alcohol-dependent Patients

PubMed Central

Han, Changwoo; Bae, Hwallip; Lee, Yu-Sang; Won, Sung-Doo; Kim, Dai Jin

2016-01-01

Objective The ratio of 2nd to 4th digit length (2D:4D) is a sexually dimorphic trait. Men have a relatively shorter second digit than fourth digit. This ratio is thought to be influenced by higher prenatal testosterone level or greater sensitivity to androgen. The purpose of this study is to investigate the relationship between alcohol dependence and 2D:4D in a Korean sample and whether 2D:4D can be a biologic marker in alcohol dependence. Methods In this study, we recruited 87 male patients with alcohol dependence from the alcohol center of one psychiatric hospital and 52 healthy male volunteers who were all employees in the same hospital as controls. We captured images of the right and left hands of patients and controls using a scanner and extracted data with a graphics program. We measured the 2D:4D of each hand and compared the alcohol dependence group with the control group. We analyzed these ratios using an independent-samples t-test. Results The mean 2D:4D of patients was 0.934 (right hand) and 0.942 (left hand), while the mean 2D:4D of controls was 0.956 (right hand) and 0.958 (left hand). Values for both hands were significantly lower for patients than controls (p<0.001, right hand; p=0.004, left hand). Conclusion Patients who are alcohol dependent have a significantly lower 2D:4D than controls, similar to the results of previous studies, which suggest that a higher prenatal testosterone level in the gonadal period is related to alcoholism. Furthermore, 2D:4D is a possible predictive marker of alcohol dependence. PMID:27121425

The Ratio of 2nd to 4th Digit Length in Korean Alcohol-dependent Patients.

PubMed

Han, Changwoo; Bae, Hwallip; Lee, Yu-Sang; Won, Sung-Doo; Kim, Dai Jin

2016-05-31

The ratio of 2nd to 4th digit length (2D:4D) is a sexually dimorphic trait. Men have a relatively shorter second digit than fourth digit. This ratio is thought to be influenced by higher prenatal testosterone level or greater sensitivity to androgen. The purpose of this study is to investigate the relationship between alcohol dependence and 2D:4D in a Korean sample and whether 2D:4D can be a biologic marker in alcohol dependence. In this study, we recruited 87 male patients with alcohol dependence from the alcohol center of one psychiatric hospital and 52 healthy male volunteers who were all employees in the same hospital as controls. We captured images of the right and left hands of patients and controls using a scanner and extracted data with a graphics program. We measured the 2D:4D of each hand and compared the alcohol dependence group with the control group. We analyzed these ratios using an independent-samples t-test. The mean 2D:4D of patients was 0.934 (right hand) and 0.942 (left hand), while the mean 2D:4D of controls was 0.956 (right hand) and 0.958 (left hand). Values for both hands were significantly lower for patients than controls (p<0.001, right hand; p=0.004, left hand). Patients who are alcohol dependent have a significantly lower 2D:4D than controls, similar to the results of previous studies, which suggest that a higher prenatal testosterone level in the gonadal period is related to alcoholism. Furthermore, 2D:4D is a possible predictive marker of alcohol dependence.

Handedness results from Complementary Hemispheric Dominance, not Global Hemispheric Dominance: Evidence from Mechanically Coupled Bilateral Movements.

PubMed

Woytowicz, Elizabeth J; Westlake, Kelly P; Whitall, Jill; Sainburg, Robert L

2018-05-09

Two contrasting views of handedness can be described as 1) complementary dominance, in which each hemisphere is specialized for different aspects of motor control, and 2) global dominance, in which the hemisphere contralateral to the dominant arm is specialized for all aspects of motor control. The present study sought to determine which motor lateralization hypothesis best predicts motor performance during common bilateral task of stabilizing an object (e.g. bread) with one hand while applying forces to the object (e.g. slicing) using the other hand. We designed an experimental equivalent of this task, performed in a virtual environment with the unseen arms supported by frictionless air-sleds. The hands were connected by a spring, and the task was to maintain the position of one hand, while moving the other hand to a target. Thus, the reaching hand was required to take account of the spring load to make smooth and accurate trajectories, while the stabilizer hand was required to impede the spring load to keep a constant position. Right-handed subjects performed two task sessions (right hand reach and left hand stabilize; left hand reach and right hand stabilize) with the order of the sessions counterbalanced between groups. Our results indicate a hand by task-component interaction, such that the right hand showed straighter reaching performance while the left showed more stable holding performance. These findings provide support for the complementary dominance hypothesis and suggest that the specializations of each cerebral hemisphere for impedance and dynamic control mechanisms are expressed during bilateral interactive tasks.

On the other hand: including left-handers in cognitive neuroscience and neurogenetics.

PubMed

Willems, Roel M; Van der Haegen, Lise; Fisher, Simon E; Francks, Clyde

2014-03-01

Left-handers are often excluded from study cohorts in neuroscience and neurogenetics in order to reduce variance in the data. However, recent investigations have shown that the inclusion or targeted recruitment of left-handers can be informative in studies on a range of topics, such as cerebral lateralization and the genetic underpinning of asymmetrical brain development. Left-handed individuals represent a substantial portion of the human population and therefore left-handedness falls within the normal range of human diversity; thus, it is important to account for this variation in our understanding of brain functioning. We call for neuroscientists and neurogeneticists to recognize the potential of studying this often-discarded group of research subjects.

'Putting your foot in it'! A window into clumsy behaviour.

PubMed

Sigmundsson, H; Whiting, H T; Ingvaldsen, R P

1999-07-01

Intra-modal matching by 7-year-old children diagnosed as having hand-eye co-ordination problems (HECP) and a control group of children without such problems was tested using a target location and matching task. The 'foot-hand' task required the children to locate a target pin with the 'big-toe' (felt target) and match the located target position with the hand, without vision. There were four conditions: location via right foot-matching the located target with the right hand (RfRh) and left hand (RfLh) and location via left foot-matching the located target with the left hand (LfLh) and right hand (LfRh). Both groups demonstrated better performance in the intra- as compared to the inter-hemispheric conditions, suggesting that the corpus callosum is not yet fully mature at this age. The HECP children showed inferior performance to the control children in three of the four conditions, the conditions where the right hemisphere was involved and/or information had to be transported across the corpus callosum (RfLh; LfLh; LfRh). Two possible explanations of these findings are put forward and discussed: right hemisphere insufficiency with or without dysfunctional corpus callosum.

Mirror man: a case of skilled deliberate mirror writing.

PubMed

McIntosh, Robert D; De Lucia, Natascia; Della Sala, Sergio

2014-01-01

Mirror writing is a striking behaviour that is common in children and can reemerge in adults following brain damage. Skilled deliberate mirror writing has also been reported, but only anecdotally. We provide the first quantitative study of skilled deliberate mirror writing. K.B. can write forward or backward, vertically upright or inverted, with the hands acting alone or simultaneously. K.B. is predominantly left handed, but writes habitually with his right hand. Of his writing formats, his left hand mirror writing is by far the most similar in style to his normal handwriting. When writing bimanually, he performs better when his two hands make mirror-symmetrical movements to write opposite scripts than if they move in the same direction to write similar scripts. He has no special facility for reading mirrored text. These features are consistent with prior anecdotal cases and support a motor basis for K.B.'s ability, according to which his skilled mirror writing results from the left hand execution of a low-level motor program for a right hand abductive writing action. Our methods offer a novel framework for investigating the sharing of motor representations across effectors.

Degree of Handedness Affects Intermanual Transfer of Skill Learning

PubMed Central

Chase, Cori; Seidler, Rachael

2008-01-01

Intermanual transfer of skill learning has often been used as a paradigm to study functional specialization and hemispheric interactions in relation to handedness. This literature has not evaluated whether degree of handedness impacts learning and intermanual transfer. Because handedness scores are related to factors that might influence intermanual transfer, such as engagement of the ipsilateral hemisphere during movement and corpus callosum volume, we tested whether degree of handedness is correlated with transfer magnitude. We had groups of left and right handed participants perform a sensorimotor adaptation task and a sequence learning task. Following learning with either the dominant or nondominant hand, participants transferred to task performance with the other hand. We evaluated whether the magnitude of learning and intermanual transfer were influenced by either direction and / or degree of handedness. Participants exhibited faster sensorimotor adaptation with the right hand, regardless of whether they were right or left handed. In addition, less strongly left handed individuals exhibited better intermanual transfer of sensorimotor adaptation, while less strongly right handed individuals exhibited better intermanual transfer of sequence learning. The findings suggest that involvement of the ipsilateral hemisphere during learning may influence intermanual transfer magnitude. PMID:18592225

Light reflection by the cuticle of C. aurigans scarabs: a biological broadband reflector of left handed circularly polarized light

NASA Astrophysics Data System (ADS)

Libby, E.; Azofeifa, D. E.; Hernández-Jiménez, M.; Barboza-Aguilar, C.; Solís, A.; García-Aguilar, I.; Arce-Marenco, L.; Hernández, A.; Vargas, W. E.

2014-08-01

Measured reflection spectra from elytra of Chrysina aurigans scarabs are reported. They show a broad reflection band for wavelengths from 0.525 to 1.0 μm with a sequence of maxima and minima reflection values superimposed on a mean value of around 40% for the high reflection band. Different mechanisms contributing to the reflection spectra have been considered, with the dominant effect, reflection of left handed circularly polarized light, being produced by a laminated left handed twisted structure whose pitch changes with depth through the procuticle in a more complex way than that characterizing broad band circular polarizers based on cholesteric liquid crystals.

76 FR 56284 - Airworthiness Directives; Airbus Model A330-200 and -300 Series Airplanes, and Model A340-200 and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-13

... describes the unsafe condition as: It was noticed in production that the distance between the wire harnesses 5376VB/2M and 5377VB/1M which are above the left-hand (LH) and right-hand (RH) door 4, and the air... production that the distance between the wire harnesses 5376VB/2M and 5377VB/1M which are above the left-hand...

[Hand hygiene technique assessment using electronic equipment in 26 Hungarian healthcare institutions].

PubMed

Lehotsky, Ákos; Morvai, Júlia; Szilágyi, László; Bánsághi, Száva; Benkó, Alíz; Haidegger, Tamás

2017-07-01

Hand hygiene is probably the most effective tool of nosocomial infection prevention, however, proper feedback and control is needed to develop the individual hand hygiene practice. Assessing the efficiency of modern education tools, and digital demonstration and verification equipment during their wide-range deployment. 1269 healthcare workers took part in a training organized by our team. The training included the assessment of the participants' hand hygiene technique to identify the most often missed areas. The hand hygiene technique was examined by a digital device. 33% of the participants disinfected their hands incorrectly. The most often missed sites are the fingertips (33% on the left hand, 37% on the right hand) and the thumbs (42% on the left hand, 32% on the right hand). The feedback has a fundamental role in the development of the hand hygiene technique. With the usage of electronic devices feedback can be provided efficiently and simply. Orv Hetil. 2017; 158(29): 1143-1148.

The Arabidopsis WAVY GROWTH 2 protein modulates root bending in response to environmental stimuli.

PubMed

Mochizuki, Susumu; Harada, Akiko; Inada, Sayaka; Sugimoto-Shirasu, Keiko; Stacey, Nicola; Wada, Takuji; Ishiguro, Sumie; Okada, Kiyotaka; Sakai, Tatsuya

2005-02-01

To understand how the direction of root growth changes in response to obstacles, light, and gravity, we characterized an Arabidopsis thaliana mutant, wavy growth 2 (wav2), whose roots show a short-pitch pattern of wavy growth on inclined agar medium. The roots of the wav2 mutant bent with larger curvature than those of the wild-type seedlings in wavy growth and in gravitropic and phototropic responses. The cell file rotations of the root epidermis of wav2-1 in the wavy growth pattern were enhanced in both right-handed and left-handed rotations. WAV2 encodes a protein belonging to the BUD EMERGENCE 46 family with a transmembrane domain at the N terminus and an alpha/beta-hydrolase domain at the C terminus. Expression analyses showed that mRNA of WAV2 was expressed strongly in adult plant roots and seedlings, especially in the root tip, the cell elongation zone, and the stele. Our results suggest that WAV2 is not involved in sensing environmental stimuli but that it negatively regulates stimulus-induced root bending through inhibition of root tip rotation.

77 FR 13230 - Airworthiness Directives; BAE SYSTEMS (OPERATIONS) LIMITED Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-06

... rulemaking (NPRM). SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain BAE SYSTEMS... crack found on the left-hand sidewall well on the nose landing gear (NLG). This proposed AD would require performing a repetitive high frequency eddy current inspection of the stiffeners on the left-hand...

Decreased bilateral cortical representation patterns in writer's cramp: a functional magnetic resonance imaging study at 3.0 T.

PubMed

Islam, Tina; Kupsch, Andreas; Bruhn, Harald; Scheurig, Christian; Schmidt, Sein; Hoffmann, Karl-Titus

2009-06-01

Functional magnetic resonance imaging was used to characterize patterns of cortical activation in response to sensory and motor tasks in patients with writer's cramp. 17 patients and 17 healthy subjects were examined during finger-tapping, index finger flexion, and electrical median nerve stimulation of both hands during electromyographic monitoring. SPM2 was used to evaluate Brodmann area (BA) 4, 1, 2, 3, 6, 40. Patients showed decreased activation in the left BA 4 with motor tasks of both hands and the left BA 1-3 with right finger-tapping. With left finger-tapping there was bilateral underactivation of single areas of the somatosensory cortex. Patients exhibited decreased activation in the bilateral BA 6 with left motor tasks and in the right BA 6 with right finger-tapping. Patients had decreased activation in bilateral BA 40 with finger-tapping of both hands. The findings suggest decreased baseline activity or an impaired activation in response to motor tasks in BA 1-4, 6, 40 in patients with writer's cramp for the dystonic and the clinically unaffected hand.

Off-road machine controls: investigating the risk of carpal tunnel syndrome.

PubMed

Oliver, M; Rickards, J; Biden, E

2000-11-01

Occupationally induced hand and wrist repetitive strain injuries (RSI) such as carpal tunnel syndrome (CTS) are a growing problem in North America. The purpose of this investigation was to apply a modification of the wrist flexion/ extension models of Armstrong and Chaffin (1978, 1979) to determine if joystick controller use in off-road machines could contribute to the development of CTS. A construction equipment cab in the laboratory was instrumented to allow force, displacement and angle measurements from 10 operators while they completed an approximately 30-min joystick motion protocol. The investigation revealed that both the external fingertip and predicted internal wrist forces resulting from the use of these joysticks were very low, indicating that the CTS risk associated with this factor was slight. However, the results also indicated that, particularly for the 'forward' and 'left' right side motions and for all left side motions, force was exerted by other portions of the fingers and hand, thereby under-predicting the tendon tension and internal wrist forces. Wrist angles observed were highest for motions that moved the joysticks to the sides rather than front to back. Thus, the 'right' and 'left' motions for both hands posed a higher risk for CTS development. When the right hand moved into the 'right' position and the left hand moved into the 'left' position, the wrist went into extension in both cases. Results indicate that neither learning nor fatigue affected the results.

Sexual dimorphism and handedness in the human corpus callosum based on magnetic resonance imaging.

PubMed

Tuncer, M C; Hatipoğlu, E S; Ozateş, M

2005-08-01

The corpus callosum (CC) is a major anatomical and functional commissure linking the two cerebral hemispheres. With MR imaging in the sagittal plane, the corpus callosum can be depicted in great detail. Mid-sagittal magnetic resonance images of 80 normal individuals were analyzed to assess whether or not the morphology of the corpus callosum and its parts are related to sex and handedness. The subjects were 40 males (20 right-handers and 20 left-handers) and 40 females (20 right-handers and 20 left-handers). The midsagittal area of the corpus callosum was divided into seven sub-areas using Witelson's method. The most striking morphological changes concerned left-handers, who had larger areas of the anterior body, posterior body and isthmus than right-handers. In addition, right-handed males had larger rostrums and isthmuses than right-handed females. These significantly increased areas were related to handedness in right-handed males. However, left-handed males had larger anterior and posterior bodies than right-handed males. In contrast, there was no significant difference between left-handers and right-handers in females. The areas of the rostrum and posterior body of the corpus callosum increased significantly with sex in males. Moreover, there were no significant age-related changes in the total corpus callosum and sub-areas of the corpus callosum. In conclusion, these anatomical changes in corpus callosum morphology require taking the sexual definition and dominant handedness into consideration.

Suicidal single gunshot injury to the head: differences in site of entrance wound and direction of the bullet path between right- and left-handed--an autopsy study.

PubMed

Nikolić, Slobodan; Zivković, Vladimir; Babić, Dragan; Juković, Fehim

2012-03-01

The aim of this study was to determine the differences in the anatomical site of a gunshot entrance wound and the direction of the bullet path between right- and left-handed subjects who committed a suicide by a single gunshot injury to the head. The retrospective autopsy study was performed for a 10-year period, and it included selected cases of single suicidal gunshot head injury, committed by handguns. We considered only contact or near-contact wounds. The sample included 479 deceased, with average age 47.1 ± 19.1 years (range, 12-89 years): 432 males and 47 females, with 317 right-handed, 25 left-handed, and 137 subjects with unknown dominant hand. In our observed sample, most cases involved the right temple as the site of entrance gunshot wound (about 67%), followed by the mouth (16%), forehead (7%), left temple (6%), submental (2%), and parietal region (1%). The left temple, right temple, and forehead were the sites of the gunshot entrance wounds, which were the best predictors of the handedness of the deceased (Spearman ρ = 0.149, P = 0.006). Our study showed that the direction of the bullet intracranial path in cases of suicide was even a more potent predictor of the handedness of the deceased (Spearman ρ = 0.263, P = 0.000; Wald = 149.503, P = 0.000).

Influence of cognitive style and interstimulus interval on the hemispheric processing of tactile stimuli.

PubMed

Minagawa, N; Kashu, K

1989-06-01

16 adult subjects performed a tactile recognition task. According to our 1984 study, half of the subjects were classified as having a left hemispheric preference for the processing of visual stimuli, while the other half were classified as having a right hemispheric preference for the processing of visual stimuli. The present task was conducted according to the S1-S2 matching paradigm. The standard stimulus was a readily recognizable object and was presented tactually to either the left or right hand of each subject. The comparison stimulus was an object-picture and was presented visually by slide in a tachistoscope. The interstimulus interval was .05 sec. or 2.5 sec. Analysis indicated that the left-preference group showed right-hand superiority, and the right-preference group showed left-hand superiority. The notion of individual hemisphericity was supported in tactile processing.

Detection of Hand and Leg Motor Tract Injury Using Novel Diffusion Tensor MRI Tractography in Children with Central Motor Dysfunction

PubMed Central

Jeong, Jeong-Won; Lee, Jessica; Kamson, David O.; Chugani, Harry T.; JuhÁsz, Csaba

2015-01-01

Purpose To examine whether an objective segmenation of corticospinal tract (CST) associated with hand and leg movements can be used to detect central motor weakness in the corresponding extremities in a pediatric population. Material and Methods This retrospective study included diffusion tensor imaging (DTI) of 25 children with central paresis affecting at least one limb (age: 9.0±4.2 years, 15 boys, 5/13/7 children with left/right/both hemispheric lesions including ischemia, cyst, and gliosis), as well as 42 pediatric control subjects with no motor dysfunction (age: 9.0±5.5 years, 21 boys, 31 healthy/11 non-lesional epilepsy children). Leg- and hand-related CST pathways were segmented using DTI-maximum a posteriori (DTI-MAP) classification. The resulting CST volumes were then divided by total supratentorial white matter volume, resulting in a marker called “normalized streamline volume ratio (NSVR)” to quantify the degree of axonal loss in separate CST pathways associated with leg and hand motor functions. A receiver operating characteristic curve was applied to measure the accuracy of this marker to identify extremities with motor weakness. Results NSVR values of hand/leg CST selectively achieved the following values of accuracy/sensitivity/specificity: 0.84/0.84/0.57, 0.82/0.81/0.55, 0.78/0.75/0.55, 0.79/0.81/0.54 at a cut-off of 0.03/0.03/0.03/0.02 for right hand CST, left hand CST, right leg CST, and left leg CST, respectively. Motor weakness of hand and leg was most likely present at the cut-off values of hand and leg NSVR (i.e., 0.029/0.028/0.025/0.020 for left-hand/right-hand/left-leg/right-leg). The control group showed a moderate age-related increase in absolute CST volumes and a biphasic age-related variation of the normalized CST volumes, which were lacking in the paretic children. Conclusions This study demonstrates that DTI-MAP classification may provide a new imaging tool to quantify axonal loss in children with central motor dysfunction. Using this technique, we found that early-life brain lesions affect the maturational trajectory of the primary motor pathway which may be used as an effective marker to facilitate evidence-based treatment of paretic children. PMID:25959649

Detection of hand and leg motor tract injury using novel diffusion tensor MRI tractography in children with central motor dysfunction.

PubMed

Jeong, Jeong-Won; Lee, Jessica; Kamson, David O; Chugani, Harry T; Juhász, Csaba

2015-09-01

To examine whether an objective segmenation of corticospinal tract (CST) associated with hand and leg movements can be used to detect central motor weakness in the corresponding extremities in a pediatric population. This retrospective study included diffusion tensor imaging (DTI) of 25 children with central paresis affecting at least one limb (age: 9.0±4.2years, 15 boys, 5/13/7 children with left/right/both hemispheric lesions including ischemia, cyst, and gliosis), as well as 42 pediatric control subjects with no motor dysfunction (age: 9.0±5.5years, 21 boys, 31 healthy/11 non-lesional epilepsy children). Leg- and hand-related CST pathways were segmented using DTI-maximum a posteriori (DTI-MAP) classification. The resulting CST volumes were then divided by total supratentorial white matter volume, resulting in a marker called "normalized streamline volume ratio (NSVR)" to quantify the degree of axonal loss in separate CST pathways associated with leg and hand motor functions. A receiver operating characteristic curve was applied to measure the accuracy of this marker to identify extremities with motor weakness. NSVR values of hand/leg CST selectively achieved the following values of accuracy/sensitivity/specificity: 0.84/0.84/0.57, 0.82/0.81/0.55, 0.78/0.75/0.55, 0.79/0.81/0.54 at a cut-off of 0.03/0.03/0.03/0.02 for right hand CST, left hand CST, right leg CST, and left leg CST, respectively. Motor weakness of hand and leg was most likely present at the cut-off values of hand and leg NSVR (i.e., 0.029/0.028/0.025/0.020 for left-hand/right-hand/left-leg/right-leg). The control group showed a moderate age-related increase in absolute CST volumes and a biphasic age-related variation of the normalized CST volumes, which were lacking in the paretic children. This study demonstrates that DTI-MAP classification may provide a new imaging tool to quantify axonal loss in children with central motor dysfunction. Using this technique, we found that early-life brain lesions affect the maturational trajectory of the primary motor pathway which may be used as an effective marker to facilitate evidence-based treatment of paretic children. Copyright © 2015 Elsevier Inc. All rights reserved.

Hypothalamic-mediated model for systemic lupus erythematosis: relation to hemispheric chemical dominance.

PubMed

Kurup, Ravi Kumar; Kurup, Parameswara Achutha

2003-11-01

The isoprenoid pathway including endogenous digoxin was assessed in systemic lupus erythematosis (SLE). All the patients with SLE were right-handed/left hemispheric dominant by the dichotic listening test. This was also studied for comparison in patients with right hemispheric and left hemispheric dominance. The isoprenoid pathway was upregulated with increased digoxin synthesis in patients with SLE and in those with right hemispheric dominance. In this group of patients (i) the tryptophan catabolites were increased and the tyrosine catabolites reduced, (ii) the dolichol and glycoconjugate levels were elevated, (iii) lysosomal stability was reduced, (iv) ubiquinone levels were low and free radical levels increased, and (v) the membrane cholesterol:phospholipid ratios were increased and membrane glycoconjugates reduced. On the other hand, in patients with left hemispheric dominance the reverse patterns were obtained. The biochemical patterns obtained in SLE is similar to those obtained in left-handed/right hemispheric chemically dominant individuals. But all the patients with SLE were right-handed/left hemispheric dominant by the dichotic listening test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. SLE occurs in right hemispheric chemically dominant individuals, and is a reflection of altered brain function. The role of the isoprenoid pathway in the pathogenesis of SLE and its relation to hemispheric dominance is discussed.

Sensitivity enhancement of a surface plasmon resonance sensor using porous metamaterial layers

NASA Astrophysics Data System (ADS)

Cherifi, Abdellatif; Bouhafs, Benamar

2017-12-01

In this work, the surface plasmon resonance (SPR) device with two porous left handed metamaterial (LHM) layers separated by an insulator gap, is investigated. The effect of the insulator gap thickness and its refractive index (RI) on the angular response of the device is analyzed. The results show that the sensitivity of the SPR sensor is enhanced compared to the standard SPR sensors. Here, the multilayer structure is probed with 738 nm-wavelength, and electromagnetic properties of active porous LHM layers are described from the effective medium theory (EMT). Furthermore, in the increase of the porosity from 0 to 0.6, the designed nanocavity exhibits a fundamental SPR mode long-range (LR) type and it can be of interest in high-performance SPR sensing.

An fMRI study of finger tapping in children and adults.

PubMed

Turesky, Ted K; Olulade, Olumide A; Luetje, Megan M; Eden, Guinevere F

2018-04-02

Functional brain imaging studies have characterized the neural bases of voluntary movement for finger tapping in adults, but equivalent information for children is lacking. When contrasted to adults, one would expect children to have relatively greater activation, reflecting compensation for an underdeveloped motor system combined with less experience in the execution of voluntary movement. To test this hypothesis, we acquired functional magnetic resonance imaging (fMRI) data on 17 healthy right-handed children (7.48 ± 0.66 years) and 15 adults (24.9 ± 2.9 years) while they performed an irregularly paced finger-tapping task in response to a visual cue (left- and right-hand examined separately). Whole-brain within-group analyses revealed that finger tapping in either age group and for either hand activated contralateral SM1, SMA, ipsilateral anterior cerebellum, and occipital cortices. We used an ANOVA factorial design to test for main effects of Age Group (children vs adults), Hand (left vs. right), and their interactions. For main effects of Age Group, children showed relatively greater activity in left SM1 (extending into bilateral SMA), and, surprisingly, adults exhibited relatively greater activity in right pre-SMA/SMA (extending into left pre-SMA/SMA), right lateral globus pallidus, left putamen, and right anterior cerebellum. The interaction of Age Group × Hand revealed that while both groups activated right SM1 during left finger tapping and exhibited signal decreases (i.e., below fixation baseline) during right finger tapping, both these responses were attenuated in children relative to adults. These data provide an important foundation by which to study children with motor disorders. © 2018 Wiley Periodicals, Inc.

Paul Wittgenstein's right arm and his phantom: the saga of a famous concert pianist and his amputation.

PubMed

Boller, François; Bogousslavsky, Julien

2015-01-01

Reports of postamputation pain and problems linked to phantom limbs have increased in recent years, particularly in relation to war-related amputations. These problems are still poorly understood and are considered rather mysterious, and they are difficult to treat. In addition, they may shed light on brain physiology and neuropsychology. Functional neuroimaging techniques now enable us to better understand their pathophysiology and to consider new rehabilitation techniques. Several artists have suffered from postamputation complications and this has influenced not only their personal life but also their artistic work. Paul Wittgenstein (1887-1961), a pianist whose right arm was amputated during the First World War, became a famous left-handed concert performer. His case provides insight into Post-World War I musical and political history. More specifically, the impact on the artistic life of this pianist illustrates various postamputation complications, such as phantom limb, stump pain, and especially moving phantom. The phantom movements of his right hand helped him develop the dexterity of his left hand. Wittgenstein played piano works that were written especially for him (the most famous being Ravel's Concerto for the Left Hand) and composed some of his own. Additionally, several famous composers had previously written for the left hand. © 2015 Elsevier B.V. All rights reserved.

A possible anatomical and biomechanical explanation of the 10% rule used in the clinical assessment of prehensile hand movements and handed dominance.

PubMed

Yielder, P; Gutnik, B; Kobrin, V; Hudson, G

2009-12-01

A current doctrine in the dynamometric approach to determine lateralization of hand function states that in 10% of cases, the non-dominant hand will be stronger than the dominant hand. In this study, a novel MRI based modelling approach was applied to the first dorsal introsseus muscle (FDI), to determine whether the 10% rule may be applied to the FDI and may be partially explained by the arrangement of the anatomical components of the FDI. Initially the force generated by the thumb segment during an isometric pushing task in the horizontal plane was measured from 25 strongly right-handed young males. Nine of these participants then had structural magnetic resonance imaging (sMRI) of the thumb and index osseous compartment. A modelling technique was developed to extract the muscle data and quantify the muscle line of action onto to the first metacarpal bone segment in order to quantify the muscle force at the point of momentary rotation--equilibrium. Eight of 25 subjects exhibited stronger force from the left hand. Six out of nine subjects from the MRI possessed significantly greater angles of attachment of the index osseous compartment on the left (non-dominant) hand. These six subjects also generated greater maximal isometric forces from the FDI of the left side. There was a significantly greater muscle volume for the right FDI muscle as compared to the left as measured from the reconstructed MRI slice data. The calculated force produced by the muscle is related to the angle of attachment of the muscle to bone in the index osseous compartment. The MRI findings indicate that the 10% rule may be anatomically and biomechanically explained.

Cerebral asymmetry for mental rotation: effects of response hand, handedness and gender.

PubMed

Johnson, Blake W; McKenzie, Kirsten J; Hamm, Jeff P

2002-10-28

We assessed lateralization of brain function during mental rotation, measuring the scalp distribution of a 400-600 ms latency event-related potential (ERP) with 128 recording electrodes. Twenty-four subjects, consisting of equal numbers of dextral and sinistral males and females, performed a mental rotation task under two response conditions (dominant non-dominant hand). For males, ERPs showed a right parietal bias regardless of response hand. For females, the parietal ERPs were slightly left-lateralized when making dominant hand responses, but strongly right-lateralized when making non-dominant hand responses. These results support the notion that visuo-spatial processing is more bilaterally organized in females. However, left hemisphere resources may be allocated to response preparation when using the non-dominant hand, forcing visuo-spatial processing to the right hemisphere.

JCE Online 99

NASA Astrophysics Data System (ADS)

Holmes, Jon L.

1999-04-01

As I write this, JCE Online is in the middle of being redesigned to make it a more usable resource. By the time you read this, the typical online page for articles of this Journal will look like Figure 1. The page has five main features:

• the page heading with the global menu bar
• the left-hand navigation bar
• the page menu bar near the top of the page and repeated near the bottom
• the main content region in the middle of the page
• the right-hand column of local navigation links

Should we perform an echocardiogram in hypertensive patients classified as having low and medium risk?

PubMed

Suárez, Carmen; Villar, José; Martel, Nieves; Extremera, Blas Gil; Suliman, Najaty; Campo, Carlos; Castellanos, Victoriano; Liébana, Antonio; Rodilla, Enrique; Nieto, Javier; Velasco, Olga; Ruilope, Luis M

2006-01-04

Left ventricular hypertrophy is an important predictor of cardiovascular risk and its detection contributes to risk stratification. However, echocardiography is not a routine procedure and electrocardiography (ECG) underestimates its prevalence. To evaluate the prevalence of echocardiographic left ventricular hypertrophy in low and medium risk non-treated hypertensive subjects, in order to find out the percentage of them who would be reclassified as high risk patients. Cross-sectional, multicenter study was performed in hospital located hypertension units. An echocardiogram was performed in 197 previously untreated hypertensive patients, > 18 years, classified as having low (61%) or medium (39%) risk, according to the OMS/ISH classification. The presence of left ventricular hypertrophy was considered if left ventricular mass index was > or = 134 or 110 g/m(2) in men and women, respectively (Devereux criteria). A logistic regression analysis was performed to identify factors associated to left ventricular hypertrophy. The prevalence of left ventricular hypertrophy was 23.9% (95% CI:17.9-29.9), 25.6% in men and 22.6% in women. In the low risk group its prevalence was 20.7% and in medium risk group 29.5%. Factors associated to left ventricular hypertrophy were: years since the diagnosis of hypertension, OR:1.1 (95% CI:1.003-1.227); systolic blood pressure, OR:1.08 (95% CI:1.029-1.138); diastolic blood pressure, OR:0.9 (95% CI:0.882-0.991); and family history of cardiovascular disease, OR:4.3 (95% CI:1.52-12.18). These findings underline the importance of performing an echocardiogram in low and high risk untreated hypertensive patients in which treatment would otherwise be delayed for even one year.

An anthropological perspective on the evolution and lateralization of the brain.

PubMed

Dawson, J L

1977-09-30

The purpose of this paper is to review the anthropological evidence relating to the cultural determinants of the right-hand first postaulted by Hertz in his classic study. Also a genetic/cultural conformity model of handedness is presented that postulates that the incidence of handedness in a society is held to result both from the genetic expression of handedness interacting with cultural pressures towards conformity. The evolutionary basis for the hemispheric functional organization into cognitive and perceptual hemispheric functions is discussed in terms of "right-handed dominant homozygotes, DD," "heterozygotes, DR," mixed-handers, and "left-handed recessive homozygotes, RR." The cross-cultural distribution of handedness provides support for this model since the more conforming agriculturalists as measured by the Asch Test have a significantly lower incidence of left-handedness (0.59%, 1.5% and 3.4%), while the more permissively socialized Eskimo and Arunta hunters, who are seen to be more independent on the Asch Test, have 11.3% and 10.5% left-handers, respectively. Also, due to the greater pressures for females to conform in agricultural societies, the incidence of female left-handedness in agricultural societies is 0% out of 330 female Ss, with 3.8%, 0.79%, and 2.5% in agricultural males, as contrasted with the Eskimo hunters who have 12.5% left-handed males and 10.3% left-handed females, showing no significant sex difference. A further Hong Kong-English study also supports the genetic/cultural conformity model with a significantly lower incidence of Hong Kong Chinese left-handers (RR: male = 2.7%, and female = 4.2%). The next section, concerned with the neonatal sex-hormone differentiation and lateralization processes, provides a neuropsychologic theory relating to spatial and linguistic skills that is relevant to the following section, which deals with relationships between laterality and cognitive style. The results are also presented for the Alaskan Eskimo in relation to hand, eye, auditory dominance and cognitive style. The analysis of Eskimo fixed-versus mixed-laterality data also confirms, as predicted, that both within and across a modality (e.g., right hand/right eye/right ear) fixed right-dominance Eskimo Ss are more field-independent than mixed-dominance Ss, while the fixed left-dominance Ss are the most field-dependent and have lower spatial skills. The discussion section reviews the papers relating to the genetic/conformity model of handedness, as well as laterality and cognitive style. The evolutionary adaptive significance of sex differences in gonadal differentiation and lateralization of the brain on spatial and linguistic skills are also reviewed. The conclusions are concerned with the implications for biosocial theory and the rapidly changing incidence of left-handedness due to accompanying changes in cultural pressures both within and across cultures.

[Needling technique of Professor Li Yan-Fang].

PubMed

Li, Li-Jun

2014-01-01

Experiences of needling techniques of Professor LI Ya- fang is introduced in this article. Gentle and superficial insertion is adopted by Professor LI in clinic. Emphases are put on the qi regulation function, needling sensation to the affected region and insertion with both hands, especially the function of the left hand as pressing hand. The gentle and superficial insertion should be done as the follows: hold the needle with the right hand, press gently along the running course of meridians with the left hand to promote qi circulation, hard pressing should be applied at acupoints to disperse the local qi and blood, insert the needle gently and quickly into the subcutaneous region with the right hand, and stop the insertion when patient has the needling sensation. While the fast needling is characterized with shallow insertion and swift manipulation: the left hand of the manipulator should press first along the running course of the meridian, and fix the local skin, hold the needle with the right hand and insert the needle quickly into the acupoint. Withdrawal of the needle should be done immediately after the reinforcing and reducing manipulations. Professor LI is accomplished in qi regulation. It is held by him that regulating qi circulation is essence of acupuncture, letting the patient get the needling sensation is the most important task of needling. Lifting, thrusting and rotation manipulations should be applied to do reinforcing or reducing. The tissue around the tip of the needle should not be too contracted or too relaxed, and the resistance should not be too strong or too weak. The feeling of the insertion hand of the practitioner should not be too smooth or too hesitant. Needle should be inserted into the skin quickly at the moment of hard pressing by the left hand. And then, slow rotation and gentle lifting and thrusting can be applied to promote the needling sensation like electric current pass through and to reach the affected region along the running course of meridians.

You Turn Me Cold: Evidence for Temperature Contagion

PubMed Central

Featherstone, Eric; Voon, Valerie; Singer, Tania; Critchley, Hugo D.; Harrison, Neil A.

2014-01-01

Introduction During social interactions, our own physiological responses influence those of others. Synchronization of physiological (and behavioural) responses can facilitate emotional understanding and group coherence through inter-subjectivity. Here we investigate if observing cues indicating a change in another's body temperature results in a corresponding temperature change in the observer. Methods Thirty-six healthy participants (age; 22.9±3.1 yrs) each observed, then rated, eight purpose-made videos (3 min duration) that depicted actors with either their right or left hand in visibly warm (warm videos) or cold water (cold videos). Four control videos with the actors' hand in front of the water were also shown. Temperature of participant observers' right and left hands was concurrently measured using a thermistor within a Wheatstone bridge with a theoretical temperature sensitivity of <0.0001°C. Temperature data were analysed in a repeated measures ANOVA (temperature × actor's hand × observer's hand). Results Participants rated the videos showing hands immersed in cold water as being significantly cooler than hands immersed in warm water, F(1,34) = 256.67, p<0.001. Participants' own hands also showed a significant temperature-dependent effect: hands were significantly colder when observing cold vs. warm videos F(1,34) = 13.83, p = 0.001 with post-hoc t-test demonstrating a significant reduction in participants' own left (t(35) = −3.54, p = 0.001) and right (t(35) = −2.33, p = 0.026) hand temperature during observation of cold videos but no change to warm videos (p>0.1). There was however no evidence of left-right mirroring of these temperature effects p>0.1). Sensitivity to temperature contagion was also predicted by inter-individual differences in self-report empathy. Conclusions We illustrate physiological contagion of temperature in healthy individuals, suggesting that empathetic understanding for primary low-level physiological challenges (as well as more complex emotions) are grounded in somatic simulation. PMID:25551826

MicroRNA-363 negatively regulates the left ventricular determining transcription factor HAND1 in human embryonic stem cell-derived cardiomyocytes.

PubMed

Wagh, Vilas; Pomorski, Alexander; Wilschut, Karlijn J; Piombo, Sebastian; Bernstein, Harold S

2014-06-06

Posttranscriptional control of mRNA by microRNA (miRNA) has been implicated in the regulation of diverse biologic processes from directed differentiation of stem cells through organism development. We describe a unique pathway by which miRNA regulates the specialized differentiation of cardiomyocyte (CM) subtypes. We differentiated human embryonic stem cells (hESCs) to cardiac progenitor cells and functional CMs, and characterized the regulated expression of specific miRNAs that target transcriptional regulators of left/right ventricular-subtype specification. From >900 known human miRNAs in hESC-derived cardiac progenitor cells and functional CMs, a subset of differentially expressed cardiac miRNAs was identified, and in silico analysis predicted highly conserved binding sites in the 3'-untranslated regions (3'UTRs) of Hand-and-neural-crest-derivative-expressed (HAND) genes 1 and 2 that are involved in left and right ventricular development. We studied the temporal and spatial expression patterns of four miRNAs in differentiating hESCs, and found that expression of miRNA (miR)-363, miR-367, miR-181a, and miR-181c was specific for stage and site. Further analysis showed that miR-363 overexpression resulted in downregulation of HAND1 mRNA and protein levels. A dual luciferase reporter assay demonstrated functional interaction of miR-363 with the full-length 3'UTR of HAND1. Expression of anti-miR-363 in-vitro resulted in enrichment for HAND1-expressing CM subtype populations. We also showed that BMP4 treatment induced the expression of HAND2 with less effect on HAND1, whereas miR-363 overexpression selectively inhibited HAND1. These data show that miR-363 negatively regulates the expression of HAND1 and suggest that suppression of miR-363 could provide a novel strategy for generating functional left-ventricular CMs.

Coordination of hand shape.

PubMed

Pesyna, Colin; Pundi, Krishna; Flanders, Martha

2011-03-09

The neural control of hand movement involves coordination of the sensory, motor, and memory systems. Recent studies have documented the motor coordinates for hand shape, but less is known about the corresponding patterns of somatosensory activity. To initiate this line of investigation, the present study characterized the sense of hand shape by evaluating the influence of differences in the amount of grasping or twisting force, and differences in forearm orientation. Human subjects were asked to use the left hand to report the perceived shape of the right hand. In the first experiment, six commonly grasped items were arranged on the table in front of the subject: bottle, doorknob, egg, notebook, carton, and pan. With eyes closed, subjects used the right hand to lightly touch, forcefully support, or imagine holding each object, while 15 joint angles were measured in each hand with a pair of wired gloves. The forces introduced by supporting or twisting did not influence the perceptual report of hand shape, but for most objects, the report was distorted in a consistent manner by differences in forearm orientation. Subjects appeared to adjust the intrinsic joint angles of the left hand, as well as the left wrist posture, so as to maintain the imagined object in its proper spatial orientation. In a second experiment, this result was largely replicated with unfamiliar objects. Thus, somatosensory and motor information appear to be coordinated in an object-based, spatial-coordinate system, sensitive to orientation relative to gravitational forces, but invariant to grasp forcefulness.

Hemispheric specialization in spontaneous gesticulation in a patient with callosal disconnection.

PubMed

Lausberg, H; Davis, M; Rothenhäusler, A

2000-01-01

This is an investigation of spontaneous gesticulation in a left-handed patient with a callosal disconnection syndrome due to infarction of the total length of the corpus callosum. After callosal infarction, the patient gesticulated predominantly unilaterally with the left hand despite left apraxia. Bilateral gesticulation occurred later on and was presumably achieved by an increase in ipsilateral proximal control. Movement analysis further indicated that the two hemispheres are specialized for certain gesture types. Gestures with emotional connotation and batons (emphasizing prosody) were generated predominantly in the right hemisphere whereas physiographics which picture the linguistic content concretely and deictics (pointing) were of left-hemispheric origin.

Comparison of the two cerebral hemispheres in inhibitory processes operative during movement preparation

PubMed Central

Klein, Pierre-Alexandre; Duque, Julie; Labruna, Ludovica; Ivry, Richard B.

2015-01-01

Neuroimaging and neuropsychological studies suggest that in right-handed individuals, the left hemisphere plays a dominant role in praxis, relative to the right hemisphere. However hemispheric asymmetries assessed with transcranial magnetic stimulation (TMS) has not shown consistent differences in corticospinal (CS) excitability of the two hemispheres during movements. In the current study, we systematically explored hemispheric asymmetries in inhibitory processes that are manifest during movement preparation and initiation. Single-pulse TMS was applied over the left or right primary motor cortex (M1LEFT and M1RIGHT, respectively) to elicit motor-evoked potentials (MEPs) in the contralateral hand while participants performed a two-choice reaction time task requiring a cued movement of the left or right index finger. In Experiments 1 and 2, TMS probes were obtained during a delay period following the presentation of the preparatory cue that provided partial or full information about the required response. MEPs were suppressed relative to baseline regardless of whether they were elicited in a cued or uncued hand. Importantly, the magnitude of these inhibitory changes in CS excitability was similar when TMS was applied over M1LEFT or M1RIGHT, irrespective of the amount of information carried by the preparatory cue. In Experiment 3, there was no preparatory cue and TMS was applied at various time points after the imperative signal. When CS excitability was probed in the cued effector, MEPs were initially inhibited and then rose across the reaction time interval. This function was similar for M1LEFT and M1RIGHT TMS. When CS excitability was probed in the uncued effector, MEPs remained inhibited throughout the RT interval. However, MEPs in right FDI became more inhibited during selection and initiation of a left hand movement, whereas MEPs in left FDI remained relatively invariant across RT interval for the right hand. In addition to these task-specific effects, there was a global difference in CS excitability across experiments between the two hemispheres. When the intensity of stimulation was set to 115% of the resting threshold, MEPs were larger when the TMS probe was applied over the M1LEFT than over M1RIGHT. In summary, while the latter result suggests that M1LEFT is more excitable than M1RIGHT, the recruitment of preparatory inhibitory mechanisms is similar within the two cerebral hemispheres. PMID:26458519

Dissociating the influence of response selection and task anticipation on corticospinal suppression during response preparation.

PubMed

Duque, Julie; Labruna, Ludovica; Cazares, Christian; Ivry, Richard B

2014-12-01

Motor behavior requires selecting between potential actions. The role of inhibition in response selection has frequently been examined in tasks in which participants are engaged in some advance preparation prior to the presentation of an imperative signal. Under such conditions, inhibition could be related to processes associated with response selection, or to more general inhibitory processes that are engaged in high states of anticipation. In Experiment 1, we manipulated the degree of anticipatory preparation. Participants performed a choice reaction time task that required choosing between a movement of the left or right index finger, and used transcranial magnetic stimulation (TMS) to elicit motor evoked potentials (MEPs) in the left hand agonist. In high anticipation blocks, a non-informative cue (e.g., fixation marker) preceded the imperative; in low anticipation blocks, there was no cue and participants were required to divide their attention between two tasks to further reduce anticipation. MEPs were substantially reduced before the imperative signal in high anticipation blocks. In contrast, in low anticipation blocks, MEPs remained unchanged before the imperative signal but showed a marked suppression right after the onset of the imperative. This effect occurred regardless of whether the imperative had signalled a left or right hand response. After this initial inhibition, left MEPs increased when the left hand was selected and remained suppressed when the right hand was selected. We obtained similar results in Experiment 2 except that the persistent left MEP suppression when the left hand was not selected was attenuated when the alternative response involved a non-homologous effector (right foot). These results indicate that, even in the absence of an anticipatory period, inhibitory mechanisms are engaged during response selection, possibly to prevent the occurrence of premature and inappropriate responses during a competitive selection process. Copyright © 2014 Elsevier Ltd. All rights reserved.

77 FR 20515 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-05

... attachment fittings and the swan neck with serviceable ones if necessary. This AD was prompted by reports of cracks on the forward attachment fittings of the left and right sides of the forward hinge of the nose... (FWD) fittings (hinge 5) of the NLG aft doors (Right Hand (RH) side or Left Hand (LH) side). The cracks...

Right Visual Field Advantage for Perceived Contrast: Correlation with an Auditory Bias and Handedness

ERIC Educational Resources Information Center

Railo, H.; Tallus, J.; Hamalainen, H.

2011-01-01

Studies have suggested that supramodal attentional resources are biased rightward due to asymmetric spatial fields of the two hemispheres. This bias has been observed especially in right-handed subjects. We presented left and right-handed subjects with brief uniform grey visual stimuli in either the left or right visual hemifield. Consistent with…

77 FR 24264 - Notice of Receipt of Petition for Decision That Nonconforming Left-Hand Drive 2006 Land Rover...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-23

..., and Roof Panel Systems, 119 New Pneumatic Tires for Vehicles other than passenger Cars, 124...-0040, Notice 1] Notice of Receipt of Petition for Decision That Nonconforming Left-Hand Drive 2006 Land Rover Range Rover Multi-Purpose Passenger Vehicles Manufactured Prior to September 1, 2006 Are Eligible...

77 FR 37773 - Airworthiness Directives; BAE Systems (Operations) Limited Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-25

... (FAA), Department of Transportation (DOT). ACTION: Final rule. SUMMARY: We are adopting a new... airplanes. This AD was prompted by a report of a crack found on the left-hand sidewall well on the nose... stiffeners on the left-hand sidewall on the NLG bay for cracks, and repair or replace the sidewall if...

9 CFR 322.2 - Export certificates; instructions concerning issuance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... new certificates in lieu of the original certificates may be issued. A certificate issued in lieu of another shall show in the left hand margin the notation “Issued in lieu of * * *”, and the number of the..., shall if available, be surrendered to the inspector in charge and marked by him to show in the left hand...

On the complexity of classical guitar playing: functional adaptations to task constraints.

PubMed

Heijink, Hank; Meulenbroek, Ruud G J

2002-12-01

The authors performed a behavioral study of the complexity of left-hand finger movements in classical guitar playing. Six professional guitarists played movement sequences in a fixed tempo. Left-hand finger movements were recorded in 3 dimensions, and the guitar sound was recorded synchronously. Assuming that performers prefer to avoid extreme joint angles when moving, the authors hypothesized 3 complexity factors. The results showed differential effects of the complexity factors on the performance measures and on participants' judgments of complexity. The results demonstrated that keeping the joints in the middle of their range is an important principle in guitar playing, and players exploit the available tolerance in timing and placement of the left-hand fingers to control the acoustic output variability.

Noninvasive brain stimulation for treatment of right- and left-handed poststroke aphasics.

PubMed

Heiss, Wolf-Dieter; Hartmann, Alexander; Rubi-Fessen, Ilona; Anglade, Carole; Kracht, Lutz; Kessler, Josef; Weiduschat, Nora; Rommel, Thomas; Thiel, Alexander

2013-01-01

Accumulating evidence from single case studies, small case series and randomized controlled trials seems to suggest that inhibitory noninvasive brain stimulation (NIBS) over the contralesional inferior frontal gyrus (IFG) of right-handers in conjunction with speech and language therapy (SLT) improves recovery from poststroke aphasia. Application of inhibitory NIBS to improve recovery in left-handed patients has not yet been reported. A total of 29 right-handed subacute poststroke aphasics were randomized to receive either 10 sessions of SLT following 20 min of inhibitory repetitive transcranial magnetic stimulation (rTMS) over the contralesional IFG or 10 sessions of SLT following sham stimulation; 2 left-handers were treated according to the same protocol with real rTMS. Language activation patterns were assessed with positron emission tomography prior to and after the treatment; 95% confidence intervals for changes in language performance scores and the activated brain volumes in both hemispheres were derived from TMS- and sham-treated right-handed patients and compared to the same parameters in left-handers. Right-handed patients treated with rTMS showed better recovery of language function in global aphasia test scores (t test, p < 0.002) as well as in picture-naming performance (ANOVA, p = 0.03) than sham-treated right-handers. In treated right-handers, a shift of activation to the ipsilesional hemisphere was observed, while sham-treated patients consolidated network activity in the contralesional hemisphere (repeated-measures ANOVA, p = 0.009). Both left-handed patients also improved, with 1 patient within the confidence limits of TMS-treated right-handers (23 points, 15.9-28.9) and the other patient within the limits of sham-treated subjects (8 points, 2.8-14.5). Both patients exhibited only a very small interhemispheric shift, much less than expected in TMS-treated right-handers, and more or less consolidated initially active networks in both hemispheres. Inhibitory rTMS over the nondominant IFG appears to be a safe and effective treatment for right-handed poststroke aphasics. In the 2 cases of left-handed aphasics no deterioration of language performance was observed with this protocol. However, therapeutic efficiency is less obvious and seems to be more related to the dominance pattern prior to the stroke than to the TMS intervention.

Seeing the body distorts tactile size perception.

PubMed

Longo, Matthew R; Sadibolova, Renata

2013-03-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception. Copyright © 2012 Elsevier B.V. All rights reserved.

Assessment of the Ipsilesional Hand Function in Stroke Survivors: The Effect of Lesion Side.

PubMed

Cunha, Bianca Pinto; de Freitas, Sandra Maria Sbeghen Ferreira; de Freitas, Paulo Barbosa

2017-07-01

The aim of this study was to examine the effect of the side of brain lesion on the ipsilesional hand function of stroke survivors. Twenty-four chronic stroke survivors, equally allocated in 2 groups according to the side of brain lesion (right or left), and 12 sex- and age-matched healthy controls performed the Jebsen-Taylor Hand Function Test (JTHFT), the Nine-Hole Peg Test (9HPT), the maximum power grip strength (PwGS max ) test, and the maximum pinch grip strength (PnGS max ) test. Only the ipsilesional hand of the stroke survivors and both hands (left and right) of the controls were assessed. PwGS max and PnGS max were similar among all tested groups. Performances in JTHFT and 9HPT were affected by the brain injury. Individuals with left brain damage showed better performance in 9HPT than individuals with right brain damage, but performance in JTHFT was similar. Individuals after a brain injury have the capacity to produce maximum strength preserved when using their ipsilesional hand. However, the dexterity of their hands and digits is affected, in particular for stroke individuals with right brain lesion. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Hemispheric resource limitations in comprehending ambiguous pictures.

PubMed

White, H; Minor, S W

1990-03-01

Ambiguous pictures (Roschach inkblots) were lateralized for 100 msec vs. 200 msec to the right and left hemispheres (RH and LH) of 32 normal right-handed males who determined which of two previously presented words (an accurate or inaccurate one) better described the inkblot. Over the first 32 trials, subjects receiving each stimulus exposure duration were less accurate when the hemisphere receiving the stimulus also controlled the hand used to register a keypress response (RH-left hand and LH-right hand trials) than when hemispheric resources were shared, i.e., when one hemisphere controlled stimulus processing and the other controlled response programming. These differences were eliminated when the 32 trials were repeated.

Toggle switch from optical bistability to multistability via an elliptically polarized field

NASA Astrophysics Data System (ADS)

Yan, Xiang-An; Ren, Bo-Quan; Wang, Li-Qiang; Liu, Yao-Wu; Yu, Hua-Wa

2017-06-01

In this paper, we propose a scheme for manipulating the behavior of optical bistability (OB) and optical multistability (OM) in an N-type four-level atomic system. In the scheme, quantum interference is optimized by the left-handed and the right-handed fields of an elliptically polarized field (EPF). The threshold and the hysteresis cycle shape of OB and OM can be controlled by modulating the intensity of the EPF. Especially, the transition from OB to OM or vice versa can also be easily realized by proper tuning the phase difference between the left-handed and right-handed polarized fields under the optimal intensity of the EPF.

Association between digital dermatoglyphics and handedness among Sinhalese in Sri Lanka

PubMed Central

Wijerathne, Buddhika TB; Rathnayake, Geetha K

2013-01-01

Background The relationship between handedness and digital dermatoglyphic patterns has never been investigated in the Sinhalese population. The goal of this study is to establish the above mentioned relationship, which would positively aid personal identification.  Findings One hundred forty Sinhalese students (70 right-handed and 70 left-handed) were studied for their digital dermatoglyphic pattern distribution. The results show that a statistically significant correlation exists for; digit 5 (Ulnar loop; P= 0.0449 and radial loop; P= 0.0248 by Fisher’s exact test) of the right hand in female, digit 1 (radial loop; P=0.0248 by Fisher’s exact test) and digit 2 (Ulnar loop; P=0.0306) of the left hand in females, digit 3 (Ulnar loop; P= 0.0486 and whorl; P= 0.0356 by Fisher’s exact test) and digit 4 (Ulnar loop; P= 0.0449 and whorl; P= 0.0301 by Fisher’s exact test) of the right hand in males, digit 4 (whorl; P=0.0160 by Fisher’s exact test) of the left hand in males. Conclusions  Statistically significant differences in handedness and digital dermatoglyphic patterns were evident among Sinhalese people. Further study with a larger sample size is recommended. PMID:24627780

A Double-Coil TMS Method to Assess Corticospinal Excitability Changes at a Near-Simultaneous Time in the Two Hands during Movement Preparation

PubMed Central

Wilhelm, Emmanuelle; Quoilin, Caroline; Petitjean, Charlotte; Duque, Julie

2016-01-01

Background: Many previous transcranial magnetic stimulation (TMS) studies have investigated corticospinal excitability changes occurring when choosing which hand to use for an action, one of the most frequent decision people make in daily life. So far, these studies have applied single-pulse TMS eliciting motor-evoked potential (MEP) in one hand when this hand is either selected or non-selected. Using such method, hand choices were shown to entail the operation of two inhibitory mechanisms, suppressing MEPs in the targeted hand either when it is non-selected (competition resolution, CR) or selected (impulse control, IC). However, an important limitation of this “Single-Coil” method is that MEPs are elicited in selected and non-selected conditions during separate trials and thus those two settings may not be completely comparable. Moreover, a more important problem is that MEPs are computed in relation to the movement of different hands. The goal of the present study was to test a “Double-Coil” method to evaluate IC and CR preceding the same hand responses by applying Double-Coil TMS over the two primary motor cortices (M1) at a near-simultaneous time (1 ms inter-pulse interval). Methods: MEPs were obtained in the left (MEPLEFT) and right (MEPRIGHT) hands while subjects chose between left and right hand key-presses in blocks using a Single-Coil or a Double-Coil method; in the latter blocks, TMS was either applied over left M1 first (TMSLRM1 group, n = 12) or right M1 first (TMSRLM1 group, n = 12). Results: MEPLEFT were suppressed preceding both left (IC) and right (CR) hand responses whereas MEPRIGHT were only suppressed preceding left (CR) but not right (IC) hand responses. This result was observed regardless of whether Single-Coil or Double-Coil TMS was applied in the two subject groups. However, in the TMSLRM1 group, the MEP suppression was attenuated in Double-Coil compared to Single-Coil blocks for both IC and CR, when probed with MEPLEFT (elicited by the second pulse). Conclusions: Although Double-Coil TMS may be a reliable method to assess bilateral motor excitability provided that a RM1-LM1 pulse order is used, further experiments are required to understand the reduced MEPLEFT changes in Double-Coil blocks when the LM1-RM1 pulse order was used. PMID:27014020

“Left Neglected,” but Only in Far Space: Spatial Biases in Healthy Participants Revealed in a Visually Guided Grasping Task

PubMed Central

de Bruin, Natalie; Bryant, Devon C.; Gonzalez, Claudia L. R.

2014-01-01

Hemispatial neglect is a common outcome of stroke that is characterized by the inability to orient toward, and attend to stimuli in contralesional space. It is established that hemispatial neglect has a perceptual component, however, the presence and severity of motor impairments is controversial. Establishing the nature of space use and spatial biases during visually guided actions amongst healthy individuals is critical to understanding the presence of visuomotor deficits in patients with neglect. Accordingly, three experiments were conducted to investigate the effect of object spatial location on patterns of grasping. Experiment 1 required right-handed participants to reach and grasp for blocks in order to construct 3D models. The blocks were scattered on a tabletop divided into equal size quadrants: left near, left far, right near, and right far. Identical sets of building blocks were available in each quadrant. Space use was dynamic, with participants initially grasping blocks from right near space and tending to “neglect” left far space until the final stages of the task. Experiment 2 repeated the protocol with left-handed participants. Remarkably, left-handed participants displayed a similar pattern of space use to right-handed participants. In Experiment 3 eye movements were examined to investigate whether “neglect” for grasping in left far reachable space had its origins in attentional biases. It was found that patterns of eye movements mirrored patterns of reach-to-grasp movements. We conclude that there are spatial biases during visually guided grasping, specifically, a tendency to neglect left far reachable space, and that this “neglect” is attentional in origin. The results raise the possibility that visuomotor impairments reported among patients with right hemisphere lesions when working in contralesional space may result in part from this inherent tendency to “neglect” left far space irrespective of the presence of unilateral visuospatial neglect. PMID:24478751

Grip Preference, Dermatoglyphics, and Hand Use in Captive Chimpanzees (Pan troglodytes)

PubMed Central

Hopkins, William D.; Russell, Jamie L.; Hostetter, Autumn; Pilcher, Dawn; Dahl, Jeremy F.

2007-01-01

This paper examined the association between grip type, hand use, and fingerprint patterns in a sample of captive chimpanzees. Grip type for simple reaching was assessed for the left and right hand and classified as thumb-index, middle-index, or single-digit responses. Fingerprint patterns were characterized as whorls, loops, or arches on each finger. The results indicated that chimpanzees exhibit significantly more thumb-index responses for the right compared to the left hand. In addition, thumb-index responses were more prevalent for subjects that had a whorl compared to a loop or arch on their thumb. The results suggest that fingerprint patterns are associated with individual differences in grasping type in chimpanzees as well as some variation in hand use. PMID:15761856

Thermographic Evaluation of the Hands of Pig Slaughterhouse Workers Exposed to Cold Temperatures.

PubMed

Tirloni, Adriana Seára; Reis, Diogo Cunha Dos; Ramos, Eliane; Moro, Antônio Renato Pereira

2017-07-26

Brazil was rated the fourth leading producer and exporter of pork meat in the world. The aim of this study was to evaluate the temperature of the hands of pig slaughterhouse workers and its relation to the thermal sensation of the hands and the use of a cutting tool. The study included 106 workers in a pig slaughterhouse. An infrared camera FlirThermaCAM E320 (Flir Systems, Wilsonville, OR, USA) was used to collect the images of the dorsal and palmar surfaces of both hands. A numerical scale was used to obtain the thermal sensation. Chi-square test, Pearson correlation and Student's t test or Wilcoxon were used ( p ≤ 0.05). The majority of workers felt cold in the hands (66%) and workers who used the knife felt the coldest. There was an association between the thermal sensation and the use of knife ( p = 0.001). Workers who used the tool showed correlation between the thermal sensation and the temperatures of the left fingers, with a difference between the temperatures of the right and left hands of those who used the knife ( p ≤ 0.05). The hands (left) that manipulated the products presented the lowest temperatures. Findings indicate that employers of pig slaughterhouses should provide gloves with adequate thermal insulation to preserve the health of workers' hands.

Thermographic Evaluation of the Hands of Pig Slaughterhouse Workers Exposed to Cold Temperatures

PubMed Central

Ramos, Eliane

2017-01-01

Brazil was rated the fourth leading producer and exporter of pork meat in the world. The aim of this study was to evaluate the temperature of the hands of pig slaughterhouse workers and its relation to the thermal sensation of the hands and the use of a cutting tool. The study included 106 workers in a pig slaughterhouse. An infrared camera FlirThermaCAM E320 (Flir Systems, Wilsonville, OR, USA) was used to collect the images of the dorsal and palmar surfaces of both hands. A numerical scale was used to obtain the thermal sensation. Chi-square test, Pearson correlation and Student’s t test or Wilcoxon were used (p ≤ 0.05). The majority of workers felt cold in the hands (66%) and workers who used the knife felt the coldest. There was an association between the thermal sensation and the use of knife (p = 0.001). Workers who used the tool showed correlation between the thermal sensation and the temperatures of the left fingers, with a difference between the temperatures of the right and left hands of those who used the knife (p ≤ 0.05). The hands (left) that manipulated the products presented the lowest temperatures. Findings indicate that employers of pig slaughterhouses should provide gloves with adequate thermal insulation to preserve the health of workers’ hands. PMID:28933764

Laterality and body ownership: Effect of handedness on experience of the rubber hand illusion.

PubMed

Smit, M; Kooistra, D I; van der Ham, I J M; Dijkerman, H C

2017-11-01

Body ownership has mainly been linked to the right hemisphere and larger interhemispheric connectivity has been shown to be associated with greater right hemispheric activation. Mixed-handed participants tend to have more interhemispheric connectivity compared to extreme handed participants. The aim of this study was to examine whether feelings of ownership as assessed with the rubber hand illusion (RHI) are differentiated by handedness and differed between the left and right hand. Sinistrals-, dextrals-, and mixed-handed individuals (n = 63) were subjected to the RHI. Stroking was synchronously and asynchronously performed on both the participant's hand and a rubber hand. Outcome measures were an embodiment questionnaire and proprioceptive drift. In contrast to our hypotheses we show a similar experience of ownership for all groups, which may indicate no hemispheric specialization for the illusion. In addition, plasticity of ownership and body ownership are similar for the left hand and right hand in all participants, which suggests similar representations for both hands in the brain. This might be useful to maintain a coherent sense of the body in space.

Training, Retention, and Transfer of Data Entry Perceptual and Motoric Processes Over Long Retention Intervals

NASA Technical Reports Server (NTRS)

Kole, James A.; Schneider, Vivian I.; Healy, Alice F.; Barshi, Immanuel

2017-01-01

Subjects trained in a standard data entry task, which involved typing numbers (e.g., 5421) using their right hands. At test (6 months post-training), subjects completed the standard task, followed by a left-hand variant (typing with their left hands) that involved the same perceptual, but different motoric, processes as the standard task. At a second test (8 months post-training), subjects completed the standard task, followed by a code variant (translating letters into digits, then typing the digits with their right hands) that involved different perceptual, but the same motoric, processes as the standard task. For each of the three tasks, half the trials were trained numbers (old) and half were new. Repetition priming (faster response times to old than new numbers) was found for each task. Repetition priming for the standard task reflects retention of trained numbers; for the left-hand variant reflects transfer of perceptual processes; and for the code variant reflects transfer of motoric processes. There was thus evidence for both specificity and generalizability of training data entry perceptual and motoric processes over very long retention intervals.

Phonological memory in sign language relies on the visuomotor neural system outside the left hemisphere language network.

PubMed

Kanazawa, Yuji; Nakamura, Kimihiro; Ishii, Toru; Aso, Toshihiko; Yamazaki, Hiroshi; Omori, Koichi

2017-01-01

Sign language is an essential medium for everyday social interaction for deaf people and plays a critical role in verbal learning. In particular, language development in those people should heavily rely on the verbal short-term memory (STM) via sign language. Most previous studies compared neural activations during signed language processing in deaf signers and those during spoken language processing in hearing speakers. For sign language users, it thus remains unclear how visuospatial inputs are converted into the verbal STM operating in the left-hemisphere language network. Using functional magnetic resonance imaging, the present study investigated neural activation while bilinguals of spoken and signed language were engaged in a sequence memory span task. On each trial, participants viewed a nonsense syllable sequence presented either as written letters or as fingerspelling (4-7 syllables in length) and then held the syllable sequence for 12 s. Behavioral analysis revealed that participants relied on phonological memory while holding verbal information regardless of the type of input modality. At the neural level, this maintenance stage broadly activated the left-hemisphere language network, including the inferior frontal gyrus, supplementary motor area, superior temporal gyrus and inferior parietal lobule, for both letter and fingerspelling conditions. Interestingly, while most participants reported that they relied on phonological memory during maintenance, direct comparisons between letters and fingers revealed strikingly different patterns of neural activation during the same period. Namely, the effortful maintenance of fingerspelling inputs relative to letter inputs activated the left superior parietal lobule and dorsal premotor area, i.e., brain regions known to play a role in visuomotor analysis of hand/arm movements. These findings suggest that the dorsal visuomotor neural system subserves verbal learning via sign language by relaying gestural inputs to the classical left-hemisphere language network.

Left occipitotemporal cortex contributes to the discrimination of tool-associated hand actions: fMRI and TMS evidence

PubMed Central

Perini, Francesca; Caramazza, Alfonso; Peelen, Marius V.

2014-01-01

Functional neuroimaging studies have implicated the left lateral occipitotemporal cortex (LOTC) in both tool and hand perception but the functional role of this region is not fully known. Here, by using a task manipulation, we tested whether tool-/hand-selective LOTC contributes to the discrimination of tool-associated hand actions. Participants viewed briefly presented pictures of kitchen and garage tools while they performed one of two tasks: in the action task, they judged whether the tool is associated with a hand rotation action (e.g., screwdriver) or a hand squeeze action (e.g., garlic press), while in the location task they judged whether the tool is typically found in the kitchen (e.g., garlic press) or in the garage (e.g., screwdriver). Both tasks were performed on the same stimulus set and were matched for difficulty. Contrasting fMRI responses between these tasks showed stronger activity during the action task than the location task in both tool- and hand-selective LOTC regions, which closely overlapped. No differences were found in nearby object- and motion-selective control regions. Importantly, these findings were confirmed by a TMS study, which showed that effective TMS over the tool-/hand-selective LOTC region significantly slowed responses for tool action discriminations relative to tool location discriminations, with no such difference during sham TMS. We conclude that left LOTC contributes to the discrimination of tool-associated hand actions. PMID:25140142

The Reconstruction and Failure Analysis of The Space Shuttle Columbia

NASA Technical Reports Server (NTRS)

Russell, Richard W.

2010-01-01

This viewgraph presentation describes a very detailed reconstruction plan and failure analysis of The Space Shuttle Columbia accident. The contents include: 1) STS-107 Timeline; 2) Foam Impact; 3) Recovery; 4) Reconstruction; 5) Reconstruction Plan; 6) Reconstruction Hanger; 7) Pathfinders; 8) Aluminum Pathfinder; 9) Early Analysis - Left MLG Door Area; 10) Emphasis Switched to Left Hand Wing Leading Edge; 11) Wing Leading Edge Subsystem (LESS); 12) 3D Reconstruction of Left WLE; 13) Left Wing Tile Table; 14) LESS Observations; 15) Left Hand Wing Debris Points to RCC 8/9 - Slumped Tile; 16) Reconstructed View of LC/P 9 tile with I/B Tile; 17) Reconstructed View of Lower C/P 9 Tile; 18) Carrier Panel 8 - Upper; 19) Left Hand Wing Debris Points to RCC 8/9 - Erosion and RCC with attach hole intact; 20) Erosion on Panel 8 Upper Outboard Rib; 21) RCC Panels 8 & 9 Erosion Features; 22) Slumping Source for Carrier Panel 9 Tile was Revealed; 23) Debris Indicated Highest Probability Initiation Site; 24) Left Hand Wing Debris Points to RCC 8/9- Metallic Deposits; 25) Relative Metallic Deposition on L/H Wing Materials; 26) Metallic Deposit Example, LH RCC 8; 27) High Level Questions; 28) Analysis Plan Challenges; 29) Analysis Techniques; 30) Analysis Approach; 31) RCC Panel 8 Erosion Features; 32) Radiographic Features; 33) Radiography WLE LH Panel 8; 34) LH RCC 8 Upper Apex; 35) LH RCC 8 - Deposit Feature: Thick Tear Shaped; 36) LH RCC 8 - Deposit Feature: Thick Globules; 37) LH RCC 8 - Deposit Feature: Spheroids; 38) LH RCC 8 - Deposit Feature: Uniform Deposit; 39) Significant Findings - Sampling All Other panels; 40) Proposed Breach Location and Plasma Flow; 41) Corroborating Information - RCC Panel Debris Locations; 42) Corroborating Information - LH OMS Pod Analysis; 43) Corroborating Information - Impact Testing; and 44) Overall Forensic Conclusions.

Effects of eye dominance (left vs. right) and cannabis use on intermanual coordination and negative symptoms in schizophrenia patients.

PubMed

Gorynia, Inge; Schwaiger, Markus; Heinz, Andreas

2014-12-01

Based on the previous findings, it has been assumed that in schizophrenia patients, eye dominance and cannabis use will affect negative symptoms and intermanual coordination (IMC), an index of interhemispheric communication. But eye dominance, specifically the clinical findings for it, has been neglected in schizophrenia research. We therefore investigated its effects in 52 right-handed (36 right-eyed and 16 left-eyed) and 51 left-handed (35 left-eyed and 16 right-eyed) schizophrenia in-patients without and with drug use. Eye dominance affected IMC in all schizophrenia patients. When comparing right- and left-handers, we found that this result was only significant in the right-handed patients and in the smaller subgroup without drug use. In the right-handers, left eye dominance-like left-handedness-was associated with higher values in IMC and less pronounced manifestation of negative symptoms, right eye dominance was not. Thus, left-eyed right-handers may be more closely related to left-handers than to right-handers. In accordance with the results from the literature, we suggest that these findings are due to better interhemispheric connections and less impairment of white matter structures, especially in right-hemispheric regions. Moreover, cannabis use was related to higher scores in IMC and less pronounced negative symptoms, but only in the right-eyed and not in the left-eyed right-handers or in the left-handers. Hence, differences in eye dominance and handedness may be partially responsible for different results in interhemispheric connections among cannabis users. In conclusion, both eye dominance and use of cannabis should be taken into account when assessing clinical symptoms in schizophrenia patients.

33 CFR 13.01-25 - Description of Gold Lifesaving Medal.

Code of Federal Regulations, 2012 CFR

2012-07-01

... monument surmounted by an American eagle; the figure of a woman stands, to the left, holding in her left hand an oak wreath, and with her right hand, preparing to inscribe the name of the recipient on the monument; to the right are grouped a mast, a yard with a sail, an anchor, a sextant, and a laurel branch...

33 CFR 13.01-25 - Description of Gold Lifesaving Medal.

Code of Federal Regulations, 2011 CFR

2011-07-01

... monument surmounted by an American eagle; the figure of a woman stands, to the left, holding in her left hand an oak wreath, and with her right hand, preparing to inscribe the name of the recipient on the monument; to the right are grouped a mast, a yard with a sail, an anchor, a sextant, and a laurel branch...

33 CFR 13.01-25 - Description of Gold Lifesaving Medal.

Code of Federal Regulations, 2014 CFR

2014-07-01

... monument surmounted by an American eagle; the figure of a woman stands, to the left, holding in her left hand an oak wreath, and with her right hand, preparing to inscribe the name of the recipient on the monument; to the right are grouped a mast, a yard with a sail, an anchor, a sextant, and a laurel branch...

33 CFR 13.01-25 - Description of Gold Lifesaving Medal.

Code of Federal Regulations, 2010 CFR

2010-07-01

... monument surmounted by an American eagle; the figure of a woman stands, to the left, holding in her left hand an oak wreath, and with her right hand, preparing to inscribe the name of the recipient on the monument; to the right are grouped a mast, a yard with a sail, an anchor, a sextant, and a laurel branch...

14 CFR Appendix B to Part 417 - Flight Hazard Area Analysis for Aircraft and Ship Protection

Code of Federal Regulations, 2010 CFR

2010-01-01

... location that is the farthest left-hand crossrange, the location that is the farthest right-hand crossrange... trajectory dispersion that are the farthest uprange, downrange, right crossrange, and left crossrange... · (NEW)1/3 Where: Rop is the over pressure distance in feet. NEW = WE · C (pounds). WE is the weight of...

47 CFR 63.53 - Form.

Code of Federal Regulations, 2011 CFR

2011-10-01

... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) EXTENSION OF LINES, NEW... more than 35.6 cm (14 in) long with a left-hand margin of 4 cm (1.5 in). This requirement shall not... than 21.6 cm (8.5 in) wide and not more than 35.6 cm (14 in) long with a left-hand margin of 4 cm (1.5...

47 CFR 63.53 - Form.

Code of Federal Regulations, 2010 CFR

2010-10-01

... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) EXTENSION OF LINES, NEW... more than 35.6 cm (14 in) long with a left-hand margin of 4 cm (1.5 in). This requirement shall not... than 21.6 cm (8.5 in) wide and not more than 35.6 cm (14 in) long with a left-hand margin of 4 cm (1.5...

Measurements of VLF polarization and wave normal direction on OGO-F

NASA Technical Reports Server (NTRS)

Helliwell, R. A.

1973-01-01

A major achievement of the F-24 experiment on OGO 6 was a verification of the theory of the polarization of proton whistlers. As predicted, the electron whistler was found to be right-hand polarized and the proton whistler left hand polarized. The transition from right- to left-hand polarization was found to occur very rapidly. Thus it appears that the experimental technique may allow great accuracy in the measurement of the cross-over frequency, a frequency that provides information on the ionic composition of the ionosphere.

Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy

NASA Astrophysics Data System (ADS)

Yamashita, Yuichi; Maki, Atsushi; Ito, Yoshitoshi; Watanabe, Eiju; Mayanagi, Yoshiaki; Koizumi, Hideaki

1996-04-01

We describe the functional topography of human brain activity due to motor stimulation by using near-infrared spectroscopy. Finger motion by each hand was used as the motor stimulation, and activity in the left fronto-central region of the brain was measured. A greater change in oxyhemoglobin concentration due to brain activity during the stimulation was obtained for the right hand than for the left hand. Localization of the activity was obtained by topographically mapping the measured changes for ten positions within the region.

Analytical solution for wave propagation through a graded index interface between a right-handed and a left-handed material.

PubMed

Dalarsson, Mariana; Tassin, Philippe

2009-04-13

We have investigated the transmission and reflection properties of structures incorporating left-handed materials with graded index of refraction. We present an exact analytical solution to Helmholtz' equation for a graded index profile changing according to a hyperbolic tangent function along the propagation direction. We derive expressions for the field intensity along the graded index structure, and we show excellent agreement between the analytical solution and the corresponding results obtained by accurate numerical simulations. Our model straightforwardly allows for arbitrary spectral dispersion.

Long-term subdural strip electrocorticographic monitoring of ictal déjà vu.

PubMed

Weinand, M E; Hermann, B; Wyler, A R; Carter, L P; Oommen, K J; Labiner, D; Ahern, G; Herring, A

1994-01-01

We report a series of 8 patients with ictal déjà vu. Subdural strip electrocorticographic (ECoG) monitoring localized the ictal epileptogenic focus as follows: right (n = 6) and left (n = 2) mesiotemporal lobe. In all 8 patients, the left hemisphere was dominant for language function based on intracarotid amytal testing. In 6 right-handed patients, ictal déjà vu was associated with a right temporal lobe focus. However, in the 2 left-handed patients, the ictal focus was left temporal lobe. Although ictal déjà vu localizes the epileptic focus to temporal lobe, this experimental phenomenon appears to lateralize to the hemisphere nondominant for handedness.

EM-1 Booster Prep, Left Aft Skirt Work-In-Progress

NASA Image and Video Library

2016-10-30

Inside the Booster Fabrication Facility at NASA's Kennedy Space Center in Florida, the left hand aft skirt for the agency's Space Launch System (SLS) rocket is ready for the assembly process. From left, are Chad Goetz, quality technician with Orbital ATK, and Robbie Blaue, quality assurance specialist with the Defense Contract Management Agency. The aft skirt was refurbished and painted in support facilities at the Hangar AF facility at Cape Canaveral Air Force Station in Florida. The space shuttle-era aft skirt will be used on the left hand booster of the SLS for Exploration Mission 1 (EM-1). NASA is preparing for EM-1, deep space missions, and the Journey to Mars.

Comment on "Polarized window for left-right symmetry and a right-handed neutrino at the Large Hadron-Electron Collider"

NASA Astrophysics Data System (ADS)

Queiroz, Farinaldo S.

2016-06-01

Reference [1 S. Mondal and S. K. Rai, Phys. Rev. D 93, 011702 (2016).] recently argued that the projected Large Hadron Electron Collider (LHeC) presents a unique opportunity to discover a left-right symmetry since the LHeC has availability for polarized electrons. In particular, the authors apply some basic pT cuts on the jets and claim that the on-shell production of right-handed neutrinos at the LHeC, which violates lepton number in two units, has practically no standard model background and, therefore, that the right-handed nature of WR interactions that are intrinsic to left-right symmetric models can be confirmed by using colliding beams consisting of an 80% polarized electron and a 7 TeV proton. In this Comment, we show that their findings, as presented, have vastly underestimated the SM background which prevents a Left-Right symmetry signal from being seen at the LHeC.

Strong rightward lateralization of the dorsal attentional network in left-handers with right sighting-eye: an evolutionary advantage.

PubMed

Petit, Laurent; Zago, Laure; Mellet, Emmanuel; Jobard, Gaël; Crivello, Fabrice; Joliot, Marc; Mazoyer, Bernard; Tzourio-Mazoyer, Nathalie

2015-03-01

Hemispheric lateralization for spatial attention and its relationships with manual preference strength and eye preference were studied in a sample of 293 healthy individuals balanced for manual preference. Functional magnetic resonance imaging was used to map this large sample while performing visually guided saccadic eye movements. This activated a bilateral distributed cortico-subcortical network in which dorsal and ventral attentional/saccadic pathways elicited rightward asymmetrical activation depending on manual preference strength and sighting eye. While the ventral pathway showed a strong rightward asymmetry irrespective of both manual preference strength and eye preference, the dorsal frontoparietal network showed a robust rightward asymmetry in strongly left-handers, even more pronounced in left-handed subjects with a right sighting-eye. Our findings brings support to the hypothesis that the origin of the rightward hemispheric dominance for spatial attention may have a manipulo-spatial origin neither perceptual nor motor per se but rather reflecting a mechanism by which a spatial context is mapped onto the perceptual and motor activities, including the exploration of the spatial environment with eyes and hands. Within this context, strongly left-handers with a right sighting-eye may benefit from the advantage of having the same right hemispheric control of their dominant hand and visuospatial attention processing. We suggest that this phenomenon explains why left-handed right sighting-eye athletes can outperform their competitors in sporting duels and that the prehistoric and historical constancy of the left-handers ratio over the general population may relate in part on the hemispheric specialization of spatial attention. © 2014 Wiley Periodicals, Inc.

Grip preference, dermatoglyphics, and hand use in captive chimpanzees (Pan troglodytes).

PubMed

Hopkins, William D; Russell, Jamie L; Hostetter, Autumn; Pilcher, Dawn; Dahl, Jeremy F

2005-09-01

This paper examined the association between grip type, hand use, and fingerprint patterns in a sample of captive chimpanzees. Grip type for simple reaching was assessed for the left and right hand and classified as thumb-index, middle-index, or single-digit responses. Fingerprint patterns were characterized as whorls, loops, or arches on each finger. The results indicated that chimpanzees exhibit significantly more thumb-index responses for the right compared to the left hand. In addition, thumb-index responses were more prevalent for subjects that had a whorl compared to a loop or arch on their thumb. The results suggest that fingerprint patterns are associated with individual differences in grasping type in chimpanzees as well as some variation in hand use. (c) 2005 Wiley-Liss, Inc.

Comparing consequences of right and left unilateral neglect in a stroke rehabilitation population.

PubMed

Wee, Joy Y M; Hopman, Wilma M

2008-11-01

This article details right and left unilateral neglect (UN) in a stroke rehabilitation population. This prospective observational cohort study documented hemipersonal neglect and hemispatial neglect in 309 of 325 stroke rehabilitation patients consecutively admitted over a 28-month period. Shoulder-hand complications, safety concerns, length of stay, discharge function, and discharge destination were documented. Of the 85 with right UN and 113 with left UN, 17.7% had expressive aphasia, and 17.7% had mixed or receptive aphasia. Hemispatial neglect was associated with hemianopsia (29.2% and 31.8% for right and left, respectively). Having both hemipersonal neglect and hemispatial neglect was related to greater safety risk (46.9% vs. 24.3%), greater incidence of shoulder-hand complications (28.3% vs. 9.9%), lower FIM scores (>10 points lower), longer length of stay (8 days), and less likelihood of discharge to home (67.3% vs. 87.4%) than subjects without UN. Results were similar for those with right and left UN. Right and left UN occur after stroke, can be detected even in the presence of aphasia, and are associated with shoulder-hand problems, lower discharge function, and lower likelihood of discharge home. Having both hemispatial neglect and hemipersonal neglect impacts people more than having either type of UN alone.

How should "ambidexterity" be estimated?

PubMed

Fagard, Jacqueline; Chapelain, Amandine; Bonnet, Philippe

2015-01-01

Weak and absent hand preferences have often been associated with developmental disorders or with cognitive functioning in the typical population. The results of different studies in this area, however, are not always coherent. One likely reason for discrepancies in findings is the diversity of cut-offs used to define ambidexterity and mixed right- and mixed left-handedness. Establishing and applying a common criterion would constitute an important step on the way to producing systematically comparable results. We thus decided to try to identify criteria for classifying individuals ambidextrous, mixed right- or left-handed or strong right- or left-handed. For that purpose, we first administered a handedness questionnaire to 716 individuals and performed multiple correspondence analyses to define handedness groups. Twenty-four participants were categorized as ambidextrous (3.3%), as opposed to mixed (29.2%) and strong (56%) right-handers, and to mixed (9.1%) and strong (2.4%) left-handers. We then compared this categorization with laterality index (LI)-based categories using different cut-offs and found that it was most correlated with LI cut-offs at -90, -30, +30 and +90, successively delimiting strong left-handedness, mixed left-handedness, ambidexterity (-30 to +30), mixed right-handedness and strong right-handedness. The characteristics of ambidextrous and lateralized individuals are also compared.

The role of hand of error and stimulus orientation in the relationship between worry and error-related brain activity: Implications for theory and practice.

PubMed

Lin, Yanli; Moran, Tim P; Schroder, Hans S; Moser, Jason S

2015-10-01

Anxious apprehension/worry is associated with exaggerated error monitoring; however, the precise mechanisms underlying this relationship remain unclear. The current study tested the hypothesis that the worry-error monitoring relationship involves left-lateralized linguistic brain activity by examining the relationship between worry and error monitoring, indexed by the error-related negativity (ERN), as a function of hand of error (Experiment 1) and stimulus orientation (Experiment 2). Results revealed that worry was exclusively related to the ERN on right-handed errors committed by the linguistically dominant left hemisphere. Moreover, the right-hand ERN-worry relationship emerged only when stimuli were presented horizontally (known to activate verbal processes) but not vertically. Together, these findings suggest that the worry-ERN relationship involves left hemisphere verbal processing, elucidating a potential mechanism to explain error monitoring abnormalities in anxiety. Implications for theory and practice are discussed. © 2015 Society for Psychophysiological Research.

Search for Heavy Neutrinos and W R Bosons with Right-Handed Couplings in a Left-Right Symmetric Model in p p Collisions at s = 7 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.

Results are presented from a search for heavy, right-handed muon neutrinos, N[mu], and right-handed W[R] bosons, which arise in the left-right symmetric extensions of the standard model. The analysis is based on a 5.0 inverse femtobarn sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected by the CMS detector at the Large Hadron Collider. No evidence is observed for an excess of events over the standard model expectation. For models with exact left-right symmetry, heavy right-handed neutrinos are excluded at 95% confidence level for a range of neutrino masses below the W[R] mass, dependent on the valuemore » of M(W[R]). The excluded region in the two-dimensional (M(W[R]), M(N[mu])) mass plane extends to M(W[R]) = 2.5 TeV.« less

Motor "dexterity"?: Evidence that left hemisphere lateralization of motor circuit connectivity is associated with better motor performance in children.

PubMed

Barber, Anita D; Srinivasan, Priti; Joel, Suresh E; Caffo, Brian S; Pekar, James J; Mostofsky, Stewart H

2012-01-01

Motor control relies on well-established motor circuits, which are critical for typical child development. Although many imaging studies have examined task activation during motor performance, none have examined the relationship between functional intrinsic connectivity and motor ability. The current study investigated the relationship between resting state functional connectivity within the motor network and motor performance assessment outside of the scanner in 40 typically developing right-handed children. Better motor performance correlated with greater left-lateralized (mean left hemisphere-mean right hemisphere) motor circuit connectivity. Speed, rhythmicity, and control of movements were associated with connectivity within different individual region pairs: faster speed was associated with more left-lateralized putamen-thalamus connectivity, less overflow with more left-lateralized supplementary motor-primary motor connectivity, and less dysrhythmia with more left-lateralized supplementary motor-anterior cerebellar connectivity. These findings suggest that for right-handed children, superior motor development depends on the establishment of left-hemisphere dominance in intrinsic motor network connectivity.

Double diffusive conjugate heat transfer: Part I

NASA Astrophysics Data System (ADS)

Azeem, Soudagar, Manzoor Elahi M.

2018-05-01

The present work is undertaken to investigate the effect of solid wall being placed at left of square cavity filled with porous medium. The presence of a solid wall in the porous medium turns the situation into a conjugate heat transfer problem. The boundary conditions are such that the left vertical surface is maintained at highest temperature and concentration whereas right vertical surface at lowest temperature and concentration in the medium. The top and bottom surfaces are adiabatic. The additional conduction equation along with the regular momentum and energy equations of porous medium are solved in an iterative manner with the help of finite element method. It is seen that the heat and mass transfer rate is lesser due to smaller thermal and concentration gradients.

8. Photocopy of photograph of West Side Milling District, dated ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Photocopy of photograph of West Side Milling District, dated c. 1905; Minneapolis Boiler Works Building visible in the center, left-hand side of photograph (3.5 inches from lower edge of photograph, and 2 inches from left-hand edge); THREE-QUARTER VIEW OF WEST AND SOUTH SIDES; LOOKING NORTHEAST - Minneapolis Boiler Works Building, 121-129 Fifth Avenue, South, Minneapolis, Hennepin County, MN

Prehension Movements in a Patient (AC) with Posterior Parietal Cortex Damage and Posterior Callosal Section

ERIC Educational Resources Information Center

Frak, Victor; Paulignan, Yves; Jeannerod, Marc; Michel, Francois; Cohen, Henri

2006-01-01

Prehension movements of the right hand were recorded in a right-handed man (AC), with an injury to the left posterior parietal cortex (PPC) and with a section of the left half of the splenium. The kinematic analysis of AC's grasping movements in direct and perturbed conditions was compared to that of five control subjects. A novel effect in…

Adult norms of the perceptual threshold of touch (PTT) in the hands and feet in relation to age, gender, and right and left side using transcutaneous electrical nerve stimulation.

PubMed

Eek, Elsy; Holmqvist, Lotta Widén; Sommerfeld, Disa K

2012-07-01

There is a lack of standardized and quantifiable measures of touch function, for clinical work. Furthermore, it is not possible to make accurate diagnostic judgments of touch function before normative values are estimated. The objectives of this study were to establish adult norms of the perceptual threshold of touch (PTT) for the hands and feet according to age and gender and to determine the effect of right/left side, handedness, height, weight, and body mass index (BMI) on the PTT. The PTT was assessed by using a high-frequency transcutaneous electrical nerve stimulator (Hf/TENS) with self-adhesive skin electrodes in 346 adults. The PTT was identified as the level registered in mA at which the participants perceived a tingling sensation. The PTT for all participants was a median of 3.75 mA (range 2.50-7.25) in the hands and a median of 10.00 (range 5.00-30.00) in the feet. With increasing age an increase of the PTT was found. Men reported higher PTT than women. The right hand had higher PTT than the left. Handedness, height, weight, and BMI did not affect the PTT. Adult norms of the PTT in the hands for age, gender, and right/left side are presented for four age groups. The present study's estimate of the PTT in the hands could be used as adult norms. Adult norms for the feet could not be estimated because the PTT values in the feet showed a great variance.

Correlations of Handgrip Strength with Selected Hand-Arm-Anthropometric Variables in Indian Inter-university Female Volleyball Players

PubMed Central

Koley, Shyamal; Pal Kaur, Satinder

2011-01-01

Purpose The purpose of this study was to estimate the dominant handgrip strength and its correlations with some hand and arm anthropometric variables in 101 randomly selected Indian inter-university female volleyball players aged 18-25 years (mean age 20.52±1.40) from six Indian universities. Methods Three anthropometric variables, i.e. height, weight, BMI, two hand anthropometric variables, viz. right and left hand width and length, four arm anthropometric variables, i.e. upper arm length, lower arm length, upper extremity length, upper arm circumference and dominant right and non-dominant handgrip strength were measured among Indian inter-university female volleyball players by standard anthropometric techniques. Results The findings of the present study indicated that Indian female volleyball players had higher mean values in eleven variables and lesser mean values in two variables than their control counterparts, showing significant differences (P<0.032-0.001) in height (t=2.63), weight (t=8.66), left hand width (t=2.10), left and right hand length (t=9.99 and 10.40 respectively), right upper arm length (t=8.48), right forearm length (t=5.41), dominant (right) and non-dominant (left) handgrip strength (t=9.37 and 6.76 respectively). In female volleyball players, dominant handgrip strength had significantly positive correlations (P=0.01) with all the variables studied. Conclusion It may be concluded that dominant handgrip strength had strong positive correlations with all the variables studied in Indian inter-university female volleyball players. PMID:22375242

TIMING VARIABILITY OF REACH TRAJECTORIES IN LEFT VERSUS RIGHT HEMISPHERE STROKE

PubMed Central

Freitas, Sandra Maria Sbeghen Ferreira; Gera, Geetanjali; Scholz, John Peter

2011-01-01

This study investigated trajectory timing variability in right and left stroke survivors and healthy controls when reaching to a centrally located target under a fixed target condition or when the target could suddenly change position after reach onset. Trajectory timing variability was investigated with a novel method based on dynamic programming that identifies the steps required to time warp one trial’s acceleration time series to match that of a reference trial. Greater trajectory timing variability of both hand and joint motions was found for the paretic arm of stroke survivors compared to their non-paretic arm or either arm of controls. Overall, the non-paretic left arm of the LCVA group and the left arm of controls had higher timing variability than the non-paretic right arm of the RCVA group and right arm of controls. The shoulder and elbow joint warping costs were consistent predictors of the hand’s warping cost for both left and right arms only in the LCVA group, whereas the relationship between joint and hand warping costs was relatively weak in control subjects and less consistent across arms in the RCVA group. These results suggest that the left hemisphere may be more involved in trajectory timing, although the results may be confounded by skill differences between the arms in these right hand dominant participants. On the other hand, arm differences did not appear to be related to differences in targeting error. The paretic left arm of the RCVA exhibited greater trajectory timing variability than the paretic right arm of the LCVA group. This difference was highly correlated with the level of impairment of the arms. Generally, the effect of target uncertainty resulted in slightly greater trajectory timing variability for all participants. The results are discussed in light of previous studies of hemispheric differences in the control of reaching, in particular, left hemisphere specialization for temporal control of reaching movements. PMID:21920508

[Effect of decimeter polarized electromagnetic radiation on germinating capacity of seeds].

PubMed

Polevik, N D

2013-01-01

The effect of a polarization structure of electromagnetic radiation on the germinating capacity of seeds of such weeds as Green foxtail (Setaria viridis) and Green amaranth (Amaranthus retroflexus) has been studied. Seeds have been exposed to impulse electromagnetic radiation in a frequency of 896 MHz with linear, elliptical right-handed and elliptical left-handed polarizations at different power flux density levels. It is determined that the effect of the right-handed polarized electromagnetic radiation increases and the influence of the left-handed polarized one reduces the germinating capacity of seeds compared to the effect of the linearly polarized electromagnetic radiation. It is shown that the seeds have an amplitude polarization selectivity as evinced by the major effect of the right-handed polarized radiation on seeds. An electrodynamic model as the right-handed elliptically polarized antenna with the given quantity of the ellipticity of polarization is suggested to use in description of this selectivity.

Venous pooling and drainage affects photoplethysmographic signals at different vertical hand positions

NASA Astrophysics Data System (ADS)

Hickey, Michelle; Phillips, Justin P.; Kyriacou, Panayiotis

2015-03-01

The aim of the current work is to investigate the possibility of augmenting pulse oximetry algorithms to enable the estimation of venous parameters in peripheral tissues. In order to further understand the contribution of venous blood to the photoplethysmographic (PPG) signal, recordings were made from six healthy volunteer subjects during an exercise in which the right hand was placed in various positions above and below heart level. The left hand was kept at heart level as a control while the right hand was moved. A custom-made two-channel dual wavelength PPG instrumentation system was used to obtain the red and infrared plethysmographic signals from both the right and left index fingers simultaneously using identical sensors. Laser Doppler flowmetry signals were also recorded from an adjacent fingertip on the right hand. Analysis of all acquired PPG signals indicated changes in both ac and dc amplitude of the right hand when the position was changed, while those obtained from the left (control) hand remained relatively constant. Most clearly, in the change from heart level to 50cm below heart level there is a substantial decrease in both dc and ac amplitudes. This decrease in dc amplitude most likely corresponds to increased venous pooling, and hence increased absorption of light. It is speculated that the decrease in ac PPG amplitude is due to reduced arterial emptying during diastole due to increased downstream resistance due to venous pooling.

Time-Frequency Cross Mutual Information Analysis of the Brain Functional Networks Underlying Multiclass Motor Imagery.

PubMed

Gong, Anmin; Liu, Jianping; Chen, Si; Fu, Yunfa

2018-01-01

To study the physiologic mechanism of the brain during different motor imagery (MI) tasks, the authors employed a method of brain-network modeling based on time-frequency cross mutual information obtained from 4-class (left hand, right hand, feet, and tongue) MI tasks recorded as brain-computer interface (BCI) electroencephalography data. The authors explored the brain network revealed by these MI tasks using statistical analysis and the analysis of topologic characteristics, and observed significant differences in the reaction level, reaction time, and activated target during 4-class MI tasks. There was a great difference in the reaction level between the execution and resting states during different tasks: the reaction level of the left-hand MI task was the greatest, followed by that of the right-hand, feet, and tongue MI tasks. The reaction time required to perform the tasks also differed: during the left-hand and right-hand MI tasks, the brain networks of subjects reacted promptly and strongly, but there was a delay during the feet and tongue MI task. Statistical analysis and the analysis of network topology revealed the target regions of the brain network during different MI processes. In conclusion, our findings suggest a new way to explain the neural mechanism behind MI.

Ontogenetic trends in gnostic hand function in 3- to 12-yr-old children.

PubMed

van Grunsven, W; Njiokiktjien, C; Vranken, M; Vuylsteke-Wauters, M

2003-06-01

The intimate relation between the sensory and motor functions of the hands during object manipulation and exploratory touch, the well-known improvement in object handling and constructive performance in ontogenesis and the emergent laterality thereof, assume changes in morphognostic capabilities in children. In this study we tried to corroborate the hypothesis of Mesker that mature and lateralized finger-thumb opposition is preceded by a stage of two-sided manual form agnosia in preschool children, followed by acquisition of morphognosis of the fingers and, finally, the thumbs. This study examined the development of gnostic hand function in 290 children from 3 to 11 years of age who drew the outlines of a meaningless wooden object passively felt with each hand without visual control. Analysis showed a clear ontogenetic change across the two age groups of increasing morphognostic function: 48% of the 6-yr.-olds drew correctly what the fingers of both left and right hands had perceived (thumbs, 14%). Of the 11-yr.-olds 91% and 61% performed perfectly with the right and left hands, respectively. The fingers preceded the thumbs in reproduction by most children, and the correct reproduction by the left thumb precedes that of the right thumb. The ontogenesis of bimanual sensorimotor functioning is discussed in the light of cortical and callosal development.

Valence-space compatibility effects depend on situated motor fluency in both right- and left-handers.

PubMed

Milhau, Audrey; Brouillet, Thibaut; Brouillet, Denis

2015-01-01

According to the body specificity hypothesis, the way we interact with our environment participates in our conceptualization of concepts and word meanings. For instance, valence is associated to horizontal space because of the motor fluency by which one acts with one's dominant hand. We propose that the decisive factor in the compatibility effects between valence and lateral actions is the interaction between the fluency of response movement and the situational constraints of the task. In a valence judgement task with positive and negative words, right-handers (Experiment 1) and left-handers (Experiment 2) responded with lateralized actions of either their dominant or their nondominant hand. To do so, we used a response device that was either congruent or noncongruent with the fluency of the response hand. Results highlighted that when the response device was congruent with the fluency of the responding hand, response times to positive evaluations were shorter than those to negative evaluations. Conversely, when the response device was noncongruent with the fluency of the responding hand, we observed faster responses for negative evaluations than for positive evaluations. Furthermore, we obtained similar patterns for right- and left-handers, supporting the idea that compatibility effects are driven by the situated fluency of the responding hand.

The relationship between frontal sinus morphology and skeletal maturation.

PubMed

Buyuk, Suleyman Kutalmıs; Simsek, Huseyin; Karaman, Ahmet

2018-01-03

The aim of this study is to evaluate the relationship between frontal sinus morphology and hand-wrist bone maturation by using postero-anterior (PA) cephalometric radiographs. The study sample consisted of 220 patients divided into eleven groups based on the hand-wrist radiographs. The right and left maximum height, width and area of the frontal sinus parameters were measured in postero-anterior cephalometric radiographs 220 subjects aged 8-18 years. The hand-wrist skeletal maturation stages were evaluated on the hand-wrist radiographs using the method of Fishman. The Kendall tau-b values were analyzed to evaluate the correlation between the hand-wrist skeletal maturation stages and the frontal sinus parameters. The right and left frontal sinus areas and widths were found to be larger in males than in females (p < 0.05). In males, a significant difference was observed in all frontal sinus parameters in different maturation stages (p < 0.001), while a statistically significant correlation was found in females between the left frontal sinus area, right frontal sinus height, right frontal sinus width and different maturation stages (p < 0.05). In conclusion, the relationship between frontal sinus dimensions obtained from PA cephalometric radiographs and hand-wrist maturation stages suggests that frontal sinuses can be used in determining growth and development.

Sustained Spatial Attention to Vibrotactile Stimulation in the Flutter Range: Relevant Brain Regions and Their Interaction

PubMed Central

Goltz, Dominique; Pleger, Burkhard; Thiel, Sabrina; Villringer, Arno; Müller, Matthias M.

2013-01-01

The present functional magnetic resonance imaging (fMRI) study was designed to get a better understanding of the brain regions involved in sustained spatial attention to tactile events and to ascertain to what extent their activation was correlated. We presented continuous 20 Hz vibrotactile stimuli (range of flutter) concurrently to the left and right index fingers of healthy human volunteers. An arrow cue instructed subjects in a trial-by-trial fashion to attend to the left or right index finger and to detect rare target events that were embedded in the vibrotactile stimulation streams. We found blood oxygen level-dependent (BOLD) attentional modulation in primary somatosensory cortex (SI), mainly covering Brodmann area 1, 2, and 3b, as well as in secondary somatosensory cortex (SII), contralateral to the to-be-attended hand. Furthermore, attention to the right (dominant) hand resulted in additional BOLD modulation in left posterior insula. All of the effects were caused by an increased activation when attention was paid to the contralateral hand, except for the effects in left SI and insula. In left SI, the effect was related to a mixture of both a slight increase in activation when attention was paid to the contralateral hand as well as a slight decrease in activation when attention was paid to the ipsilateral hand (i.e., the tactile distraction condition). In contrast, the effect in left posterior insula was exclusively driven by a relative decrease in activation in the tactile distraction condition, which points to an active inhibition when tactile information is irrelevant. Finally, correlation analyses indicate a linear relationship between attention effects in intrahemispheric somatosensory cortices, since attentional modulation in SI and SII were interrelated within one hemisphere but not across hemispheres. All in all, our results provide a basis for future research on sustained attention to continuous vibrotactile stimulation in the range of flutter. PMID:24367642

[Motor asymmetry and learning new skills in animals].

PubMed

Budilin, S Iu; Pletneva, E V; Ioffe, M E; Arsen'ev, G N

2014-01-01

The aim was to examine the relationship between the ability to learn new motor skills and preference to the right or left front paw when performing manipulation movements in rats. As a new skill used the Morris water maze, in which the animals are initially trained to detect platform hidden under water at the swim of the sector of the opposite platform, and then when sailing from sectors on the left or the right of the platform. Preference paw was determined by using the taking of animal food from a narrow horizontal tube and, accordingly, the rats were divided into left-handedness and right-handedness. We found that when changing the place of launch, that is the first voyage from the left or right of the sector, are right-handed, unlike left-handed, spent significantly more time to find the platform.

In vitro resolution of the dimer bridge of the minute virus of mice (MVM) genome supports the modified rolling hairpin model for MVM replication.

PubMed

Liu, Q; Yong, C B; Astell, C R

1994-06-01

Previous characterization of the terminal sequences of the minute virus of mice (MVM) genome demonstrated that the right hand palindrome contains two sequences, each the inverted complement of the other. However, the left hand palindrome was shown to exist as a unique sequence [Astell et al., J. Virol. 54: 179-185 (1985)]. The modified rolling hairpin (MRH) model for MVM replication provided an explanation of how the right hand palindrome could undergo hairpin transfer to generate two sequences, while the left end palindrome within the dimer bridge could undergo asymmetric resolution and retain the unique left end sequence. This report describes in vitro resolution of the wild-type dimer bridge sequence of MVM using recombinant (baculovirus) expressed NS-1 and a replication extract from LA9 cells. The resolution products are consistent with those predicted by the MRH model, providing support for this replication mechanism. In addition, mutant dimer bridge clones were constructed and used in the resolution assay. The mutant structures included removal of the asymmetry in the hairpin stem, inversion of the sequence at the initiating nick site, and a 2-bp deletion within one stem of the dimer bridge. In all cases, the mutant dimer bridge structures are resolved; however, the resolution pattern observed with the mutant dimer bridge compared with the wild-type dimer bridge is shifted toward symmetrical resolution. These results suggest that sequences within the left hand hairpin (and hence dimer bridge sequence) are responsible for asymmetric resolution and conservation of the unique sequence within the left hand palindrome of the MVM genome.

Can digit ratio (2D:4D) studies be helpful in explaining the aetiology of idiopathic gynecomastia?

PubMed

Kasielska-Trojan, Anna; Antoszewski, Bogusław

2015-01-01

Aetiology of idiopathic form of gynecomastia is unknown and it has not been established if it is related to factors present at the prenatal period or if it is caused by yet unidentified environmental conditions. The aim of this study is to compare digit ratio (2D:4D) in men with idiopathic gynecomastia and unaffected male and female controls from the general population. The study involved 250 subjects (50 men with idiopathic gynecomastia, 100 control men and 100 control women). Eight measurements were taken: body height, waist and hip circumferences, II and IV digits' lengths (right and left), and body weight, and 4 indices were calculated: BMI, WHR, and 2D:4D for the right and left hand. 2D:4D in men with gynecomastia ([median (I-III quartiles)]: 1.03 (1.01-1.04) for right hand and 1.03 (1.01-1.03) for left hand) was significantly different than the ratio in control men [0.97 (0.95-0.99)] for right and left hand) (p<0.0001) and similar to the ratio found in control women [1.02 (1-1.03)] for right and left hand) (p=1). Men with gynecomastia were characterized with higher values of the following variables: weight, waist and hip circumferences, BMI and WHR. Their body height was significantly greater than in women (p<0.0001) but similar to the values observed in control men (p=0.2687). The findings presented in this study may influence the aetiology-related classification of gynecomastia and justify introducing the new group: "gynecomastia related to the prenatal sex hormones disturbances". Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Cortical language lateralization in right handed normal subjects using functional magnetic resonance imaging.

PubMed

Vikingstad, E M; George, K P; Johnson, A F; Cao, Y

2000-04-01

In 95% of right handed individuals the left hemisphere is dominant for speech and language function. The evidence for this is accumulated primarily from clinical populations. We investigated cortical topography of language function and lateralization in a sample of the right handed population using functional magnetic resonance imaging and two lexical-semantic paradigms. Activated cortical language networks were assessed topographically and quantitatively by using a lateralization index. As a group, we observed left hemispheric language dominance. Individually, the lateralization index varied continuously from left hemisphere dominant to bilateral representation. In males, language primarily lateralized to left, and in females, approximately half had left lateralization and the other half had bilateral representation. Our data indicate that a previous view of female bilateral hemispheric dominance for language (McGlone, 1980. Sex differences in human brain asymmetry: a critical survey. Behav Brain Sci 3:215-263; Shaywitz et al., 1995. Sex differences in the functional organization of the brain for language. Nature 373:607-609) simplifies the complexity of cortical language distribution in this population. Analysis of the distribution of the lateralization index in our study allowed us to make this difference in females apparent.

The Role of Hand Dominance in Beginning Braille Readers

ERIC Educational Resources Information Center

Wright, Tessa

2009-01-01

In this article, the author examines the role of "hand dominance" in beginning braille readers. "Hand dominance" refers to whether an individual is "right handed" or "left handed." The data for these analyses were taken from the Alphabetic Braille and Contracted Braille Study (ABC Braille Study). The ABC Braille Study was a five-year nonrandomized…

Transient involuntary mirror writing triggered by anxiety.

PubMed

Della Sala, Sergio; Calia, Clara; De Caro, Maria Fara; McIntosh, Robert D

2015-01-01

Mirror writing (MW) has mainly been observed in left-hemisphere-damaged patients writing with the left hand. This study evaluated the presence of MW in 24 patients with mild cognitive impairment (MCI). We found that MW is not a typical feature of MCI. However, one woman (FC), mislabeled initially with MCI but in fact affected by anxiety, showed florid MW when writing with her left hand, which resolved as her anxiety receded. This case study supports anecdotal reports of MW triggered by anxiety, and the features of FC's performance indicate a motor rather than a perceptual basis for the phenomenon.

16. OPERATOR STAND. OPERATOR STOOD BETWEEN RAILINGS AND CONTROLLED DREDGING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. OPERATOR STAND. OPERATOR STOOD BETWEEN RAILINGS AND CONTROLLED DREDGING OPERATIONS USING TWO LEVERS FROM CEILING, THREE LEVELS ON THE FLOOR, AND TWO FLOOR PEDDLES. RIGHT HAND CONTROLLED SHOT GUN SWINGER (BOOM MOVE TO RIGHT WHEN PUSHED FORWARD, LEFT WHEN PULLED BACK, AND, IF LUCKY, STOPPED WHEN IN CENTER POSITION). LEFT HAND CONTROLLED THROTTLE. FLOOR LEVER AND FLOOR PEDDLE ON LEFT CONTROLLED THE BACKING LINE FRICTION. MIDDLE LEVER AND PEDDLE, STUCK IN FLOOR CONTROLLED THE MAIN HOIST FRICTION. LEVER ON RIGHT CONTROLLED THE CYLINDER DRAIN VALVE. - Dredge CINCINNATI, Docked on Ohio River at foot of Lighthill Street, Pittsburgh, Allegheny County, PA

Improving motor performance without training: the effect of combining mirror visual feedback with transcranial direct current stimulation.

PubMed

von Rein, Erik; Hoff, Maike; Kaminski, Elisabeth; Sehm, Bernhard; Steele, Christopher J; Villringer, Arno; Ragert, Patrick

2015-04-01

Mirror visual feedback (MVF) during motor training has been shown to improve motor performance of the untrained hand. Here we thought to determine if MVF-induced performance improvements of the left hand can be augmented by upregulating plasticity in right primary motor cortex (M1) by means of anodal transcranial direct current stimulation (a-tDCS) while subjects trained with the right hand. Participants performed a ball-rotation task with either their left (untrained) or right (trained) hand on two consecutive days (days 1 and 2). During training with the right hand, MVF was provided concurrent with two tDCS conditions: group 1 received a-tDCS over right M1 (n = 10), whereas group 2 received sham tDCS (s-tDCS, n = 10). On day 2, performance was reevaluated under the same experimental conditions compared with day 1 but without tDCS. While baseline performance of the left hand (day 1) was not different between groups, a-tDCS exhibited stronger MVF-induced performance improvements compared with s-tDCS. Similar results were observed for day 2 (without tDCS application). A control experiment (n = 8) with a-tDCS over right M1 as outlined above but without MVF revealed that left hand improvement was significantly less pronounced than that induced by combined a-tDCS and MVF. Based on these results, we provide novel evidence that upregulating activity in the untrained M1 by means of a-tDCS is capable of augmenting MVF-induced performance improvements in young normal volunteers. Our findings suggest that concurrent MVF and tDCS might have synergistic and additive effects on motor performance of the untrained hand, a result of relevance for clinical approaches in neurorehabilitation and/or exercise science. Copyright © 2015 the American Physiological Society.

Distinct contribution of the parietal and temporal cortex to hand configuration and contextual judgements about tools.

PubMed

Andres, Michael; Pelgrims, Barbara; Olivier, Etienne

2013-09-01

Neuropsychological studies showed that manipulatory and semantic knowledge can be independently impaired in patients with upper-limb apraxia, leading to different tool use disorders. The present study aimed to dissociate the brain regions involved in judging the hand configuration or the context associated to tool use. We focussed on the left supramarginalis gyrus (SMG) and left middle temporal gyrus (MTG), whose activation, as evidenced by functional magnetic resonance imaging (fMRI) studies, suggests that they may play a critical role in tool use. The distinctive location of SMG in the dorsal visual stream led us to postulate that this parietal region could play a role in processing incoming information about tools to shape hand posture. In contrast, we hypothesized that MTG, because of its interconnections with several cortical areas involved in semantic memory, could contribute to retrieving semantic information necessary to create a contextual representation of tool use. To test these hypotheses, we used neuronavigated transcranial magnetic stimulation (TMS) to interfere transiently with the function of either left SMG or left MTG in healthy participants performing judgement tasks about either hand configuration or context of tool use. We found that SMG virtual lesions impaired hand configuration but not contextual judgements, whereas MTG lesions selectively interfered with judgements about the context of tool use while leaving hand configuration judgements unaffected. This double dissociation demonstrates that the ability to infer a context of use or a hand posture from tool perception relies on distinct processes, performed in the temporal and parietal regions. The present findings suggest that tool use disorders caused by SMG lesions will be characterized by difficulties in selecting the appropriate hand posture for tool use, whereas MTG lesions will yield difficulties in using tools in the appropriate context. Copyright © 2012. Published by Elsevier Ltd.

Dissipative vibrational model for chiral recognition in olfaction

NASA Astrophysics Data System (ADS)

Tirandaz, Arash; Taher Ghahramani, Farhad; Shafiee, Afshin

2015-09-01

We examine the olfactory discrimination of left- and right-handed enantiomers of chiral odorants based on the odorant-mediated electron transport from a donor to an acceptor of the olfactory receptors embodied in a biological environment. The chiral odorant is effectively described by an asymmetric double-well potential whose minima are associated to the left- and right-handed enantiomers. The introduced asymmetry is considered an overall measure of chiral interactions. The biological environment is conveniently modeled as a bath of harmonic oscillators. The resulting spin-boson model is adapted by a polaron transformation to derive the corresponding Born-Markov master equation with which we obtain the elastic and inelastic electron tunneling rates. We show that the inelastic tunneling through left- and right-handed enantiomers occurs with different rates. The discrimination mechanism depends on the ratio of tunneling frequency to localization frequency.

Determination of the absolute chirality of tellurium using resonant diffraction with circularly polarized x-rays.

PubMed

Tanaka, Y; Collins, S P; Lovesey, S W; Matsumami, M; Moriwaki, T; Shin, S

2010-03-31

Many proteins, sugars and pharmaceuticals crystallize into two forms that are mirror images of each other (enantiomers) like our right and left hands. Tellurium is one enantiomer having a space group pair, P3(1)21 (right-handed screw) and P3(2)21 (left-handed screw). X-ray diffraction with dispersion correction terms has been playing an important role in determining the handedness of enantiomers for a long time. However, this approach is not applicable for an elemental crystal such as tellurium or selenium. We have demonstrated that positive and negative circularly polarized x-rays at the resonant energy of tellurium can be used to absolutely distinguish right from left tellurium. This method is applicable to chiral motifs that occur in biomolecules, liquid crystals, ferroelectrics and antiferroelectrics, multiferroics, etc.

Parity at the Planck scale

NASA Astrophysics Data System (ADS)

Arzano, Michele; Gubitosi, Giulia; Magueijo, João

2018-06-01

We explore the possibility that well known properties of the parity operator, such as its idempotency and unitarity, might break down at the Planck scale. Parity might then do more than just swap right and left polarized states and reverse the sign of spatial momentum k: it might generate superpositions of right and left handed states, as well as mix momenta of different magnitudes. We lay down the general formalism, but also consider the concrete case of the Planck scale kinematics governed by κ-Poincaré symmetries, where some of the general features highlighted appear explicitly. We explore some of the observational implications for cosmological fluctuations. Different power spectra for right handed and left handed tensor modes might actually be a manifestation of deformed parity symmetry at the Planck scale. Moreover, scale-invariance and parity symmetry appear deeply interconnected.

Finger Length Ratio (2D:4D) in Central India and an Attempt to Verify Fraternal Birth Order Effect: A Population Based Cross-Sectional Study

PubMed Central

Maitra, Chaitali; Jha, Dilip Kumar; Biswas, Rakesh

2016-01-01

Introduction A normal physiology of a human being is not mere a series of functions occurring with specific intensities and timing. There are lot of factors that may change the normal physiological activity within normal limits. Finger length ratio is one of the markers of intrauterine androgen exposure and it is debated and contradicted by many authors. Digit ratio varies among the ethnicities. Many Indian studies show that there is considerable difference in finger length ratio in different population. Data regarding Central India was not found on extensive search. Aim To find out the finger length ratio and explore the birth order effect on finger length ratio among the first two successive born in the said population. Materials and Methods We conducted a survey on 1500 volunteer persons (800 male and 700 female) over two years of time. We measured the length of the index finger (2D) and ring finger (4D) of both the hands and asked about their birth order history to find out the digit ratio for Central India population and any existing correlation of the same with birth order. T Test and Analysis of Variance (ANOVA) were used for the measure of significance and difference among the groups. The p< 0.05 was considered to be significant. Results Our study reports that, study population mean for right hand 2D:4D ratio was 0.976 (SD±0.031) and for left hand it was found to be 0.969 (SD±0.035). For males, mean finger length ratio for right hand was 0.967 (SD±0.033) and 0.963 (SD±0.037) for left hand. In females the mean Finger length ratio was 0.982 (SD±0.027) for right hand and 0.974 (SD±0.034) for the left hand respectively. Finger length ratio was found to be significantly less (p=0.03) in males for right hand. No significant (p=0.24) difference was observed for left hand. When assessed fraternal birth order effect among the eldest, second born with elder brother and second born with elder sister groups, no significant (p>0.05) variation for finger length ratio of right and left hands observed in both male and female population. Conclusion Our study reports that the finger length ratio (2D:4D) for Central India population did not show significant association between finger length ratio and fraternal birth order among the first two successive born. PMID:28208849

Finger Length Ratio (2D:4D) in Central India and an Attempt to Verify Fraternal Birth Order Effect: A Population Based Cross-Sectional Study.

PubMed

Maitra, Arjun; Maitra, Chaitali; Jha, Dilip Kumar; Biswas, Rakesh

2016-12-01

A normal physiology of a human being is not mere a series of functions occurring with specific intensities and timing. There are lot of factors that may change the normal physiological activity within normal limits. Finger length ratio is one of the markers of intrauterine androgen exposure and it is debated and contradicted by many authors. Digit ratio varies among the ethnicities. Many Indian studies show that there is considerable difference in finger length ratio in different population. Data regarding Central India was not found on extensive search. To find out the finger length ratio and explore the birth order effect on finger length ratio among the first two successive born in the said population. We conducted a survey on 1500 volunteer persons (800 male and 700 female) over two years of time. We measured the length of the index finger (2D) and ring finger (4D) of both the hands and asked about their birth order history to find out the digit ratio for Central India population and any existing correlation of the same with birth order. T Test and Analysis of Variance (ANOVA) were used for the measure of significance and difference among the groups. The p< 0.05 was considered to be significant. Our study reports that, study population mean for right hand 2D:4D ratio was 0.976 (SD±0.031) and for left hand it was found to be 0.969 (SD±0.035). For males, mean finger length ratio for right hand was 0.967 (SD±0.033) and 0.963 (SD±0.037) for left hand. In females the mean Finger length ratio was 0.982 (SD±0.027) for right hand and 0.974 (SD±0.034) for the left hand respectively. Finger length ratio was found to be significantly less (p=0.03) in males for right hand. No significant (p=0.24) difference was observed for left hand. When assessed fraternal birth order effect among the eldest, second born with elder brother and second born with elder sister groups, no significant (p>0.05) variation for finger length ratio of right and left hands observed in both male and female population. Our study reports that the finger length ratio (2D:4D) for Central India population did not show significant association between finger length ratio and fraternal birth order among the first two successive born.

Beaming Circularly Polarized Photons from Quantum Dots Coupled with Plasmonic Spiral Antenna (Postprint)

DTIC Science & Technology

2014-01-01

SYMBOLS Acronym Definition SPP Surface Plasmon Polaritons RHC Right-Hand Circular LHC Left-Hand Circular FIB Focused Ion Beam RHS Right-Handed Spiral CCD Charge-Coupled Detector FWHM Full Width at Half Maximum

Eclectic lefty-hand: Conjectures on Jimi Hendrix, handedness, and Electric Ladyland.

PubMed

Christman, Stephen

2010-01-01

An analysis of Jimi Hendrix's guitar playing and song writing is presented in light of the effects of his mixed-right-handedness on motoric and conceptual processing. It is argued that (i) his mixed-handedness allowed him greater integration of the roles of his left and right hands in guitar playing and (ii) his right-handedness conferred specific benefits in playing a left-handed guitar. In terms of his song writing, the greater interhemispheric interaction (and consequent greater access to right hemisphere processing) associated with mixed-handedness is argued to characterise aspects of his lyrics and vocal delivery.

Retroperitoneoscopic living donor nephrectomy: initial experience with a unique hand-assisted approach.

PubMed

Capolicchio, J-P; Feifer, A; Plante, M K; Tchervenkov, J

2011-01-01

The retroperitoneoscopic (RP) approach to live donor nephrectomy (LDN) may be advantageous for the donor because it avoids mobilization of peritoneal organs and provides direct access to the renal vessels. Notwithstanding, this approach is not popular, likely because of the steeper learning curve. We feel that hand-assistance (HA) can reduce the learning curve and in this study, we present our experience with a novel hand-assist approach to retroperitoneoscopic live donor nephrectomy (HARP-LDN). Over a one-yr period, 10 consecutive patients underwent left HARP-LDN with a mean body mass index of 29 and three with prior left abdomen surgery. The surgical technique utilizes a 7 cm, muscle-sparing incision for the hand-port with two endoscopic ports. Operative time was an average of 155 min., with no open conversions. Mean blood loss was 68 mL, and warm ischemia time was 2.5 min. Hospital stay averaged 2.7 d with postoperative complications limited to one urinary retention. Our modified HARP approach to left LDN is safe, effective and can be performed expeditiously. Our promising initial results require a larger patient cohort to confirm the advantages of the hand-assisted retroperitoneal technique. © 2010 John Wiley & Sons A/S.

Resonant slepton production and right sneutrino dark matter in left-right supersymmetry

NASA Astrophysics Data System (ADS)

Frank, Mariana; Fuks, Benjamin; Huitu, Katri; Rai, Santosh Kumar; Waltari, Harri

2017-05-01

Right-handed sneutrinos are natural components of left-right symmetric supersymmetric models where the gauge sector is extended to include right-handed weak interactions. Unlike in other models where right-handed sneutrinos are gauge singlets, here the right sneutrino is part of a doublet and could be a dark matter candidate whose annihilation proceeds via gauge interactions. We investigate this possibility, and find that relic density, low-energy observable and direct supersymmetry search constraints can be satisfied when the lightest supersymmetric particle is a right-handed sneutrino. We introduce benchmarks for left-right supersymmetric realizations where either a sneutrino or a neutralino is the lightest superpartner. We then study the LHC signals arising through resonant right-handed slepton production via a W R gauge-boson exchange that lead to final states enriched in leptons, additionally containing a large amount of missing transverse momentum, and featuring a low jet multiplicity. We find that such a resonant production would boost the chances of discovering these weakly interacting supersymmetric particles for a mass range extending beyond 1 TeV already with a luminosity of 100 fb-1. Finally, we compare sneutrino versus neutralino scenarios, and comment on differences with other sneutrino dark matter models.

Homochirality and the origin of life

NASA Astrophysics Data System (ADS)

Pohl, Robert; Leitner, J. J.; Firneis, M. G.

2012-05-01

Homochirality is generally considered a crucial signature for life on Earth, which uses left-handed amino acids and right-handed sugars. A mirror-image life, using right-handed amino acids and left- handed sugars, is perfectly conceivable and might have developed on another planet. Life which would simultaneously use both right- and left-handed forms of the same biological molecules is unlikely for geometrical reasons. Secondary peptide structures are not possible without one-handedness. Various theories try to explain the origin of homochirality. Physicists used as argument the phenomenon of parity violation discovered on 60Co, which does not explain homochirality on prebiotic substances. Astrophysicists suggested that the observed enantiomeric excesses could have been induced by circularly polarized light arising from dust scattering in regions of high mass star formations or even due to super nova remnants or pulsars. An extraterrestrial origin of homochiral substances is discusses as well as catalytic processes on early Earth using different mineral surfaces. Thermodynamics i.e. its 2nd law is considered to explain homochirality as consequence of increasing entropy. There are many questions not yet answered. The author looks forward to discuss some of them with interested scientists.

Frequency of the first feature in action sequences influences feature binding.

PubMed

Mattson, Paul S; Fournier, Lisa R; Behmer, Lawrence P

2012-10-01

We investigated whether binding among perception and action feature codes is a preliminary step toward creating a more durable memory trace of an action event. If so, increasing the frequency of a particular event (e.g., a stimulus requiring a movement with the left or right hand in an up or down direction) should increase the strength and speed of feature binding for this event. The results from two experiments, using a partial-repetition paradigm, confirmed that feature binding increased in strength and/or occurred earlier for a high-frequency (e.g., left hand moving up) than for a low-frequency (e.g., right hand moving down) event. Moreover, increasing the frequency of the first-specified feature in the action sequence alone (e.g., "left" hand) increased the strength and/or speed of action feature binding (e.g., between the "left" hand and movement in an "up" or "down" direction). The latter finding suggests an update to the theory of event coding, as not all features in the action sequence equally determine binding strength. We conclude that action planning involves serial binding of features in the order of action feature execution (i.e., associations among features are not bidirectional but are directional), which can lead to a more durable memory trace. This is consistent with physiological evidence suggesting that serial order is preserved in an action plan executed from memory and that the first feature in the action sequence may be critical in preserving this serial order.

QCD with Chiral Imbalance: models vs. lattice

NASA Astrophysics Data System (ADS)

Andrianov, Alexander; Andrianov, Vladimir; Espriu, Domenec

2017-03-01

In heavy ion collisions (HIC) at high energies there may appear new phases of matter which must be described by QCD. These phases may have different color and flavour symmetries associated with the constituents involved in collisions as well as various space-time symmetries of hadron matter. Properties of the QCD medium in such a matter can be approximately described, in particular, by a number of right-handed (RH) and left-handed (LH) light quarks. The chiral imbalance (ChI) is characterized by the difference between the numbers of RH and LH quarks and supposedly occurs in the fireball after HIC. Accordingly we have to introduce a quark chiral (axial) chemical potential which simulates a ChI emerging in such a phase. In this report we discuss the possibility of a phase with Local spatial Parity Breaking (LPB) in such an environment and outline conceivable signatures for the registration of LPB as well as the appearance of new states in the spectra of scalar, pseudoscalar and vector particles as a consequence of local ChI. The comparison of the results obtained in the effective QCD- motivated models with lattice data is also performed.

Intraoperative left subclavian artery occlusion with left hand ischaemia and steal syndrome in the left internal thoracic artery

PubMed Central

Jelenc, Matija; Kneževič, Ivan; Stankovič, Milenko; Geršak, Borut

2012-01-01

We present a case of a 62-year old man with a left main stenosis, left coronary artery dominance, normal ejection fraction and no valvular pathology, and status post right carotid artery stenting, who was scheduled for elective coronary revascularization. We performed off-pump coronary revascularization, anastomosing the left internal thoracic artery to the left anterior descending artery, and three separate saphenous vein grafts to the intermediate artery and the first and second obtuse marginals, respectively. Proximally, the right internal thoracic artery was used as the inflow for all three venous grafts due to a heavily calcified ascending aorta. During the construction of the distal anastomoses to the obtuse marginals, the arterial pressure in the left radial artery suddenly dropped. The left hand was found to be pale and pulseless. A femoral artery catheter was placed for pressure monitoring and the anastomoses were completed as planned. Intraoperative transit-time graft flow measurement showed a reversed flow in the left internal thoracic artery. Postoperatively, angiography was performed showing a subtotal stenosis of the proximal left subclavian artery. The artery was dilated and stented. The postoperative course was uneventful and the patient was discharged on the 12th postoperative day. PMID:22767542

Auditory Evoked Potential Mismatch Negativity in Normal-Hearing Adults

PubMed Central

Schwade, Laura Flach; Didoné, Dayane Domeneghini; Sleifer, Pricila

2017-01-01

Introduction  Mismatch Negativity (MMN) corresponds to a response of the central auditory nervous system. Objective  The objective of this study is to analyze MMN latencies and amplitudes in normal-hearing adults and compare the results between ears, gender and hand dominance. Methods  This is a cross-sectional study. Forty subjects participated, 20 women and 20 men, aged 18 to 29 years and having normal auditory thresholds. A frequency of 1000Hz (standard stimuli) and 2000Hz (deviant stimuli) was used to evoked the MMN. Results  Mean latencies in the right ear were 169.4ms and 175.3ms in the left ear, with mean amplitudes of 4.6µV in the right ear and 4.2µV in the left ear. There was no statistically significant difference between ears. The comparison of latencies between genders showed a statistically significant difference for the right ear, being higher in the men than in women. There was no significant statistical difference between ears for both right-handed and left-handed group. However, the results indicated that the latency of the right ear was significantly higher for the left handers than the right handers. We also found a significant result for the latency of the left ear, which was higher for the right handers. Conclusion  It was possible to obtain references of values for the MMN. There are no differences in the MMN latencies and amplitudes between the ears. Regarding gender, the male group presented higher latencies in relation to the female group in the right ear. Some results indicate that there is a significant statistical difference of the MMN between right- and left-handed individuals. PMID:28680490

Reduced dream-recall frequency in left-handed adolescents: a replication.

PubMed

Schredl, Michael; Beaton, Alan A; Henley-Einion, Josie; Blagrove, Mark

2014-01-01

The ability to recall a dream upon waking up in the morning has been linked to a broad variety of factors such as personality, creativity, sleep behaviour and cognitive function. There have been conflicting findings as to whether dream recall is related more to the right or to the left hemisphere, and conflicting findings regarding the relationship of dream-recall frequency to handedness. We have found previously that right- and mixed-handers report having more dreams than left-handers, a finding more pronounced among adolescents than adults. In the present sample of 3535 participants aged from 6 to 18 years, right-handedness and mixed/inconsistent handedness were associated with higher dream-recall frequency compared to that of left-handed persons, again especially in adolescents compared with children. Further research is required to uncover the reason for the lower frequency of dream recall by left-handers.

Trial-by-trial analysis of intermanual transfer during visuomotor adaptation

PubMed Central

Wojaczynski, Greg J.; Ivry, Richard B.

2011-01-01

Studies of intermanual transfer have been used to probe representations formed during skill acquisition. We employ a new method that provides a continuous assay of intermanual transfer, intermixing right- and left-hand trials while limiting visual feedback to right-hand movements. We manipulated the degree of awareness of the visuomotor rotation, introducing a 22.5° perturbation in either an abrupt single step or gradually in ∼1° increments every 10 trials. Intermanual transfer was observed with the direction of left-hand movements shifting in the opposite direction of the rotation over the course of training. The transfer on left-hand trials was less than that observed in the right hand. Moreover, the magnitude of transfer was larger in our mixed-limb design compared with the standard blocked design in which transfer is only probed at the end of training. Transfer was similar in the abrupt and gradual groups, suggesting that awareness of the perturbation has little effect on intermanual transfer. In a final experiment, participants were provided with a strategy to offset an abrupt rotation, a method that has been shown to increase error over the course of training due to the operation of sensorimotor adaptation. This deterioration was also observed on left-hand probe trials, providing further support that awareness has little effect on intermanual transfer. These results indicate that intermanual transfer is not dependent on the implementation of cognitively assisted strategies that participants might adopt when they become aware that the visuomotor mapping has been perturbed. Rather, the results indicate that the information available to processes involved in adaptation entails some degree of effector independence. PMID:21917998

Common origin of 3.55 keV x-ray line and gauge coupling unification with left-right dark matter

NASA Astrophysics Data System (ADS)

Borah, Debasish; Dasgupta, Arnab; Patra, Sudhanwa

2017-12-01

We present a minimal left-right dark matter framework that can simultaneously explain the recently observed 3.55 keV x-ray line from several galaxy clusters and gauge coupling unification at high energy scale. Adopting a minimal dark matter strategy, we consider both left and right handed triplet fermionic dark matter candidates which are stable by virtue of a remnant Z2≃(-1 )B -L symmetry arising after the spontaneous symmetry breaking of left-right gauge symmetry to that of the standard model. A scalar bitriplet field is incorporated whose first role is to allow radiative decay of right handed triplet dark matter into the left handed one and a photon with energy 3.55 keV. The other role this bitriplet field at TeV scale plays is to assist in achieving gauge coupling unification at a high energy scale within a nonsupersymmetric S O (10 ) model while keeping the scale of left-right gauge symmetry around the TeV corner. Apart from solving the neutrino mass problem and giving verifiable new contributions to neutrinoless double beta decay and charged lepton flavor violation, the model with TeV scale gauge bosons can also give rise to interesting collider signatures like diboson excess, dilepton plus two jets excess reported recently in the large hadron collider data.

45. 800 H.P. WATER WHEEL UNIT (LEFT HAND) DIRECT CONNECTED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

45. 800 H.P. WATER WHEEL UNIT (LEFT HAND) DIRECT CONNECTED TO A 500 K.W. G.E. CO. GENERATOR, SPEED 176 R.P.M., HEAD OF WATER 305 FT EFF., FOR SANTA ANA RIVER NO. 2 PLANT. ABNER DOBLE CO., ENGINEERS, SAN FRANCISCO, AUG. 29, 1904. TRACED FROM DOBLE BLUE PRINT, SEPT. 9, 1911. SCE drawing no. 5698. - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

Constraints on grip selection in hemiparetic cerebral palsy: effects of lesional side, end-point accuracy, and context.

PubMed

Steenbergen, Bert; Meulenbroek, Ruud G J; Rosenbaum, David A

2004-04-01

This study was concerned with selection criteria used for grip planning in adolescents with left or right hemiparetic cerebral palsy. In the first experiment, we asked participants to pick up a pencil and place the tip in a pre-defined target region. We varied the size of the target to test the hypothesis that increased end-point precision demands would favour the use of a grip that affords end-state comfort. In the second experiment, we studied grip planning in three task contexts that were chosen to let us test the hypothesis that a more functional task context would likewise promote the end-state comfort effect. When movements were performed with the impaired hand, we found that participants with right hemiparesis (i.e., left brain damage) aimed for postural comfort at the start rather than at the end of the object-manipulation phase in both experiments. By contrast, participants with left hemiparesis (i.e., right brain damage) did not favour a particular selection criterion with the impaired hand in the first experiment, but aimed for postural comfort at the start in the second experiment. When movements were performed with the unimpaired hand, grip selection criteria again differed for right and left hemiparetic participants. Participants with right hemiparesis did not favour a particular selection criterion with the unimpaired hand in the first experiment and only showed the end-state comfort effect in the most functional tasks of the second experiment. By contrast, participants with left hemiparesis showed the end-state comfort effect in all conditions of both experiments. These data suggest that the left hemisphere plays a special role in action planning, as has been recognized before, and that one of the deficits accompanying left brain damage is a deficit in forward movement planning, which has not been recognized before. Our findings have both theoretical and clinical implications.

Optically active single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Peng, Xiaobin; Komatsu, Naoki; Bhattacharya, Sumanta; Shimawaki, Takanori; Aonuma, Shuji; Kimura, Takahide; Osuka, Atsuhiro

2007-06-01

The optical, electrical and mechanical properties of single-walled carbon nanotubes (SWNTs) are largely determined by their structures, and bulk availability of uniform materials is vital for extending their technological applications. Since they were first prepared, much effort has been directed toward selective synthesis and separation of SWNTs with specific structures. As-prepared samples of chiral SWNTs contain equal amounts of left- and right-handed helical structures, but little attention has been paid to the separation of these non-superimposable mirror image forms, known as optical isomers. Here, we show that optically active SWNT samples can be obtained by preferentially extracting either right- or left-handed SWNTs from a commercial sample. Chiral `gable-type' diporphyrin molecules bind with different affinities to the left- and right-handed helical nanotube isomers to form complexes with unequal stabilities that can be readily separated. Significantly, the diporphyrins can be liberated from the complexes afterwards, to provide optically enriched SWNTs.

Two-gun suicide by simultaneous shots to the head: interdisciplinary reconstruction on the basis of scene investigation, autopsy findings, GSR analysis and examination of firearms, bullets and cartridge cases.

PubMed

Grosse Perdekamp, Markus; Nadjem, Hadi; Merkel, Joachim; Braunwarth, Roland; Pollak, Stefan; Thierauf, Annette

2011-07-01

Suicidal shots fired simultaneously to the head from two handguns are rare. The authors report about a recent case in which a Smith & Wesson cal. 9 mm pistol and a Smith & Wesson cal. .357 Magnum revolver were used. Sitting on a sofa, a 33-year-old man (member of a shooting club) fired two simultaneous shots to the head; the pistol held in the left hand was discharged into the left temple, and the revolver held in the right hand was fired into the mouth. Both weapons remained in the respective hands. An upside-down muzzle imprint in the left temporal region and recoil injuries of a mandibular incisor, and the lower lip indicated that both the pistol and the revolver had been held in an inverted manner at the time of discharge. Blood stains (backspatter) and gunshot residues were present on both firing hands, whereas forward spatter originating from the exit wounds was deposited on the wall behind the suicide's head.

Potentially risky postural behaviors during worksite keyboard use

PubMed Central

Baker, Nancy A.; Redfern, Mark

2016-01-01

Objective This study describes the frequency and distribution of potentially risky postural behaviors of keyboard users. Method Forty-three subjects’ keyboard postural behaviors were rated with the Keyboard – Personal Computer Style instrument (K-PeCS) while they worked at their own workstations. The frequency and distribution of keyboard postural behaviors, and the associations and differences between the right and left sides were assessed. Results Generally, each static body posture had a single criterion that occurred most frequently, (e.g. elbow flexion posture 80 – 120 degrees), while dynamic postures of the wrists and hands were distributed throughout their criteria. Right and left side postural behaviors were significantly associated for shoulder flexion, elbow flexion, hand displacement, wrist extension, forearm rotation, isolated 5th digit, MCP hyperextension, and wrist support use, and significantly different for hand displacement, isolated thumb, number of digits used, and MCP hyperextension. Conclusion Potentially problematic keyboard postural behaviors are common among keyboard users. Our results suggest that occupational therapists must systematically assess body, arm, wrist, and hand postures on both the right and left sides to be able to develop the most effective intervention strategies. PMID:19708467

Number magnitude to finger mapping is disembodied and topological.

PubMed

Plaisier, Myrthe A; Smeets, Jeroen B J

2011-03-01

It has been shown that humans associate fingers with numbers because finger counting strategies interact with numerical judgements. At the same time, there is evidence that there is a relation between number magnitude and space as small to large numbers seem to be represented from left to right. In the present study, we investigated whether number magnitude to finger mapping is embodied (related to the order of fingers on the hand) or disembodied (spatial). We let healthy human volunteers name random numbers between 1 and 30, while simultaneously tapping a random finger. Either the hands were placed directly next to each other, 30 cm apart, or the hands were crossed such that the left hand was on the right side of the body mid-line. The results show that naming a smaller number than the previous one was associated with tapping a finger to the left of the previously tapped finger. This shows that there is a spatial (disembodied) mapping between number magnitude and fingers. Furthermore, we show that this mapping is topological rather than metrically scaled.

Current direction-dependent modulation of human hand motor function by intermittent theta burst stimulation (iTBS).

PubMed

Shirota, Yuichiro; Dhaka, Suman; Paulus, Walter; Sommer, Martin

2017-05-22

Transcranial magnetic stimulation (TMS) with different current directions can activate different sets of neurons. Current direction can also affect the results of repetitive TMS. To test the influence of uni-directional intermittent theta burst stimulation (iTBS) using different current directions, namely posteroanterior (PA) and anteroposterior (AP), on motor behaviour. In a cross-over design, PA- and AP-iTBS was applied over the left primary motor cortex in 19 healthy, right-handed volunteers. Performance of a finger-tapping task was recorded before and 0, 10, 20, and 30min after the iTBS. The task was conducted with the right and left hands separately at each time point. As a control, AP-iTBS with reduced intensity was applied to 14 participants in a separate session (AP weak condition). The finger-tapping count with the left hand was decreased after PA-iTBS. Neither AP- nor AP weak -iTBS altered the performance. Current direction had a significant impact on the after-effects of iTBS. Copyright © 2017 Elsevier B.V. All rights reserved.

Competition between B-Z and B-L transitions in a single DNA molecule: Computational studies

NASA Astrophysics Data System (ADS)

Kwon, Ah-Young; Nam, Gi-Moon; Johner, Albert; Kim, Seyong; Hong, Seok-Cheol; Lee, Nam-Kyung

2016-02-01

Under negative torsion, DNA adopts left-handed helical forms, such as Z-DNA and L-DNA. Using the random copolymer model developed for a wormlike chain, we represent a single DNA molecule with structural heterogeneity as a helical chain consisting of monomers which can be characterized by different helical senses and pitches. By Monte Carlo simulation, where we take into account bending and twist fluctuations explicitly, we study sequence dependence of B-Z transitions under torsional stress and tension focusing on the interaction with B-L transitions. We consider core sequences, (GC) n repeats or (TG) n repeats, which can interconvert between the right-handed B form and the left-handed Z form, imbedded in a random sequence, which can convert to left-handed L form with different (tension dependent) helical pitch. We show that Z-DNA formation from the (GC) n sequence is always supported by unwinding torsional stress but Z-DNA formation from the (TG) n sequence, which are more costly to convert but numerous, can be strongly influenced by the quenched disorder in the surrounding random sequence.

Three New Structures of Left-Handed RadA Helical Filaments: Structural Flexibility of N-Terminal Domain Is Critical for Recombinase Activity

PubMed Central

Chang, Yu-Wei; Ko, Tzu-Ping; Lee, Chien-Der; Chang, Yuan-Chih; Lin, Kuei-Ann; Chang, Chia-Seng; Wang, Andrew H.-J.; Wang, Ting-Fang

2009-01-01

RecA family proteins, including bacterial RecA, archaeal RadA, and eukaryotic Dmc1 and Rad51, mediate homologous recombination, a reaction essential for maintaining genome integrity. In the presence of ATP, these proteins bind a single-strand DNA to form a right-handed nucleoprotein filament, which catalyzes pairing and strand exchange with a homologous double-stranded DNA (dsDNA), by as-yet unknown mechanisms. We recently reported a structure of RadA left-handed helical filament, and here present three new structures of RadA left-handed helical filaments. Comparative structural analysis between different RadA/Rad51 helical filaments reveals that the N-terminal domain (NTD) of RadA/Rad51, implicated in dsDNA binding, is highly flexible. We identify a hinge region between NTD and polymerization motif as responsible for rigid body movement of NTD. Mutant analysis further confirms that structural flexibility of NTD is essential for RadA's recombinase activity. These results support our previous hypothesis that ATP-dependent axial rotation of RadA nucleoprotein helical filament promotes homologous recombination. PMID:19295907

Measurement of Hybrid III Dummy Properties and Analytical Simulation Data Base Development

DTIC Science & Technology

1988-02-01

Rotation 50 for Itunading Manikin 29 Ilbow Vlexion-Extention at 00 Rotation for )7 oatvd Manikin 30U 1 lbow Y’l.A,*o-" r t inuon at 900 Medial Potation I8...Upper Am 129 10 Left Upper Arm 130 11 Right Fcreerm 131 12 Left Forearm 132 13 R :%ght Hand 133 14 Left Hand 134 15 Seated Right Upper Leg 135 16 Seated...Point Height 3.ref +.1 -- -- D "HO Point Location from 5.4ref_.l - - Beck Line R Shoulder Pivot Location 3.5+.2 3.7 4.4 from Beck Line I Thigh

Search for a Heavy Neutrino and Right-Handed W of the Left-Right Symmetric Model with Cms Detector

NASA Astrophysics Data System (ADS)

Tlisov, Danila

2013-11-01

This work describes the first search for signals from the production of right-handed WR bosons and heavy neutrinos Nℓ (ℓ = e, μ), that arise naturally in the left-right symmetric extension to the Standard Model, with the CMS Experiment at the LHC using the 7 TeV pp collision data collected in 2010 and 2011 corresponding to an integrated luminosity of 240 pb-1. No excess over expectations from Standard Model processes is observed. For models with exact left-right symmetry (the same coupling in the left and right sectors) we exclude the region in the two-dimensional parameter space that extends to (MWR, MNℓ) = (1700 GeV, 600 GeV).

Mirror Observation of Finger Action Enhances Activity in Anterior Intraparietal Sulcus: A Functional Magnetic Resonance Imaging Study

PubMed Central

Murayama, Takashi; Takasugi, Jun; Monma, Masahiko; Oga, Masaru

2013-01-01

Mirror therapy can be used to promote recovery from paralysis in patients with post-stroke hemiplegia, There are a lot of reports that mirror-image observation of the unilateral moving hand enhanced the excitability of the primary motor area (M1) ipsilateral to the moving hand in healthy subjects. but the neural mechanisms underlying its therapeutic effects are currently unclear. To investigate this issue, we used functional magnetic resonance imaging to measure activity in brain regions related to visual information processing during mirror image movement observation. Thirteen healthy subjects performed a finger-thumb opposition task with the left and right hands separately, with or without access to mirror observation. In the mirror condition, one hand was reflected in a mirror placed above the abdomen in the MRI scanner. In the masked mirror condition, subjects performed the same task but with the mirror obscured. In both conditions, the other hand was held at rest behind the mirror. A between-task comparison (mirror versus masked mirror) revealed significant activation in the ipsilateral hemisphere in the anterior intraparietal sulcus (aIP) while performing all tasks, regardless of which hand was used. The right aIP was significantly activated while moving the right hand. In contrast, in the left aIP, a small number of voxels showed a tendency toward activation during both left and right hand movement. The enhancement of ipsilateral aIP activity by the mirror image observation of finger action suggests that bimodal aIP neurons can be activated by visual information. We propose that activation in the M1 ipsilateral to the moving hand can be induced by information passing through the ventral premotor area from the aIP. PMID:25792898

Acute immobilisation facilitates premotor preparatory activity for the non-restrained hand when facing grasp affordances.

PubMed

Kühn, Simone; Werner, Anika; Lindenberger, Ulman; Verrel, Julius

2014-05-15

Use and non-use of body parts during goal-directed action are major forces driving reorganisation of neural processing. We investigated changes in functional brain activity resulting from acute short-term immobilisation of the dominant right hand. Informed by the concept of object affordances, we predicted that the presence or absence of a limb restraint would influence the perception of graspable objects in a laterally specific way. Twenty-three participants underwent fMRI scanning during a passive object-viewing task before the intervention as well as with and without wearing an orthosis. The right dorsal premotor cortex and the left cerebellum were more strongly activated when the handle of an object was oriented towards the left hand while the right hand was immobilised compared with a situation where the hand was not immobilised. The cluster in the premotor cortex showing an interaction between condition (with restraint, without restraint) and stimulus action side (right vs. left) overlapped with the general task vs. baseline contrast prior to the intervention, confirming its functional significance for the task. These results show that acute immobilisation of the dominant right hand leads to rapid changes of the perceived affordance of objects. We conclude that changes in action requirements lead to almost instantaneous changes in functional activation patterns, which in turn may trigger structural cortical plasticity. Copyright © 2014. Published by Elsevier Inc.

The embodied nature of motor imagery processes highlighted by short-term limb immobilization.

PubMed

Meugnot, Aurore; Almecija, Yves; Toussaint, Lucette

2014-01-01

We investigated the embodied nature of motor imagery processes through a recent use-dependent plasticity approach, a short-term limb immobilization paradigm. A splint placed on the participants' left-hand during a brief period of 24 h was used for immobilization. The immobilized participants performed two mental rotation tasks (a hand mental rotation task and a number mental rotation task) before (pre-test) and immediately after (post-test) the splint removal. The control group did not undergo the immobilization procedure. The main results showed an immobilization-induced effect on left-hand stimuli, resulting in a lack of task-repetition benefit. By contrast, accuracy was higher and response times were shorter for right-hand stimuli. No immobilization-induced effects appeared for number stimuli. These results revealed that the cognitive representation of hand movements can be modified by a brief period of sensorimotor deprivation, supporting the hypothesis of the embodied nature of motor simulation processes.

Unilateral muscle contractions enhance creative thinking.

PubMed

Goldstein, Abraham; Revivo, Ketty; Kreitler, Michal; Metuki, Nili

2010-12-01

Following the notion of relative importance of the right hemisphere (RH) in creative thinking, we explored the possibility of enhancing creative problem solving by artificially activating the RH ahead of time using unilateral hand contractions. Participants attempted to complete the Remote Associates Test after squeezing a ball with either their left or right hand. As predicted, participants who contracted their left hand (thus activating the RH) achieved higher scores than those who used their right hand and those who did not contract either hand. Our findings indicate that tilting the hemispheric balance toward the processing mode of one hemisphere by motor activation can greatly influence the outcome of thought processes. Regardless of the specific mechanism involved, this technique has the potential for acting as a therapeutic or remedial manipulation and could have wide applications in aiding individuals with language impairments or other disorders that are believed to be related to hemispheric imbalances.

Evaluation of skeletal maturation by comparing the hand wrist radiograph and cervical vertebrae as seen in lateral cephalogram.

PubMed

Mahajan, Shally

2011-01-01

Aim of this study was to determine the validity of cervical vertebrae radiographic assessment to predict skeletal maturation. Left-hand wrist and lateral cephalometric radiographs of 100 Bangalore children aged 8-18 years, divided into 10 groups of 10 subjects each with equal distribution of males and females, were measured. On left-hand wrist radiograph, the classification of Fishman was used to assess skeletal maturation. Cervical vertebrae maturation was evaluated with lateral cephalometric radiograph, using the stages developed by Hassel and Farman. The changes in hand wrist and cervical vertebrae were correlated. Significant association was observed between skeletal maturation indicator stages and cervical vertebrae maturation indicator stages. Correlation coefficient was found to be significant (P<0.0001). The results of the study indicated that the cervical vertebrae maturation and hand wrist skeletal maturation was significantly related.

Differential activation in the primary motor cortex during individual digit movement in focal hand dystonia vs. healthy.

PubMed

Kimberley, Teresa J; Pickett, Kristen A

2012-01-01

The pathophysiology of focal hand dystonia (FHD) is not clearly understood. Previous studies have reported increased and decreased cortical activity associated with motor tasks. The aim of this study was to investigate blood oxygen level dependent (BOLD) signal changes in functional magnetic resonance imaging within the hand area of primary motor cortex during cued movement of individual digits. Eight healthy individuals and five individuals with right hand FHD participated. Beta weight contrasts were examined within the hand area of the motor cortex. In both groups, BOLD signal changes in the hemisphere contralateral to the moving hand were greater in the left hemisphere than the right. Between groups, no difference was found during control of the left hand, but a significant difference was seen during right hand movement; specifically, individuals with dystonia showed increased contralateral and decreased ipsilateral cortical response associated with the affected hand as compared to healthy individuals. This suggests a similar, albeit exaggerated pattern of activation in individuals with FHD on the affected side. These results suggest different levels of ipsilateral and contralateral activation between healthy and dystonic individuals but also show a relative difference between symptomatic and asymptomatic control within the patient population.

New excitations in the Thirring model

NASA Astrophysics Data System (ADS)

Cortés, J. L.; Gamboa, J.; Schmidt, I.; Zanelli, J.

1998-12-01

The quantization of the massless Thirring model in the light-cone using functional methods is considered. The need to compactify the coordinate x- in the light-cone spacetime implies that the quantum effective action for left-handed fermions contains excitations similar to abelian instantons produced by composite of left-handed fermions. Right-handed fermions don't have a similar effective action. Thus, quantum mechanically, chiral symmetry must be broken as a result of the topological excitations. The conserved charge associated to the topological states is quantized. Different cases with only fermionic excitations or bosonic excitations or both can occur depending on the boundary conditions and the value of the coupling.

Cortical correlates of neuromotor development in healthy children.

PubMed

Garvey, M A; Ziemann, U; Bartko, J J; Denckla, M B; Barker, C A; Wassermann, E M

2003-09-01

To examine the relationship between acquisition of fine motor skills in childhood and development of the motor cortex. We measured finger tapping speed and mirror movements in 43 healthy right-handed subjects (6-26 years of age). While recording surface electromyographic activity from right and left first dorsal interosseus, we delivered focal transcranial magnetic stimulation (TMS) over the hand areas of each motor cortex. We measured motor evoked potential (MEP) threshold, and ipsilateral (iSP) and contralateral (CSP) silent periods. As children got older, finger speeds got faster, MEP threshold decreased, iSP duration increased and latency decreased. Finger tapping speed got faster as motor thresholds and iSP latency decreased, but was unrelated to CSP duration. In all subjects right hemisphere MEP thresholds were higher than those on the left and duration of right hemisphere CSP was longer than that on the left. Children under 10 years of age had higher left hand mirror movement scores, and fewer left hemisphere iSPs which were of longer duration. Maturation of finger tapping skills is closely related to developmental changes in the motor threshold and iSP latency. Studies are warranted to explore the relationship between these measures and other neuromotor skills in children with motor disorders. TMS can provide important insights into certain functional aspects of neurodevelopment in children.

Effects of two-handed task training on upper limb function of chronic hemiplegic patients after stroke

PubMed Central

Yang, Byung Il; Song, Bo Kyoung; Joung, Sang Mi

2017-01-01

[Purpose] The purpose of this study was to determine whether two-handed task training is effective on motor learning of injured cerebral cortex activation and upper extremity function recovery after stroke. [Subjects and Methods] Two hemiplegic subjects participated in this study: one patient was affected on the dominant side of the body and the other was affected on the non-dominant side of the body, and both scored in the range of 58–66 in the Fugl-Meyer assessment. The excitability of the corticospinal tract and Manual Function Test were examined. [Results] The excitability of the corticospinal tract and the Manual Function Test showed significant differences in the activation of both sides of the cerebral cortex and in the variation in learning effect of upper extremity motor function recovery in patients with hemiplegic non-dominant hand (left). [Conclusion] The results suggested that two-handed task training had a different influence on dominant hand (right) and non-dominant hand (left) motor recovery. PMID:28210051

White-matter microstructure and language lateralization in left-handers: a whole-brain MRI analysis.

PubMed

Perlaki, Gabor; Horvath, Reka; Orsi, Gergely; Aradi, Mihaly; Auer, Tibor; Varga, Eszter; Kantor, Gyongyi; Altbäcker, Anna; John, Flora; Doczi, Tamas; Komoly, Samuel; Kovacs, Norbert; Schwarcz, Attila; Janszky, Jozsef

2013-08-01

Most people are left-hemisphere dominant for language. However the neuroanatomy of language lateralization is not fully understood. By combining functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we studied whether language lateralization is associated with cerebral white-matter (WM) microstructure. Sixteen healthy, left-handed women aged 20-25 were included in the study. Left-handers were targeted in order to increase the chances of involving subjects with atypical language lateralization. Language lateralization was determined by fMRI using a verbal fluency paradigm. Tract-based spatial statistics analysis of DTI data was applied to test for WM microstructural correlates of language lateralization across the whole brain. Fractional anisotropy and mean diffusivity were used as indicators of WM microstructural organization. Right-hemispheric language dominance was associated with reduced microstructural integrity of the left superior longitudinal fasciculus and left-sided parietal lobe WM. In left-handed women, reduced integrity of the left-sided language related tracts may be closely linked to the development of right hemispheric language dominance. Our results may offer new insights into language lateralization and structure-function relationships in human language system. Copyright © 2013 Elsevier Inc. All rights reserved.

From the left to the right: How the brain compensates progressive loss of language function.

PubMed

Thiel, Alexander; Habedank, Birgit; Herholz, Karl; Kessler, Josef; Winhuisen, Lutz; Haupt, Walter F; Heiss, Wolf-Dieter

2006-07-01

In normal right-handed subjects language production usually is a function oft the left brain hemisphere. Patients with aphasia following brain damage to the left hemisphere have a considerable potential to compensate for the loss of this function. Sometimes, but not always, areas of the right hemisphere which are homologous to language areas of the left hemisphere in normal subjects are successfully employed for compensation but this integration process may need time to develop. We investigated right-handed patients with left hemisphere brain tumors as a model of continuously progressive brain damage to left hemisphere language areas using functional neuroimaging and transcranial magnetic stimulation (TMS) to identify factors which determine successful compensation of lost language function. Only patients with slowly progressing brain lesions recovered right-sided language function as detected by TMS. In patients with rapidly progressive lesions no right-sided language function was found and language performance was linearly correlated with the lateralization of language related brain activation to the left hemisphere. It can thus be concluded that time is the factor which determines successful integration of the right hemisphere into the language network for compensation of lost left hemisphere language function.

Anosognosia for hemiparesis after left-sided stroke.

PubMed

Baier, Bernhard; Vucurevic, Goran; Müller-Forell, Wibke; Glassl, Oliver; Geber, Christian; Dieterich, Marianne; Karnath, Hans-Otto

2014-12-01

In patients with left-sided lesions, anosognosia for hemiparesis (AHP) seems to be a rare phenomenon. It has been discussed whether this rareness might be due to an inevitable bias due to language dysfunction and whether the left hemisphere's role for our self-awareness of motor actions thus is underestimated. By applying functional magnetic resonance imaging (fMRI) we examined whether patients with AHP following a left hemisphere stroke show a regular, left-sided or a reversed, right-sided lateralization of language functions. Only the former observation would argue for an original role of the left hemisphere in self-awareness about limb function. In a consecutive series of 44 acute left-sided stroke patients, only one patient (=2%) was identified showing AHP. In this case, we could verify by using fMRI that lateralization of AHP and spatial neglect on the one hand and of language functions on the other hand were reversed. The present single case observation thus argues against an original role of the left hemisphere in self-awareness about limb function. We discuss the data in the context of previous observations in the literature. Copyright © 2014 Elsevier Ltd. All rights reserved.

Did Caravaggio employ optical projections? An image analysis of the parity in the artist's paintings

NASA Astrophysics Data System (ADS)

Stork, David G.

2011-03-01

We examine one class of evidence put forth in support of the recent claim that the Italian Baroque master Caravaggio secretly employed optical projectors as a direct drawing aid. Specically, we test the claims that there is an "abnormal number" of left-handed gures in his works and, more specically, that "During the Del Monte period he had too many left-handed models." We also test whether there was a reversal in the handedness of specic models in different paintings. Such evidence would be consistent with the claim that Caravaggio switched between using a convex-lens projector to using a concave-mirror projector and would support, but not prove, the claim that Caravaggio used optical projections. We estimate the parity (+ or -) of each of Caravaggio's 76 appropriate oil paintings based on the handedness of gures, the orientation of asymmetric objects, placement of scabbards, depicted text, and so on, and search for statistically significant changes in handedness in figures. We also track the direction of the illumination over time in the artist's uvre. We discuss some historical evidence as it relates to the question of his possible use of optics. We nd the proportion of left-handed figures lower than that in the general population (not higher), and no significant change in estimated handedness even of individual models. Optical proponents have argued that Bacchus (1597) portrays a left-handed gure, but we give visual and cultural evidence showing that this gure is instead right-handed, thereby rebutting this claim that the painting was executed using optical projections. Moreover, scholars recently re-discovered the image of the artist with easel and canvas reflected in the carafe of wine at the front left in the tableau in Bacchus, showing that this painting was almost surely executed using traditional (non-optical) easel methods. We conclude that there is 1) no statistically signicant abnormally high number of left-handed gures in Caravaggio's uvre, including during any limited working period, 2) no statistically significant change in handedness among all gures or even individual gures that might be consistent with a change in optical projector, and 3) the visual and cultural evidence in Bacchus shows the gure was right-handed and that the artist executed this work by traditional (non-optical) easel methods. We conclude that the general parity and handedness evidence does not support the claim that Caravaggio employed optical projections.

Association between growth stunting with dental development and skeletal maturation stage.

PubMed

Flores-Mir, Carlos; Mauricio, Franco Raul; Orellana, Maria Fernanda; Major, Paul William

2005-11-01

The aim of this study was to determine the influence of growth stunting on the maturation stage of the medium phalanx of the third finger (MP3) and the dental development of the left mandibular canine in 280 high school children (140 stunted and 140 normal controls; equally distributed by sex) between 9.5 and 16.5 years of age, from a representative Peruvian school. Periapical radiographs of the MP3 from the left hand were used to determine the skeletal maturity stage, according to an adaptation of the Hägg and Taranger method. Panoramic radiographs were used to determine the dental maturity stage of the lower left canine, according to Demirjian method. Stunting was determined by relating height and age, according to the World Health Organization recommendations. There was no statistically significant difference in the skeletal maturation stage (P = .134) and the dental development stage (P = .497) according to nutritional status, even when considering different age groups (P > .183). A high correlation (r = 0.85) was found between both maturity indicators regardless of the nutritional status (growth stunted, r = 0.855 and normal controls, r = 0.863) or sex (boys, r = 0.809 and girls, r = 0.892). When skeletal level was considered, correlations values were similar between advanced (r = 0.903) and average (r = 0.895) maturers but lower (r = 0.751) for delayed maturers. Growth stunting was not associated with dental development and skeletal maturity stages in Peruvian school children.

Attention-shift vs. response-priming explanations for the spatial cueing effect in cross-modal tasks.

PubMed

Paavilainen, Petri; Illi, Janne; Moisseinen, Nella; Niinisalo, Maija; Ojala, Karita; Reinikainen, Johanna; Vainio, Lari

2016-06-01

The task-irrelevant spatial location of a cue stimulus affects the processing of a subsequent target. This "Posner effect" has been explained by an exogenous attention shift to the spatial location of the cue, improving perceptual processing of the target. We studied whether the left/right location of task-irrelevant and uninformative tones produces cueing effects on the processing of visual targets. Tones were presented randomly from left or right. In the first condition, the subsequent visual target, requiring response either with the left or right hand, was presented peripherally to left or right. In the second condition, the target was a centrally presented left/right-pointing arrow, indicating the response hand. In the third condition, the tone and the central arrow were presented simultaneously. Data were recorded on compatible (the tone location and the response hand were the same) and incompatible trials. Reaction times were longer on incompatible than on compatible trials. The results of the second and third conditions are difficult to explain with the attention-shift model emphasizing improved perceptual processing in the cued location, as the central target did not require any location-based processing. Consequently, as an alternative explanation they suggest response priming in the hand corresponding to the spatial location of the tone. Simultaneous lateralized readiness potential (LRP) recordings were consistent with the behavioral data, the tone cues eliciting on incompatible trials a fast preparation for the incorrect response and on compatible trials preparation for the correct response. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Why PeV scale left-right symmetry is a good thing

NASA Astrophysics Data System (ADS)

Yajnik, Urjit A.

2017-10-01

Left-right symmetric gauge theory presents a minimal paradigm to accommodate massive neutrinos with all the known conserved symmetries duly gauged. The work presented here is based on the argument that the see-saw mechanism does not force the new right-handed symmetry scale to be very high, and as such some of the species from the spectrum of the new gauge and Higgs bosons can have masses within a few orders of magnitude of the TeV scale. The scale of the left-right parity breaking in turn can be sequestered from the Planck scale by supersymmetry. We have studied several formulations of such just beyond Standard Model (JBSM) theories for their consistency with cosmology. Specifically, the need to eliminate phenomenologically undesirable domain walls gives many useful clues. The possibility that the exact left-right symmetry breaks in conjunction with supersymmetry has been explored in the context of gauge mediation, placing restrictions on the available parameter space. Finally, we have also studied a left-right symmetric model in the context of metastable supersymmetric vacua and obtained constraints on the mass scale of right-handed symmetry. In all the cases studied, the mass scale of the right-handed neutrino M_R remains bounded from above, and in some of the cases the scale 10^9 GeV favourable for supersymmetric thermal leptogenesis is disallowed. On the other hand, PeV scale remains a viable option, and the results warrant a more detailed study of such models for their observability in collider and astroparticle experiments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kulagin, D. V.; Levchenko, G. G.; Savchenko, A. S.

The features of refraction (including the Goos-Hanchen effect) of a TM or TE bulk electromagnetic wave incident from outside on the surface of a chiral magnetoelectric with the homogeneous antisymmetric magnetoelectric interaction has been analytically studied on an example of the two-sublattice model of a multiferroic. In particular, it has been shown that the requirement that the diagonal components of the permeability and permittivity tensors are simultaneously negative is not necessary for the implementation of the properties of a left-handed medium. The results have been generalized to the case of an easy-axis antiferromagnet with an antisymmetry center with the 4{submore » z}{sup {+-}}2{sub x}{sup +}I{sup -} structure in the static external magnetic field perpendicular to the easy axis of magnetization. Some results of this work were preliminarily reported in D.V. Kulagin, G.G. Levchenko, A.S. Savchenko, A.S. Tarasenko, and S.V. Tarasenko, JETP Lett. 92, 511 (2010).« less

Exotic meson decays in the environment with chiral imbalance

NASA Astrophysics Data System (ADS)

Andrianov, A. A.; Andrianov, V. A.; Espriu, D.; Iakubovich, A. V.; Putilova, A. E.

2017-10-01

An emergence of Local Parity Breaking (LPB) in central heavy-ion collisions (HIC) at high energies is discussed. LPB in the fireball can be produced by a difference between the number densities of right- and left-handed chiral fermions (Chiral Imbalance) which is implemented by a chiral (axial) chemical potential. The effective meson lagrangian induced by QCD is extended to the medium with Chiral Imbalance and the properties of light scalar and pseudoscalar mesons (π, α0) are analyzed. It is shown that exotic decays of scalar mesons arise as a result of mixing of π and α0 vacuum states in the presence of chiral imbalance. The pion electromagnetic formfactor obtains an unusual parity-odd supplement which generates a photon polarization asymmetry in pion polarizability. We hope that the above pointed indications of LPB can be identified in experiments on LHC, RHIC, CBM FAIR and NICA accelerators.

On the stability of nongyrotropic ion populations - A first (analytic and simulation) assessment

NASA Technical Reports Server (NTRS)

Brinca, A. L.; Borda De Agua, L.; Winske, D.

1993-01-01

The wave and dispersion equations for perturbations propagating parallel to an ambient magnetic field in magnetoplasmas with nongyrotropic ion populations show, in general, the occurrence of coupling between the parallel (left- and right-hand circularly polarized electromagnetic and longitudinal electrostatic) eigenmodes of the associated gyrotropic medium. These interactions provide a means to driving linearly one mode with free-energy sources of other modes in homogeneous media. Different types of nongyrotropy bring about distinct classes of coupling. The stability of a hydrogen magnetoplasma with anisotropic, nongyrotropic protons that only couple the electromagnetic modes to each other is investigated analytically (via solution of the derived dispersion equation) and numerically (via simulation with a hybrid code). Nongyrotropy enhances growth and enlarges the unstable spectral range relative to the corresponding gyrotropic situation. The relevance of the properties of nongyrotropic populations to space plasma environments is also discussed.

Churg-Strauss syndrome and hemorrhagic vasculitis

PubMed Central

Marques, Rui Moreira; Cabral, Ana Rita; Monteiro, Antonio; Henriques, Pedro

2011-01-01

Churg-Strauss syndrome (CSS) is a rare syndrome characterized by sinusitis, asthma and peripheral eosinophilia. This vasculitic syndrome affects medium and small-sized vessels, the lung being the most commonly affected organ, followed by the skin. The authors report a case of a 59-year-old male with a past history of asthma and allergic rhinitis. He presented necrohemorragic lesions in the distal phalanx of the 2nd, 3rd and 4th fingers of the left-hand and petechial lesions in the plant of both feet, accompanied by asthenia, anorexia and weight loss. The analytical study revealed leukocytosis with eosinophilia, elevated inflammatory parameters and p-ANCA positive antibodies. The diagnosis of CSS was established based on clinical and histopathological data. Cutaneous manifestations of hemorragic vasculitis are rare in CSS syndrome but can be the first manifestation of the disease. The recognition of this presentation is important for the early diagnosis and treatment of this syndrome. PMID:25386301

18. William E. Barrett, Photographer, August 1975. EXPOSED VIEW OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. William E. Barrett, Photographer, August 1975. EXPOSED VIEW OF LOWER PULLEYS OF LEFT-HAND MILL. LOWER LEFT IS BAND SAW PULLEY. UPPER LEFT IS TENSION WHEEL. LARGE PULLEY ON RIGHT IS DRIVE WHEEL FROM POWER SOURCE. - Meadow River Lumber Company, Highway 60, Rainelle, Greenbrier County, WV

Neural basis of understanding communicative actions: Changes associated with knowing the actor's intention and the meanings of the actions.

PubMed

Möttönen, Riikka; Farmer, Harry; Watkins, Kate E

2016-01-29

People can communicate by using hand actions, e.g., signs. Understanding communicative actions requires that the observer knows that the actor has an intention to communicate and the meanings of the actions. Here, we investigated how this prior knowledge affects processing of observed actions. We used functional MRI to determine changes in action processing when non-signers were told that the observed actions are communicative (i.e., signs) and learned the meanings of half of the actions. Processing of hand actions activated the left and right inferior frontal gyrus (IFG, BA 44 and 45) when the communicative intention of the actor was known, even when the meanings of the actions remained unknown. These regions were not active when the observers did not know about the communicative nature of the hand actions. These findings suggest that the left and right IFG play a role in understanding the intention of the actor, but do not process visuospatial features of the communicative actions. Knowing the meanings of the hand actions further enhanced activity in the anterior part of the IFG (BA 45), the inferior parietal lobule and posterior inferior and middle temporal gyri in the left hemisphere. These left-hemisphere language regions could provide a link between meanings and observed actions. In sum, the findings provide evidence for the segregation of the networks involved in the neural processing of visuospatial features of communicative hand actions and those involved in understanding the actor's intention and the meanings of the actions. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Contralesional arm preference depends on hemisphere of damage and target location in unilateral stroke patients

PubMed Central

Mani, Saandeep; Przybyla, Andrzej; Good, David C.; Haaland, Kathleen Y.; Sainburg, Robert L.

2014-01-01

Background Previous research has shown that during simulated activities of daily living right handed stroke patients use their contralesional arm more after left than right hemisphere stroke. These findings were attributed to a hand preference effect. However, these decisions about when to use the contralesional arm may be modulated by where in the work space the task is performed, a factor that could be used in physical rehabilitation to influence recovery by decreasing learned non-use. Objective To examine how target location and side of stroke influences arm selection choices for simple reaching movements. Methods Fourteen right-handed stroke patients (7 with left hemisphere damage, 7 with right hemisphere damage) with similar degree of hemiparesis (Fugl-Meyer motor score), and 16 right-handed control subjects participated in this experiment. Thirty-two targets were presented throughout the reachable horizontal plane workspace in a pseudo-random fashion, and the subjects were asked to select one hand to reach the target on each trial. Results The left hemisphere damaged group chose their contralesional arm significantly more often than the right hemisphere damaged group. Patients with right hemisphere damage also chose their left (contralesional) arm significantly less than the control group. However, these patterns of choice were most pronounced in the center of the workspace. Conclusion Both the side of hemisphere damage and workspace location played a significant role in the choice of whether to use the contralesional arm for reaching. These findings have implications for structuring rehabilitation for unilateral stroke patients. PMID:24523143

High salt solution structure of a left-handed RNA double helix

PubMed Central

Popenda, Mariusz; Milecki, Jan; Adamiak, Ryszard W.

2004-01-01

Right-handed RNA duplexes of (CG)n sequence undergo salt-induced helicity reversal, forming left-handed RNA double helices (Z-RNA). In contrast to the thoroughly studied Z-DNA, no Z-RNA structure of natural origin is known. Here we report the NMR structure of a half-turn, left-handed RNA helix (CGCGCG)2 determined in 6 M NaClO4. This is the first nucleic acid motif determined at such high salt. Sequential assignments of non-exchangeable proton resonances of the Z-form were based on the hitherto unreported NOE connectivity path [H6(n)-H5′/H5″(n)-H8(n+1)-H1′(n+1)-H6(n+2)] found for left-handed helices. Z-RNA structure shows several conformational features significantly different from Z-DNA. Intra-strand but no inter-strand base stacking was observed for both CpG and GpC steps. Helical twist angles for CpG steps have small positive values (4–7°), whereas GpC steps have large negative values (−61°). In the full-turn model of Z-RNA (12.4 bp per turn), base pairs are much closer to the helix axis than in Z-DNA, thus both the very deep, narrow minor groove with buried cytidine 2′-OH groups, and the major groove are well defined. The 2′-OH group of cytidines plays a crucial role in the Z-RNA structure and its formation; 2′-O-methylation of cytidine, but not of guanosine residues prohibits A to Z helicity reversal. PMID:15292450

Similarities and Differences between RNA and DNA Double-Helical Structures in Circular Dichroism Spectroscopy: A SAC-CI Study.

PubMed

Miyahara, Tomoo; Nakatsuji, Hiroshi; Sugiyama, Hiroshi

2016-11-17

The helical structures of DNA and RNA are investigated experimentally using circular dichroism (CD) spectroscopy. The signs and the shapes of the CD spectra are much different between the right- and left-handed structures as well as between DNA and RNA. The main difference lies in the sign at around 295 nm of the CD spectra: it is positive for the right-handed B-DNA and the left-handed Z-RNA but is negative for the left-handed Z-DNA and the right-handed A-RNA. We calculated the SAC-CI CD spectra of DNA and RNA using the tetramer models, which include both hydrogen-bonding and stacking interactions that are important in both DNA and RNA. The SAC-CI results reproduced the features at around 295 nm of the experimental CD spectra of each DNA and RNA, and elucidated that the strong stacking interaction between the two base pairs is the origin of the negative peaks at 295 nm of the CD spectra for both DNA and RNA. On the basis of these facts, we discuss the similarities and differences between RNA and DNA double-helical structures in the CD spectroscopy based on the ChiraSac methodology.

Two-Dimensional Simulation of Left-Handed Metamaterial Flat Lens Using Remcon XFDTD

NASA Technical Reports Server (NTRS)

Wilson, Jeffrey D.; Reinert, Jason M.

2006-01-01

Remcom's XFDTD software was used to model the properties of a two-dimensional left-handed metamaterial (LHM) flat lens. The focusing capability and attenuation of the material were examined. The results showed strong agreement with experimental results and theoretical predictions of focusing effects and focal length. The inherent attenuation in the model corresponds well with the experimental results and implies that the code does a reasonably accurate job of modeling the actual metamaterial.

Orion EM-1 Forward Skirt Move from Hangar AF to BFF

NASA Image and Video Library

2017-08-30

The Exploration Mission-1 (EM-1) left-hand forward skirt for NASA's Space Launch System (SLS) solid rocket boosters arrives inside the high bay at the Booster Fabrication Facility (BFF) at NASA's Kennedy Space Center in Florida. In the BFF, the forward skirt will be inspected and prepared for use on the left-hand solid rocket booster for EM-1. NASA's Orion spacecraft will fly atop the SLS rocket on its first uncrewed flight test.

Distorted own-body representations in patients with dizziness and during caloric vestibular stimulation.

PubMed

Lopez, Christophe; Nakul, Estelle; Preuss, Nora; Elzière, Maya; Mast, Fred W

2018-06-06

There is increasing evidence that vestibular disorders evoke deficits reaching far beyond imbalance, oscillopsia and spatial cognition. Yet, how vestibular disorders affect own-body representations, in particular the perceived body shape and size, has been overlooked. Here, we explored vestibular contributions to own-body representations using two approaches. Study 1 measured the occurrence and severity of distorted own-body representations in 60 patients with dizziness and 60 healthy controls using six items from the Cambridge Depersonalization Scale. 12% of the patients have experienced distorted own-body representations (their hands or feet felt larger or smaller), 37% reported abnormal sense of agency, 35% reported disownership for the body, and 22% reported disembodiment. These proportions were larger in patients than controls. Study 2 aimed at testing whether artificial stimulation of the vestibular apparatus produced comparable distortions of own-body representations in healthy volunteers. We compared the effects of right-warm/left-cold caloric vestibular stimulation (CVS), left-warm/right-cold CVS and sham CVS on internal models of the left and right hands using a pointing task. The perceived length of the dorsum of the hand was increased specifically during left-warm/right-cold CVS, and this effect was found for both hands. Our studies show a vestibular contribution to own-body representations and should help understand the complex symptomatology of patients with dizziness.

The posterior parietal cortex (PPC) mediates anticipatory motor control.

PubMed

Krause, Vanessa; Weber, Juliane; Pollok, Bettina

2014-01-01

Flexible and precisely timed motor control is based on functional interaction within a cortico-subcortical network. The left posterior parietal cortex (PPC) is supposed to be crucial for anticipatory motor control by sensorimotor feedback matching. Intention of the present study was to disentangle the specific relevance of the left PPC for anticipatory motor control using transcranial direct current stimulation (tDCS) since a causal link remains to be established. Anodal vs. cathodal tDCS was applied for 10 min over the left PPC in 16 right-handed subjects in separate sessions. Left primary motor cortex (M1) tDCS served as control condition and was applied in additional 15 subjects. Prior to and immediately after tDCS, subjects performed three tasks demanding temporal motor precision with respect to an auditory stimulus: sensorimotor synchronization as measure of anticipatory motor control, interval reproduction and simple reaction. Left PPC tDCS affected right hand synchronization but not simple reaction times. Motor anticipation was deteriorated by anodal tDCS, while cathodal tDCS yielded the reverse effect. The variability of interval reproduction was increased by anodal left M1 tDCS, whereas it was reduced by cathodal tDCS. No significant effects on simple reaction times were found. The present data support the hypothesis that left PPC is causally involved in right hand anticipatory motor control exceeding pure motor implementation as processed by M1 and possibly indicating subjective timing. Since M1 tDCS particularly affects motor implementation, the observed PPC effects are not likely to be explained by alterations of motor-cortical excitability. Copyright © 2014 Elsevier Inc. All rights reserved.

Hand preferences in captive orangutans (Pongo pygmaeus).

PubMed

O'malley, Robert C; McGrew, W C

2006-07-01

The strength of the evidence for population-level handedness in the great apes is a topic of considerable debate, yet there have been few studies of handedness in orangutans. We conducted a study of manual lateralization in a captive group of eight orangutans (Pongo pygmaeus) ranking the degrees of manual preference according to a defined framework. We analyzed five behavioral patterns: eat (one- and two-handed), make/modify tool, oral tool-use, and manual tool-use. Although some individuals showed significant manual preferences for one or more tasks, at the group-level both one-handed and two-handed eating, oral tool-use, and make/modify tool were ranked at level 1 (unlateralized). Manual tool-use was ranked at level 2, with four subjects demonstrating significant hand preferences, but no group-level bias to the right or left. Four subjects also showed hand specialization to the right or left across several tasks. These results are consistent with most previous studies of manual preference in orangutans. The emergence of manual lateralization in orangutans may relate to more complex manipulative tasks. We hypothesize that more challenging manual tasks elicit stronger hand preferences.

Is the hand to speech what speech is to the hand?

PubMed

Mildner, V

2000-01-01

Interference between the manual and the verbal performance on two types of concurrent verbal-manual tasks was studied on a sample of 48 female right-handers. The more complex verbal task (storytelling) affected both hands significantly, the less complex (essentially phonemic) task affected only the right hand, with insignificant negative influence on the left-hand performance. No significant reciprocal effects of the motor task on verbalization were found.

Laterality of Grooming and Tool Use in a Group of Captive Bonobos (Pan paniscus).

PubMed

Brand, Colin M; Marchant, Linda F; Boose, Klaree J; White, Frances J; Rood, Tabatha M; Meinelt, Audra

2017-01-01

Humans exhibit population level handedness for the right hand; however, the evolution of this behavioral phenotype is poorly understood. Here, we compared the laterality of a simple task (grooming) and a complex task (tool use) to investigate whether increasing task difficulty elicited individual hand preference among a group of captive bonobos (Pan paniscus). Subjects were 17 bonobos housed at the Columbus Zoo and Aquarium. Laterality of grooming was recorded using group scans; tool use was recorded using all-occurrence sampling. Grooming was characterized as unimanual or bimanual, and both tasks were scored as right-handed or left-handed. Most individuals did not exhibit significant hand preference for unimanual or bimanual (asymmetrical hand use) grooming, although 1 individual was lateralized for each. For the 8 subjects who engaged in termite fishing enough for statistical testing, 7 individuals exhibited significant laterality and strong individual hand preference. Four subjects preferred their left hand, 3 preferred their right, and 1 had no preference. Grooming, a simple behavior, was not lateralized in this group, yet a more complex behavior revealed a strong individual hand preference, and these results are congruent with other recent findings that demonstrate complex tasks elicit hand preference in bonobos. © 2017 S. Karger AG, Basel.

Pure associative tactile agnosia for the left hand: clinical and anatomo-functional correlations.

PubMed

Veronelli, Laura; Ginex, Valeria; Dinacci, Daria; Cappa, Stefano F; Corbo, Massimo

2014-09-01

Associative tactile agnosia (TA) is defined as the inability to associate information about object sensory properties derived through tactile modality with previously acquired knowledge about object identity. The impairment is often described after a lesion involving the parietal cortex (Caselli, 1997; Platz, 1996). We report the case of SA, a right-handed 61-year-old man affected by first ever right hemispheric hemorrhagic stroke. The neurological examination was normal, excluding major somaesthetic and motor impairment; a brain magnetic resonance imaging (MRI) confirmed the presence of a right subacute hemorrhagic lesion limited to the post-central and supra-marginal gyri. A comprehensive neuropsychological evaluation detected a selective inability to name objects when handled with the left hand in the absence of other cognitive deficits. A series of experiments were conducted in order to assess each stage of tactile recognition processing using the same stimulus sets: materials, 3D geometrical shapes, real objects and letters. SA and seven matched controls underwent the same experimental tasks during four sessions in consecutive days. Tactile discrimination, recognition, pantomime, drawing after haptic exploration out of vision and tactile-visual matching abilities were assessed. In addition, we looked for the presence of a supra-modal impairment of spatial perception and of specific difficulties in programming exploratory movements during recognition. Tactile discrimination was intact for all the stimuli tested. In contrast, SA was able neither to recognize nor to pantomime real objects manipulated with the left hand out of vision, while he identified them with the right hand without hesitations. Tactile-visual matching was intact. Furthermore, SA was able to grossly reproduce the global shape in drawings but failed to extract details of objects after left-hand manipulation, and he could not identify objects after looking at his own drawings. This case confirms the existence of selective associative TA as a left hand-specific deficit in recognizing objects. This deficit is not related to spatial perception or to the programming of exploratory movements. The cross-modal transfer of information via visual perception permits the activation of a partially degraded image, which alone does not allow the proper recognition of the initial tactile stimulus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mental rotation of body parts and non-corporeal objects in patients with idiopathic cervical dystonia.

PubMed

Fiorio, Mirta; Tinazzi, Michele; Ionta, Silvio; Fiaschi, Antonio; Moretto, Giuseppe; Edwards, Mark J; Bhatia, Kailash P; Aglioti, Salvatore M

2007-06-11

Mental rotation of body parts is performed through inner simulation of actual movements, and is likely to rely upon cortical and subcortical systems (e.g. motor and premotor areas and basal ganglia) involved in motor planning and execution. Studies indicate that sensory and motor deficits, such as for example pain, limb amputation or focal hand dystonia, bring about a specific impairment in mental rotation of the affected body parts. Here we explored the ability of patients affected by idiopathic cervical dystonia (CD) to mentally rotate affected (neck) and unaffected (hands and feet) body districts. The experimental stimuli consisted of realistic photos of left or right hands or feet and the head of a young men with a black patch on the left or the right eye. As non-corporeal stimulus the front view of a car with a black patch on the left or the right headlight was used. The stimuli were presented at six different degrees of orientations. Twelve CD patients and 12 healthy participants were asked to verbally report whether the hands or feet were left or right, or whether the patch was on the left or the right eye or headlight. Reaction times and accuracy in performing the laterality tasks on the four stimuli were collected. Results showed that CD patients are slow in mental rotation of stimuli representing body parts, namely hand, foot and head. This abnormality was not due to a general impairment in mental rotation per se, since patients' ability to rotate a non-corporeal object (a car) was not significantly different from that of healthy participants. We posit that the deficit in mental rotation of body parts in CD patients may derive from a defective integration of body- and world-related knowledge, a process that is likely to allow a general representation of "me in the external world".

Negative Stimulus-Response Compatibility Observed with a Briefly Displayed Image of a Hand

ERIC Educational Resources Information Center

Vainio, Lari

2011-01-01

Manual responses can be primed by viewing an image of a hand. The left-right identity of the viewed hand reflexively facilitates responses of the hand that corresponds to the identity. Previous research also suggests that when the response activation is triggered by an arrow, which is backward-masked and presented briefly, the activation manifests…

Persistent Left Unilateral Mirror Writing: A Neuropsychological Case Study

ERIC Educational Resources Information Center

Angelillo, Valentina G.; De Lucia, Natascia; Trojano, Luigi; Grossi, Dario

2010-01-01

Mirror writing (MW) is a rare disorder in which a script runs in direction opposite to normal and individual letters are reversed. The disorder generally occurs after left-hemisphere lesions, is transient and is observed on the left hand, whereas usually motor impairments prevent assessment of direction of right handwriting. We describe a…

The Economic Consequences of Being Left-Handed: Some Sinister Results

ERIC Educational Resources Information Center

Denny, Kevin; O' Sullivan, Vincent

2007-01-01

This paper estimates the effects of handedness on earnings. Augmenting a conventional earnings equation with an indicator of left-handedness shows there is a positive effect on male earnings with manual workers enjoying a slightly larger premium. These results are inconsistent with the view that left-handers in general are handicapped either…

A Fluent Language Disorder Following Antepartum Left-Hemisphere Brain Injury.

ERIC Educational Resources Information Center

Feldman, Heidi M.; And Others

1992-01-01

This article describes the language development in a left-handed young child with a left middle cerebral artery infarction. Patterns of development observed between 36 and 60 months of age are described as a transient jargon or fluent aphasia possibly resulting from initial reliance on an uninjured right hemisphere. (Author/DB)

76 FR 37247 - Airworthiness Directives; Learjet Inc. Model 45 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-27

... the left engine accessory compartment, and corrective actions if necessary. This new AD also requires...) Replace the left engine fuel and hydraulic tubing and install a tubing support channel using new parts. (2... other damage of the case drain tube from the hydraulic pump case installed on the left-hand engine, and...

Rotational movement (circling) in normal humans: sex difference and relationship to hand, foot and eye preference.

PubMed

Bracha, H S; Seitz, D J; Otemaa, J; Glick, S D

1987-05-19

An endogenous asymmetry in striatal dopaminergic function has been identified in rats, and related to spontaneous and drug-induced circling (rotation, turning). We have developed an electronic device for measuring in humans the same kinds of rotational movements observed in rats. Our data indicate that, without being aware of the type of information being obtained, normal men and women rotate preferentially to the left or to the right during a routine day. Women had higher average rates of rotation than men. Males that were consistently right-sided (left-hemisphere dominant) for hand, foot and eye dominance rotated more to the right than to the left, whereas left-hemisphere dominant females rotated more to the left than to the right. Subjects tested on two occasions, 6 weeks apart, exhibited consistent (significantly correlated) rotational preferences--this was much more evident in left-hemisphere dominant than in mixed dominance individuals. In view of similar animal data, the device used in this study may become a useful and objective means for obtaining quantitative information regarding the status of basal ganglia function in humans.

Can culture influence body-specific associations between space and valence?

PubMed

de la Fuente, Juanma; Casasanto, Daniel; Román, Antonio; Santiago, Julio

2015-05-01

People implicitly associate positive ideas with their dominant side of space and negative ideas with their non-dominant side. Right-handers tend to associate "good" with "right" and "bad" with "left," but left-handers associate "bad" with "right" and "good" with "left." Whereas right-handers' implicit associations align with idioms in language and culture that link "good" with "right," left-handers' implicit associations go against them. Can cultural conventions modulate the body-specific association between valence and left-right space? Here, we compared people from Spanish and Moroccan cultures, which differ in the strength of taboos against the use of the left hand, and therefore in their preference for the right. Results showed stronger explicit associations between space and valence in Moroccan participants than in Spaniards, but they did not show any increased tendency for right-handed Moroccans to associate "good" with "right" implicitly. Despite differences in cultural conventions between Spaniards and Moroccans, we find no evidence for a cross-cultural difference in the implicit association between space and valence, which appears to depend on patterns of bodily experience. © 2014 Cognitive Science Society, Inc.

Change of Command ceremony

NASA Image and Video Library

2015-09-05

ISS044E086857 (09/05/2015) --- Cosmonaut Gennady Padalka (center in red shirt) handed command of the International Space Station to NASA astronaut Scott Kelly (front left with microphone) on Sept. 5, 2015. In the background the rest of the space station crew was on hand (from left to right): ESA(European Space Agency) astronaut Andreas Mogensen (back), Russian cosmonauts Mikhail Kornienko, Sergey Volkov and Oleg Kononenko, Kazakh cosmonaut Aidyn Aimbetov, Japan Aerospace Exploration Agency (JAXA) astronaut Kimiya Yui and NASA astronaut Kjell Lindgren.

Nonlinear propagation of electromagnetic waves in negative-refraction-index composite materials.

PubMed

Kourakis, I; Shukla, P K

2005-07-01

We investigate the nonlinear propagation of electromagnetic waves in left-handed materials. For this purpose, we consider a set of coupled nonlinear Schrödinger (CNLS) equations, which govern the dynamics of coupled electric and magnetic field envelopes. The CNLS equations are used to obtain a nonlinear dispersion, which depicts the modulational stability profile of the coupled plane-wave solutions in left-handed materials. An exact (in)stability criterion for modulational interactions is derived, and analytical expressions for the instability growth rate are obtained.

Orion EM-1 Forward Skirt Move from Hangar AF to BFF

NASA Image and Video Library

2017-08-30

The Exploration Mission-1 (EM-1) left-hand forward skirt for NASA's Space Launch System (SLS) solid rocket boosters arrives at the entrance to the high bay at the Booster Fabrication Facility (BFF) at NASA's Kennedy Space Center in Florida. In the BFF, the forward skirt will be inspected and prepared for use on the left-hand solid rocket booster for EM-1. NASA's Orion spacecraft will fly atop the SLS rocket on its first uncrewed flight test.

Orion EM-1 Forward Skirt Move from Hangar AF to BFF

NASA Image and Video Library

2017-08-30

The Exploration Mission-1 (EM-1) left-hand forward skirt for NASA's Space Launch System (SLS) solid rocket boosters arrives at the Booster Fabrication Facility (BFF) at NASA's Kennedy Space Center in Florida from Hangar AE at Cape Canaveral Air Force Station. In the BFF, the forward skirt will be inspected and prepared for use on the left-hand solid rocket booster for EM-1. NASA's Orion spacecraft will fly atop the SLS rocket on its first uncrewed flight test.

Sites that Can Produce Left-handed Amino Acids in the Supernova Neutrino Amino Acid Processing Model

NASA Astrophysics Data System (ADS)

Boyd, Richard N.; Famiano, Michael A.; Onaka, Takashi; Kajino, Toshitaka

2018-03-01

The Supernova Neutrino Amino Acid Processing model, which uses electron anti-neutrinos and the magnetic field from a source object such as a supernova to selectively destroy one amino acid chirality, is studied for possible sites that would produce meteoroids with partially left-handed amino acids. Several sites appear to provide the requisite magnetic field intensities and electron anti-neutrino fluxes. These results have obvious implications for the origin of life on Earth.

Orion EM-1 Forward Skirt Transport from Hangar AF to BFF

NASA Image and Video Library

2017-08-30

The Exploration Mission-1 (EM-1) left-hand forward skirt for NASA's Space Launch System (SLS) solid rocket boosters is transported by truck to the Booster Fabrication Facility (BFF) at NASA's Kennedy Space Center in Florida from Hangar AE at Cape Canaveral Air Force Station. In the BFF, the forward skirt will be inspected and prepared for use on the left-hand solid rocket booster for EM-1. NASA's Orion spacecraft will fly atop the SLS rocket on its first uncrewed flight test.

Aft Skirt Move from Hangar AF to BFF

NASA Image and Video Library

2016-09-08

The left hand aft skirt for NASA’s Space Launch System (SLS) rocket arrives at the Booster Fabrication Facility at the agency’s Kennedy Space Center in Florida, from the Hangar AF facility at Cape Canaveral Air Force Station. The space shuttle-era aft skirt, was inspected, resurfaced, primed and painted for use on the left hand booster of the SLS rocket for Exploration Mission 1 (EM-1). NASA is preparing for EM-1, deep-space missions, and the journey to Mars.

Effect of the Aging Temperature of Steel on the Parameters of Fatigue Resistance and Microstrain

NASA Astrophysics Data System (ADS)

Myl'nikov, V. V.; Romanov, A. D.; Shetulov, D. I.; Khlybov, A. A.

2016-07-01

The interrelation of the parameters of microplastic strain, the slope of the left-hand branch of the fatigue curve, and the fatigue limit of a maraging steel is studied. The growth in the microplastic strain is shown to match the growth in the fatigue limit and the decrease in the slope of the left-hand branch of the fatigue curve. The strength of the steel decreases with decrease in the temperature of post-quenching aging.

Role of the posterior parietal cortex in updating reaching movements to a visual target.

PubMed

Desmurget, M; Epstein, C M; Turner, R S; Prablanc, C; Alexander, G E; Grafton, S T

1999-06-01

The exact role of posterior parietal cortex (PPC) in visually directed reaching is unknown. We propose that, by building an internal representation of instantaneous hand location, PPC computes a dynamic motor error used by motor centers to correct the ongoing trajectory. With unseen right hands, five subjects pointed to visual targets that either remained stationary or moved during saccadic eye movements. Transcranial magnetic stimulation (TMS) was applied over the left PPC during target presentation. Stimulation disrupted path corrections that normally occur in response to target jumps, but had no effect on those directed at stationary targets. Furthermore, left-hand movement corrections were not blocked, ruling out visual or oculomotor effects of stimulation.

Callosal disconnection syndrome in a left-handed patient due to infarction of the total length of the corpus callosum.

PubMed

Lausberg, H; Göttert, R; Münssinger, U; Boegner, F; Marx, P

1999-03-01

We report on a left-handed patient with an ischemic infarction affecting exclusively the total length of the corpus callosum. This lesion clinically correlated with an almost complete callosal disconnection syndrome as described in callosotomy subjects, including unilateral verbal anosmia, hemialexia, unilateral ideomotor apraxia, unilateral agraphia, unilateral tactile anomia, unilateral constructional apraxia, lack of somesthetic transfer and dissociative phenomena. Despite the patient's left-handedness, his pattern of deficits was similar to the disconnection syndrome found in right-handers. Our report focusses on motor dominance and praxis. We followed-up the improvement in left apraxia and investigated the ability to initiate and learn a new visuo-motor skill. The results permit two tentative assumptions: (1) that the improvement in left apraxia was due to a compensatory increase in ipsilateral proximal muscle control, and (2) that motor dominance, i.e. the competence to initiate and learn a new movement pattern, was hemispherically dissociable from manual dominance in the sense of praxis control.

The impact of finger counting habits on arithmetic in adults and children.

PubMed

Newman, Sharlene D; Soylu, Firat

2014-07-01

Here, we explored the impact of finger counting habits on arithmetic in both adults and children. Two groups of participants were examined, those that begin counting with their left hand (left-starters) and those that begin counting with their right hand (right-starters). For the adults, performance on an addition task in which participants added 2 two-digit numbers was compared. The results revealed that left-starters were slower than right-starters when adding and they had lower forward and backward digit-span scores. The children (aged 5-12) showed similar results on a single-digit timed addition task-right-starters outperformed left-starters. However, the children did not reveal differences in working memory or verbal and non-verbal intelligence as a function of finger counting habit. We argue that the motor act of finger counting influences how number is represented and suggest that left-starters may have a more bilateral representation that accounts for the slower processing.

Views of STS-3 crew during departure activites at Ellington with family

NASA Technical Reports Server (NTRS)

1982-01-01

Views of STS-3 crew, Astronauts Jack R. Lousma, left, and C. Gordon Fullerton prior to their departure in T-38 aircraft from Ellington Air Force Base for the launch of STS-3 (28700); Some of the family members of astronaut crew are greeted by a crowd of spectators on hand for Lousma and Fullerton's departure. Matthew Lousma is standing at the microphone in center of the frame, flanked by Mrs. Gratia Kay Lousma (left) and Mrs. Maria Fullerton. Left to right in front are Mary Lousma, Andrew Fullerton and Molly Fullerton (28701-2); Astronaut Lousma walks away from microphone after greeting news media representatives and public prior to departure for Kennedy (28703); Astronaut Lousma talking to Fullerton, left, and Astronuat Brewster H. Shaw, center before boarding T-38's to leave for KSC (28704); Lousma, left, and Fullerton pause at Ellington prior to their departure in T-38 aircraft for KSC (28705); Lousma, right, and Fullerton greet crowd on hand at Ellington for their departure to KSC

Pilot usage of decoupled flight path and pitch controls

NASA Technical Reports Server (NTRS)

Berkhout, J.; Osgood, R.; Berry, D.

1985-01-01

Data from decoupled flight maneuvers have been collected and analyzed for four AFTI-F-16 pilots operating this aircraft's highly augmented fly-by-wire control system, in order to obtain spectral density, cross spectra, and Bode amplitude data, as well as coherences and phase angles for the two longitudinal axis control functions of each of 50 20-sec epochs. The analysis of each epoch yielded five distinct plotted parameters for the left hand twist grip and right hand sidestick controller output time series. These two control devices allow the left hand to generate vertical translation, direct lift, or pitch-pointing commands that are decoupled from those of the right hand. Attention is given to the control patterns obtained for decoupled normal flight, air-to-air gun engagement decoupled maneuvering, and decoupled air-to-surface bombing run maneuvering.

Co-speech hand movements during narrations: What is the impact of right vs. left hemisphere brain damage?

PubMed

Hogrefe, Katharina; Rein, Robert; Skomroch, Harald; Lausberg, Hedda

2016-12-01

Persons with brain damage show deviant patterns of co-speech hand movement behaviour in comparison to healthy speakers. It has been claimed by several authors that gesture and speech rely on a single production mechanism that depends on the same neurological substrate while others claim that both modalities are closely related but separate production channels. Thus, findings so far are contradictory and there is a lack of studies that systematically analyse the full range of hand movements that accompany speech in the condition of brain damage. In the present study, we aimed to fill this gap by comparing hand movement behaviour in persons with unilateral brain damage to the left and the right hemisphere and a matched control group of healthy persons. For hand movement coding, we applied Module I of NEUROGES, an objective and reliable analysis system that enables to analyse the full repertoire of hand movements independent of speech, which makes it specifically suited for the examination of persons with aphasia. The main results of our study show a decreased use of communicative conceptual gestures in persons with damage to the right hemisphere and an increased use of these gestures in persons with left brain damage and aphasia. These results not only suggest that the production of gesture and speech do not rely on the same neurological substrate but also underline the important role of right hemisphere functioning for gesture production. Copyright © 2016 Elsevier Ltd. All rights reserved.

[The cross-sectional area of the median nerve by sonography in the diagnosis of carpal tunnel syndrome].

PubMed

Sabag-Ruiz, Enrique; Higuera-Lugo, Cirilo Omar; Ornelas-Aguirre, José Manuel; Gómez-Alcalá, Alejandro V

2009-01-01

To measure the median nerve cross-sectional area (MNCSA) at the carpal tunnel (CT) level by sonography (S) in a Mexican population. A comparative cross-sectional design study with a nonprobabilistic sampling with 50 women and 50 men in good health were submitted for measuring MNCSA at the level of the CT. Other variables like sex; side and degree of daily hand activity were also studied. The analysis was made by descriptive statistics, and Mann-Whitney U or Kruskal-Wallis tests. The mean MNCSA was 0.063 +/- 0.015 cm(2), in women; in men it was 0.072 +/- 0.018 cm(2); the difference was significant (p < 0.004). The median MNCSA among women was 0.062 cm(2) in the right side and 0.060 cm(2) in the left (90th percentile for both hands of 0.084 cm(2)); in men, it was of 0.070 cm(2) in the right hand and of 0.069 cm(2) in the left (90th percentile for both hands of 0.097 cm(2)). The difference between women and men was significant in each side, but not between right and left hands (p = 0.21). There was no correlation between age and MNCSA on either side, or with hand activity. A MNCSA value of 0.1 cm(2) for men and 0.09 cm(2) for women is proposed as a standard parameter for the Mexican population.

Comparative study on the muscular load of the arms using hair driers.

PubMed

Harada, H; Katsuura, T; Kikuchi, Y

1995-12-01

The purpose of the present study was to evaluate the muscular load of the arm when combing the hair using different "kuru-kuru" type of hair driers. Ten female students (20-24 years old) volunteered as subjects. Five combing patterns were conducted as follows: 1) comb outer layer of right side of hair using right hand, 2) comb outer layer of left side of hair using right hand, 3) comb inner layer of left side of hair using right hand, 4) comb outer layer of back hair using right hand, and 5) comb inner layer of right side of hair using left hand. Surface EMGs were recorded from M. flexor carpi ulnaris, M. brachioradialis, M. biceps brachii, M. triceps brachii, M. deltoideus and M. trapezius of both sides of body. Integrated EMGs (iEMGs) were used to evaluate muscular load for each of the seven different types of hair driers used. The relationship between iEMGs and weight, center of gravity, diameter, length, and circumference of each hair drier were examined. The weight of hair driers tended to be the effective factor on the muscular load. Muscular load also had a tendency to be affected by the shape of the grips. With regard to the hand size, the longer the thumb length, the smaller is the muscular load. It was suggested that a relatively large diameter of the bulb-shaped grip of the drier gave a smaller muscular load among the hair driers examined in the present experiment.

Hemispheric asymmetries of a motor memory in a recognition test after learning a movement sequence.

PubMed

Leinen, Peter; Panzer, Stefan; Shea, Charles H

2016-11-01

Two experiments utilizing a spatial-temporal movement sequence were designed to determine if the memory of the sequence is lateralized in the left or right hemisphere. In Experiment 1, dominant right-handers were randomly assigned to one of two acquisition groups: a left-hand starter and a right-hand starter group. After an acquisition phase, reaction time (RT) was measured in a recognition test by providing the learned sequential pattern in the left or right visual half-field for 150ms. In a retention test and two transfer tests the dominant coordinate system for sequence production was evaluated. In Experiment 2 dominant left-handers and dominant right-handers had to acquire the sequence with their dominant limb. The results of Experiment 1 indicated that RT was significantly shorter when the acquired sequence was provided in the right visual field during the recognition test. The same results occurred in Experiment 2 for dominant right-handers and left-handers. These results indicated a right visual field left hemisphere advantage in the recognition test for the practiced stimulus for dominant left and right-handers, when the task was practiced with the dominant limb. Copyright © 2016 Elsevier B.V. All rights reserved.

Are there any left-right asymmetries in saccade parameters? Examination of latency, gain, and peak velocity.

PubMed

Vergilino-Perez, Dorine; Fayel, Alexandra; Lemoine, Christelle; Senot, Patrice; Vergne, Judith; Doré-Mazars, Karine

2012-06-05

Hemispheric specialization in saccadic control is still under debate. Here we examine the latency, gain, and peak velocity of reactive and voluntary leftward and rightward saccades to assess the respective roles of eye and hand dominance. Participants with contrasting hand and eye dominance were asked to make saccades toward a target displayed at 5°, 10°, or 15° left or right of the central fixation point. In separate sessions, reactive and voluntary saccades were elicited by Gap-200, Gap-0, Overlap-600, and Antisaccade procedures. Left-right asymmetries were not found in saccade latencies but appeared in saccade gain and peak velocity. Regardless of the dominant hand, saccades directed to the ipsilateral side relative to the dominant eye had larger amplitudes and faster peak velocities. Left-right asymmetries can be explained by naso-temporal differences for some subjects and by eye dominance for others. Further investigations are needed to examine saccadic parameters more systematically in relation to eye dominance. Indeed, any method that allows one to determine ocular dominance from objective measures based on saccade parameters should greatly benefit clinical applications, such as monovision surgery.

The fighting hypothesis in combat: how well does the fighting hypothesis explain human left-handed minorities?

PubMed

Groothuis, Ton G G; McManus, I C; Schaafsma, Sara M; Geuze, Reint H

2013-06-01

The strong population bias in hand preference in favor of right-handedness seems to be a typical human trait. An elegant evolutionary hypothesis explaining this trait is the so-called fighting hypothesis that postulates that left-handedness is under frequency-dependent selection. The fighting hypothesis assumes that left-handers, being in the minority because of health issues, are still maintained in the population since they would have a greater chance of winning in fights than right-handers due to a surprise effect. This review critically evaluates the assumptions and evidence for this hypothesis and concludes that some evidence, although consistent with the fighting hypothesis, does not directly support it and may also be interpreted differently. Other supportive data are ambiguous or open for both statistical and theoretical criticism. We conclude that, presently, evidence for the fighting hypothesis is not particularly strong, but that there is little evidence to reject it either. The hypothesis thus remains an intuitively plausible explanation for the persistent left-hand preference in the population. We suggest alternative explanations and several ways forward for obtaining more crucial data for testing this frequently cited hypothesis. © 2013 New York Academy of Sciences.

Language dominance in neurologically normal and epilepsy subjects: a functional MRI study.

PubMed

Springer, J A; Binder, J R; Hammeke, T A; Swanson, S J; Frost, J A; Bellgowan, P S; Brewer, C C; Perry, H M; Morris, G L; Mueller, W M

1999-11-01

Language dominance and factors that influence language lateralization were investigated in right-handed, neurologically normal subjects (n = 100) and right-handed epilepsy patients (n = 50) using functional MRI. Increases in blood oxygenation-dependent signal during a semantic language activation task relative to a non-linguistic, auditory discrimination task provided an index of language system lateralization. As expected, the majority of both groups showed left hemisphere dominance, although a continuum of activation asymmetry was evident, with nearly all subjects showing some degree of right hemisphere activation. Using a categorical dominance classification, 94% of the normal subjects were considered left hemisphere dominant and 6% had bilateral, roughly symmetric language representation. None of the normal subjects had rightward dominance. There was greater variability of language dominance in the epilepsy group, with 78% showing left hemisphere dominance, 16% showing a symmetric pattern and 6% showing right hemisphere dominance. Atypical language dominance in the epilepsy group was associated with an earlier age of brain injury and with weaker right hand dominance. Language lateralization in the normal group was weakly related to age, but was not significantly related to sex, education, task performance or familial left-handedness.

B decays in an asymmetric left-right model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frank, Mariana; Hayreter, Alper; Turan, Ismail

2010-08-01

Motivated by recently observed disagreements with the standard model predictions in B decays, we study b{yields}d, s transitions in an asymmetric class of SU(2){sub L}xSU(2){sub R}xU(1){sub B-L} models, with a simple one-parameter structure of the right-handed mixing matrix for the quarks, which obeys the constraints from kaon physics. We use experimental constraints on the branching ratios of b{yields}s{gamma}, b{yields}ce{nu}{sub e}, and B{sub d,s}{sup 0}-B{sub d,s}{sup 0} mixing to restrict the parameters of the model: g{sub R}/g{sub L}, M{sub W{sub 2}}, M{sub H}{sup {+-}}, tan{beta} as well as the elements of the right-handed quark mixing matrix V{sub CKM}{sup R}. We presentmore » a comparison with the more commonly used (manifest) left-right symmetric model. Our analysis exposes the parameters most sensitive to b transitions and reveals a large parameter space where left- and right-handed quarks mix differently, opening the possibility of observing marked differences in behavior between the standard model and the left-right model.« less

5. DETAIL VIEW OF RADIAN GATE (LEFT, IN RAISED POSITION) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. DETAIL VIEW OF RADIAN GATE (LEFT, IN RAISED POSITION) AND HAND- OPERATED GATE HOISTS (RIGHT), LOOKING WEST - Upper Souris National Wildlife Refuge, Dam 87, Souris River Basin, Foxholm, Surrey (England), ND

Left lobe of the prostate during clinical prostate cancer screening: the dark side of the gland for right-handed examiners.

PubMed

Ploussard, G; Nicolaiew, N; Mongiat-Artus, P; Terry, S; Allory, Y; Vacherot, F; Abbou, C-C; Desgrandchamps, F; Salomon, L; de la Taille, A

2014-06-01

The predictive value of the abnormality side during digital rectal examination (DRE) has never been studied, suggesting that physicians examined the left lobe of the gland as well as the right lobe. We aimed to assess the predictive value of the side of DRE abnormality for prostate cancer (PCa) detection and aggressiveness in right-handed urologists. An analysis of a prospective database was carried out that included all consecutive men undergoing prostate biopsies between 2001 and 2012. The main end point was the predictive value of the abnormality side during DRE for cancer detection in clinically suspicious unilateral T2 disease. The diagnostic performance of left- versus right-sided abnormality was also assessed in terms of sensitivity, specificity and negative/positive predictive values. Overall, 308 patients had a suspicious unilateral clinical disease (detection rate 57.5%). The cancer detection rate was significantly higher in case of left-sided compared with right-sided clinical T2 stage (odds ratio 2.1). In case of left-sided disease, the number of positive cores, the rate of perineural invasion, the rate of primary grade 4 pattern and the percentage of cancer involvement per core were significantly higher compared with those reported for right-sided disease. The predictive value of abnormality laterality for cancer detection and aggressiveness remained statistically independent in multivariate models. The positive predictive value for cancer detection was 64.6 in case of suspicious left-sided disease versus 46.9 in case of right-sided disease. The risks of detecting PCa and aggressive disease on biopsy are significantly higher when DRE reveals a suspicious left-sided clinical disease as compared with right-sided disease. Right-handed physicians should be aware of this variance in diagnostic performance and potential underdetection of left-sided clinical disease, and should improve their examination of the left lobe of the gland by conducting longer exams or changing the patient's position.

Science in the Making: Right Hand, Left Hand. I: A BBC television programme broadcast in 1953.

PubMed

McManus, I C; Rawles, Richard; Moore, James; Freegard, Matthew

2010-01-01

In August 1953, the BBC broadcast a television science programme entitled Science in the Making: Right Hand, Left Hand. The programme was broadcast live, being presented by Dr Jacob Bronowski in collaboration with Dr Kenneth Smith, and produced by George Noordhof. It not only presented a popular account of current ideas about right- and left-handedness, by using a group of celebrities (and a chimpanzee) in the studio, but also asked viewers to complete a brief questionnaire on handedness, which was printed in the Radio Times. Recently 6,336 of the returned questionnaires, which were said to have been analysed by Sir Cyril Burt and a colleague, were found in the archive of the Psychology Department of University College London. The present paper describes what we have discovered about the programme from various sources, including the producer and the son of Dr Kenneth Smith, and also presents basic descriptions of the postcards and the response to the programme. In two subsequent papers we will describe our analysis of the data from the postcards, which represents an unusual, large-scale survey of handedness in the mid-twentieth century.

The effects of voice and manual control mode on dual task performance

NASA Technical Reports Server (NTRS)

Wickens, C. D.; Zenyuh, J.; Culp, V.; Marshak, W.

1986-01-01

Two fundamental principles of human performance, compatibility and resource competition, are combined with two structural dichotomies in the human information processing system, manual versus voice output, and left versus right cerebral hemisphere, in order to predict the optimum combination of voice and manual control with either hand, for time-sharing performance of a dicrete and continuous task. Eight right handed male subjected performed a discrete first-order tracking task, time-shared with an auditorily presented Sternberg Memory Search Task. Each task could be controlled by voice, or by the left or right hand, in all possible combinations except for a dual voice mode. When performance was analyzed in terms of a dual-task decrement from single task control conditions, the following variables influenced time-sharing efficiency in diminishing order of magnitude, (1) the modality of control, (discrete manual control of tracking was superior to discrete voice control of tracking and the converse was true with the memory search task), (2) response competition, (performance was degraded when both tasks were responded manually), (3) hemispheric competition, (performance degraded whenever two tasks were controlled by the left hemisphere) (i.e., voice or right handed control). The results confirm the value of predictive models invoice control implementation.

Search for W' $$\\to $$ tb decays in the lepton + jets final state in pp collisions at $$\\sqrt{s}$$ = 8 TeV

DOE PAGES

Chatrchyan, Serguei

2014-05-23

Results are presented from a search for the production of a heavy gauge boson W' decaying into a top and a bottom quark, using a data set collected by the CMS experiment at sqrt(s) = 8 TeV and corresponding to an integrated luminosity of 19.5 inverse femtobarns. Various models of W'-boson production are studied by allowing for an arbitrary combination of left- and right-handed couplings. The analysis is based on the detection of events with a lepton (e, mu), jets, and missing transverse energy in the final state. No evidence for W'-boson production is found and 95% confidence level uppermore » limits on the production cross section times branching fraction are obtained. For W' bosons with purely right-handed couplings, and for those with left-handed couplings assuming no interference effects, the observed 95% confidence level limit is M(W') > 2.05 TeV. For W' bosons with purely left-handed couplings, including interference effects, the observed 95% confidence level limit is M(W') > 1.84 TeV. The results presented in this paper are the most stringent limits published to date.« less

Squamous Cell Carcinoma in Combination with a Symbrachydactyly: Initial Management and Long-Term Followup

PubMed Central

Sanchez, Tomas; Walder, Daniel; Esenwein, Philipp

2014-01-01

A 68-year-old female patient presented with a rapidly growing, exulcerating tumor of the left hand in the area of a congenital symbrachydactyly at the digiti II and III. A biopsy of the tumor showed a squamous cell carcinoma. Further workup showed two suspicious axillar enhancements with no evidence of bony infiltration and no further metastasis. An amputation of the second and third ray of the left hand at the metacarpal level and additionally an axillar revision and lymph node dissection were performed and confirmed the suspicion of a squamous cell carcinoma, fortunately without affection of any lymph nodes. After 9 years the patient showed an excellent function of the left hand. Symbrachydactyly malformations and squamous cell carcinoma of the hand are both rare conditions. We could not find a reference that shows a common genetic condition to both and so far this is the first description of a squamous cell carcinoma in the region of a symbrachydactyly. It remains unclear whether our case is a coincidence of two rare independent diseases or there is a pathogenetic link between the malformation and the tumor on a genetic level. PMID:25024859

Squamous cell carcinoma in combination with a symbrachydactyly: initial management and long-term followup.

PubMed

Sanchez, Tomas; Walder, Daniel; Esenwein, Philipp

2014-01-01

A 68-year-old female patient presented with a rapidly growing, exulcerating tumor of the left hand in the area of a congenital symbrachydactyly at the digiti II and III. A biopsy of the tumor showed a squamous cell carcinoma. Further workup showed two suspicious axillar enhancements with no evidence of bony infiltration and no further metastasis. An amputation of the second and third ray of the left hand at the metacarpal level and additionally an axillar revision and lymph node dissection were performed and confirmed the suspicion of a squamous cell carcinoma, fortunately without affection of any lymph nodes. After 9 years the patient showed an excellent function of the left hand. Symbrachydactyly malformations and squamous cell carcinoma of the hand are both rare conditions. We could not find a reference that shows a common genetic condition to both and so far this is the first description of a squamous cell carcinoma in the region of a symbrachydactyly. It remains unclear whether our case is a coincidence of two rare independent diseases or there is a pathogenetic link between the malformation and the tumor on a genetic level.

No specific role for the manual motor system in processing the meanings of words related to the hand

PubMed Central

Postle, Natasha; Ashton, Roderick; McFarland, Ken; de Zubicaray, Greig I.

2013-01-01

The present study explored whether semantic and motor systems are functionally interwoven via the use of a dual-task paradigm. According to embodied language accounts that propose an automatic and necessary involvement of the motor system in conceptual processing, concurrent processing of hand-related information should interfere more with hand movements than processing of unrelated body-part (i.e., foot, mouth) information. Across three experiments, 100 right-handed participants performed left- or right-hand tapping movements while repeatedly reading action words related to different body-parts, or different body-part names, in both aloud and silent conditions. Concurrent reading of single words related to specific body-parts, or the same words embedded in sentences differing in syntactic and phonological complexity (to manipulate context-relevant processing), and reading while viewing videos of the actions and body-parts described by the target words (to elicit visuomotor associations) all interfered with right-hand but not left-hand tapping rate. However, this motor interference was not affected differentially by hand-related stimuli. Thus, the results provide no support for proposals that body-part specific resources in cortical motor systems are shared between overt manual movements and meaning-related processing of words related to the hand. PMID:23378833

Towards Development of a 3-State Self-Paced Brain-Computer Interface

PubMed Central

Bashashati, Ali; Ward, Rabab K.; Birch, Gary E.

2007-01-01

Most existing brain-computer interfaces (BCIs) detect specific mental activity in a so-called synchronous paradigm. Unlike synchronous systems which are operational at specific system-defined periods, self-paced (asynchronous) interfaces have the advantage of being operational at all times. The low-frequency asynchronous switch design (LF-ASD) is a 2-state self-paced BCI that detects the presence of a specific finger movement in the ongoing EEG. Recent evaluations of the 2-state LF-ASD show an average true positive rate of 41% at the fixed false positive rate of 1%. This paper proposes two designs for a 3-state self-paced BCI that is capable of handling idle brain state. The two proposed designs aim at detecting right- and left-hand extensions from the ongoing EEG. They are formed of two consecutive detectors. The first detects the presence of a right- or a left-hand movement and the second classifies the detected movement as a right or a left one. In an offline analysis of the EEG data collected from four able-bodied individuals, the 3-state brain-computer interface shows a comparable performance with a 2-state system and significant performance improvement if used as a 2-state BCI, that is, in detecting the presence of a right- or a left-hand movement (regardless of the type of movement). It has an average true positive rate of 37.5% and 42.8% (at false positives rate of 1%) in detecting right- and left-hand extensions, respectively, in the context of a 3-state self-paced BCI and average detection rate of 58.1% (at false positive rate of 1%) in the context of a 2-state self-paced BCI. PMID:18288260

Touch and feel? Using the rubber hand paradigm to investigate self-touch enhancement in right-hemisphere stroke patients.

PubMed

White, Rebekah C; Aimola Davies, Anne M; Kischka, Udo; Davies, Martin

2010-01-01

Following stroke, a patient may fail to report touch administered by another person but claim that she feels touch when it is self-administered. We investigated three explanations for self-touch enhancement: (1) proprioceptive information from the administering hand, (2) attentional modulation, and (3) temporal expectation. Tactile sensation was assessed with vision precluded, and with the affected hand positioned in the left and right hemispace. In four of six experiments, the somatic rubber hand paradigm was used: the Examiner administered stimulation to the patient's affected left hand while guiding the patient's right hand to administer synchronous stimulation to a prosthetic hand. Even though the patient's two hands were not in contact, patients detected the same number of stimulations as when they touched their own hand directly (self-administered condition). Moreover, there was no decline in rates of detection when potentially informative movements of the administering hand were restricted. This demonstrates that patients feel rather than infer stimulation under conditions of self-touch. When patients received stimulation to the affected hand in the opposite hemispace to the hand administering touch to the prosthetic hand, all but one showed self-touch enhancement. Thus, neither proprioceptive information nor attentional modulation at the spatial region of the administering hand provided a sufficient explanation for self-touch enhancement. A follow-up experiment indicated an important role for temporal expectation: a delay, between the patient's stimulation of the prosthetic hand and the Examiner's stimulation of the patient's affected hand, eliminated the self-touch enhancement effect.

Brain Regions Associated to a Kinesthetic Illusion Evoked by Watching a Video of One's Own Moving Hand

PubMed Central

Kaneko, Fuminari; Blanchard, Caroline; Lebar, Nicolas; Nazarian, Bruno; Kavounoudias, Anne; Romaiguère, Patricia

2015-01-01

It is well known that kinesthetic illusions can be induced by stimulation of several sensory systems (proprioception, touch, vision…). In this study we investigated the cerebral network underlying a kinesthetic illusion induced by visual stimulation by using functional magnetic resonance imaging (fMRI) in humans. Participants were instructed to keep their hand still while watching the video of their own moving hand (Self Hand) or that of someone else's moving hand (Other Hand). In the Self Hand condition they experienced an illusory sensation that their hand was moving whereas the Other Hand condition did not induce any kinesthetic illusion. The contrast between the Self Hand and Other Hand conditions showed significant activation in the left dorsal and ventral premotor cortices, in the left Superior and Inferior Parietal lobules, at the right Occipito-Temporal junction as well as in bilateral Insula and Putamen. Most strikingly, there was no activation in the primary motor and somatosensory cortices, whilst previous studies have reported significant activation in these regions for vibration-induced kinesthetic illusions. To our knowledge, this is the first study that indicates that humans can experience kinesthetic perception without activation in the primary motor and somatosensory areas. We conclude that under some conditions watching a video of one's own moving hand could lead to activation of a network that is usually involved in processing copies of efference, thus leading to the illusory perception that the real hand is indeed moving. PMID:26287488

Brain Regions Associated to a Kinesthetic Illusion Evoked by Watching a Video of One's Own Moving Hand.

PubMed

Kaneko, Fuminari; Blanchard, Caroline; Lebar, Nicolas; Nazarian, Bruno; Kavounoudias, Anne; Romaiguère, Patricia

2015-01-01

It is well known that kinesthetic illusions can be induced by stimulation of several sensory systems (proprioception, touch, vision…). In this study we investigated the cerebral network underlying a kinesthetic illusion induced by visual stimulation by using functional magnetic resonance imaging (fMRI) in humans. Participants were instructed to keep their hand still while watching the video of their own moving hand (Self Hand) or that of someone else's moving hand (Other Hand). In the Self Hand condition they experienced an illusory sensation that their hand was moving whereas the Other Hand condition did not induce any kinesthetic illusion. The contrast between the Self Hand and Other Hand conditions showed significant activation in the left dorsal and ventral premotor cortices, in the left Superior and Inferior Parietal lobules, at the right Occipito-Temporal junction as well as in bilateral Insula and Putamen. Most strikingly, there was no activation in the primary motor and somatosensory cortices, whilst previous studies have reported significant activation in these regions for vibration-induced kinesthetic illusions. To our knowledge, this is the first study that indicates that humans can experience kinesthetic perception without activation in the primary motor and somatosensory areas. We conclude that under some conditions watching a video of one's own moving hand could lead to activation of a network that is usually involved in processing copies of efference, thus leading to the illusory perception that the real hand is indeed moving.

Anisotropy of electromagnetically induced left-handedness in atomic three-level media based upon bianisotropic polarizabilities and tensor character

NASA Astrophysics Data System (ADS)

Krowne, Clifford M.

2008-05-01

A three-level atomic system, configured as either a gaseous medium or a solid state material, with a driving field establishing a Rabi frequency of control, is tested by a probe field. The medium has bianisotropic microscopic polarizability and magnetizability, from which the permittivity and permeability tensors are derived. Non-isotropy and polarization dependence for left-handedness (negative index of refraction) is demonstrated through examination of tensor components in the detuning frequency spectrum. These results have important implications for use in optical or electronic devices.

Development of a Wearable Controller for Gesture-Recognition-Based Applications Using Polyvinylidene Fluoride.

PubMed

Van Volkinburg, Kyle; Washington, Gregory

2017-08-01

This paper reports on a wearable gesture-based controller fabricated using the sensing capabilities of the flexible thin-film piezoelectric polymer polyvinylidene fluoride (PVDF) which is shown to repeatedly and accurately discern, in real time, between right and left hand gestures. The PVDF is affixed to a compression sleeve worn on the forearm to create a wearable device that is flexible, adaptable, and highly shape conforming. Forearm muscle movements, which drive hand motions, are detected by the PVDF which outputs its voltage signal to a developed microcontroller-based board and processed by an artificial neural network that was trained to recognize the generated voltage profile of right and left hand gestures. The PVDF has been spatially shaded (etched) in such a way as to increase sensitivity to expected deformations caused by the specific muscles employed in making the targeted right and left gestures. The device proves to be exceptionally accurate both when positioned as intended and when rotated and translated on the forearm.

The effect of handedness on spatial and motor representation of pitch patterns in pianists

PubMed Central

2018-01-01

This study investigated the effect of handedness on pianists’ abilities to adjust their keyboard performance skills to new spatial and motor mappings. Left- and right-handed pianists practiced simple melodies on a regular MIDI piano keyboard (practice) and were then asked to perform these with modified melodic contours (the same or reversed melodic contour causing a change of fingering) and on a reversed MIDI piano keyboard (test). The difference of performance duration between the practice and the test phase as well as the amount of errors played were used as test measures. Overall, a stronger effect for modified melodic contours than for the reversed keyboard was observed. Furthermore, we observed a trend of left-handed pianists to be quicker and more accurate in playing melodies when reversing their fingering with reversed contours in their left-hand performances. This suggests that handedness may influence pianists’ skill to adjust to new spatial and motor mappings. PMID:29718946