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.

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.

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.

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

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.

Hand preferences for bimanual coordination in 29 bonobos (Pan paniscus).

PubMed

Chapelain, Amandine S; Hogervorst, Eef

2009-01-03

Brain lateralization has long been thought to be unique to humans. To investigate the origins and functions of this feature, researchers study behavioural laterality in other animals. Despite a substantial database, manual laterality in non-human primates remains a controversial topic. We give here a review of the main findings on manual preference in great apes. This article presents data on hand preferences for a bimanual coordination in 29 bonobos (Pan paniscus). The study aims to provide data on manual laterality for a complex bimanual task in this very interesting and rarely studied species. Hand preferences were assessed using the 'tube task'. This task has been used with other species, which allows reliable data comparisons. The task requires a bimanual coordinated precise action: the subject holds the tube with one hand while reaching for food inside with the other hand. As a complex task, this measure has been shown to be efficient in revealing hand preferences. It has revealed group-level right bias in chimpanzees. Bonobos had never been tested. We recorded both independent bouts (counting only the first pattern of a sequence of identical actions) and frequency (counting every action). The bonobos exhibited strong hand preferences. With frequency, 11 bonobos were classified as right-handed, 15 were left-handed and 3 had no preference. With bouts, 8 bonobos were right-handed, 9 were left-handed and 12 had no preference. No group-level bias appeared. The results are discussed in relation with previous findings and theories on brain lateralization.

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.

Writing with the non-dominant hand: cross-handedness trainability in adult individuals.

PubMed

Walker, L; Henneberg, M

2007-03-01

Adult volunteers (8 males and 13 females) aged 20-56 years, both right- and left-handed, were asked to train their non-preferred hand to write two standard sentences by practising daily over a 28-day period. At the end of this period their non-preferred-hand writing was of good quality and participants felt quite comfortable performing this task. The quality of non-preferred-hand writing achieved was unrelated to age. We postulate that handedness, in terms of actual performance, may be less pronounced than is suggested by studies of hand preference.

Auditory Evoked Potentials and Hand Preference in 6-Month-Old Infants: Possible Gender-Related Differences in Cerebral Organization.

ERIC Educational Resources Information Center

Shucard, Janet L.; Shucard, David W.

1990-01-01

Verbal and musical stimuli were presented to infants in a study of the relations of evoked potential left-right amplitude asymmetries to gender and hand preference. There was a relation between asymmetry and hand preference, and for girls, between asymmetry and stimulus condition. Results suggest a gender difference in cerebral hemisphere…

Handedness in Nature: First Evidence on Manual Laterality on Bimanual Coordinated Tube Task in Wild Primates

PubMed Central

Zhao, Dapeng; Hopkins, William D.; Li, Baoguo

2012-01-01

Handedness is a defining feature of human manual skill and understanding the origin of manual specialization remains a central topic of inquiry in anthropology and other sciences. In this study, we examined hand preference in a sample of wild primates on a task that requires bimanual coordinated actions (tube task) that has been widely used in captive primates. The Sichuan snub-nosed monkey (Rhinopithecus roxellana) is an arboreal Old World monkey species that is endemic to China, and 24 adult individuals from the Qinling Mountains of China were included for the analysis of hand preference in the tube task. All subjects showed strong individual hand preferences and significant group-level left-handedness was found. There were no significant differences between males and females for either direction or strength of hand preference. Strength of hand preferences of adults was significantly greater than juveniles. Use of the index finger to extract the food was the dominant extractive-act. Our findings represent the first evidence of population-level left-handedness in wild Old World monkeys, and broaden our knowledge on evaluating primate hand preference via experimental manipulation in natural conditions. PMID:22410843

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.

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.

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.

Hand Preference for Writing and Associations with Selected Demographic and Behavioral Variables in 255,100 Subjects: The BBC Internet Study

ERIC Educational Resources Information Center

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

2006-01-01

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…

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.

Laterality and Directional Preferences in Preschool Children.

ERIC Educational Resources Information Center

Tan, Lesley E.

1982-01-01

Directional preference for horizontal hand movements was investigated in 49 right- and 49 left-handed four-year-olds using three drawing tests. Directionality for more complex perceptual-motor tasks has a different basis than directionality for simple tasks; such directionality is established at a later age but only for the right hand. (Author/CM)

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].

Asymmetries in mother-infant behaviour in Barbary macaques (Macaca sylvanus)

PubMed Central

Spiezio, Caterina; Hopkins, William Donald

2018-01-01

Asymmetries in the maternal behaviour and anatomy might play an important role in the development of primate manual lateralization. In particular, early life asymmetries in mother’s and infant’s behaviour have been suggested to be associated with the development of the hand preference of the offspring. The aim of this study was to investigate the presence of behavioural asymmetries in different behavioural categories of mother-infant dyads of zoo-living Barbary macaques (Macaca sylvanus). The study subjects were 14 Barbary macaques involved in seven mother-infant dyads housed in Parco Natura Viva, Italy. For the mothers, bouts of hand preference for maternal cradling and infant retrieval were collected. For the infants, we focused on nipple preference and hand preference for clinging on mother ventrum. Moreover, we collected bouts of hand preference for food reaching in both groups. No significant group-level bias was found for any of the behavioural categories in either mothers or infants. However, at the individual level, six out of seven mothers showed a significant cradling bias, three toward the right hand and three toward the left hand. Moreover, all infants showed a significant nipple preference, six toward the mother’s right nipple, one toward the left nipple. Furthermore, a significant correlation was found between the infant nipple preference and their hand preference for food reaching, suggesting that maternal environment rather than behaviour might affect the development of hand preference in Old World monkeys. Our findings seem partially to add to previous literature on perceptual lateralization in different species of non-primate mammals, reporting a lateral bias in mother-infant interactions. Given the incongruences between our study and previous research in great apes and humans, our results seem to suggest possible phylogenetic differences in the lateralization of mothers and infants within the Primates order. PMID:29761052

Gaussian Mixture Modeling of Hemispheric Lateralization for Language in a Large Sample of Healthy Individuals Balanced for Handedness

PubMed Central

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

2014-01-01

Hemispheric lateralization for language production and its relationships with manual preference and manual preference strength were studied in a sample of 297 subjects, including 153 left-handers (LH). A hemispheric functional lateralization index (HFLI) for language was derived from fMRI acquired during a covert sentence generation task as compared with a covert word list recitation. The multimodal HFLI distribution was optimally modeled using a mixture of 3 and 4 Gaussian functions in right-handers (RH) and LH, respectively. Gaussian function parameters helped to define 3 types of language hemispheric lateralization, namely “Typical” (left hemisphere dominance with clear positive HFLI values, 88% of RH, 78% of LH), “Ambilateral” (no dominant hemisphere with HFLI values close to 0, 12% of RH, 15% of LH) and “Strongly-atypical” (right-hemisphere dominance with clear negative HFLI values, 7% of LH). Concordance between dominant hemispheres for hand and for language did not exceed chance level, and most of the association between handedness and language lateralization was explained by the fact that all Strongly-atypical individuals were left-handed. Similarly, most of the relationship between language lateralization and manual preference strength was explained by the fact that Strongly-atypical individuals exhibited a strong preference for their left hand. These results indicate that concordance of hemispheric dominance for hand and for language occurs barely above the chance level, except in a group of rare individuals (less than 1% in the general population) who exhibit strong right hemisphere dominance for both language and their preferred hand. They call for a revisit of models hypothesizing common determinants for handedness and for language dominance. PMID:24977417

Gaussian mixture modeling of hemispheric lateralization for language in a large sample of healthy individuals balanced for handedness.

PubMed

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

2014-01-01

Hemispheric lateralization for language production and its relationships with manual preference and manual preference strength were studied in a sample of 297 subjects, including 153 left-handers (LH). A hemispheric functional lateralization index (HFLI) for language was derived from fMRI acquired during a covert sentence generation task as compared with a covert word list recitation. The multimodal HFLI distribution was optimally modeled using a mixture of 3 and 4 Gaussian functions in right-handers (RH) and LH, respectively. Gaussian function parameters helped to define 3 types of language hemispheric lateralization, namely "Typical" (left hemisphere dominance with clear positive HFLI values, 88% of RH, 78% of LH), "Ambilateral" (no dominant hemisphere with HFLI values close to 0, 12% of RH, 15% of LH) and "Strongly-atypical" (right-hemisphere dominance with clear negative HFLI values, 7% of LH). Concordance between dominant hemispheres for hand and for language did not exceed chance level, and most of the association between handedness and language lateralization was explained by the fact that all Strongly-atypical individuals were left-handed. Similarly, most of the relationship between language lateralization and manual preference strength was explained by the fact that Strongly-atypical individuals exhibited a strong preference for their left hand. These results indicate that concordance of hemispheric dominance for hand and for language occurs barely above the chance level, except in a group of rare individuals (less than 1% in the general population) who exhibit strong right hemisphere dominance for both language and their preferred hand. They call for a revisit of models hypothesizing common determinants for handedness and for language dominance.

Hand Preference for Precision Grasping Predicts Language Lateralization

ERIC Educational Resources Information Center

Gonzalez, Claudia L. R.; Goodale, Melvyn A.

2009-01-01

We investigated whether or not there is a relationship between hand preference for grasping and hemispheric dominance for language--and how each of these is related to other traditional measures of handedness. To do this we asked right- and left-handed participants to put together two different sets of 3D puzzles made out of big or very small…

Birth Position, Neonatal Head Position Preference, and Hand Preference in 19-Week-Old-Infants.

ERIC Educational Resources Information Center

Goodwin, Rhoda S.

This study investigated the hypotheses that 1) infants delivered from a left occiput anterior or transverse position (LOA/LOT) would exhibit a right supine head orientation in the neonatal examination and a right hand preference at 19 weeks of age; and 2) infants delivered from a right occiput anterior or transverse position (ROA/ROT) would…

Plasticity of Lateralization: Schooling Predicts Hand Preference but not Hand Skill Asymmetry in a Non-Industrial Society

ERIC Educational Resources Information Center

Geuze, Reint H.; Schaafsma, Sara M.; Lust, Jessica M.; Bouma, Anke; Schiefenhovel, Wulf; Groothuis, Ton G. G.

2012-01-01

Considerable variation in the frequency of left-handedness between cultures has been reported, ranging from 0.5 to 24%. This variation in hand preference may have evolved under natural or cultural selection. It has been suggested that schooling affects handedness but as in most human societies only a selected and minor part of the population does…

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.

[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.

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 sound of one-hand clapping: handedness and perisylvian neural correlates of a communicative gesture in chimpanzees

PubMed Central

Meguerditchian, Adrien; Gardner, Molly J.; Schapiro, Steven J.; Hopkins, William D.

2012-01-01

Whether lateralization of communicative signalling in non-human primates might constitute prerequisites of hemispheric specialization for language is unclear. In the present study, we examined (i) hand preference for a communicative gesture (clapping in 94 captive chimpanzees from two research facilities) and (ii) the in vivo magnetic resonance imaging brain scans of 40 of these individuals. The preferred hand for clapping was defined as the one in the upper position when the two hands came together. Using computer manual tracing of regions of interest, we measured the neuroanatomical asymmetries for the homologues of key language areas, including the inferior frontal gyrus (IFG) and planum temporale (PT). When considering the entire sample, there was a predominance of right-handedness for clapping and the distribution of right- and left-handed individuals did not differ between the two facilities. The direction of hand preference (right- versus left-handed subjects) for clapping explained a significant portion of variability in asymmetries of the PT and IFG. The results are consistent with the view that gestural communication in the common ancestor may have been a precursor of language and its cerebral substrates in modern humans. PMID:22217719

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.

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

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.

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.

Hand preference for sending mobile-phone text messages: associations with sex, writing hand, and throwing hand.

PubMed

Lambert, Anthony; Hallett, Charlene

2009-07-01

Hand preference for sending mobile-phone text messages ("texting") and its relationship with hand preference for other activities were investigated in a questionnaire study with 886 participants. Overall rates of both sinistrality and dextrality were reduced for texting, in comparison with other activities, due to the substantial number of individuals who use both hands simultaneously when performing this activity. Because they both involve verbal expression, it was hypothesised that the association between hand preferences for texting and writing might be stronger than the association between either of these tasks and more spatial activities, such as throwing. This prediction was not confirmed, either in the sample as a whole or in a sub-group of individuals who reported writing and throwing with opposite hands. Females were less likely than males to use their left hand when sending text messages. Implications of these findings are discussed, in relation to theoretical views of handedness and in relation to practical aspects of mobile-phone design.

Hand preference consistency and simple rhythmic bimanual coordination in preschool children.

PubMed

Mori, Shiro; Iteya, Misaki; Gabbard, Carl

2007-06-01

This study examined whether strength of hand preference is associated with rhythmic bimanual coordination. 27 preschool children ages 4 to 6 years, identified as 10 right-, 8 left-, and 9 mixed-handed, were evaluated on accuracy and stability with a bimanual tapping task requiring intermodal matching. The primary hypothesis was that consistent right- and left-handers would have an advantage over mixed-handers given higher hemispheric maturation, possibly the corpus callosum, which may be the main interhemispheric communication conduit. A significant difference was noted among the three groups, with right-handers having higher accuracy and stability. This finding suggests that bimanual coordination in young children may be influenced by handedness, which may also be related to the development of interhemispheric communication.

Transfer and interference of motor skills in people with intellectual disability.

PubMed

Mohan, A; Singh, A P; Mandal, M K

2001-08-01

Atypical laterality (i.e. the lack of a clear pattern of lateralization) has been found to be a characteristic feature of individuals with intellectual disability (ID). The evidence for this has been based on 'handedness' studies which have contained little information about the ability of people with ID to carry out interhemispheric tasks reflecting bilateral transfer or interference. The present study examined this capacity in individuals with ID by utilizing bilateral transfer and interference paradigms. Right-handed subjects with ID (IQ = 55-76) and controls matched for age and sex were tested for bilateral transfer of motor skill in contralateral hands with a mirror-drawing task. The subjects were also tested for their ability to perform a finger-tapping task while processing verbal and non-verbal stimuli. The findings indicated that people with ID are significantly deficient relative to matched controls in bilateral transfer of motor skills from their non-preferred (left) hand to their preferred (right) one. The effect of interference during performance of the dual task was significantly greater in individuals with ID. Subjects with ID were found to perform better with their non-preferred than with their preferred hand. A within-group comparison revealed that right-handed performance was more affected by interference than left in these subjects.

Relationship between Manual Preferences for Object Manipulation and Pointing Gestures in Infants and Toddlers

ERIC Educational Resources Information Center

Vauclair, Jacques; Imbault, Juliette

2009-01-01

The aim of this study was to measure the pattern of hand preferences for pointing gestures as a function of object-manipulation handedness in 123 infants and toddlers (10-40 months). The results showed that not only right-handers but also left-handers and ambidextrous participants tended to use their right hand for pointing. There was a…

Magical Ideation, Creativity, Handedness, and Cerebral Asymmetries: A Combined Behavioural and fMRI Study

ERIC Educational Resources Information Center

Badzakova-Trajkov, Gjurgjica; Haberling, Isabelle S.; Corballis, Michael C.

2011-01-01

Magical ideation has been shown to be related to measures of hand preference, in which those with mixed handedness exhibit higher levels of magical ideation than those with either consistent left- or right-handedness. It is unclear whether the relation between magical ideation and hand preference is the result of a bias in questionnaire-taking…

Frontoparietal Tracts Linked to Lateralized Hand Preference and Manual Specialization.

PubMed

Howells, Henrietta; Thiebaut de Schotten, Michel; Dell'Acqua, Flavio; Beyh, Ahmad; Zappalà, Giuseppe; Leslie, Anoushka; Simmons, Andrew; Murphy, Declan G; Catani, Marco

2018-04-21

Humans show a preference for using the right hand over the left for tasks and activities of everyday life. While experimental work in non-human primates has identified the neural systems responsible for reaching and grasping, the neural basis of lateralized motor behavior in humans remains elusive. The advent of diffusion imaging tractography for studying connectional anatomy in the living human brain provides the possibility of understanding the relationship between hemispheric asymmetry, hand preference, and manual specialization. In this study, diffusion tractography was used to demonstrate an interaction between hand preference and the asymmetry of frontoparietal tracts, specifically the dorsal branch of the superior longitudinal fasciculus, responsible for visuospatial integration and motor planning. This is in contrast to the corticospinal tract and the superior cerebellar peduncle, for which asymmetry was not related to hand preference. Asymmetry of the dorsal frontoparietal tract was also highly correlated with the degree of lateralization in tasks requiring visuospatial integration and fine motor control. These results suggest a common anatomical substrate for hand preference and lateralized manual specialization in frontoparietal tracts important for visuomotor processing.

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.

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.

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.

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

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.

Left Preference for Sport Tasks Does Not Necessarily Indicate Left-Handedness: Sport-Specific Lateral Preferences, Relationship with Handedness and Implications for Laterality Research in Behavioural Sciences

PubMed Central

Loffing, Florian; Sölter, Florian; Hagemann, Norbert

2014-01-01

In the elite domain of interactive sports, athletes who demonstrate a left preference (e.g., holding a weapon with the left hand in fencing or boxing in a ‘southpaw’ stance) seem overrepresented. Such excess indicates a performance advantage and was also interpreted as evidence in favour of frequency-dependent selection mechanisms to explain the maintenance of left-handedness in humans. To test for an overrepresentation, the incidence of athletes' lateral preferences is typically compared with an expected ratio of left- to right-handedness in the normal population. However, the normal population reference values did not always relate to the sport-specific tasks of interest, which may limit the validity of reports of an excess of ‘left-oriented’ athletes. Here we sought to determine lateral preferences for various sport-specific tasks (e.g., baseball batting, boxing) in the normal population and to examine the relationship between these preferences and handedness. To this end, we asked 903 participants to indicate their lateral preferences for sport-specific and common tasks using a paper-based questionnaire. Lateral preferences varied considerably across the different sport tasks and we found high variation in the relationship between those preferences and handedness. In contrast to unimanual tasks (e.g., fencing or throwing), for bimanually controlled actions such as baseball batting, shooting in ice hockey or boxing the incidence of left preferences was considerably higher than expected from the proportion of left-handedness in the normal population and the relationship with handedness was relatively low. We conclude that (i) task-specific reference values are mandatory for reliably testing for an excess of athletes with a left preference, (ii) the term ‘handedness’ should be more cautiously used within the context of sport-related laterality research and (iii) observation of lateral preferences in sports may be of limited suitability for the verification of evolutionary theories of handedness. PMID:25141020

Left preference for sport tasks does not necessarily indicate left-handedness: sport-specific lateral preferences, relationship with handedness and implications for laterality research in behavioural sciences.

PubMed

Loffing, Florian; Sölter, Florian; Hagemann, Norbert

2014-01-01

In the elite domain of interactive sports, athletes who demonstrate a left preference (e.g., holding a weapon with the left hand in fencing or boxing in a 'southpaw' stance) seem overrepresented. Such excess indicates a performance advantage and was also interpreted as evidence in favour of frequency-dependent selection mechanisms to explain the maintenance of left-handedness in humans. To test for an overrepresentation, the incidence of athletes' lateral preferences is typically compared with an expected ratio of left- to right-handedness in the normal population. However, the normal population reference values did not always relate to the sport-specific tasks of interest, which may limit the validity of reports of an excess of 'left-oriented' athletes. Here we sought to determine lateral preferences for various sport-specific tasks (e.g., baseball batting, boxing) in the normal population and to examine the relationship between these preferences and handedness. To this end, we asked 903 participants to indicate their lateral preferences for sport-specific and common tasks using a paper-based questionnaire. Lateral preferences varied considerably across the different sport tasks and we found high variation in the relationship between those preferences and handedness. In contrast to unimanual tasks (e.g., fencing or throwing), for bimanually controlled actions such as baseball batting, shooting in ice hockey or boxing the incidence of left preferences was considerably higher than expected from the proportion of left-handedness in the normal population and the relationship with handedness was relatively low. We conclude that (i) task-specific reference values are mandatory for reliably testing for an excess of athletes with a left preference, (ii) the term 'handedness' should be more cautiously used within the context of sport-related laterality research and (iii) observation of lateral preferences in sports may be of limited suitability for the verification of evolutionary theories of handedness.

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.

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.

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.

The association between hemispheric specialization for language production and for spatial attention depends on left-hand preference strength.

PubMed

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

2016-12-01

Cerebral lateralization for language production and spatial attention and their relationships with manual preference strength (MPS) were assessed in a sample of 293 healthy volunteers, including 151 left-handers, using fMRI during covert sentence production (PROD) and line bisection judgment (LBJ) tasks, as compared to high- and low-level reference tasks. At the group level, we found the expected complementary hemispheric specialization (HS) with leftward asymmetries for PROD within frontal and temporal regions and rightward asymmetries for LBJ within frontal and posterior occipito-parieto-temporal regions. Individual hemispheric (HLI) and regional (frontal and occipital) lateralization indices (LI) were then calculated on the activation maps for PROD and LBJ. We found a correlation between the degree of rightward cerebral asymmetry and the leftward behavioral attentional bias recorded during LBJ task. This correlation was found when LBJ-LI was computed over the hemispheres, in the frontal lobes, but not in the occipital lobes. We then investigated whether language production and spatial attention cerebral lateralization relate to each other, and whether manual preference was a variable that impacted the complementary HS of these functions. No correlation was found between spatial and language LIs in the majority of our sample of participants, including right-handers with a strong right-hand preference (sRH, n=97) and mixed-handers (MH, n=97), indicating that these functions lateralized independently. By contrast, in the group of left-handers with a strong left-hand preference (sLH, n= 99), a negative correlation was found between language and spatial lateralization. This negative correlation was found when LBJ-LI and PROD-LI were computed over the hemispheres, in the frontal lobes and between the occipital lobes for LBJ and the frontal lobes for PROD. These findings underline the importance to include sLH in the study sample to reveal the underlying mechanisms of complementary HS. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Relation between Handedness Indices and Reproductive Success in a Non-Industrial Society

PubMed Central

Schaafsma, Sara M.; Geuze, Reint H.; Lust, Jessica M.; Schiefenhövel, Wulf; Groothuis, Ton G. G.

2013-01-01

The evolution of handedness in human populations has intrigued scientists for decades. However, whether handedness really affects Darwinian fitness is unclear and not yet studied in a non-industrial society where selection pressures on health and handedness are likely to be similar to the situation in which handedness has evolved. We measured both hand preference and asymmetry of hand skill (speed of fine motor control, measured by a pegboard task, and accuracy of throwing), as they measure different aspects of handedness. We investigated the associations between both the direction (left versus right) and strength (the degree to which a certain preference or asymmetry in skill is manifested, independent of the direction) of handedness. We analyzed to what extent these measures predict the number of offspring and self-reported illness in a non-industrial society in Papua, Indonesia. As it is known that body height and fitness are correlated, data on body height was also collected. Due to low numbers of left-handers we could not investigate the associations between direction of hand preference and measures of Darwinian fitness. We found a positive association between strength of asymmetry of hand skill (pegboard) and the number of children men sired. We also found a positive association for men between strength of hand preference and number of children who died within the first three years of life. For women we found no such effects. Our results may indicate that strength of handedness, independent of direction, has fitness implications and that the persistence of the polymorphism in handedness may be ascribed to either balancing selection on strength of asymmetry of hand skill versus strength of hand preference, or sexual antagonistic selection. No relationships between health and handedness were found, perhaps due to disease related selective disappearance of subjects with a specific handedness. PMID:23704893

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.

Handedness and spinal deformity.

PubMed

Goldberg, C J; Moore, D P; Fogarty, E E; Dowling, F E

2006-01-01

Biological lateralisation is clearly manifest in scoliosis, yet its relevance is unclear. Goldberg et al. (Spine. 15(2):61-64. 1990) found an association between curve pattern and hand-preference in a screened population, but no increase in sinistrality. Milenkovic et al, (European Journal of Epidemiology, 19:969-972,2004) concluded left-handedness was a risk factor in a screened group. The database was reassessed to determine whether clinically significant scoliosis was associated with sinistrality or differed from the population norm of 10%. Patients attending the scoliosis clinic were asked their preferred writing hand. 1,636 patients were identified with complete data. Overall, left handedness occurred in 11.5%, greater than the general population (p=0.04) Left hand preference was found to be increased in boys with infantile idiopathic scoliosis and in girls with infantile, juvenile, congenital and syndromic scoliosis, but was reduced in girls with adolescent idiopathic scoliosis. Scoliosis lateralisation was random in infantile and congenital scoliosis, while left curve patterns were decreased in girls with juvenile idiopathic scoliosis and increased in boys with syndromic scoliosis. Curve pattern and handedness correlated in asymmetry in boys and girls and in girls with radiologically confirmed adolescent idiopathic scoliosis, but not in any other type. This study cannot confirm findings of left-handedness as a risk factor for spinal deformity. Its incidence is reduced in girls with adolescent idiopathic scoliosis, and the increased sinistrality in infantile scoliosis is not a new finding (Rauterberg & Tonnis Ger. Z.Orthop. 109(14):676-689. 1971). Lateralisation is undoubtedly a factor in scoliosis, but does not have a simple causal relationship, probably deriving from the underlying scoliotic process, rather than contributing to it.

The Performance of Left-Handed Participants on a Preferential Reaching Test

ERIC Educational Resources Information Center

Mamolo, Carla M.; Roy, Eric A.; Bryden, Pamela J.; Rohr, Linda E.

2005-01-01

Previous research in our laboratory has examined the distribution of preferred hand (PH) reaches in working space with right-handed participants. In one study, we examined the effects of tool position and task demands on the frequency of PH reaches with right-handers (Mamolo, Roy, Bryden, & Rohr, 2004). We found that PH reaches were at a maximum…

Laterality of foetal self-touch in relation to maternal stress.

PubMed

Reissland, Nadja; Aydin, Ezra; Francis, Brian; Exley, Kendra

2015-01-01

This longitudinal observational study investigated whether foetuses change their hand preference with gestational age, and also examined the effects of maternal stress on lateralized foetal self-touch. Following ethical approval, fifteen healthy foetuses (eight girls and seven boys) were scanned four times from 24 to 36 weeks gestation. Self-touch behaviours which resulted in a touch of the foetal face/head were coded in 60 scans for 10 min and analysed in terms of frequency of the foetuses using left and right hands to touch their face. The joint effects of foetal age, stress and sex on laterality were assessed. We modelled the proportion of right self-touches for each foetal scan using a generalized linear mixed model, taking account of the repeated measures design. There was substantial variability in hand preference between foetuses. However, there was no significant increase in the proportion of right-handed touches with foetal age. No sex differences in handedness were identified. However, maternally reported stress level was significantly positively related to foetal left-handed self-touches (odds ratio 0.915; p < .0001). This longitudinal study provides important new insights into the effect of recent maternal stress on foetal predominant hand use during self-touch.

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

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.

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.

Looking at eye dominance from a different angle: is sighting strength related to hand preference?

PubMed

Carey, David P; Hutchinson, Claire V

2013-10-01

Sighting dominance (the behavioural preference for one eye over the other under monocular viewing conditions) has traditionally been thought of as a robust individual trait. However, Khan and Crawford (2001) have shown that, under certain viewing conditions, eye preference reverses as a function of horizontal gaze angle. Remarkably, the reversal of sighting from one eye to the other depends on which hand is used to reach out and grasp the target. Their procedure provides an ideal way to measure the strength of monocular preference for sighting, which may be related to other indicators of hemispheric specialisation for speech, language and motor function. Therefore, we hypothesised that individuals with consistent side preferences (e.g., right hand, right eye) should have more robust sighting dominance than those with crossed lateral preferences. To test this idea, we compared strength of eye dominance in individuals who are consistently right or left sided for hand and foot preference with those who are not. We also modified their procedure in order to minimise a potential image size confound, suggested by Banks et al. (2004) as an explanation of Khan and Crawford's results. We found that the sighting dominance switch occurred at similar eccentricities when we controlled for effects of hand occlusion and target size differences. We also found that sighting dominance thresholds change predictably with the hand used. However, we found no evidence for relationships between strength of hand preference as assessed by questionnaire or by pegboard performance and strength of sighting dominance. Similarly, participants with consistent hand and foot preferences did not show stronger eye preference as assessed using the Khan and Crawford procedure. These data are discussed in terms of indirect relationships between sighting dominance, hand preference and cerebral specialisation for language and motor control. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of target animacy on hand preference in Sichuan snub-nosed monkeys (Rhinopithecus roxellana).

PubMed

Zhao, Dapeng; Tian, Xiangling; Liu, Xinchen; Chen, Zhuoyue; Li, Baoguo

2016-09-01

Twenty-eight captive Sichuan snub-nosed monkeys (Rhinopithecus roxellana) were involved in the current study. Many individuals showed handedness, with a modest tendency toward left-hand use especially for animate targets, although no group-level handedness was found. There was no significant gender difference in the direction and strength of hand preference for both targets. Females showed a significantly higher overall rate of actions toward animate targets than inanimate targets for both hands, whereas males displayed almost the reversed pattern. There were no significant interactions between lateral hand use and target animacy for either males or females. Most individuals showed rightward or leftward laterality shift trends between inanimate and animate targets. These findings to some extent support the existence of a potential trend concerning a categorical neural distinction between targets demanding functional manipulation (inanimate objects) and those demanding social manipulation (animate objects), even though specialized hand preference based on target animacy has not been fully established in this arboreal Old World monkey species.

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

Hand and Grasp Selection in a Preferential Reaching Task: The Effects of Object Location, Orientation, and Task Intention.

PubMed

Scharoun, Sara M; Scanlan, Kelly A; Bryden, Pamela J

2016-01-01

As numerous movement options are available in reaching and grasping, of particular interest are what factors influence an individual's choice of action. In the current study a preferential reaching task was used to assess the propensity for right handers to select their preferred hand and grasp a coffee mug by the handle in both independent and joint action object manipulation contexts. Mug location (right-space, midline, and left-space) and handle orientation (toward, away, to left, and to right of the participant) varied in four tasks that differed as a function of intention: (1) pick-up (unimanual, independent); (2) pick-up and pour (bimanual, independent); (3) pick-up and pass (unimanual, joint action); and (4) pick-up, pour and pass (bimanual, joint action). In line with previous reports, a right-hand preference for unimanual tasks was observed. Furthermore, extending existing literature to a preferential reaching task, role differentiation between the hands in bimanual tasks (i.e., preferred hand mobilizing, non-preferred hand stabilizing) was displayed. Finally, right-hand selection was greatest in right space, albeit lower in bimanual tasks compared to what is typically reported in unimanual tasks. Findings are attributed to the desire to maximize biomechanical efficiency in reaching. Grasp postures were also observed to reflect consideration of efficiency. More specifically, within independent object manipulation (pick-up; pick-up and pour) participants only grasped the mug by the handle when it afforded a comfortable posture. Furthermore, in joint action (pick-up and pass; pick-up, pour and pass), the confederate was only offered the handle if the intended action of the confederate was similar or required less effort than that of the participant. Together, findings from the current study add to our knowledge of hand and grasp selection in unimanual and bimanual object manipulation, within the context of both independent and joint action tasks.

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.

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.

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.

Comparative Assessment of Handedness for a Coordinated Bimanual Task in Chimpanzees (Pan troglodytes), Gorillas (Gorilla gorilla), and Orangutans (Pongo pygmaeus)

PubMed Central

Hopkins, William D.; Stoinski, Tara S.; Lukas, Kristen E.; Ross, Stephen R.; Wesley, Michael J.

2007-01-01

Hand preferences for a coordinated bimanual task were assessed in a sample of 31 captive gorillas (Gorilla gorilla) and 19 captive orangutans (Pongo pygmaeus) and were compared with chimpanzee (Pan troglodytes) hand preferences in subjects that were matched on the basis of age, sex, and rearing history. The task required that the apes remove food from the inside edges of a symmetrical polyvinyl chloride pipe presented to them in their home cages. The results indicate significant species differences with chimpanzees showing population-level right-handedness and orangutans showing population-level left-handedness. The gorillas showed a nonsignificant trend toward right-handedness. The results are discussed in terms of possible ecological or biomechanical factors that may influence hand preferences in different ape species. PMID:14498806

Lateralization and performance asymmetries in the termite fishing of wild chimpanzees in the goualougo triangle, republic of Congo.

PubMed

Sanz, Crickette M; Morgan, David B; Hopkins, William D

2016-11-01

The nearly universal right hand preference manifested by human populations is one of the most pronounced manifestations of population-level lateralization. Morphological and archeological evidence indicate that this behavioral specialization may have emerged among our hominin ancestors. Whether population-level behavioral asymmetries are evident in non-human animals remains a topic of considerable scientific debate, with the most consistent evidence of population-level trends emerging from studies of chimpanzees (Pan troglodytes). However, previous studies of population-level lateralization in wild apes have relied upon data sets pooled across populations to reach adequate sample sizes. Our aim was to test for population-level handedness within a single wild chimpanzee population, and also to determine if performance asymmetries were associated with handedness. To address these questions, we coded handedness and duration of fishing probe insertions from remote video footage of chimpanzee visitation to termite nests (totaling 119 hr) in the Goualougo Triangle, Republic of Congo. Similar to reports from other populations, chimpanzees in the Goualougo Triangle showed robust individual hand preferences for termite fishing. There were 46 right-handed, 39 left-handed, and 4 ambiguously-handed individuals. Though we did not detect an overall significant population-level handedness (t(88) = 0.83, n.s.) in this study, males showed a greater right hand preference than females. Further, we found that average dipping latencies were significantly faster for right- compared to left-handed chimpanzees. Possible explanations and evolutionary implications of taxa- and task-specific patterns of population-level laterality are discussed. Am. J. Primatol. 78:1190-1200, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Magical ideation, creativity, handedness, and cerebral asymmetries: a combined behavioural and fMRI study.

PubMed

Badzakova-Trajkov, Gjurgjica; Häberling, Isabelle S; Corballis, Michael C

2011-08-01

Magical ideation has been shown to be related to measures of hand preference, in which those with mixed handedness exhibit higher levels of magical ideation than those with either consistent left- or right-handedness. It is unclear whether the relation between magical ideation and hand preference is the result of a bias in questionnaire-taking behaviour or of some neuropsychological concomitant of cerebral specialization. We sought to replicate this finding and further investigate how magical ideation is related to other measures of laterality, including handedness based on finger-tapping performance, and cerebral asymmetries for language, spatial judgment, and face processing as revealed by fMRI. Creative achievement was also assessed by questionnaire and correlated with magical ideation and the other measures. Magical ideation and creativity were positively correlated, and both were negatively correlated with absolute hand preference but not with hand performance or with any of the cerebral asymmetries being assessed. The results do not support the notion that the observed association between magical ideation, creativity and hand preference has a neuropsychological explanation based on reduced cerebral lateralization. Copyright © 2011 Elsevier Ltd. All rights reserved.

Aiming in adults: sex and laterality effects.

PubMed

Barral, Jérôme; Debû, Bettina

2004-07-01

The purpose of the study was to twofold: to investigate gender-related differences in the asymmetry of aiming with the preferred and non-preferred hand in right-handed adults, and to examine the effect of the spatial requirements of the task on these asymmetries. The hypothesis was that if cognitive functions are more asymmetrically localised in men than in women, one should observe greater left-right differences on some variables in men than in women. Eleven men and eleven women were required to aim fast and accurately at one of three possible targets under a choice reaction time protocol. Performance and kinematics data were analysed. Results revealed an effect of target location on the left hand advantage in reaction time, and gender-related effects on movement time, accuracy, and on the velocity profiles. Overall, women performed more slowly and accurately than men. This gender-related effect could not be accounted for by differential strategies with regard to speed or accuracy, lending support to the idea that differences exist in the neural mechanisms of movement control between the two genders. Finally, although the results show a hand effect on terminal accuracy in men only, they do not support the hypothesis of a greater asymmetry of movement control in men.

The effects of mothers' past infant-holding preferences on their adult children's face processing lateralisation.

PubMed

Vervloed, Mathijs P J; Hendriks, Angélique W; van den Eijnde, Esther

2011-04-01

Face processing development is negatively affected when infants have not been exposed to faces for some time because of congenital cataract blocking all vision (Le Grand, Mondloch, Maurer, & Brent, 2001). It is not clear, however, whether more subtle differences in face exposure may also have an influence. The present study looked at the effect of the mother's preferred side of holding an infant, on her adult child's face processing lateralisation. Adults with a mother who had a left-arm preference for holding infants were compared with adults with a mother who had a right-arm holding preference. All participants were right-handed and had been exclusively bottle-fed during infancy. The participants were presented with two chimeric faces tests, one involving emotion and the other one gender. The left-arm held individuals showed a normal left-bias on the chimeric face tests, whereas the right-arm held individuals a significantly decreased left-bias. The results might suggest that reduced exposure to high quality emotional information on faces in infancy results in diminished right-hemisphere lateralisation for face processing. Copyright © 2011 Elsevier Inc. All rights reserved.

19 CFR 144.32 - Statement of quantity; charges and liens.

Code of Federal Regulations, 2013 CFR

2013-04-01

... shall have indicated thereon, preferably in the lower part of the left-hand margin if there is no space... statement shall indicate: (1) The quantity (i.e., the number of outer containers, or tons, etc.) in the...

19 CFR 144.32 - Statement of quantity; charges and liens.

Code of Federal Regulations, 2014 CFR

2014-04-01

... shall have indicated thereon, preferably in the lower part of the left-hand margin if there is no space... statement shall indicate: (1) The quantity (i.e., the number of outer containers, or tons, etc.) in the...

19 CFR 144.32 - Statement of quantity; charges and liens.

Code of Federal Regulations, 2012 CFR

2012-04-01

... shall have indicated thereon, preferably in the lower part of the left-hand margin if there is no space... statement shall indicate: (1) The quantity (i.e., the number of outer containers, or tons, etc.) in the...

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

19 CFR 144.32 - Statement of quantity; charges and liens.

Code of Federal Regulations, 2011 CFR

2011-04-01

... shall have indicated thereon, preferably in the lower part of the left-hand margin if there is no space... a portion of an original lot has been transferred to a new owner in accordance with subpart C of...

19 CFR 144.32 - Statement of quantity; charges and liens.

Code of Federal Regulations, 2010 CFR

2010-04-01

... shall have indicated thereon, preferably in the lower part of the left-hand margin if there is no space... a portion of an original lot has been transferred to a new owner in accordance with subpart C of...

Relationship between the Short-Term Visual Memory and IQ in the Right-and Left-Handed Subjects Trained in Different Educational Programs: I-General Assessment

ERIC Educational Resources Information Center

Yilmaz, Yavuz; Yetkin, Yalçin

2014-01-01

The relationship between mean intelligence quotient (IQ), hand preferences and visual memory (VM) were investigated on (N = 612) males and females students trained in different educational programs in viewpoint of laterality. IQ was assessed by cattle's culture Fair intelligence test-A (CCFIT-A). The laterality of the one side of the body was…

Relationships between hand laterality and verbal and spatial skills in 436 healthy adults balanced for handedness.

PubMed

Mellet, E; Jobard, G; Zago, L; Crivello, F; Petit, L; Joliot, M; Mazoyer, B; Tzourio-Mazoyer, N

2014-01-01

The relationship between manual laterality and cognitive skills remains highly controversial. Some studies have reported that strongly lateralised participants had higher cognitive performance in verbal and visuo-spatial domains compared to non-lateralised participants; however, others found the opposite. Moreover, some have suggested that familial sinistrality and sex might interact with individual laterality factors to alter cognitive skills. The present study addressed these issues in 237 right-handed and 199 left-handed individuals. Performance tests covered various aspects of verbal and spatial cognition. A principal component analysis yielded two verbal and one spatial factor scores. Participant laterality assessments included handedness, manual preference strength, asymmetry of motor performance, and familial sinistrality. Age, sex, education level, and brain volume were also considered. No effect of handedness was found, but the mean factor scores in verbal and spatial domains increased with right asymmetry in motor performance. Performance was reduced in participants with a familial history of left-handedness combined with a non-maximal preference strength in the dominant hand. These results elucidated some discrepancies among previous findings in laterality factors and cognitive skills. Laterality factors had small effects compared to the adverse effects of age for spatial cognition and verbal memory, the positive effects of education for all three domains, and the effect of sex for spatial cognition.

Salivary testosterone levels are unrelated to handedness or cerebral lateralization for language.

PubMed

Papadatou-Pastou, Marietta; Martin, Maryanne; Mohr, Christine

2017-03-01

Behavioural and cerebral lateralization are thought to be controlled, at least in part, by prenatal testosterone (T) levels, explaining why sex differences are found in both laterality traits. The present study investigated hormonal effects on laterality using adult salivary T levels, to explore the adequacy of competing theories: the Geschwind, Behan and Galaburda, the callosal, and the sexual differentiation hypotheses. Sixty participants (15 right-handers and 15 left-handers of each sex) participated. Behavioural lateralization was studied by means of hand preference tests (i.e., the Edinburgh Handedness Inventory and the Quantification of Hand Preference test) and a hand skill test (i.e., the Peg-Moving test) whereas cerebral lateralization for language was studied using the Consonant-Vowel Dichotic Listening test and the Visual Half-Field Lexical Decision test. Salivary T and cortisol (C) concentrations were measured by luminescence immunoassay. Canonical correlations did not reveal significant relationships between T levels and measures of hand preference, hand skill, or language laterality. Thus, our findings add to the growing literature showing no relationship between T concentrations with behavioural or cerebral lateralization. It is claimed that prenatal T is not a major determinant of individual variability in either behavioural or cerebral lateralization.

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.

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.

Motor laterality as an indicator of speech laterality.

PubMed

Flowers, Kenneth A; Hudson, John M

2013-03-01

The determination of speech laterality, especially where it is anomalous, is both a theoretical issue and a practical problem for brain surgery. Handedness is commonly thought to be related to speech representation, but exactly how is not clearly understood. This investigation analyzed handedness by preference rating and performance on a reliable task of motor laterality in 34 patients undergoing a Wada test, to see if they could provide an indicator of speech laterality. Hand usage preference ratings divided patients into left, right, and mixed in preference. Between-hand differences in movement time on a pegboard task determined motor laterality. Results were correlated (χ2) with speech representation as determined by a standard Wada test. It was found that patients whose between-hand difference in speed on the motor task was small or inconsistent were the ones whose Wada test speech representation was likely to be ambiguous or anomalous, whereas all those with a consistently large between-hand difference showed clear unilateral speech representation in the hemisphere controlling the better hand (χ2 = 10.45, df = 1, p < .01, η2 = 0.55) This relationship prevailed across hand preference and level of skill in the hands itself. We propose that motor and speech laterality are related where they both involve a central control of motor output sequencing and that a measure of that aspect of the former will indicate the likely representation of the latter. A between-hand measure of motor laterality based on such a measure may indicate the possibility of anomalous speech representation. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Motor skill for tool-use is associated with asymmetries in Broca's area and the motor hand area of the precentral gyrus in chimpanzees (Pan troglodytes).

PubMed

Hopkins, William D; Meguerditchian, Adrien; Coulon, Olivier; Misiura, Maria; Pope, Sarah; Mareno, Mary Catherine; Schapiro, Steven J

2017-02-01

Among nonhuman primates, chimpanzees are well known for their sophistication and diversity of tool use in both captivity and the wild. The evolution of tool manufacture and use has been proposed as a driving mechanism for the development of increasing brain size, complex cognition and motor skills, as well as the population-level handedness observed in modern humans. Notwithstanding, our understanding of the neurological correlates of tool use in chimpanzees and other primates remains poorly understood. Here, we assessed the hand preference and performance skill of chimpanzees on a tool use task and correlated these data with measures of neuroanatomical asymmetries in the inferior frontal gyrus (IFG) and the pli-de-passage fronto-parietal moyen (PPFM). The IFG is the homolog to Broca's area in the chimpanzee brain and the PPFM is a buried gyrus that connects the pre- and post-central gyri and corresponds to the motor-hand area of the precentral gyrus. We found that chimpanzees that performed the task better with their right compared to left hand showed greater leftward asymmetries in the IFG and PPFM. This association between hand performance and PPFM asymmetry was particularly robust for right-handed individuals. Based on these findings, we propose that the evolution of tool use was associated with increased left hemisphere specialization for motor skill. We further suggest that lateralization in motor planning, rather than hand preference per se, was selected for with increasing tool manufacture and use in Hominid evolution. Copyright © 2016 Elsevier B.V. All rights reserved.

Motor skill for tool-use is associated with asymmetries in Broca’s area and the motor hand area of the precentral gyrus in chimpanzees (Pan troglodytes)

PubMed Central

Hopkins, William D.; Meguerditchian, Adrien; Coulon, Olivier; Misiura, Maria; Pope, Sarah; Mareno, Mary Catherine; Schapiro, Steven J.

2017-01-01

Among nonhuman primates, chimpanzees are well known for their sophistication and diversity of tool use in both captivity and the wild. The evolution of tool manufacture and use has been proposed as a driving mechanism for the development of increasing brain size, complex cognition and motor skills, as well as the population-level handedness observed in modern humans. Notwithstanding, our understanding of the neurological correlates of tool use in chimpanzees and other primates remains poorly understood. Here, we assessed the hand preference and performance skill of chimpanzees on a tool use task and correlated these data with measures of neuroanatomical asymmetries in the inferior frontal gyrus (IFG) and the pli-de-passage fronto-parietal moyen (PPFM). The IFG is the homolog to Broca’s area in the chimpanzee brain and the PPFM is a buried gyrus that connects the pre- and post-central gyri and corresponds to the motor-hand area of the precentral gyrus. We found that chimpanzees that performed the task better with their right compared to left hand showed greater leftward asymmetries in the IFG and PPFM. This association between hand performance and PPFM asymmetry was particularly robust for right-handed individuals. Based on these findings, we propose that the evolution of tool use was associated with increased left hemisphere specialization for motor skill. We further suggest that lateralization in motor planning, rather than hand preference per se, was selected for with increasing tool manufacture and use in Hominid evolution. PMID:27816558

Handedness and schizotypy: The potential effect of changing the writing-hand.

PubMed

Tsuang, Hui-Chun; Chen, Wei J; Kuo, Shu-Yu; Hsiao, Po-Chang

2016-08-30

Mixed-handedness, which has been associated with schizotypy in recent studies, might exist for at least two different reasons: it is innate or it has been forced. We examined whether the association between mixed-handedness and schizotypy differs depending on its source. We enrolled 3485 college students in Taiwan. We used both the Perceptual Aberration Scale and Schizotypal Personality Questionnaire to assess schizotypy, and the Annett Hand Preference Questionnaire to assess handedness. Two ways of classifying handedness were examined: the three-way classification based on Annett's categories and mixed- vs. non-mixed-handedness based on Degree of Handedness. Both mixed-handedness groups showed higher positive schizotypy scores. Among mixed handers, those who had been required to change their writing hand from left to right had higher positive schizotypy scores. Being forced to change writing hand seemed to be related to a higher level of schizotypy. The potential effect of the social pressure against using the left hand for writing is discussed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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.

The Effects of Stress on Neuropsychological Tests of Attention and Memory

DTIC Science & Technology

1993-06-14

Employment: 10. Your preferred hand: Employed full-time Employed pan- time Unemployed Laid Off __ Right Left SpouSE (it applicable...J.E., & Friedman, Lucy N. (1969). Psychic cost of adaptation to an environmental stressor. Journal of Personality and Social Psychology, 12, 200-210

Quality of life differences in patients with right- versus left-sided facial paralysis: Universal preference of right-sided human face recognition.

PubMed

Ryu, Nam Gyu; Lim, Byung Woo; Cho, Jae Keun; Kim, Jin

2016-09-01

We investigated whether experiencing right- or left-sided facial paralysis would affect an individual's ability to recognize one side of the human face using hybrid hemi-facial photos by preliminary study. Further investigation looked at the relationship between facial recognition ability, stress, and quality of life. To investigate predominance of one side of the human face for face recognition, 100 normal participants (right-handed: n = 97, left-handed: n = 3, right brain dominance: n = 56, left brain dominance: n = 44) answered a questionnaire that included hybrid hemi-facial photos developed to determine decide superiority of one side for human face recognition. To determine differences of stress level and quality of life between individuals experiencing right- and left-sided facial paralysis, 100 patients (right side:50, left side:50, not including traumatic facial nerve paralysis) answered a questionnaire about facial disability index test and quality of life (SF-36 Korean version). Regardless of handedness or hemispheric dominance, the proportion of predominance of the right side in human face recognition was larger than the left side (71% versus 12%, neutral: 17%). Facial distress index of the patients with right-sided facial paralysis was lower than that of left-sided patients (68.8 ± 9.42 versus 76.4 ± 8.28), and the SF-36 scores of right-sided patients were lower than left-sided patients (119.07 ± 15.24 versus 123.25 ± 16.48, total score: 166). Universal preference for the right side in human face recognition showed worse psychological mood and social interaction in patients with right-side facial paralysis than left-sided paralysis. This information is helpful to clinicians in that psychological and social factors should be considered when treating patients with facial-paralysis. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

End-state comfort trumps handedness in object manipulation.

PubMed

Coelho, Chase J; Studenka, Breanna E; Rosenbaum, David A

2014-04-01

A goal of research on human perception and performance is to explore the relative importance of constraints shaping action selection. The present study concerned the relative importance of two constraints that have not been directly contrasted: (1) the tendency to grasp objects in ways that afford comfortable or easy-to-control final postures; and (2) the tendency to grasp objects with the dominant rather than the nondominant hand. We asked participants to reach out and grasp a horizontal rod whose left or right end was to be placed into a target after a 90° rotation. In one condition, we told participants which hand to use and let them choose an overhand or underhand initial grasp. In another condition, we told participants which grasp to use and let them choose either hand. Participants sacrificed hand preference to perform the task in a way that ensured a comfortable or easy to control thumb-up posture at the time of object placement, indicating that comfort trumped handedness. A second experiment confirmed that comfort was indeed higher for thumb-down postures than thumb-up postures. A third experiment confirmed that the choice data could be linked to objective performance differences. The results point to the importance of identifying constraint weightings for action selection and support an account of hand selection that ascribes hand preference to sensitivity to performance differences. The results do not support the hypothesis that hand preference simply reflects a bias to use the dominant hand.

An X-linked three allele model of hand preference and hand posture for writing.

PubMed

McKeever, Walter F

2004-04-01

This paper describes a genetic model of hand preferences for writing and for handwriting posture (HWP). The challenge of devising an X-linked model for these aspects of human handedness was posed by the results of a large family handedness study (McKeever, 2000) that showed evidence of such linkage. Because X-linkage for handedness has been widely regarded as untenable, the prospects for developing such a model were not initially encouraging, but ultimately a viable model did suggest itself. Family studies of handedness and leading theories of handedness are briefly described, as is some of the research on HWP motivated by the theory of Levy and Nagylaki (1972). It is argued that there is evidence that HWP reflects a biological dictate and not just individual "choices" or "adaptations" to writing in a left-to-right direction with the left hand. The model proposes that inverted handwriting posture is not necessarily highly related to speech and language lateralities of sinistrals, but that it reveals an interhemispheric mediation of writing. It is hypothesised that it reflects a specialisation of the left angular gyrus (with some possible extension into the supramarginal gyrus) for the storage of movement and timing sequences of cursive writing, and right hemisphere motor programming of the motor output of writing. It is also argued that no family handedness study conducted to date is adequate for testing the predictions of extant handedness theories, and the often wide variations between the results of family handedness studies are noted. It is suggested that fMRI studies could definitively test the HWP hypotheses of the model and that the hypothesis of X-linkage could be tested definitively should studies of the human genome identify a gene for handedness.

Compound measure of hand-foot-eye preference masked opposite turning behavior in healthy right-handers and non-right-handers: technical comment on Mohr et al. (2003).

PubMed

Mohr, C; Bracha, H S

2004-10-01

A previous article reported opposite turning behavior in right-handers and non-right-handers (C. Mohr. T. Landis, H. S. Bracha, & P. Brugger, 2003). This observation appears contradictory to the 1st study on long-term spontaneous turning behavior in healthy participants (H. S. Bracha, D. J. Seitz, J. Otemaa, & S. D. Click, 1987). These latter authors found a complex interaction between hemispheric dominance, preferred turning side, and sex. C. Mohr et al. (2003) argued that the differentiation of the population in hemisphere-dominant groups by a compound measure of hand-foot-eye preference might have masked their recent finding. Thus, this commentary presents a reanalysis of the original data set (H. S. Bracha et al., 1987). Replicating recent observation, right-handers preferred left-sided turns; and non-righthanders, right-sided turns. This replication strengthens the proposition that handedness and turning behavior might depend on interhemispheric dopamine asymmetries. Copyright 2004 APA.

C3I: Issues of Command and Control

DTIC Science & Technology

1991-01-01

your eye on the meatball "—the lights on the left-hand side that have to be kept horizontal. The pilots are trained to focus not on the ship, not on...might pass to that pilot and reduced it down to "Keep your eye on the meatball ." |STl DIN! | But you know what the pilot’s preferences are: to come... meatball works and this is my point: you can have information reduction and compression only when you know preferences. All the other characteristics

Handedness shapes children's abstract concepts.

PubMed

Casasanto, Daniel; Henetz, Tania

2012-03-01

Can children's handedness influence how they represent abstract concepts like kindness and intelligence? Here we show that from an early age, right-handers associate rightward space more strongly with positive ideas and leftward space with negative ideas, but the opposite is true for left-handers. In one experiment, children indicated where on a diagram a preferred toy and a dispreferred toy should go. Right-handers tended to assign the preferred toy to a box on the right and the dispreferred toy to a box on the left. Left-handers showed the opposite pattern. In a second experiment, children judged which of two cartoon animals looked smarter (or dumber) or nicer (or meaner). Right-handers attributed more positive qualities to animals on the right, but left-handers to animals on the left. These contrasting associations between space and valence cannot be explained by exposure to language or cultural conventions, which consistently link right with good. Rather, right- and left-handers implicitly associated positive valence more strongly with the side of space on which they can act more fluently with their dominant hands. Results support the body-specificity hypothesis (Casasanto, 2009), showing that children with different kinds of bodies think differently in corresponding ways. Copyright © 2011 Cognitive Science Society, Inc.

Lack of Association of Handedness with Inattention and Hyperactivity Symptoms in ADHD

ERIC Educational Resources Information Center

Ghanizadeh, Ahmad

2013-01-01

Objective: Findings about the association of left-handedness and ADHD are inconsistent. While abnormal brain laterality is reported in children with ADHD, it is unclear if hand preference is associated with ADHD, severity symptoms, age, gender, comorbid psychiatric problems, or parental characteristics. Method: Subjects were 520 boys and girls…

The Brain Connection: The Corpus Callosum is Larger in Left-Handers.

ERIC Educational Resources Information Center

Witelson, Sandra F.

1985-01-01

Discusses the neurobiological basis for functional specialization of the cerebral hemispheres, indicating that the size of the corpus callosum is correlated with the neurophysiological measure of hand preference. In postmortem examinations of 42 subjects there were no sex differences, but mixed-handers had significantly larger total areas of the…

Adverse birth factors predict cognitive ability, but not hand preference.

PubMed

Nicholls, Michael E R; Johnston, David W; Shields, Michael A

2012-09-01

There is a persistent theory that birth stress and subsequent brain pathology play an important role in the manifestation of left-handedness. Evidence for this theory, however, is mixed and studies are often beset with problems related to small sample sizes and unreliable health reports. TO avoid these issues, this study used a sample of approximately 10,000 children from the British Cohort Study. The study contains objective birth-health reports and comprehensive measures of socioeconomic status, handedness, cognitive ability, and behavioral/health issues. Regression analyses showed that variables associated with birth stress affected cognitive/behavioral/health outcomes of the child. Despite this, these same factors did not affect the direction or degree of hand preference. We have therefore demonstrated a dissociation whereby adverse birth factors affect the brain's cognitive ability, but not handedness, and by implication, cerebral lateralization. The study also demonstrated a link between left-handedness and reduced levels of cognitive ability. This link cannot be due a generalized birth-stress mechanism and may be caused by specific mechanisms related to changes in cerebral dominance.

The Impact of Handedness, Sex, and Cognitive Abilities on Left-Right Discrimination: A Behavioral Study.

PubMed

Constant, Martin; Mellet, Emmanuel

2018-01-01

The present study examined the relationship between left-right discrimination (LRD) performance and handedness, sex and cognitive abilities. In total, 31 men and 35 women - with a balanced ratio of left-and right-handers - completed the Bergen Left-Right Discrimination Test. We found an advantage of left-handers in both identifying left hands and in verifying "left" propositions. A sex effect was also found, as women had an overall higher error rate than men, and increasing difficulty impacted their reaction time more than it did for men. Moreover, sex interacted with handedness and manual preference strength. A negative correlation of LRD reaction time with visuo-spatial and verbal long-term memory was found independently of sex, providing new insights into the relationship between cognitive skills and performance on LRD.

Is the future the right time?

PubMed

Ouellet, Marc; Santiago, Julio; Israeli, Ziv; Gabay, Shai

2010-01-01

Spanish and English speakers tend to conceptualize time as running from left to right along a mental line. Previous research suggests that this representational strategy arises from the participants' exposure to a left-to-right writing system. However, direct evidence supporting this assertion suffers from several limitations and relies only on the visual modality. This study subjected to a direct test the reading hypothesis using an auditory task. Participants from two groups (Spanish and Hebrew) differing in the directionality of their orthographic system had to discriminate temporal reference (past or future) of verbs and adverbs (referring to either past or future) auditorily presented to either the left or right ear by pressing a left or a right key. Spanish participants were faster responding to past words with the left hand and to future words with the right hand, whereas Hebrew participants showed the opposite pattern. Our results demonstrate that the left-right mapping of time is not restricted to the visual modality and that the direction of reading accounts for the preferred directionality of the mental time line. These results are discussed in the context of a possible mechanism underlying the effects of reading direction on highly abstract conceptual representations.

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

Handedness for Unimanual Grasping in 564 Great Apes: The Effect on Grip Morphology and a Comparison with Hand Use for a Bimanual Coordinated Task

PubMed Central

Meguerditchian, Adrien; Phillips, Kimberley A.; Chapelain, Amandine; Mahovetz, Lindsay M.; Milne, Scott; Stoinski, Tara; Bania, Amanda; Lonsdorf, Elizabeth; Schaeffer, Jennifer; Russell, Jamie; Hopkins, William D.

2015-01-01

A number of factors have been proposed to influence within and between species variation in handedness in non-human primates. In the initial study, we assessed the influence of grip morphology on hand use for simple reaching in a sample of 564 great apes including 49 orangutans Pongo pygmaeus, 66 gorillas Gorilla gorilla, 354 chimpanzees Pan troglodytes and 95 bonobos Pan paniscus. Overall, we found a significant right hand bias for reaching. We also found a significant effect of the grip morphology of hand use. Grasping with the thumb and index finger was more prevalent in the right compared to left hand in all four species. There was no significant sex effect on the patterns of handedness. In a subsample of apes, we also compared consistency in hand use for simple reaching with previously published data on a task that measures handedness for bimanual actions. We found that the ratio of subjects with consistent right compared to left hand use was more prevalent in bonobos, chimpanzees and gorillas but not orangutans. However, for all species, the proportion of subjects with inconsistent hand preferences between the tasks was relatively high suggesting some measures may be more sensitive in assessing handedness than others. PMID:26635693

Handedness for Unimanual Grasping in 564 Great Apes: The Effect on Grip Morphology and a Comparison with Hand Use for a Bimanual Coordinated Task.

PubMed

Meguerditchian, Adrien; Phillips, Kimberley A; Chapelain, Amandine; Mahovetz, Lindsay M; Milne, Scott; Stoinski, Tara; Bania, Amanda; Lonsdorf, Elizabeth; Schaeffer, Jennifer; Russell, Jamie; Hopkins, William D

2015-01-01

A number of factors have been proposed to influence within and between species variation in handedness in non-human primates. In the initial study, we assessed the influence of grip morphology on hand use for simple reaching in a sample of 564 great apes including 49 orangutans Pongo pygmaeus, 66 gorillas Gorilla gorilla, 354 chimpanzees Pan troglodytes and 95 bonobos Pan paniscus. Overall, we found a significant right hand bias for reaching. We also found a significant effect of the grip morphology of hand use. Grasping with the thumb and index finger was more prevalent in the right compared to left hand in all four species. There was no significant sex effect on the patterns of handedness. In a subsample of apes, we also compared consistency in hand use for simple reaching with previously published data on a task that measures handedness for bimanual actions. We found that the ratio of subjects with consistent right compared to left hand use was more prevalent in bonobos, chimpanzees and gorillas but not orangutans. However, for all species, the proportion of subjects with inconsistent hand preferences between the tasks was relatively high suggesting some measures may be more sensitive in assessing handedness than others.

Persisting aphasia, cerebral dominance, and painting in the famous artist Carl Fredrik Reuterswärd.

PubMed

Colombo-Thuillard, F; Assal, G

2007-01-01

What about artistic creativity following a cerebral lesion? We studied the case of a prominent right-handed Swedish painter and sculptor who suffered a cerebral hemorrhage at the age of 55 years. The patient displayed a lesion of the left capsular lenticular region, which resulted in a right hemiplegia and sensory loss, with aphasia of the subcortical type. The linguistic impairments recovered well but at 1 year postonset, the right hand was still completely paralyzed. After a period of a few weeks, during which the patient refused to use his nondominant hand, he produced his first left-handed drawing, and by 1 year postonset, he had once again resumed an intensive artistic activity using his nondominant hand. The pictorial works were reviewed by several renowned art specialists: changes of style and even of contents were judged without loss of artistic quality. The result was described as a gain in emotional and artistic intensity. We discuss our observation in the context of the literature and focus on the crucial role of cerebral dominance and hand preference. We conclude that pictorial creativity and language are distinct forms of expressions.

The coordination patterns observed when two hands reach-to-grasp separate objects.

PubMed

Bingham, Geoffrey P; Hughes, Kirstie; Mon-Williams, Mark

2008-01-01

What determines coordination patterns when both hands reach to grasp separate objects at the same time? It is known that synchronous timing is preferred as the most stable mode of bimanual coordination. Nonetheless, normal unimanual prehension behaviour predicts asynchrony when the two hands reach towards unequal targets, with synchrony restricted to targets equal in size and distance. Additionally, sufficiently separated targets require sequential looking. Does synchrony occur in all cases because it is preferred in bimanual coordination or does asynchrony occur because of unimanual task constraints and the need for sequential looking? We investigated coordinative timing when participants (n = 8) moved their right (preferred) hand to the same object at a fixed distance but the left hand to objects of different width (3, 5, and 7 cm) and grip surface size (1, 2, and 3 cm) placed at different distances (20, 30, and 40 cm) over 270 randomised trials. The hand movements consisted of two components: (1) an initial component (IC) during which the hand reached towards the target while forming an appropriate grip aperture, stopping at (but not touching) the object; (2) a completion component (CC) during which the finger and thumb closed on the target. The two limbs started the IC together but did not interact until the deceleration phase when evidence of synchronisation began to appear. Nonetheless, asynchronous timing was present at the end of the IC and preserved through the CC even with equidistant targets. Thus, there was synchrony but requirements for visual information ultimately yielded asynchronous coordinative timing.

The control of sequential aiming movements: the influence of practice and manual asymmetries on the one-target advantage.

PubMed

Lavrysen, Ann; Helsen, Werner F; Tremblay, Luc; Elliott, Digby; Adam, Jos J; Feys, Peter; Buekers, Martinus J

2003-04-01

The present experiment was conducted to explore the effect of practice on the one-target advantage in manual aiming, as well as asymmetries in intermanual transfer of training. Reaction and movement times for the first movement were longer in the 2-target than in the 1-target task, regardless of the amount of practice, hand preference and practice hand. When two movements were required, peak velocity was lower and, proportionally, more time was spent after peak velocity. Our kinematic results suggest that the one-target advantage is related to both predefined strategies as well as movement implementation processes during execution. Therefore, an integration of advance planning and on-line explanations for the one-target advantage is suggested. Regarding manual asymmetries, right-handers showed more transfer of training from the left to the right hand than vice versa. Left-handers exhibited a reversed pattern of asymmetric transfer of training to right-handers, but they were more disadvantaged using their non-dominant hand. These latter two findings have implications for models of manual asymmetry and upper limb control.

Handed behavior in hagfish--an ancient vertebrate lineage--and a survey of lateralized behaviors in other invertebrate chordates and elongate vertebrates.

PubMed

Miyashita, Tetsuto; Palmer, A Richard

2014-04-01

Hagfish represent an ancient lineage of boneless and jawless vertebrates. Among several curious behaviors they exhibit, solitary individuals in one dominant genus of hagfish (Eptatretus spp.) regularly rest in a tightly coiled posture. We present the first systematic treatment of this distinctive behavior. Individual northeastern Pacific hagfish (E. stoutii) exhibited significant handedness (preferred orientation of coiling). However, right-coiling and left-coiling individuals were equally common in the population. Individual hagfish likely develop a preference for one direction by repeating the preceding coiling direction. We also revisit classical accounts of chordate natural history and compare the coiling behavior of Eptatretus with other handed or lateralized behaviors in non-vertebrate chordates, lampreys, and derived vertebrates with elongate bodies. Handed behaviors occur in many of these groups, but they likely evolved independently. In contrast to vertebrates, morphological asymmetries may bias lateralized larval behaviors toward one side in cephalochordates and tunicates. As a consequence, no known handed behavior can be inferred to have existed in the common ancestor of vertebrates.

Digit reversal in children's writing: a simple theory and its empirical validation.

PubMed

Fischer, Jean-Paul

2013-06-01

This article presents a simple theory according to which the left-right reversal of single digits by 5- and 6-year-old children is mainly due to the application of an implicit right-writing or -orienting rule. A number of nontrivial predictions can be drawn from this theory. First, left-oriented digits (1, 2, 3, 7, and 9) will be reversed more frequently than the other asymmetrical digits (4, 5, and 6). Second, for some pairs of digits, the correct writing of the preceding digit will statistically predict the reversal of the current digit and vice versa. Third, writing hand will have little effect on the frequency of reversals, and the relative frequencies with which children reverse the asymmetrical digits will be similar regardless of children's preferred writing hand. Fourth, children who reverse the left-oriented digits the most are also those who reverse the other asymmetrical digits the least. An empirical study involving 367 5- and 6-year-olds confirmed these predictions. Copyright © 2013 Elsevier Inc. All rights reserved.

Practice Perspectives of Left-Handed Clinical Dental Students in India

PubMed Central

Puranik, Manjunath P; Uma, SR

2016-01-01

Introduction Handedness becomes important for students during their training period. Limited literature is available regarding the same. Aim The purpose of this study was to assess the dental practice perspectives and determine the hand preference and discomfort level among the Left-Handed (LH) clinical dental students. Materials and Methods A 30-item survey tool was used to conduct a cross-sectional survey among four successive LH cohorts (third and final year undergraduates, dental interns and postgraduates) in all the dental colleges of Bengaluru, Karnataka, India, during the year 2014. Results A total of 84 students completed the survey, response rate being 100%. About one-third (37%) reported that their institution was not properly equipped to accommodate LH students. Majority felt that LH dentists were at a higher risk of developing musculoskeletal complications. Mouth mirror handling showed equal distribution for handedness as compared to the other dental activities, whereas discomfort levels were negligible (“without any difficulty”). Dental practice perspective scores significantly correlated with the difficulty levels (r=-0.333, p<0.001). Conclusion Overall, the left-handers had a right dental practice perspective and their responses indicate a need to address their issues empathetically. PMID:27891465

Peripheral, functional and postural asymmetries related to the preferred chewing side in adults with natural dentition.

PubMed

Rovira-Lastra, B; Flores-Orozco, E I; Ayuso-Montero, R; Peraire, M; Martinez-Gomis, J

2016-04-01

The aim of this cross-sectional study was to determine the preferred chewing side and whether chewing side preference is related to peripheral, functional or postural lateral preferences. One hundred and forty-six adults with natural dentition performed three masticatory assays, each consisting of five trials of chewing three pieces of silicon placed into a latex bag for 20 cycles, either freestyle or unilaterally on the right- or left-hand side. Occlusal contact area in the intercuspal position, maximum bite force, masticatory performance and cycle duration were measured and the lateral asymmetry of these variables was calculated. Laterality tests were performed to determine handedness, footedness, earedness and eyedness as functional preferences, and hand-clasping, arm-folding and leg-crossing as postural lateral preferences. The preferred chewing side was determined using three different methods: assessment of the first chewing cycle for each trial, calculation of the asymmetry index from all cycles and application of a visual analogue scale. Bivariate relationship and multiple linear regression analyses were performed. Among unilateral chewers, 77% of them preferred the right side for chewing. The factors most closely related to the preferred chewing side were asymmetry of bite force, asymmetry of masticatory performance and earedness, which explained up to 16% of the variance. Although several functional or postural lateral preferences seem to be related to the preferred chewing side, peripheral factors such as asymmetry of bite force and of masticatory performance are the most closely related to the preferred chewing side in adults with natural dentition. © 2015 John Wiley & Sons Ltd.

Right-handed double-helix ultrashort DNA yields chiral nematic phases with both right- and left-handed director twist

PubMed Central

Zanchetta, Giuliano; Giavazzi, Fabio; Nakata, Michi; Buscaglia, Marco; Cerbino, Roberto; Clark, Noel A.; Bellini, Tommaso

2010-01-01

Concentrated solutions of duplex-forming DNA oligomers organize into various mesophases among which is the nematic (N∗), which exhibits a macroscopic chiral helical precession of molecular orientation because of the chirality of the DNA molecule. Using a quantitative analysis of the transmission spectra in polarized optical microscopy, we have determined the handedness and pitch of this chiral nematic helix for a large number of sequences ranging from 8 to 20 bases. The B-DNA molecule exhibits a right-handed molecular double-helix structure that, for long molecules, always yields N∗ phases with left-handed pitch in the μm range. We report here that ultrashort oligomeric duplexes show an extremely diverse behavior, with both left- and right-handed N∗ helices and pitches ranging from macroscopic down to 0.3 μm. The behavior depends on the length and the sequence of the oligomers, and on the nature of the end-to-end interactions between helices. In particular, the N∗ handedness strongly correlates with the oligomer length and concentration. Right-handed phases are found only for oligomers shorter than 14 base pairs, and for the sequences having the transition to the N∗ phase at concentration larger than 620 mg/mL. Our findings indicate that in short DNA, the intermolecular double-helical interactions switch the preferred liquid crystal handedness when the columns of stacked duplexes are forced at high concentrations to separations comparable to the DNA double-helix pitch, a regime still to be theoretically described. PMID:20876125

Blood pressure differences between arms and association of dominant hands with blood pressure differences and carotid atherosclerosis.

PubMed

Maeda, Shinji

2013-06-01

Guidelines for the management of hypertension recommend that blood pressure (BP) should be measured twice at every visit; it should be measured in both arms at the first visit, and the right arm BP or higher BP should be recorded. Manufacturers of home BP monitors tend to design the device for measurement of left arm BP. The arm preferred for BP measurement differs according to the methods recommended by the society and according to the home BP monitors. The BP difference (ΔBP) is calculated by subtracting left arm BP from right arm BP. Here, we aim to first investigate which hand will give the most accurate reading by a sphygmomanometer in daily medical practice. Second, we wish to assess the association of the dominant hand with absolute BP difference (|ΔBP|) of at least 10 mmHg and with early atherosclerotic markers in a subanalysis. We found that 6.4% of outpatients were left handed, and the percentage of individuals with systolic |ΔBP| (|ΔSBP|) and diastolic |ΔBP| (|ΔDBP|) of at least 10 mmHg was 14.4 and 7.2%, respectively. The dominant hand was not significantly associated with |ΔBP| of at least 10 mmHg or early atherosclerotic markers. This study suggests that BP measured in one arm is substitutable with that of the other arm because of a lack of association of |ΔBP| with the dominant hand. However, BP of both arms should be actively measured in new outpatients with moderate fever, lifestyle-related diseases, vascular events, age 65 years and above, and smoking history, all of which are factors potentially associated with |ΔBP| of at least 10 mmHg, regardless of the dominant hand.

Impact of manual preference on directionality in children's drawings.

PubMed

Picard, Delphine

2011-01-01

The effects of handedness on directionality in drawing are already well documented in the literature, at least as far as adults are concerned. The present study investigates the impact of manual preference on directionality as seen in the drawing product and drawing process, from a developmental point of view. A total of 120 children aged 5 to 9, both right and left-handed drawers, volunteered for the study. Children were asked to draw twice from memory a set of six common objects. Results indicate that directionality in drawing product varies significantly according to manual preference in the 9-year-old children, but not in the younger age groups. The concomitant increase between 7 and 9 years of age in the use of preferred stroke directions and the impact of manual preference in the drawing process suggests that biomechanical factors might play an important role in behavioural asymmetries in drawing.

Neonatal transection of the corpus callosum affects paw preference lateralization of adult Swiss mice.

PubMed

Manhães, Alex C; Krahe, Thomas E; Caparelli-Dáquer, Egas; Ribeiro-Carvalho, Anderson; Schmidt, Sergio L; Filgueiras, Cláudio C

2003-09-11

In the present work, the hypothesis that the ontogenetic development of the corpus callosum (CC) affects the establishment of behavioral lateralization was tested by studying paw preference performance in adult Swiss mice that were subjected to mid-sagittal transection of the CC on the first postnatal day. Magnitude and direction of laterality were evaluated independently. No significant differences between groups were found for the magnitude of paw preference. On the other hand, the transected group presented a significant populational bias favoring the left paw that was not present in the control groups. These results lend support to the hypothesis that the development of the CC plays a role in the establishment of the normal pattern of behavioral lateralization.

Pilot Study: The Role of the Hemispheric Lateralization in Mental Disorders by Use of the Limb (Eye, Hand, Foot) Dominance.

PubMed

Goodarzi, Naser; Dabbaghi, Parviz; Valipour, Habib; Vafadari, Behnam

2015-04-01

Based on the previous studies, we know that the hemispheric lateralization defects, increase the probability of psychological disorders. We also know that dominant limb is controlled by dominant hemisphere and limb preference is used as an indicator for hemisphere dominance. In this study we attempted to explore the hemispheric dominance by the use of three limbs (hand, foot and eye). We performed this survey on two samples, psychiatric patients compared with normal population. For this purpose, knowing that the organ dominance is stabilized in adolescence, and age has no effect on the people above 15, we used 48 high school girls and 65 boys as the final samples of normal population. The patient group included 57 male and 26 female who were chronic psychiatric patients. The result shows that left-eye dominance is more in patients than the normal group (P=0.000) but the handedness and footedness differences are not significance. In psychotic, bipolar and depressive disorders, eye dominance had significant difference (P=0.018). But this is not true about hand and foot dominance. Our findings proved that generally in psychiatric patients, left-eye dominance is more common, left-eye dominance is also more in psychotic and depressive disorders. It is less common in bipolar disorders.

Creativity and psychopathology: higher rates of psychosis proneness and nonright-handedness among creative artists compared to same age and gender peers.

PubMed

Preti, Antonio; Vellante, Marcello

2007-10-01

Creative people have been found to score higher on psychopathologic scales in standardized tests, particularly on the scales that measure traits of psychoticism, and to be more likely to report an excess of nonright handedness compared with controls. However, results are inconsistent across surveys and methodologies, and the contribution of substance abuse has rarely been measured. In this study, 80 creative artists were compared with 80 matched noncreative controls on the Annett Hand Preference Questionnaire (HPQ), the Peters et al. Delusions Inventory, and the General Health Questionnaire. Creative artists were statistically more likely to admit the use of the left hand on the HPQ, with more widespread left hand use reported by artists involved in the creative activities traditionally associated with the right hemisphere (music and painting). They also scored higher on the Peters et al. Delusions Inventory independently from the level of psychopathology (measured with the General Health Questionnaire), from their laterality score (measured with the HPQ), and from their higher use of both licit and illicit drugs.

Decreased interlimb differences in female basketball players.

PubMed

Akpinar, Selcuk

2016-12-01

Hand preference can be influenced by some factors like sensory information and sports participation. In many sports, it is always desirable to have the similar performance of both hands to adapt to the fast changes of the game. Elite basketball players use their left non-dominant hand more accurately and more frequently during the game compared to amateurs. However, there is no quantitative data to explain this phenomenon. The aim of the study was to test whether participation of long-term basketball training influences interlimb difference and also observed more accurate and more frequent usage of the non-dominant hand in basketball players that can be explained by some kinematic variables during an aiming task. Professional right-handed female basketball players and age-matched non-athletes were asked to reach one of three targets in a virtual reality environment setup with either their non-dominant or dominant hand. Two kinematic parameters depicting motor performance asymmetries were measured: accuracy and hand path deviation from linearity (HPDL). No interlimb differences for basketball players but significant asymmetrical performance for non-athletes were observed. Although the aiming task used in this study is not a basketball specific task, basketball players still displayed better performance compared to non-athletes in both accuracy and HPDL. The current study implies that not only sensorimotor information but also participation of long-term sports activity can modify interlimb difference. Moreover, basketball players having symmetrical motor performance of both hands, which was found in this study, can indirectly explain the more frequent usage of the non-dominant left hand in basketball players.

Do Left- and Right-Handed People Have Similar Iron Deposition in the Basal Ganglia?

PubMed

Wang, Dan; Li, Yue-Hua; Wang, He

2016-01-01

This study aimed to investigate whether right-, left-, or mixed-handed people differ in terms of iron deposition using susceptibility weighted imaging in healthy subjects. A total of 87 people (right-handed, 51 subjects; left-handed, 19 subjects; mixed-handed, 17 subjects) aged 20 to 40 years participated. All underwent magnetic resonance examination, including conventional and susceptibility weighted imaging sequences. Phase images were used to quantify iron deposition in the head of the caudate nucleus and lenticular nucleus. The radian angle value was calculated and compared between the 3 (right-, left-, or mixed-handed) groups. There was no significant difference in the radian angle values between left-, right-, or mixed-handed people for either the right or left side of the caudate nucleus head. However, the amount of iron deposition in the left lenticular nucleus was significantly higher for right-handed than for the left-handed subjects (P < 0.001) and significantly higher for mixed-handed than for left-handed subjects (P = 0.006). In addition, the amount of iron deposition in the right lenticular nucleus was significantly lower for left-handed than for right-handed subjects (P < 0.001). The results revealed no significant differences in iron deposition in the head of the caudate nucleus. However, there was a significant difference in iron deposition in the lenticular nucleus between left- and right-handed subjects and between left- and mixed-handed subjects.

Functional resting-state connectivity of the human motor network: differences between right- and left-handers.

PubMed

Pool, Eva-Maria; Rehme, Anne K; Eickhoff, Simon B; Fink, Gereon R; Grefkes, Christian

2015-04-01

Handedness is associated with differences in activation levels in various motor tasks performed with the dominant or non-dominant hand. Here we tested whether handedness is reflected in the functional architecture of the motor system even in the absence of an overt motor task. Using resting-state functional magnetic resonance imaging we investigated 18 right- and 18 left-handers. Whole-brain functional connectivity maps of the primary motor cortex (M1), supplementary motor area (SMA), dorsolateral premotor cortex (PMd), pre-SMA, inferior frontal junction and motor putamen were compared between right- and left-handers. We further used a multivariate linear support vector machine (SVM) classifier to reveal the specificity of brain regions for classifying handedness based on individual resting-state maps. Using left M1 as seed region, functional connectivity analysis revealed stronger interhemispheric functional connectivity between left M1 and right PMd in right-handers as compared to left-handers. This connectivity cluster contributed to the individual classification of right- and left-handers with 86.2% accuracy. Consistently, also seeding from right PMd yielded a similar handedness-dependent effect in left M1, albeit with lower classification accuracy (78.1%). Control analyses of the other resting-state networks including the speech and the visual network revealed no significant differences in functional connectivity related to handedness. In conclusion, our data revealed an intrinsically higher functional connectivity in right-handers. These results may help to explain that hand preference is more lateralized in right-handers than in left-handers. Furthermore, enhanced functional connectivity between left M1 and right PMd may serve as an individual marker of handedness. Copyright © 2015 Elsevier Inc. All rights reserved.

Functional resting-state connectivity of the human motor network: Differences between right- and left-handers

PubMed Central

Pool, Eva-Maria; Rehme, Anne K.; Eickhoff, Simon B.; Fink, Gereon R.; Grefkes, Christian

2016-01-01

Handedness is associated with differences in activation levels in various motor tasks performed with the dominant or non-dominant hand. Here we tested whether handedness is reflected in the functional architecture of the motor system even in the absence of an overt motor task. Using resting-state functional magnetic resonance imaging we investigated 18 right- and 18 left-handers. Whole-brain functional connectivity maps of the primary motor cortex (M1), supplementary motor area (SMA), dorsolateral premotor cortex (PMd), pre-SMA, inferior frontal junction and motor putamen were compared between right- and left-handers. We further used a multivariate linear support vector machine (SVM) classifier to reveal the specificity of brain regions for classifying handedness based on individual resting-state maps. Using left M1 as seed region, functional connectivity analysis revealed stronger interhemispheric functional connectivity between left M1 and right PMd in right-handers as compared to left-handers. This connectivity cluster contributed to the individual classification of right- and left-handers with 86.2% accuracy. Consistently, also seeding from right PMd yielded a similar handedness-dependent effect in left M1, albeit with lower classification accuracy (78.1%). Control analyses of the other resting-state networks including the speech and the visual network revealed no significant differences in functional connectivity related to handedness. In conclusion, our data revealed an intrinsically higher functional connectivity in right-handers. These results may help to explain that hand preference is more lateralized in right-handers than in left-handers. Furthermore, enhanced functional connectivity between left M1 and right PMd may serve as an individual marker of handedness. PMID:25613438

Prism adaptation in alternately exposed hands.

PubMed

Redding, Gordon M; Wallace, Benjamin

2013-08-01

We assessed intermanual transfer of the proprioceptive realignment aftereffects of prism adaptation in right-handers by examining alternate target pointing with the two hands for 40 successive trials, 20 with each hand. Adaptation for the right hand was not different as a function of exposure sequence order or postexposure test order, in contrast with adaptation for the left hand. Adaptation was greater for the left hand when the right hand started the alternate pointing than when the sequence of target-pointing movements started with the left hand. Also, the largest left-hand adaptation appeared when that hand was tested first after exposure. Terminal error during exposure varied in cycles for the two hands, converging on zero when the right hand led, but no difference appeared between the two hands when the left hand led. These results suggest that transfer of proprioceptive realignment occurs from the right to the left hand during both exposure and postexposure testing. Such transfer reflects the process of maintaining spatial alignment between the two hands. Normally, the left hand appears to be calibrated with the right-hand spatial map, and when the two hands are misaligned, the left-hand spatial map is realigned with the right-hand spatial map.

[Cerebral dominance. A study on left-handedness in a Mexican population group].

PubMed

Silva-Rodríguez, A; Escobar-Izquierdo, A

1996-01-01

The term "cerebral dominance" suggests that one hemisphere is leader and the other subordinate; however, cerebral dominance concerning all psychic functions is less frequent than we could suppose. Among the functions in which cerebral dominance is manifested the most notorious is the manual preference. Thus according to the hand being used for general motor activities the persons are named right-handers or left-handers; nevertheless people are less lateralized than we could suppose, and most right-handers may have hidden left-handedness. In order to obtain some data on this subject in Mexican population, a study was done in 300 university students. Of the 275 right-handers only 144 fulfilled the requirements to qualify as such after performing the complementary tests; 25 left-handers came to a mere amount of 5. The data indicate that partial lateralization is more frequent than total lateralization.

Pilot Study: The Role of the Hemispheric Lateralization in Mental Disorders by Use of the Limb (Eye, Hand, Foot) Dominance

PubMed Central

Goodarzi, Naser; Dabbaghi, Parviz; Valipour, Habib; Vafadari, Behnam

2015-01-01

Introduction: Based on the previous studies, we know that the hemispheric lateralization defects, increase the probability of psychological disorders. We also know that dominant limb is controlled by dominant hemisphere and limb preference is used as an indicator for hemisphere dominance. In this study we attempted to explore the hemispheric dominance by the use of three limbs (hand, foot and eye). Methods: We performed this survey on two samples, psychiatric patients compared with normal population. For this purpose, knowing that the organ dominance is stabilized in adolescence, and age has no effect on the people above 15, we used 48 high school girls and 65 boys as the final samples of normal population. The patient group included 57 male and 26 female who were chronic psychiatric patients. Results: The result shows that left-eye dominance is more in patients than the normal group (P=0.000) but the handedness and footedness differences are not significance. In psychotic, bipolar and depressive disorders, eye dominance had significant difference (P=0.018). But this is not true about hand and foot dominance. Discussion: Our findings proved that generally in psychiatric patients, left-eye dominance is more common, left-eye dominance is also more in psychotic and depressive disorders. It is less common in bipolar disorders. PMID:27307954

Left-handed skeletally mature baseball players have smaller humeral retroversion in the throwing arm than right-handed players.

PubMed

Takenaga, Tetsuya; Goto, Hideyuki; Sugimoto, Katsumasa; Tsuchiya, Atsushi; Fukuyoshi, Masaki; Nakagawa, Hiroki; Nozaki, Masahiro; Takeuchi, Satoshi; Otsuka, Takanobu

2017-12-01

It is known that the humeral retroversion of baseball players is greater in the throwing arm than in the nonthrowing arm. An investigation measuring dry bone specimens also showed that the right humerus had greater retroversion than the left. Considering these facts, it was hypothesized that humeral retroversion would differ between right- and left-handed players. This study aimed to compare the bilateral humeral retroversion between right- and left-handed skeletally mature baseball players. We investigated 260 (196 right-handed and 64 left-handed) male baseball players who belonged to a college or amateur team. Bilateral humeral retroversion was assessed using an ultrasound-assisted technique (humeral torsion angle [HTA]) as described by previous studies. Analysis of covariance, adjusted for handedness and baseball position, assessed the effect of throwing arm dominance on HTA. In comparison of the throwing arm, HTA was significantly smaller in left-handed (left humerus) than in right-handed (right humerus) players (77° vs. 81°; P < .001). In comparison of the nonthrowing arm, HTA was significantly greater in left-handed (right humerus) than in right-handed (left humerus) players (73° vs. 69°; P < .001). The mean side-to-side difference of HTA was significantly smaller in left-handed than in right-handed players (3° vs. 12°; P < .001). Humeral retroversion of left-handed skeletally mature baseball players was significantly smaller in the throwing arm, greater in the nonthrowing arm, and smaller in side-to-side differences than that of right-handed players. These findings may be key to understanding some of the biomechanical differences between right- and left-handed baseball players. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Left-hand dominance in children: Prevalence and maternal stereotypes in a South-east Nigerian city.

PubMed

Uwaezuoke, Samuel N; Eke, Christopher B; Nwobi, Emmanuel A

2015-01-01

The objectives of the study are to estimate the prevalence of left-hand dominance among children of selected mothers in an urban city and to determine the mothers' stereotypes about left-handedness. A cross-sectional study of mothers (N = 222) selected by systematic random sampling was done. The mothers were interviewed with structured questionnaires. Data were analyzed with appropriate descriptive statistics on SPSS. The estimated prevalence of left-hand dominance in their children was 7.52%. A left-handed mother was more likely to have a left-handed child. A substantial number of the mothers held negative stereotypes about left-hand dominance and showed a good knowledge about other types of handedness with a significant difference in the responses between right-handers and left-handers. The prevalence of left-hand dominance in their children supports previous reports which show that left-handedness usually occurs in less than 10% of the population. The mothers' negative stereotypes signify the likelihood of stigmatizing the children with this hand dominance.

The Impact of Handedness, Sex, and Cognitive Abilities on Left–Right Discrimination: A Behavioral Study

PubMed Central

Constant, Martin; Mellet, Emmanuel

2018-01-01

The present study examined the relationship between left–right discrimination (LRD) performance and handedness, sex and cognitive abilities. In total, 31 men and 35 women – with a balanced ratio of left-and right-handers – completed the Bergen Left–Right Discrimination Test. We found an advantage of left-handers in both identifying left hands and in verifying “left” propositions. A sex effect was also found, as women had an overall higher error rate than men, and increasing difficulty impacted their reaction time more than it did for men. Moreover, sex interacted with handedness and manual preference strength. A negative correlation of LRD reaction time with visuo-spatial and verbal long-term memory was found independently of sex, providing new insights into the relationship between cognitive skills and performance on LRD. PMID:29636718

Single-molecule study of DNA unlinking by eukaryotic and prokaryotic type-II topoisomerases

PubMed Central

Charvin, G.; Bensimon, D.; Croquette, V.

2003-01-01

Type-II topoisomerases are responsible for untangling DNA during replication by removing supercoiled and interlinked DNA structures. Using a single-molecule micromanipulation setup, we follow the real-time decatenation of two mechanically braided DNA molecules by Drosophila melanogaster topoisomerase (Topo) II and Escherichia coli Topo IV. Although Topo II relaxes left-handed (L) and right-handed (R-) braids similarly at a rate of ≈2.9 s–1, Topo IV has a marked preference for L-braids, which it relaxes completely and processively at a rate of ≈2.4 s–1. However, Topo IV can unlink R-braids at about half that rate when they supercoil to form L-plectonemes. These results imply that the preferred substrate for unlinking by Topo IV has the symmetry of an L-crossing and shed new light on the decatenation of daughter strands during DNA replication, which are usually assumed to be linked in an R-braid. PMID:12902541

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.

Golf hand prosthesis performance of transradial amputees.

PubMed

Carey, Stephanie L; Wernke, Matthew M; Lura, Derek J; Kahle, Jason T; Dubey, Rajiv V; Highsmith, M Jason

2015-06-01

Typical upper limb prostheses may limit sports participation; therefore, specialized terminal devices are often needed. The purpose of this study was to evaluate the ability of transradial amputees to play golf using a specialized terminal device. Club head speed, X-factor, and elbow motion of two individuals with transradial amputations using an Eagle Golf terminal device were compared to a non-amputee during a golf swing. Measurements were collected pre/post training with various stances and grips. Both prosthesis users preferred a right-handed stance initially; however, after training, one preferred a left-handed stance. The amputees had slower club head speeds and a lower X-factor compared to the non-amputee golfer, but increased their individual elbow motion on the prosthetic side after training. Amputees enjoyed using the device, and it may provide kinematic benefits indicated by the increase in elbow flexion on the prosthetic side. The transradial amputees were able to swing a golf club with sufficient repetition, form, and velocity to play golf recreationally. Increased elbow flexion on the prosthetic side suggests a potential benefit from using the Eagle Golf terminal device. Participating in recreational sports can increase amputees' health and quality of life. © The International Society for Prosthetics and Orthotics 2014.

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.

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.

Infant Hand Preference and the Development of Cognitive Abilities

PubMed Central

Michel, George F.; Campbell, Julie M.; Marcinowski, Emily C.; Nelson, Eliza L.; Babik, Iryna

2016-01-01

Hand preference develops in the first two postnatal years with nearly half of infants exhibiting a consistent early preference for acquiring objects. Others exhibit a more variable developmental trajectory but by the end of their second postnatal year, most exhibit a consistent hand preference for role-differentiated bimanual manipulation. According to some forms of embodiment theory, these differences in hand use patterns should influence the way children interact with their environments, which, in turn, should affect the structure and function of brain development. Such early differences in brain development should result in different trajectories of psychological development. We present evidence that children with consistent early hand preferences exhibit advanced patterns of cognitive development as compared to children who develop a hand preference later. Differences in the developmental trajectory of hand preference are predictive of developmental differences in language, object management skills, and tool-use skills. As predicted by Casasanto’s body-specificity hypothesis, infants with different hand preferences proceed along different developmental pathways of cognitive functioning. PMID:27047431

Ambidexterity and magical ideation.

PubMed

Barnett, Kylie J; Corballis, Michael C

2002-01-01

In a sample of 250 healthy undergraduate students, scores on a scale of magical ideation rose to a peak at the point of ambilaterality on a scale of hand preference, and fell away with increasing right- or left-handedness. This effect mirrors that reported by Crow, Crow, Done, and Leask (1998) who found a dip in academic abilities at the point of ambilaterality, or what they call ''the point of hemispheric indecision''. We relate these findings to genetic theories of laterality in which one allele (RS+) codes for left-cerebral dominance while the other (RS-) leaves laterality to chance. RS-- homozygotes may be susceptible to a lack of dominance, resulting in a disposition to magical ideation and an increased risk of schizophrenia, but also enhanced creativity and lateral thinking.

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

Cortical Asymmetries during Hand Laterality Task Vary with Hand Laterality: A fMRI Study in 295 Participants

PubMed Central

Mellet, Emmanuel; Mazoyer, Bernard; Leroux, Gaelle; Joliot, Marc; Tzourio-Mazoyer, Nathalie

2016-01-01

The aim of this study was to characterize, using fMRI, the functional asymmetries of hand laterality task (HLT) in a sample of 295 participants balanced for handedness. During HLT, participants have to decide whether the displayed picture of a hand represent a right or a left hand. Pictures of hands’ back view were presented for 150 ms in the right or left hemifield. At the whole hemisphere level, we evidenced that the laterality of the hand and of the hemifield in which the picture was displayed combined their effects on the hemispheric asymmetry in an additive way. We then identified a set of 17 functional homotopic regions of interest (hROIs) including premotor, motor, somatosensory and parietal regions, whose activity and asymmetry varied with the laterality of the presented hands. When the laterality of a right hand had to be evaluated, these areas showed stronger leftward asymmetry, the hROI located in the primary motor area showing a significant larger effect than all other hROIs. In addition a subset of six parietal regions involved in visuo-motor integration together with two postcentral areas showed a variation in asymmetry with hemifield of presentation. Finally, while handedness had no effect at the hemispheric level, two regions located in the parietal operculum and intraparietal sulcus exhibited larger leftward asymmetry with right handedness independently of the hand of presentation. The present results extend those of previous works in showing a shift of asymmetries during HLT according to the hand presented in sensorimotor areas including primary motor cortex. This shift was not affected by manual preference. They also demonstrate that the coordination of visual information and handedness identification of hands relied on the coexistence of contralateral motor and visual representations in the superior parietal lobe and the postcentral gyrus. PMID:27999536

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.

Effect of Reinforcement History on Hand Choice in an Unconstrained Reaching Task

PubMed Central

Stoloff, Rebecca H.; Taylor, Jordan A.; Xu, Jing; Ridderikhoff, Arne; Ivry, Richard B.

2011-01-01

Choosing which hand to use for an action is one of the most frequent decisions people make in everyday behavior. We developed a simple reaching task in which we vary the lateral position of a target and the participant is free to reach to it with either the right or left hand. While people exhibit a strong preference to use the hand ipsilateral to the target, there is a region of uncertainty within which hand choice varies across trials. We manipulated the reinforcement rates for the two hands, either by increasing the likelihood that a reach with the non-dominant hand would successfully intersect the target or decreasing the likelihood that a reach with the dominant hand would be successful. While participants had minimal awareness of these manipulations, we observed an increase in the use of the non-dominant hand for targets presented in the region of uncertainty. We modeled the shift in hand use using a Q-learning model of reinforcement learning. The results provided a good fit of the data and indicate that the effects of increasing and decreasing the rate of positive reinforcement are additive. These experiments emphasize the role of decision processes for effector selection, and may point to a novel approach for physical rehabilitation based on intrinsic reinforcement. PMID:21472031

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.

Behavioral Lateralization and Optimal Route Choice in Flying Budgerigars

PubMed Central

Bhagavatula, Partha S.; Claudianos, Charles; Ibbotson, Michael R.; Srinivasan, Mandyam V.

2014-01-01

Birds flying through a cluttered environment require the ability to choose routes that will take them through the environment safely and quickly. We have investigated some of the strategies by which they achieve this. We trained budgerigars to fly through a tunnel in which they encountered a barrier that offered two passages, positioned side by side, at the halfway point. When one of the passages was substantially wider than the other, the birds tended to fly through the wider passage to continue their transit to the end of the tunnel, regardless of whether this passage was on the right or the left. Evidently, the birds were selecting the safest and quickest route. However, when the two passages were of equal or nearly equal width, some individuals consistently preferred the left-hand passage, while others consistently preferred the passage on the right. Thus, the birds displayed idiosyncratic biases when choosing between alternative routes. Surprisingly - and unlike most of the instances in which behavioral lateralization has previously been discovered - the bias was found to vary from individual to individual, in its direction as well as its magnitude. This is very different from handedness in humans, where the majority of humans are right-handed, giving rise to a so-called ‘population’ bias. Our experimental results and mathematical model of this behavior suggest that individually varying lateralization, working in concert with a tendency to choose the wider aperture, can expedite the passage of a flock of birds through a cluttered environment. PMID:24603285

Factoring handedness data: I. Item analysis.

PubMed

Messinger, H B; Messinger, M I

1995-12-01

Recently in this journal Peters and Murphy challenged the validity of factor analyses done on bimodal handedness data, suggesting instead that right- and left-handers be studied separately. But bimodality may be avoidable if attention is paid to Oldfield's questionnaire format and instructions for the subjects. Two characteristics appear crucial: a two-column LEFT-RIGHT format for the body of the instrument and what we call Oldfield's Admonition: not to indicate strong preference for handedness item, such as write, unless "... the preference is so strong that you would never try to use the other hand unless absolutely forced to...". Attaining unimodality of an item distribution would seem to overcome the objections of Peters and Murphy. In a 1984 survey in Boston we used Oldfield's ten-item questionnaire exactly as published. This produced unimodal item distributions. With reflection of the five-point item scale and a logarithmic transformation, we achieved a degree of normalization for the items. Two surveys elsewhere based on Oldfield's 20-item list but with changes in the questionnaire format and the instructions, yielded markedly different item distributions with peaks at each extreme and sometimes in the middle as well.

The southpaw advantage? Lateral preference in mixed martial arts.

PubMed

Baker, Joseph; Schorer, Jörg

2013-01-01

Performers with a left-orientation have a greater likelihood of obtaining elite levels of performance in many interactive sports. This study examined whether combat stance orientation was related to skill and success in Mixed Martial Arts fighters. Data were extracted for 1468 mixed martial artists from a reliable and valid online data source. Measures included fighting stance, win percentage and an ordinal measure of skill based on number of fights. The overall analysis revealed that the fraction of fighters using a southpaw stance was greater than the fraction of left-handers in the general population, but the relationship between stance and hand-preference is not well-understood. Furthermore, t-tests found no statistically significant relationship between laterality and winning percentage, although there was a significant difference between stances for number of fights. Southpaw fighters had a greater number of fights than those using an orthodox stance. These results contribute to an expanding database on the influence of laterality on sport performance and a relatively limited database on variables associated with success in mixed martial arts.

Dynamic stimuli: accentuating aesthetic preference biases.

PubMed

Friedrich, Trista E; Harms, Victoria L; Elias, Lorin J

2014-01-01

Despite humans' preference for symmetry, artwork often portrays asymmetrical characteristics that influence the viewer's aesthetic preference for the image. When presented with asymmetrical images, aesthetic preference is often given to images whose content flows from left-to-right and whose mass is located on the right of the image. Cerebral lateralization has been suggested to account for the left-to-right directionality bias; however, the influence of cultural factors, such as scanning habits, on aesthetic preference biases is debated. The current research investigates aesthetic preference for mobile objects and landscapes, as previous research has found contrasting preference for the two image types. Additionally, the current experiment examines the effects of dynamic movement on directionality preference to test the assumption that static images are perceived as aesthetically equivalent to dynamic images. After viewing mirror-imaged pairs of pictures and videos, right-to-left readers failed to show a preference bias, whereas left-to-right readers preferred stimuli with left-to-right directionality regardless of the location of the mass. The directionality bias in both reading groups was accentuated by the videos, but the bias was significantly stronger in left-to-right readers. The findings suggest that scanning habits moderate the leftward bias resulting from hemispheric specialization and that dynamic stimuli further fluent visual processing.

[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

Distribution of paw preference in mongrel and tortoise-shell cats and the relation of hemispheric weight to paw preference: sexual dimorphism in paw use and its relation to hemispheric weight.

PubMed

Tan, U

1993-06-01

The distribution of the right minus left (R - L) paw use and its relation to hemispheric weight was studied in tortoise-shell cats. Paw preference was assessed by a food reaching test. All males (N = 9) were left-preferent; females (N = 13) were predominantly right-preferent. There was an inverse relationship between the degree of left-paw preference and the right-brain weight in males (no correlation with left-brain weight). In females, the R - L paw use showed a negative linear correlation with the right- and left-brain weights: the right-pawedness decreased and the left-pawedness increased as the right- and left-brain weights increased. The distributions of the R - L paw use as well as the relationships between brain-weight and pawedness exhibited sexual dimorphism. The results suggest that mainly the genetic and hormonal factors may play an important role in emergence of motor asymmetry in cats. Annett's right shift theory of handedness was also discussed in light of these results.

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.

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.

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…

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.

Impulsive artistic creativity as a presentation of transient cognitive alterations.

PubMed

Finkelstein, Y; Vardi, J; Hod, I

1991-01-01

A 27-year-old right-handed male mosaic artisan who had not shown any interest in drawing or artistic activity was admitted to the Department of Neurology for attacks of bizarre behavior and convulsive disorder. The patient reported feeling "waves" engulfing him during the attacks, leaving him floating helplessly. During some attacks, the patient impulsively initiated drawing activity. Interictal sleep-deprivation EEG showed a left frontotemporal focus of paroxysmal discharge. Brain tomography with SPECT showed low 99Tc-HMPAO uptake in the left frontoparietal region. Psychodiagnostic tests gave evidence of dysfunction of the left frontal region, with preference of the right hemisphere. It is suggested that the attacks of altered cognitive state were, in this case, provoked by spreading depression of the left hemisphere, while the integrative functions of the right hemisphere remained intact. Thus, the impulsive artistic creativity during the attacks may represent a "release phenomenon" of the complex visuospatial skills of the right (subdominant) hemisphere. This symptomatology of transient cognitive alterations is unique and, to the best of our knowledge, has not been previously reported.

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.

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

Grasping with the eyes of your hands: hapsis and vision modulate hand preference.

PubMed

Stone, Kayla D; Gonzalez, Claudia L R

2014-02-01

Right-hand preference has been demonstrated for visually guided reaching and grasping. Grasping, however, requires the integration of both visual and haptic cues. To what extent does vision influence hand preference for grasping? Is there a hand preference for haptically guided grasping? Two experiments were designed to address these questions. In Experiment 1, individuals were tested in a reaching-to-grasp task with vision (sighted condition) and with hapsis (blindfolded condition). Participants were asked to put together 3D models using building blocks scattered on a tabletop. The models were simple, composed of ten blocks of three different shapes. Starting condition (Vision-First or Hapsis-First) was counterbalanced among participants. Right-hand preference was greater in visually guided grasping but only in the Vision-First group. Participants who initially built the models while blindfolded (Hapsis-First group) used their right hand significantly less for the visually guided portion of the task. To investigate whether grasping using hapsis modifies subsequent hand preference, participants received an additional haptic experience in a follow-up experiment. While blindfolded, participants manipulated the blocks in a container for 5 min prior to the task. This additional experience did not affect right-hand use on visually guided grasping but had a robust effect on haptically guided grasping. Together, the results demonstrate first that hand preference for grasping is influenced by both vision and hapsis, and second, they highlight how flexible this preference could be when modulated by hapsis.

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.

Is strength of handedness reliable over repeated testing? An examination of typical development and autism spectrum disorder

PubMed Central

Scharoun, Sara M.; Bryden, Pamela J.

2015-01-01

Despite a lack of agreement concerning the age at which adult-like patterns of handedness emerge, it is generally understood that hand preference presents early in life and development is variable. Young children (ages 3–5 years) are described as having weak hand preference; however, older children (ages 7–10 years) display stronger patterns. Here, strength of hand preference refers to reliable use of the preferred hand. In comparison to their typically developing (TD) peers, individuals with autism spectrum disorder (ASD) are described as having a weak hand preference. This study aimed to extend the literature to assess three measures of handedness (Waterloo Handedness Questionnaire – WHQ, Annett pegboard – AP, and WatHand Cabinet Test – WHCT) in two repeated sessions. The first research question aimed to delineate if the strength of hand use changes across testing sessions as a function of age in typical development. Right-handed children reported a reliable preference for the right hand on the WHQ, similar to adults. A marginally significant difference was revealed between 3- to 4- and 5- to 6-year-olds on the AP. This was attributed to weak lateralization in 3- to 4-year-olds, where the establishment of hand preference by age 6 leads to superior performance with the preferred hand in 5- to 6-year-olds. Finally, for the WHCT, 3- to 4-year-olds had the highest bimanual score, indicating use of the same hand to lift the cabinet door and retrieve an object. It is likely that the task was not motorically complex enough to drive preferred hand selection for older participants. The second research question sought to determine if there is difference between (TD) children and children with ASD. No differences were revealed; however, children with ASD did display variable AP performance, providing partial support for previous literature. Findings will be discussed in light of relevant literature. PMID:25691875

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

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.

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)

Individual differences in hemispheric preference and emotion regulation difficulties

PubMed Central

Gupta, Garima; Dubey, Akanksha; Saxena, Prachi; Pandey, Rakesh

2011-01-01

Background: Hemisphericity or individual difference in the preference to use the left or the right hemispheric mode of information processing has been associated with various emotion-related differences. For example, the right hemisphericity has been linked with inhibition of emotional expression, feeling of tension, greater impulsivity etc. These observations suggest that right hemisphericity may be associated with greater difficulties in regulating emotions. However, direct empirical tests of such theoretical proposition are very thin. Aim: In view of this, the present study aims to investigate how and to what extent individual difference in hemispheric preference relate to emotion regulation. Materials and Methods: Thirty-two right-handed male subjects in the age range 18 to 20 years were assessed on self-report measures of hemispheric preference and emotion regulation difficulties. The correlation between dimensions of hemispheric preference and difficulties in regulating emotions was computed. A series of stepwise multiple regression analyses were also done to explore the relative significance of various dimensions of hemispheric preference in predicting emotion regulation difficulties. Results: The findings revealed that in general a preference for the right hemispheric mode of information processing was associated with greater emotion regulation difficulties. The correlation analysis indicated that while impulse control difficulties and difficulties in engaging goal directed behavior was associated with preference for almost all the right hemispheric mode of information processing, the nonacceptance of emotional responses and limited access to emotion regulation was related to preference for only global/synthetic (a right hemispheric) mode of information processing. Similarly, the lack of emotional clarity facet of emotion regulation difficulties correlated significantly with a preference for the emotional mode of information processing (again a right hemispheric mode). The results of stepwise multiple regression analyses, however, indicated that “nonacceptance of emotional responses’ and ‘limited access to emotion regulation strategies” facets of emotion regulation difficulties were best predicted by a preference for the global/synthetic mode of information processing. While others like difficulties engaging in goal-directed behaviour, impulse control difficulties, and lack of emotional clarity were best predicted by a preference for visuo-spatial rather than the verbal mode of information processing. Conclusion: Overall, the findings imply that greater preference for right hemispheric mode of information processing as compared to the left is associated with greater difficulties in regulating emotions. PMID:22969178

An Amino Acid Code to Define a Protein’s Tertiary Packing Surface

PubMed Central

Fraga, Keith J.; Joo, Hyun; Tsai, Jerry

2015-01-01

One difficult aspect of the protein-folding problem is characterizing the non-specific interactions that define packing in protein tertiary structure. To better understand tertiary structure, this work extends the knob-socket model by classifying the interactions of a single knob residue packed into a set of contiguous sockets, or a pocket made up of 4 or more residues. The knob-socket construct allows for a symbolic two-dimensional mapping of pockets. The two-dimensional mapping of pockets provides a simple method to investigate the variety of pocket shapes in order to understand the geometry of protein tertiary surfaces. The diversity of pocket geometries can be organized into groups of pockets that share a common core, which suggests that some interactions in pockets are ancillary to packing. Further analysis of pocket geometries displays a preferred configuration that is right-handed in α-helices and left-handed in β-sheets. The amino acid composition of pockets illustrates the importance of non-polar amino acids in packing as well as position specificity. As expected, all pocket shapes prefer to pack with hydrophobic knobs; however, knobs are not selective for the pockets they pack. Investigating side-chain rotamer preferences for certain pocket shapes uncovers no strong correlations. These findings allow a simple vocabulary based on knobs and sockets to describe protein tertiary packing that supports improved analysis, design and prediction of protein structure. PMID:26575337

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.

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.

Hand preference patterns in expert basketball players: interrelations between basketball-specific and everyday life behavior.

PubMed

Stöckel, Tino; Vater, Christian

2014-12-01

In the present study we examined the interrelation of everyday life handedness and hand preference in basketball, as an area of expertise that requires individuals being proficient with both their non-dominant and dominant hand. A secondary aim was to elucidate the link between basketball-specific practice, hand preference in basketball and everyday life handedness. Therefore, 176 expert basketball players self-reported their hand preference for activities of daily living and for basketball-specific behavior as well as details about their basketball-specific history via questionnaire. We found that compared to the general population the one-hand bias was significantly reduced for both everyday life and basketball-specific hand preference (i.e., a higher prevalence of mixed-handed individuals), and that both concepts were significantly related. Moreover, only preference scores for lay-up and dribbling skills were significantly related to measures of basketball-specific practice. Consequently, training-induced modulations of lateral preference seem to be very specific to only a few basketball-specific skills, and do not generalize to other skills within the domain of basketball nor do they extend into everyday life handedness. The results are discussed in terms of their relevance regarding theories of handedness and their practical implications for the sport of basketball. Copyright © 2014 Elsevier B.V. All rights reserved.

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

Strength of hand preference and dual task performance by common marmosets.

PubMed

Piddington, T; Rogers, L J

2013-01-01

Study of avian and piscine species has shown that animals with stronger lateralization of the brain are able to perform two tasks presented simultaneously better than can animals with weaker lateralization. We investigated whether this might apply also to primates by testing common marmosets to see whether there is a relationship between the strength of hand preference, as an indicator of strength of brain lateralization, and the ability to carry out two tasks simultaneously. A model predator was introduced into the testing room while the marmoset was foraging. Marmosets with stronger hand preferences detected the 'predator' after shorter latency than those with weaker hand preferences. Furthermore, the marmosets with stronger hand preferences produced more mobbing (tsik) vocalizations when they reacted to the predators than did those with weaker hand preferences. There was no such association between hand preference and either latency to respond to the predator or mobbing reaction when the marmosets were not foraging at the time the predator was introduced. Hence, strength of lateralization is associated with the ability to perform foraging and predator detection simultaneously. These results are discussed with reference to the evolution of brain lateralization.

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

...,” “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...

More than 500,000 years of right-handedness in Europe.

PubMed

Frayer, David W; Lozano, Marina; Bermúdez de Castro, José M; Carbonell, Eudald; Arsuaga, Juan Luis; Radovčić, Jakov; Fiore, Ivana; Bondioli, Luca

2012-01-01

Considerable research supports the high frequency of right-handedness in living Homo sapiens, with worldwide rates of approximately nine right- for every one left-hander. Right-handedness appears to be a uniquely human trait, as no other primate species, no matter how proficient in tool use, shows frequencies even close to the strong right bias typical of humans (Cashmore, Uomini, & Chapelain, 2008; McGrew & Marchant 1997; Steele & Uomini, 2009). Here we review our research on human fossils from Sima de los Huesos (Atapuerca, Spain) and their likely descendants, the European Neandertals. We document hand preference in fossils by scratch patterns that occur on the labial (lip) face of incisors and canines, and contend that these patterns provide a reliable means for identifying predominant hand use in these samples. Manipulatory marks on the anterior teeth show a persistent pattern of right-handed actions, implying that the modern human pattern of dominant right-handedness extends deep into the European past.

Crossed aphasia following cerebral infarction in a right-handed patient with atypical cerebral language dominance.

PubMed

Tan, Xiaoping; Guo, Yang; Dun, Saihong; Sun, Hongzan

2018-05-18

Crossed aphasia (CA), usually referred to as an acquired language disturbance, is caused by a lesion in the cerebral hemisphere ipsilateral to the dominant hand, and the exact mechanism is not clear. The development of handedness is influenced by education and training and the impact of habitualization, while language is more susceptible to the impact of speech habits, and it is not absolutely accurate to judge cerebral language dominance by the degree of hand preference. We describe a case of CA after right hemispheric stroke in a right-handed patient with atypical language dominance and attempt to analyze the mechanism of CA based on functional imaging methods, including arterial spin labeling (ASL) and positron emission tomography/magnetic resonance imaging (PET-MRI). Brain MRI at 24 h after admission showed a large cerebral infarction in the right cerebral hemisphere, including the posteroinferior part of Broca's area in the right frontal lobe, the right temporal lobe, and the right occipital lobe. The patient exhibited a non-fluent aphasia on a standard language test (the Aphasia Battery of Chinese [ABC]) performed on the 7th day after onset. Thus, atypical language dominance was suspected. One week after admission, ASL imaging showed high perfusion in the infarct core zone and low perfusion in the left cerebellar hemisphere. Two months later, PET/MRI demonstrated low metabolism in the posterior frontal lobe, temporal lobe, temporal occipital junction area, and the right basal ganglia. The findings suggest that the patient has right-sided cerebral language dominance, or that both hemispheres have linguistic functions. Not all patients show linguistic capabilities on the side opposite hand preference. The language dominance should be predicted by a combination of clinical manifestations and functional imaging techniques.

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.

A Combined fMRI and DTI Examination of Functional Language Lateralization and Arcuate Fasciculus Structure: Effects of Degree versus Direction of Hand Preference

ERIC Educational Resources Information Center

Propper, Ruthe E.; O'Donnell, Lauren J.; Whalen, Stephen; Tie, Yanmei; Norton, Isaiah H.; Suarez, Ralph O.; Zollei, Lilla; Radmanesh, Alireza; Golby, Alexandra J.

2010-01-01

The present study examined the relationship between hand preference degree and direction, functional language lateralization in Broca's and Wernicke's areas, and structural measures of the arcuate fasciculus. Results revealed an effect of degree of hand preference on arcuate fasciculus structure, such that consistently-handed individuals,…

[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.

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.

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…

Hand preferences in two unimanual and two bimanual coordinated tasks in the black-handed spider monkey (Ateles geoffroyi).

PubMed

Motes Rodrigo, Alba; Ramirez Torres, Carlos Eduardo; Hernandez Salazar, Laura Teresa; Laska, Matthias

2018-05-01

Spider monkeys are interesting to study with regard to hand preferences, as they are one of the few primate species that lack a thumb and, thus, are unable to perform a precision grip. Further, being platyrrhine primates, they also largely lack independent motor control of the digits and, thus, have only limited manual dexterity. It was therefore the aim of the present study to assess hand preferences in black-handed spider monkeys ( Ateles geoffroyi ) in 4 tasks differing in task demand: simple unimanual reaching for food and 3 versions of the widely used tube task, including 2 bimanual versions that differ from each other in the degree of fine motor control needed and a unimanual version that does not require coordinated action of the hands. We found that black-handed spider monkeys display significant hand preferences at the individual, but not at the population, level. This was true both in the 2 bimanual coordinated tasks and in the 2 unimanual tasks. Further, our results show that the majority of animals were consistent in the hand they preferred in these 4 tasks. Our findings only partially support the notion that task demand positively correlates with strength of hand preference. Finally, we found that the index finger was the most frequently used digit in all 3 tube tasks, although the animals also used other digits and 2- and 3-finger combinations to extract food from a tube. We conclude that limited manual dexterity does not prevent spider monkeys from displaying strong and consistent hand preferences at the individual level. (PsycINFO Database Record (c) 2018 APA, 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.

Manual lateralization in macaques: handedness, target laterality and task complexity.

PubMed

Regaiolli, Barbara; Spiezio, Caterina; Vallortigara, Giorgio

2016-01-01

Non-human primates represent models to understand the evolution of handedness in humans. Despite several researches have been investigating non-human primates handedness, few studies examined the relationship between target position, hand preference and task complexity. This study aimed at investigating macaque handedness in relation to target laterality and tastiness, as well as task complexity. Seven pig-tailed macaques (Macaca nemestrina) were involved in three different "two alternative choice" tests: one low-level task and two high-level tasks (HLTs). During the first and the third tests macaques could select a preferred food and a non-preferred food, whereas by modifying the design of the second test, macaques were presented with no-difference alternative per trial. Furthermore, a simple-reaching test was administered to assess hand preference in a social context. Macaques showed hand preference at individual level both in simple and complex tasks, but not in the simple-reaching test. Moreover, target position seemed to affect hand preference in retrieving an object in the low-level task, but not in the HLT. Additionally, individual hand preference seemed to be affected from the tastiness of the item to be retrieved. The results suggest that both target laterality and individual motivation might influence hand preference of macaques, especially in simple tasks.

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.

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.

Grip force coordination during bimanual tasks in unilateral cerebral palsy.

PubMed

Islam, Mominul; Gordon, Andrew M; Sköld, Annika; Forssberg, Hans; Eliasson, Ann-Christin

2011-10-01

The aim of the study was to investigate coordination of fingertip forces during an asymmetrical bimanual task in children with unilateral cerebral palsy (CP). Twelve participants (six males, six females; mean age 14y 4mo, SD 3.3y; range 9-20y;) with unilateral CP (eight right-sided, four left-sided) and 15 age-matched typically developing participants (five males, 10 females; mean age 14y 3mo, SD 2.9y; range 9-18y,) were included. Participants were instructed to hold custom-made grip devices in each hand and place one device on top of the other. The grip force and load force were recorded simultaneously in both hands. Temporal coordination between the two hands was impaired in the participants with CP (compared with that in typically developing participants), that is they initiated the task by decreasing grip force in the releasing hand before increasing the force in the holding hand. The grip force increase in the holding hand was also smaller in participants with CP (involved hand/non-dominant hand releasing, p<0.001; non-involved hand/dominant hand releasing, p=0.007), indicating deficient scaling of force amplitude. The impairment was greater when participants with CP used their non-involved hand as the holding hand. Temporal coordination and scaling of fingertip forces were impaired in both hands in participants with CP. The non-involved hand was strongly affected by activity in the involved hand, which may explain why children with unilateral CP prefer to use only one hand during tasks that are typically performed with both hands. © The Authors. Developmental Medicine & Child Neurology © 2011 Mac Keith Press.

All-angle negative refraction and active flat lensing of ultraviolet light.

PubMed

Xu, Ting; Agrawal, Amit; Abashin, Maxim; Chau, Kenneth J; Lezec, Henri J

2013-05-23

Decades ago, Veselago predicted that a material with simultaneously negative electric and magnetic polarization responses would yield a 'left-handed' medium in which light propagates with opposite phase and energy velocities--a condition described by a negative refractive index. He proposed that a flat slab of left-handed material possessing an isotropic refractive index of -1 could act like an imaging lens in free space. Left-handed materials do not occur naturally, and it has only recently become possible to achieve a left-handed response using metamaterials, that is, electromagnetic structures engineered on subwavelength scales to elicit tailored polarization responses. So far, left-handed responses have typically been implemented using resonant metamaterials composed of periodic arrays of unit cells containing inductive-capacitive resonators and conductive wires. Negative refractive indices that are isotropic in two or three dimensions at microwave frequencies have been achieved in resonant metamaterials with centimetre-scale features. Scaling the left-handed response to higher frequencies, such as infrared or visible, has been done by shrinking critical dimensions to submicrometre scales by means of top-down nanofabrication. This miniaturization has, however, so far been achieved at the cost of reduced unit-cell symmetry, yielding a refractive index that is negative along only one axis. Moreover, lithographic scaling limits have so far precluded the fabrication of resonant metamaterials with left-handed responses at frequencies beyond the visible. Here we report the experimental implementation of a bulk metamaterial with a left-handed response to ultraviolet light. The structure, based on stacked plasmonic waveguides, yields an omnidirectional left-handed response for transverse magnetic polarization characterized by a negative refractive index. By engineering the structure to have a refractive index close to -1 over a broad angular range, we achieve Veselago flat lensing, in free space, of arbitrarily shaped, two-dimensional objects beyond the near field. We further demonstrate active, all-optical modulation of the image transferred by the flat lens.

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.

Internet design preferences of patients with cancer.

PubMed

Chernecky, Cynthia; Macklin, Denise; Walter, Jennifer

2006-07-01

To describe computer experience and preferences for multimedia design. Prospective, descriptive. Physician office and outpatient cancer centers in an urban area in the southeastern United States. Convenience sample of 22 volunteer patients with cancer from four racial groups. A questionnaire on computer experiences was followed by a hands-on computer session with questions regarding preferences for seven interface items. Data termination occurred when sample size was obtained. Design of Internet education site for patients. Variables include preferences, computer, cancer, multimedia, and education. Eighty-two percent had personal computers, 41% used a computer daily, and 95% believed that computers would be a good avenue for learning about cancer care. Preferences included display colors in blue and green hues; colored buttons; easy-to-read text; graphics with a simple design and large, clear pictures; serif font in dark type; light-colored background; and larger photo size in a rectangle shape. Most popular graphic icons as metaphors were 911 for emergency, picture of skull and crossbones for danger, and a picture of a string on an index finger representing reminder. The simple layout most preferred for appearances was one that included text and pictures, read from left to right, and was symmetrical in its placement of pictures and text on the page. Preferences are necessary to maintain interest and support navigation through computer designs to enhance the translation of knowledge to patients. Development of multimedia based on patient preferences will enhance education, learning, and, ultimately, quality patient care.

Weak hand preference in children with down syndrome is associated with language deficits.

PubMed

Groen, M A; Yasin, I; Laws, G; Barry, J G; Bishop, D V M

2008-04-01

This study explores associations between language ability and hand preference in children with Down syndrome. Compared to typically developing children of the same age, children with Down syndrome showed weaker hand preference, were less consistent in the hand they used and also less willing to reach to extreme positions in contralateral space. Within the group of children with Down syndrome, those who showed a stronger or more consistent hand preference had better language and memory skills. This association could not be explained by differences in non-verbal cognitive ability or hearing loss. These findings are discussed within the theory of neurolinguistic development proposed by Locke [Locke (1997). Brain & Language, 58, 265-326].

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.

Etiological aspect of left-handedness in adolescents.

PubMed

Dragović, Milan; Milenković, Sanja; Kocijancić, Dusica; Zlatko, Sram

2013-01-01

Lateralization of brain functions such as language and manual dominance (hand preferences and fine motor control) are most likely under genetic control. However, this does not preclude the effect of various environmental factors on functional brain lateralization. A strong association of non-right-handedness (left- and mixed-handedness) with various neurodevelopmental conditions (e.g. schizophrenia, autism, Rett syndrome) implies that in some cases, non-right-handedness may be acquired rather than inherited (i.e., pathologically determined). The aim of the study was: (a) re-investigation of several known risk factors for left-handedness (age of mother and/or father, twin pregnancies, and birth order), and (b) examination of hitherto uninvestigated factors (type of birth, Apgar score, maternal smoking during pregnancy). Putative, causative environmental agents for this shift in manual distributions are explored in a sample of 1031 high school students (404 males and 627 females) from Belgrade. Both pre-existing (age of parents, twin pregnancy, and birth order) and new (Apgar score, maternal smoking, type of birth) putative agents are examined. We found that maternal smoking and low Apgar score (2-6) can significantly increase risk for left-handedness (p=0.046 and p=0.042, respectively).The remaining factors showed no significant association with left-handedness in adolescents. Our study clearly demonstrates that left-handedness may be related to maternal smoking during pregnancy and a low Apgar score on birth.

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.

Inexact nonlinear improved fuzzy chance-constrained programming model for irrigation water management under uncertainty

NASA Astrophysics Data System (ADS)

Zhang, Chenglong; Zhang, Fan; Guo, Shanshan; Liu, Xiao; Guo, Ping

2018-01-01

An inexact nonlinear mλ-measure fuzzy chance-constrained programming (INMFCCP) model is developed for irrigation water allocation under uncertainty. Techniques of inexact quadratic programming (IQP), mλ-measure, and fuzzy chance-constrained programming (FCCP) are integrated into a general optimization framework. The INMFCCP model can deal with not only nonlinearities in the objective function, but also uncertainties presented as discrete intervals in the objective function, variables and left-hand side constraints and fuzziness in the right-hand side constraints. Moreover, this model improves upon the conventional fuzzy chance-constrained programming by introducing a linear combination of possibility measure and necessity measure with varying preference parameters. To demonstrate its applicability, the model is then applied to a case study in the middle reaches of Heihe River Basin, northwest China. An interval regression analysis method is used to obtain interval crop water production functions in the whole growth period under uncertainty. Therefore, more flexible solutions can be generated for optimal irrigation water allocation. The variation of results can be examined by giving different confidence levels and preference parameters. Besides, it can reflect interrelationships among system benefits, preference parameters, confidence levels and the corresponding risk levels. Comparison between interval crop water production functions and deterministic ones based on the developed INMFCCP model indicates that the former is capable of reflecting more complexities and uncertainties in practical application. These results can provide more reliable scientific basis for supporting irrigation water management in arid areas.

[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.

Contribution of the posterior parietal cortex in reaching, grasping, and using objects and tools

PubMed Central

Vingerhoets, Guy

2014-01-01

Neuropsychological and neuroimaging data suggest a differential contribution of posterior parietal regions during the different components of a transitive gesture. Reaching requires the integration of object location and body position coordinates and reaching tasks elicit bilateral activation in different foci along the intraparietal sulcus. Grasping requires a visuomotor match between the object's shape and the hand's posture. Lesion studies and neuroimaging confirm the importance of the anterior part of the intraparietal sulcus for human grasping. Reaching and grasping reveal bilateral activation that is generally more prominent on the side contralateral to the hand used or the hemifield stimulated. Purposeful behavior with objects and tools can be assessed in a variety of ways, including actual use, pantomimed use, and pure imagery of manipulation. All tasks have been shown to elicit robust activation over the left parietal cortex in neuroimaging, but lesion studies have not always confirmed these findings. Compared to pantomimed or imagined gestures, actual object and tool use typically produces activation over the left primary somatosensory region. Neuroimaging studies on pantomiming or imagery of tool use in healthy volunteers revealed neural responses in possibly separate foci in the left supramarginal gyrus. In sum, the parietal contribution of reaching and grasping of objects seems to depend on a bilateral network of intraparietal foci that appear organized along gradients of sensory and effector preferences. Dorsal and medial parietal cortex appears to contribute to the online monitoring/adjusting of the ongoing prehensile action, whereas the functional use of objects and tools seems to involve the inferior lateral parietal cortex. This functional input reveals a clear left lateralized activation pattern that may be tuned to the integration of acquired knowledge in the planning and guidance of the transitive movement. PMID:24634664

Voxel-wise grey matter asymmetry analysis in left- and right-handers.

PubMed

Ocklenburg, Sebastian; Friedrich, Patrick; Güntürkün, Onur; Genç, Erhan

2016-10-28

Handedness is thought to originate in the brain, but identifying its structural correlates in the cortex has yielded surprisingly incoherent results. One idea proclaimed by several authors is that structural grey matter asymmetries might underlie handedness. While some authors have found significant associations with handedness in different brain areas (e.g. in the central sulcus and precentral sulcus), others have failed to identify such associations. One method used by many researchers to determine structural grey matter asymmetries is voxel based morphometry (VBM). However, it has recently been suggested that the standard VBM protocol might not be ideal to assess structural grey matter asymmetries, as it establishes accurate voxel-wise correspondence across individuals but not across both hemispheres. This could potentially lead to biased and incoherent results. Recently, a new toolbox specifically geared at assessing structural asymmetries and involving accurate voxel-wise correspondence across hemispheres has been published [F. Kurth, C. Gaser, E. Luders. A 12-step user guide for analyzing voxel-wise gray matter asymmetries in statistical parametric mapping (SPM), Nat Protoc 10 (2015), 293-304]. Here, we used this new toolbox to re-assess grey matter asymmetry differences in left- vs. right-handers and linked them to quantitative measures of hand preference and hand skill. While we identified several significant left-right asymmetries in the overall sample, no difference between left- and right-handers reached significance after correction for multiple comparisons. These findings indicate that the structural brain correlates of handedness are unlikely to be rooted in macroscopic grey matter area differences that can be assessed with VBM. Future studies should focus on other potential structural correlates of handedness, e.g. structural white matter asymmetries. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Contribution of the posterior parietal cortex in reaching, grasping, and using objects and tools.

PubMed

Vingerhoets, Guy

2014-01-01

Neuropsychological and neuroimaging data suggest a differential contribution of posterior parietal regions during the different components of a transitive gesture. Reaching requires the integration of object location and body position coordinates and reaching tasks elicit bilateral activation in different foci along the intraparietal sulcus. Grasping requires a visuomotor match between the object's shape and the hand's posture. Lesion studies and neuroimaging confirm the importance of the anterior part of the intraparietal sulcus for human grasping. Reaching and grasping reveal bilateral activation that is generally more prominent on the side contralateral to the hand used or the hemifield stimulated. Purposeful behavior with objects and tools can be assessed in a variety of ways, including actual use, pantomimed use, and pure imagery of manipulation. All tasks have been shown to elicit robust activation over the left parietal cortex in neuroimaging, but lesion studies have not always confirmed these findings. Compared to pantomimed or imagined gestures, actual object and tool use typically produces activation over the left primary somatosensory region. Neuroimaging studies on pantomiming or imagery of tool use in healthy volunteers revealed neural responses in possibly separate foci in the left supramarginal gyrus. In sum, the parietal contribution of reaching and grasping of objects seems to depend on a bilateral network of intraparietal foci that appear organized along gradients of sensory and effector preferences. Dorsal and medial parietal cortex appears to contribute to the online monitoring/adjusting of the ongoing prehensile action, whereas the functional use of objects and tools seems to involve the inferior lateral parietal cortex. This functional input reveals a clear left lateralized activation pattern that may be tuned to the integration of acquired knowledge in the planning and guidance of the transitive movement.

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.

Manual asymmetry in older adults on a complex coincidence-anticipation task.

PubMed

Rodrigues, Paula Cristina Dos Santos; Silva, João Miguel Carvalho da; Barreiros, João Manuel Pardal; Vasconcelos, Maria Olga Fernandes

2018-04-20

Age-related asymmetrical functional decline was tested in a sample of 57 right-handed volunteers between 65 and 85 years of age. Participants performed a complex coincidence-anticipation (CA) task with both preferred and non-preferred hands. Results demonstrated that the proficiency of a complex CA task was similar for the 2 age groups, but different for the 2 hands. The non-preferred hand was more proficient for temporal accuracy but not for response timing, which was similar for both hands. Moreover, the lack of interaction between age and hand both in response timing and response accuracy reveal symmetric performance across ages.

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.

Differential effects of galvanic vestibular stimulation on arm position sense in right- vs. left-handers.

PubMed

Schmidt, Lena; Artinger, Frank; Stumpf, Oliver; Kerkhoff, Georg

2013-04-01

The human brain is organized asymmetrically in two hemispheres with different functional specializations. Left- and right-handers differ in many functional capacities and their anatomical representations. Right-handers often show a stronger functional lateralization than left-handers, the latter showing a more bilateral, symmetrical brain organization. Recent functional imaging evidence shows a different lateralization of the cortical vestibular system towards the side of the preferred hand in left- vs. right-handers as well. Since the vestibular system is involved in somatosensory processing and the coding of body position, vestibular stimulation should affect such capacities differentially in left- vs. right-handers. In the present, sham-stimulation-controlled study we explored this hypothesis by studying the effects of galvanic vestibular stimulation (GVS) on proprioception in both forearms in left- and right-handers. Horizontal arm position sense (APS) was measured with an opto-electronic device. Second, the polarity-specific online- and after-effects of subsensory, bipolar GVS on APS were investigated in different sessions separately for both forearms. At baseline, both groups did not differ in their unsigned errors for both arms. However, right-handers showed significant directional errors in APS of both arms towards their own body. Right-cathodal/left-anodal GVS, resulting in right vestibular cortex activation, significantly deteriorated left APS in right-handers, but had no detectable effect on APS in left-handers in either arm. These findings are compatible with a right-hemisphere dominance for vestibular functions in right-handers and a differential vestibular organization in left-handers that compensates for the disturbing effects of GVS on APS. Moreover, our results show superior arm proprioception in left-handers in both forearms. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Area- and band-specific representations of hand movements by local field potentials in caudal cingulate motor area and supplementary motor area of monkeys

PubMed Central

Yokoyama, Osamu; Nakayama, Yoshihisa

2016-01-01

The caudal cingulate motor area (CMAc) and the supplementary motor area (SMA) play important roles in movement execution. The present study examined the neural mechanisms underlying these roles by investigating local field potentials (LFPs) from these areas while monkeys pressed buttons with either their left or right hand. During hand movement, power increases in the high-gamma (80–120 Hz) and theta (3–8 Hz) bands and a power decrease in the beta (12–30 Hz) band were observed in both the CMAc and SMA. High-gamma and beta activity in the SMA predominantly represented contralateral hand movements, whereas activity in the CMAc preferentially represented movement of either hand. Theta activity in both brain regions most frequently reflected movement of either hand, but a contralateral hand bias was more evident in the SMA than in the CMAc. An analysis of the relationships of the laterality representations between the high-gamma and theta bands at each recording site revealed that, irrespective of the hand preference for the theta band, the high-gamma band in the SMA preferentially represented contralateral hand movement, whereas the high-gamma band in the CMAc represented movement of either hand. These findings suggest that the input-output relationships for ipsilateral and contralateral hand movements in the CMAc and SMA differ in terms of their functionality. The CMAc may transform the input signals representing general aspects of movement into commands to perform movements with either hand, whereas the SMA may transform the input signals into commands to perform movement with the contralateral hand. PMID:26792884

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.

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.

Consistency of hand preference: predictions to intelligence and school achievement.

PubMed

Kee, D W; Gottfried, A; Bathurst, K

1991-05-01

Gottfried and Bathurst (1983) reported that hand preference consistency measured over time during infancy and early childhood predicts intellectual precocity for females, but not for males. In the present study longitudinal assessments of children previously classified by Gottfried and Bathurst as consistent or nonconsistent in cross-time hand preference were conducted during middle childhood (ages 5 to 9). Findings show that (a) early measurement of hand preference consistency for females predicts school-age intellectual precocity, (b) the locus of the difference between consistent vs. nonconsistent females is in verbal intelligence, and (c) the precocity of the consistent females was also revealed on tests of school achievement, particularly tests of reading and mathematics.

[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

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.

Hemisphericity style and belief in ESP.

PubMed

Roig, M; Neaman, M A

1992-12-01

108 students were classified as preferring either a style of left or right hemisphericity using Zenhausern's Preference Questionnaire. The students then completed two scales designed to measure belief in extrasensory perception (ESP). Students who scored as preferring a right style scored higher on belief in ESP than those who preferred a left style. The results are consistent with previous findings which suggest a connection between right hemisphere functions (e.g., imagery) and belief in ESP.

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.

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

Is the side with the best masticatory performance selected for chewing?

PubMed

Rovira-Lastra, Bernat; Flores-Orozco, Elan Ignacio; Salsench, Juan; Peraire, Maria; Martinez-Gomis, Jordi

2014-12-01

This study assessed the degree of relationship between masticatory laterality and lateral asymmetry of masticatory performance using silicon pieces enclosed in a latex bag. Forty-two young adults with natural dentition participated in this cross-sectional, observational study. They performed four different masticatory assays, each consisting of five trials of chewing three pieces of silicon for 20 cycles. In one assay, they were asked to masticate unbagged silicon free-style, whilst in the three other assays they were asked to masticate bagged silicon free-style, unilaterally on the right-hand side and unilaterally on the left-hand side. The preferred chewing side was determined by calculating the asymmetry index for both the free-style assays. Masticatory performance was determined by sieving the silicon particles and the cycle duration was also recorded. Data were analysed using independent samples or paired t-test and linear regression. Masticatory function using the bagged silicon was similar to that using the unbagged silicon. A significant and positive relationship was observed between the preferred chewing side expressed as the asymmetry index and the side with better masticatory performance. Alternate unilateral chewers demonstrated better masticatory performance than unilateral chewers. However, when free-style and unilateral chewing were compared for each subject, unilateral chewing was found to be as efficient as - or even more efficient than - free-style chewing. There is a positive association between the preferred chewing side and the more efficient side. Alternate unilateral mastication per se does not promote better masticatory performance than consistently unilateral mastication. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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

Childrens' left-turning preference is not modulated by magical ideation.

PubMed

Streuli, Jürg C; Obrist, Gina; Brugger, Peter

2017-01-01

The literature on human turning preferences is inconsistent. While the few studies with children below 14 years of age uniformly describe an overall left-turning (counterclockwise) tendency, a recent Internet study with more than 1500 adults found a right-sided (clockwise) bias. We set out to investigate spontaneous turning behaviour in children age 5-3 years and, based on neuropsychiatric work in adults, also explored a potential association with magical thinking. Findings indicated a clear left-turning preference, independent of a participant's sex and handedness. Whether a child responded a question about the existence of extrasensory communication in the affirmative or not was unrelated to direction and size of turning bias and lateral preference. Our results are consistent with a left-sided turning preference reported for children, but in opposition to the clockwise bias recently described in a large-scale study with adults. Whether they point to a maturational gradient in the preferred direction of spontaneous whole-body rotation or rather to a lack of comparability between measures used in observational versus Internet-based studies remains to be further investigated. Regarding a purported association between body turns and magical thinking, our study is preliminary, as only one single question was used to probe the latter.

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.

Astrosociology and Science Fiction: a Synergy

NASA Astrophysics Data System (ADS)

Caroti, Simone

2010-01-01

Both astrosociology and science fiction have claimed outer space as their preferred turf. Astrosociology did so in order to study the impact of space on human societies, and to develop a set of protocols that earthbound governments can utilize to prepare us for the next phase of humanity's adventure outside our home planet. Science fiction, on the other hand, found in outer space a fitting environment for dramatizing in a work of fiction the potential outcomes attending the kind of decision astrosociology is trying to foster in actuality. This paper explores the relationship between the two fields, and examines ways in which science fiction can contribute to the creation of an astrosociological consciousness. Particular attention will be given to the most relevant commonality that the two fields share: both astrosociology and science fiction are earthbound disciplines, areas of inquiry created by those who never left earth for those who never left earth. They can potentially function as partners in the endeavor of educating the bulk of humanity on the subject of space flight and space colonization.

Asymmetric balance control between legs for quiet but not for perturbed stance.

PubMed

Vieira, Osvaldo; Coelho, Daniel Boari; Teixeira, Luis Augusto

2014-10-01

Interlateral performance asymmetry in upright balance control was evaluated in this investigation by comparing unipedal stance on the right versus the left leg. Participants were healthy young adults, hand-foot congruent preference for the right body side. Balance performance was evaluated in unperturbed quiet stance and in the recovery of balance stability following a mechanical perturbation induced by unexpected load release. Evaluation was made under availability of full sensory information, and under deprivation of vision combined with distortion of sensory inputs from the feet soles. Results from perturbed posture revealed that muscular response latency and postural sway were symmetric between the legs. Unipedal stance was more stable when the body was supported on the right as compared with the left leg. No interaction was found between leg and sensory condition. Our findings are interpreted as resulting from specialization of the sensorimotor system controlling the right leg for continuous low-magnitude postural adjustments, while corrections to large-scale stance sway are symmetrically controlled between body sides.

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.

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.

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.

Prophylactic antibiotics for simple hand lacerations: time for a clinical trial?

PubMed

Zehtabchi, Shahriar; Yadav, Kabir; Brothers, Elizabeth; Khan, Feras; Singh, Savitri; Wilcoxson, R Daniel; Malhotra, Shweta

2012-09-01

Simple hand lacerations (not involving bones, tendons, nerves, or vessels) are a common emergency department (ED) complaint. Whilst the practices of irrigation, debridement, foreign body removal, and suture repair are well accepted, the use of prophylactic antibiotics is not. Without evidenced-based guidelines, practice is left to physician preference. The aim of this study was to assess the need for, and the feasibility to perform, a randomised controlled trial to evaluate the role of prophylactic antibiotics in simple hand lacerations. The study was done in three phases: (1) estimation of the national ED burden of simple hand lacerations and the use of antibiotic prophylaxis; (2) assessment of indications for antibiotic prophylaxis and (3) investigation of patient willingness to enrol in a randomised controlled trial and their preferred outcomes from simple hand lacerations. For Phase 1, we analysed the 2007 National Hospital Ambulatory Medical Care Survey. For Phase 2, we surveyed ED physicians in three urban teaching institutions (two in Brooklyn, NY and one in Washington, DC). For Phase 3, we surveyed ED patients at the same three institutions. Phase 1: out of 116.8 million ED visits nationally in 2007, 1.8 million (1.6%) were due to simple hand lacerations, of which 1.3 million (71%) required repair. Of those repaired, 27% (95% CI, 19-35%) were prescribed prophylactic antibiotics, most commonly cephalexin (73%). Phase 2: out of 108 providers surveyed, 69 (64%) responded. 16% (95% CI, 9-27%) reported prescribing prophylactic antibiotics routinely, most commonly cephalexin (84%, 95% CI, 67-93%). The degree of contamination was the most important factor (91%, 95% CI, 82-96%) in the physicians' decision to prescribe antibiotics. Phase 3: of the 490 patients surveyed, 64% (95% CI, 60-68%) expressed interest in participating in a study to evaluate the use of prophylactic antibiotics. Their primary concern was prevention of infection (77%, 95% CI, 73-81%). Simple hand lacerations represent a substantial number of ED visits in the United States. Absence of clear guidelines, disparity in physician practice, and patient interest in infection prevention all support performing a prospective randomised controlled trial to establish the role of antibiotic prophylaxis in simple hand lacerations. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

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.

The structural basis of actinomycin D–binding induces nucleotide flipping out, a sharp bend and a left-handed twist in CGG triplet repeats

PubMed Central

Lo, Yu-Sheng; Tseng, Wen-Hsuan; Chuang, Chien-Ying; Hou, Ming-Hon

2013-01-01

The potent anticancer drug actinomycin D (ActD) functions by intercalating into DNA at GpC sites, thereby interrupting essential biological processes including replication and transcription. Certain neurological diseases are correlated with the expansion of (CGG)n trinucleotide sequences, which contain many contiguous GpC sites separated by a single G:G mispair. To characterize the binding of ActD to CGG triplet repeat sequences, the structural basis for the strong binding of ActD to neighbouring GpC sites flanking a G:G mismatch has been determined based on the crystal structure of ActD bound to ATGCGGCAT, which contains a CGG triplet sequence. The binding of ActD molecules to GCGGC causes many unexpected conformational changes including nucleotide flipping out, a sharp bend and a left-handed twist in the DNA helix via a two site-binding model. Heat denaturation, circular dichroism and surface plasmon resonance analyses showed that adjacent GpC sequences flanking a G:G mismatch are preferred ActD-binding sites. In addition, ActD was shown to bind the hairpin conformation of (CGG)16 in a pairwise combination and with greater stability than that of other DNA intercalators. Our results provide evidence of a possible biological consequence of ActD binding to CGG triplet repeat sequences. PMID:23408860

Imagining class: A study into material social class position, subjective identification, and voting behavior across Europe.

PubMed

D'Hooge, Lorenzo; Achterberg, Peter; Reeskens, Tim

2018-02-01

The traditional approach to class voting has largely ignored the question whether material class positions coincide with subjective class identification. Following Sosnaud et al. (2013), this study evaluates party preferences when Europeans' material and subjective social class do not coincide. Seminal studies on voting behavior have suggested that members of lower classes are more likely to vote for the economic left and cultural right and that higher classes demonstrate the opposite pattern. Yet, these studies have on the one hand overlooked the possibility that there is a mismatch between the material class people can be classified in and the class they think they are part of, and on the other hand the consequences of this discordant class identification on voting behavior. Analyzing the 2009 wave of the European Elections Study, we find that the majority of the Europeans discordantly identify with the middle class, whereas only a minority of the lower and higher classes concordantly identify with their material social class. Further, material class only seems to predict economic voting behavior when it coincides with subjective class; for instance, individuals who have an inflated class identification are more likely to vote for the economic left, even when they materially can be classified as middle or high class. We conclude this paper with a discussion on scholarly debates concerning class and politics. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Using Contingent Reinforcement to Augment Muscle Activation After Perinatal Brachial Plexus Injury: A Pilot Study.

PubMed

Duff, S V; Sargent, B; Kutch, J J; Berggren, J; Leiby, B E; Fetters, L

2017-10-20

Examine the feasibility of increasing muscle activation with electromyographically (EMG)-triggered musical-video as reinforcement for children with perinatal brachial plexus injury (PBPI). Six children with PBPI (9.3 ± 6.3 months; 5 female, 1 male) and 13 typically developing (TD) controls (7.8 ± 3.5 months; 4 female, 9 males) participated. The left arm was affected in 5/6 children with PBPI. We recorded the integral (Vs) of biceps activation with surface EMG during two conditions per arm in one session: (1) 100 second (s) baseline without reinforcement and (2) 300 s reinforcement (musical-video triggered to play with biceps activation above threshold [V]). We examined the relation between the mean integral with reinforcement and hand preference. Mean biceps activation significantly increased from baseline in the affected arm of the group with PBPI by the 2nd (p < .008) and 3rd (p < .0004) 100 s intervals of reinforcement. Six of 6 children with PBPI and 12/13 TD controls increased activation in at least one arm. A lower integral was linked with hand preference for the unaffected right side in the PBPI group. This study supports contingent reinforcement as a feasible method to increase muscle activation. Future work will examine training dose and intensity to increase arm function.

Obstacle traversal and route choice in flying honeybees: Evidence for individual handedness

PubMed Central

Ong, Marielle; Bulmer, Michael; Groening, Julia

2017-01-01

Flying insects constantly face the challenge of choosing efficient, safe and collision-free routes while navigating through dense foliage. We examined the route-choice behavior of foraging honeybees when they encountered a barrier which could be traversed by flying through one of two apertures, positioned side by side. When the bees’ choice behavior was averaged over the entire tested population, the two apertures were chosen with equal frequency when they were equally wide. When the apertures were of different width, the bees, on average, showed a preference for the wider aperture, which increased sharply with the difference between the aperture widths. Thus, bees are able to discriminate the widths of oncoming gaps and choose the passage which is presumably safer and quicker to transit. Examination of the behavior of individual bees revealed that, when the two apertures were equally wide, ca. 55% of the bees displayed no side bias in their choices. However, the remaining 45% showed varying degrees of bias, with one half of them preferring the left-hand aperture, and the other half the right-hand aperture. The existence of distinct individual biases was confirmed by measuring the times required by biased bees to transit various aperture configurations: The transit time was longer if a bee’s intrinsic bias forced it to engage with the narrower aperture. Our results show that, at the population level, bees do not exhibit ‘handedness’ in choosing routes; however, individual bees display an idiosyncratic bias that can range from a strong left bias, through zero bias, to a strong right bias. In honeybees, previous studies of olfactory and visual learning have demonstrated clear biases at the population level. To our knowledge, our study is the first to uncover the existence of individually distinct biases in honeybees. We also show how a distribution of biases among individual honeybees can be advantageous in facilitating rapid transit of a group of bees through a cluttered environment, without any centralized decision-making or control. PMID:29095830

Genetic basis in motor skill and hand preference for tool use in chimpanzees (Pan troglodytes).

PubMed

Hopkins, William D; Reamer, Lisa; Mareno, Mary Catherine; Schapiro, Steven J

2015-02-07

Chimpanzees are well known for their tool using abilities. Numerous studies have documented variability in tool use among chimpanzees and the role that social learning and other factors play in their development. There are also findings on hand use in both captive and wild chimpanzees; however, less understood are the potential roles of genetic and non-genetic mechanisms in determining individual differences in tool use skill and laterality. Here, we examined heritability in tool use skill and handedness for a probing task in a sample of 243 captive chimpanzees. Quantitative genetic analysis, based on the extant pedigrees, showed that overall both tool use skill and handedness were significantly heritable. Significant heritability in motor skill was evident in two genetically distinct populations of apes, and between two cohorts that received different early social rearing experiences. We further found that motor skill decreased with age and that males were more commonly left-handed than females. Collectively, these data suggest that though non-genetic factors do influence tool use performance and handedness in chimpanzees, genetic factors also play a significant role, as has been reported in humans. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

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.

Left and right brain-oriented hemisity subjects show opposite behavioral preferences.

PubMed

Morton, Bruce E

2012-01-01

Recently, three independent, intercorrelated biophysical measures have provided the first quantitative measures of a binary form of behavioral laterality called "Hemisity," a term referring to inherent opposite right or left brain-oriented differences in thinking and behavioral styles. Crucially, the right or left brain-orientation of individuals assessed by these methods was later found to be essentially congruent with the thicker side of their ventral gyrus of the anterior cingulate cortex (vgACC) as revealed by a 3 min MRI procedure. Laterality of this putative executive structural element has thus become the primary standard defining individual hemisity. Here, the behavior of 150 subjects, whose hemisity had been calibrated by MRI, was assessed using five MRI-calibrated preference questionnaires, two of which were new. Right and left brain-oriented subjects selected opposite answers (p > 0.05) for 47 of the 107 "either-or," forced choice type preference questionnaire items. The resulting 30 hemisity subtype preference differences were present in several areas. These were: (1) in logical orientation, (2) in type of consciousness, (3) in fear level and sensitivity, (4) in social-professional orientation, and (5) in pair bonding-spousal dominance style. The right and left brain-oriented hemisity subtype subjects, sorted on the anatomical basis of upon which brain side their vgACC was thickest, showed 30 significant differences in their "either-or" type of behavioral preferences.

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.

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...

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.

Carpal tunnel syndrome: assessment of surgeon and patient preferences and priorities for decision-making.

PubMed

Hageman, Michiel G J S; Kinaci, Ahmet; Ju, Kevin; Guitton, Thierry G; Mudgal, Chaitanya S; Ring, David

2014-09-01

This study tested the null hypothesis that there are no differences between the preferences of hand surgeons and those patients with carpal tunnel syndrome (CTS) facing decisions about management of CTS (ie, the preferred content of a decision aid). One hundred three hand surgeons of the Science of Variation Group and 79 patients with CTS completed a survey about their priorities and preferences in decision making regarding the management of CTS. The questionnaire was structured according the Ottawa Decision Support Framework for the development of a decision aid. Important areas on which patient and hand surgeon interests differed included a preference for nonpainful, nonoperative treatment and confirmation of the diagnosis with electrodiagnostic testing. For patients, the main disadvantage of nonoperative treatment was that it was likely to be only palliative and temporary. Patients preferred, on average, to take the lead in decision making, whereas physicians preferred shared decision making. Patients and physicians agreed on the value of support from family and other physicians in the decision-making process. There were some differences between patient and surgeon priorities and preferences regarding decision making for CTS, particularly the risks and benefits of diagnostic and therapeutic procedures. Information that helps inform patients of their options based on current best evidence might help patients understand their own preferences and values, reduce decisional conflict, limit surgeon-to-surgeon variations, and improve health. Copyright © 2014 American Society for Surgery of the Hand. All rights reserved.

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.

Atypical speech lateralization in adults with developmental coordination disorder demonstrated using functional transcranial Doppler ultrasound.

PubMed

Hodgson, Jessica C; Hudson, John M

2017-03-01

Research using clinical populations to explore the relationship between hemispheric speech lateralization and handedness has focused on individuals with speech and language disorders, such as dyslexia or specific language impairment (SLI). Such work reveals atypical patterns of cerebral lateralization and handedness in these groups compared to controls. There are few studies that examine this relationship in people with motor coordination impairments but without speech or reading deficits, which is a surprising omission given the prevalence of theories suggesting a common neural network underlying both functions. We use an emerging imaging technique in cognitive neuroscience; functional transcranial Doppler (fTCD) ultrasound, to assess whether individuals with developmental coordination disorder (DCD) display reduced left-hemisphere lateralization for speech production compared to control participants. Twelve adult control participants and 12 adults with DCD, but no other developmental/cognitive impairments, performed a word-generation task whilst undergoing fTCD imaging to establish a hemispheric lateralization index for speech production. All participants also completed an electronic peg-moving task to determine hand skill. As predicted, the DCD group showed a significantly reduced left lateralization pattern for the speech production task compared to controls. Performance on the motor skill task showed a clear preference for the dominant hand across both groups; however, the DCD group mean movement times were significantly higher for the non-dominant hand. This is the first study of its kind to assess hand skill and speech lateralization in DCD. The results reveal a reduced leftwards asymmetry for speech and a slower motor performance. This fits alongside previous work showing atypical cerebral lateralization in DCD for other cognitive processes (e.g., executive function and short-term memory) and thus speaks to debates on theories of the links between motor control and language production. © 2016 The Authors. Journal of Neuropsychology published by John Wiley & Sons Ltd on behalf of British Psychological Society.

Clues from hands/Part 2. Personal details about patients revealed by hand examination.

PubMed

Schilli, Karen Danielle; Stricklin, Sherea Monica; Payne, Katie Sue; Rader, Ryan Kent; Stoecker, William V

2014-01-01

This is the second part of a two-part article on personal details revealed by hand examination. Examining hands to determine daily activities was the focus of Part 1 in the July/August 2014 Missouri Medicine. Personal traits and preferences, including pets, nutrition and psychology are presented here. These articles serve as a guide for visual clues on the hands to discern a patient's daily activities and personal preference, thereby providing social information that may help establish rapport between patient and physician and may have medical significance.

Laterality related to the successive selection of Dutch national youth soccer players.

PubMed

Verbeek, Jan; Elferink-Gemser, Marije T; Jonker, Laura; Huijgen, Barbara C H; Visscher, Chris

2017-11-01

In the general population, estimates of left-foot preference are around 20%. In soccer, specific tasks create positional demands, requiring 40% of the players to be left-footed. Whether and how this is related to the selection of players is unknown. To examine the successive selection of soccer players for Dutch national youth teams in relation to foot preference, 280 youth players (age = 16.2 ± 1.08 years) were monitored from the U16 through the U19 teams over the last 5 years. No difference in successive selection between left- and right-footed players was found (p < 0.05). Regardless of foot preference, more than 50% of the selected players were deselected out of a national youth team after 2 years. On average, 31% of the national youth players were left-footed, which is higher than expected, based on population estimates (χ 2 (1) = 37.49, p < 0.001, w = 0.27). However, there was an under-representation of left-footed players, based on expected positional demands (i.e., attack, midfield, defence) (χ 2 (1) = 16.83, p < 0.001, w = 0.18). The conclusion is that left-foot preference increases the probability of selection in Dutch national youth soccer teams.

Effects of subjective preference of colors on attention-related occipital theta oscillations.

PubMed

Kawasaki, Masahiro; Yamaguchi, Yoko

2012-01-02

Human daily behaviors are often affected by subjective preferences. Studies have shown that physical responses are affected by unconscious preferences before conscious decision making. Accordingly, attention-related neural activities could be influenced by unconscious preferences. However, few neurological data exist on the relationship between visual attention and subjective preference. To address this issue, we focused on lateralization during visual attention and investigated the effects of subjective color preferences on visual attention-related brain activities. We recorded electroencephalograph (EEG) data during a preference judgment task that required 19 participants to choose their preferred color from 2 colors simultaneously presented to the right and left hemifields. In addition, to identify oscillatory activity during visual attention, we conducted a control experiment in which the participants focused on either the right or the left color without stating their preference. The EEG results showed enhanced theta (4-6 Hz) and decreased alpha (10-12 Hz) activities in the right and left occipital electrodes when the participants focused on the color in the opposite hemifield. Occipital theta synchronizations also increased contralaterally to the hemifield to which the preferred color was presented, whereas the alpha desynchronizations showed no lateralization. The contralateral occipital theta activity lasted longer than the ipsilateral occipital theta activity. Interestingly, theta lateralization was observed even when the preferred color was presented to the unattended side in the control experiment, revealing the strength of the preference-related theta-modulation effect irrespective of visual attention. These results indicate that subjective preferences modulate visual attention-related brain activities. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

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.

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.

What's Left of the Left-Right Dimension? Why the Economic Policy Positions of Europeans Do Not Fit the Left-Right Dimension.

PubMed

Otjes, Simon

2018-01-01

In political science the economic left-right dimension plays a central role. A growing body of evidence shows that the economic policy preferences of a large segment of citizens do not scale sufficiently. Using Mokken scale analysis, this study determines the causes of this phenomenon. Differences in the extent to which the economic policy preferences of citizens fit the left-right dimension can be explained in terms of the interaction between individual level and political system-level variables: citizens who spend more attention to politicians with views that conform to the left-right dimension, have views that conform to the left-right dimension. There is also a role for the legacy of communist dictatorship: citizens who were socialised in democratic countries have views that fit the left-right dimension better than those socialised during communism.

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.

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.

Magical ideation and its relation to lateral preference.

PubMed

Nicholls, Michael E R; Orr, Catherine A; Lindell, Annukka K

2005-11-01

Schizophrenia and schizotypal personality have been linked to sinistrality as well as ambidextrality. The current study clarifies the relation between laterality and schizotypal personality by administering a battery of laterality questionnaires to measure hand, eye, ear, and foot preference in a group of 933 university students. To determine whether the relationship between schizotypy and laterality is limited to self-report measures, performance asymmetries between the hands were measured with tapping rate. There was no difference between dextrals and sinistrals in schizotypal personality, as indexed by the Magical Ideation (MI) scale. MI was higher, however, for individuals with a weak preference for either hand or eye compared to those with a strong dominance. In addition, individuals inconsistent in their lateral preference across modalities showed higher MI scores. Performance asymmetries had no effect on MI scores. This lack of effect was attributed to the inability of performance measures, such as tapping rate, to identify ambidextrals. The results support research linking schizotypal personality to ambidextrality and weak cerebral dominance and demonstrate that the association extends to modalities other than hand preference.

Cradling Side Preference Is Associated with Lateralized Processing of Baby Facial Expressions in Females

ERIC Educational Resources Information Center

Huggenberger, Harriet J.; Suter, Susanne E.; Reijnen, Ester; Schachinger, Hartmut

2009-01-01

Women's cradling side preference has been related to contralateral hemispheric specialization of processing emotional signals; but not of processing baby's facial expression. Therefore, 46 nulliparous female volunteers were characterized as left or non-left holders (HG) during a doll holding task. During a signal detection task they were then…

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

Head-turning asymmetries during kissing and their association with lateral preference.

PubMed

Ocklenburg, Sebastian; Güntürkün, Onur

2009-01-01

A head-turning bias to the right side is one of the earliest functional asymmetries in human development and is already present during the final weeks of gestation. To test whether head-turning preference is related to other lateral preferences in adults, kissing behaviour of participants towards a symmetrical doll was observed to assess their spontaneous head-turning preference. Additionally, participants' individual handedness, footedness, and eye preference were determined using questionnaires. A significant difference in handedness and footedness, but not eye preference, was found between left- and right-kissers, with right-kissers showing a stronger right-sided bias than left-kissers. These results support the assumption that the head-turning bias in humans may be able to induce or enhance other asymmetries of perception and action.

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

A Preliminary Study of the Human Brain Response to Oral Sucrose and its Association with Recent Drinking

PubMed Central

Kareken, David A.; Dzemidzic, Mario; Oberlin, Brandon G.; Eiler, William J.A.

2014-01-01

Background A preference for sweet tastes has been repeatedly shown to be associated with alcohol preference in both animals and humans. In this study, we tested the extent to which recent drinking is related to blood oxygen dependent (BOLD) activation from an intensely sweet solution in orbitofrontal areas known to respond to primary rewards. Methods Sixteen right-handed, non-treatment seeking, healthy volunteers (mean age 26 years; 75% male) were recruited from the community. All underwent a taste test using a range of sucrose concentrations, as well as functional magnetic resonance imaging (fMRI) during pseudorandom, event-driven stimulation with water and a 0.83M concentration of sucrose in water. Results [Sucrose > Water] provoked significant BOLD activation in primary gustatory cortex and amygdala, as well as in the right ventral striatum and in bilateral orbitofrontal cortex. Drinks/drinking day correlated significantly with the activation as extracted from the left orbital area (r = 0.52, p = 0.04 after correcting for a bilateral comparison). Using stepwise multiple regression, the addition of rated sucrose-liking accounted for significantly more variance in drinks/drinking day than did left orbital activation alone (multiple R= 0.79, p = 0.002). Conclusions Both the orbitofrontal response to an intensely sweet taste, as well as rated liking of that taste, accounted for significant variance in drinking behavior. The brain response to sweet tastes may be an important phenotype of alcoholism risk. PMID:23841808

Ten-dimensional anthropomorphic arm control in a human brain-machine interface: difficulties, solutions, and limitations

NASA Astrophysics Data System (ADS)

Wodlinger, B.; Downey, J. E.; Tyler-Kabara, E. C.; Schwartz, A. B.; Boninger, M. L.; Collinger, J. L.

2015-02-01

Objective. In a previous study we demonstrated continuous translation, orientation and one-dimensional grasping control of a prosthetic limb (seven degrees of freedom) by a human subject with tetraplegia using a brain-machine interface (BMI). The current study, in the same subject, immediately followed the previous work and expanded the scope of the control signal by also extracting hand-shape commands from the two 96-channel intracortical electrode arrays implanted in the subject’s left motor cortex. Approach. Four new control signals, dictating prosthetic hand shape, replaced the one-dimensional grasping in the previous study, allowing the subject to control the prosthetic limb with ten degrees of freedom (three-dimensional (3D) translation, 3D orientation, four-dimensional hand shaping) simultaneously. Main results. Robust neural tuning to hand shaping was found, leading to ten-dimensional (10D) performance well above chance levels in all tests. Neural unit preferred directions were broadly distributed through the 10D space, with the majority of units significantly tuned to all ten dimensions, instead of being restricted to isolated domains (e.g. translation, orientation or hand shape). The addition of hand shaping emphasized object-interaction behavior. A fundamental component of BMIs is the calibration used to associate neural activity to intended movement. We found that the presence of an object during calibration enhanced successful shaping of the prosthetic hand as it closed around the object during grasping. Significance. Our results show that individual motor cortical neurons encode many parameters of movement, that object interaction is an important factor when extracting these signals, and that high-dimensional operation of prosthetic devices can be achieved with simple decoding algorithms. ClinicalTrials.gov Identifier: NCT01364480.

Random motor generation in a finger tapping task: influence of spatial contingency and of cortical and subcortical hemispheric brain lesions

PubMed Central

Annoni, J.; Pegna, A.

1997-01-01

OBJECTIVE—To test the hypothesis that, during random motor generation, the spatial contingencies inherent to the task would induce additional preferences in normal subjects, shifting their performances farther from randomness. By contrast, perceptual or executive dysfunction could alter these task related biases in patients with brain damage.
METHODS—Two groups of patients, with right and left focal brain lesions, as well as 25 right handed subjects matched for age and handedness were asked to execute a random choice motor task—namely, to generate a random series of 180 button presses from a set of 10 keys placed vertically in front of them.
RESULTS—In the control group, as in the left brain lesion group, motor generation was subject to deviations from theoretical expected randomness, similar to those when numbers are generated mentally, as immediate repetitions (successive presses on the same key) are avoided. However, the distribution of button presses was also contingent on the topographic disposition of the keys: the central keys were chosen more often than those placed at extreme positions. Small distances were favoured, particularly with the left hand. These patterns were influenced by implicit strategies and task related contingencies.
 By contrast, right brain lesion patients with frontal involvement tended to show a more square distribution of key presses—that is, the number of key presses tended to be more equally distributed. The strategies were also altered by brain lesions: the number of immediate repetitions was more frequent when the lesion involved the right frontal areas yielding a random generation nearer to expected theoretical randomness. The frequency of adjacent key presses was increased by right anterior and left posterior cortical as well as by right subcortical lesions, but decreased by left subcortical lesions.
CONCLUSIONS—Depending on the side of the lesion and the degree of cortical-subcortical involvement, the deficits take on a different aspect and direct repetions and adjacent key presses have different patterns of alterations. Motor random generation is therefore a complex task which seems to necessitate the participation of numerous cerebral structures, among which those situated in the right frontal, left posterior, and subcortical regions have a predominant role.

 PMID:9408109

Feasibility: An important but neglected issue in patient hand hygiene.

PubMed

Knighton, Shanina C; McDowell, Cherese; Rai, Herleen; Higgins, Patricia; Burant, Christopher; Donskey, Curtis J

2017-06-01

Patient hand hygiene may be a useful strategy to prevent acquisition of pathogens and to reduce the risk for transmission by colonized patients. Several studies demonstrate that patients and long-term-care facility (LTCF) residents may have difficulty using hand hygiene products that are provided; however, none of them measure feasibility for patients to use different hand hygiene products. A convenience sample of 42 hospitalized patients and 46 LTCF residents was assessed for their ability to use 3 hand sanitizer products (8-oz pushdown pump bottle, 2-oz pocket-sized bottle with a reclosable lid, and alcohol-impregnated hand wipes). The time (seconds) required for accessing each product was compared among acute-care patients and LTCF residents. Participants provided feedback on which product they preferred and found easiest to use. Of 88 participants, 86 (97.7%) preferred the pushdown pump, 2 (2.3%) preferred the bottle with the reclosable lid, and none preferred the hand wipes. For both hospitalized patients and LTCF residents, the average time required to access the pushdown pump was significantly less than the time required to access the other products (pushdown pump, 0.45 seconds; bottle with reclosable lid, 3.86 seconds; and wipes, 5.66 seconds; P < .001). Feasibility and ease of use should be considered in the selection of hand hygiene products for patients and LTCF residents. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

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

Human Infants' Preference for Left-to-Right Oriented Increasing Numerical Sequences

PubMed Central

de Hevia, Maria Dolores; Girelli, Luisa; Addabbo, Margaret; Macchi Cassia, Viola

2014-01-01

While associations between number and space, in the form of a spatially oriented numerical representation, have been extensively reported in human adults, the origins of this phenomenon are still poorly understood. The commonly accepted view is that this number-space association is a product of human invention, with accounts proposing that culture, symbolic knowledge, and mathematics education are at the roots of this phenomenon. Here we show that preverbal infants aged 7 months, who lack symbolic knowledge and mathematics education, show a preference for increasing magnitude displayed in a left-to-right spatial orientation. Infants habituated to left-to-right oriented increasing or decreasing numerical sequences showed an overall higher looking time to new left-to-right oriented increasing numerical sequences at test (Experiment 1). This pattern did not hold when infants were presented with the same ordinal numerical information displayed from right to left (Experiment 2). The different pattern of results was congruent with the presence of a malleable, context-dependent baseline preference for increasing, left-to-right oriented, numerosities (Experiment 3). These findings are suggestive of an early predisposition in humans to link numerical order with a left-to-right spatial orientation, which precedes the acquisition of symbolic abilities, mathematics education, and the acquisition of reading and writing skills. PMID:24802083

Side preference in adults for holding infants: contributions of sex and handedness in a test of imagination.

PubMed

Harris, L J; Almerigi, J B; Kirsch, E A

2000-01-01

Five hundred one right-handers (150 men, 351 women) and 53 left-handers (15 men, 38 women) were asked to imagine holding a young infant in their arms. Right-handers reported significant left-side biases--in 68% of the men and 73% of the women. For left-handers, side preferences were weaker, the left-side bias dropping to 47% for men and 60% for women, with neither figure different from chance. The results are discussed in the context of theory and research on the functional neuroanatomy of attention, emotional arousal, and the generation, maintenance, and manipulation of mental images.

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...

Laterality in hand use across four tool-use behaviors among the wild chimpanzees of Bossou, Guinea, West Africa.

PubMed

Humle, Tatyana; Matsuzawa, Tetsuro

2009-01-01

Population-level right handedness is a human universal, whose evolutionary origins are the source of considerable empirical and theoretical debate. Although our closest neighbor, the chimpanzee, shows some evidence for population-level handedness in captivity, there is little evidence from the wild. Tool-use measures of hand use in chimpanzees have yielded a great deal of variation in directionality and strength in hand preference, which still remains largely unexplored and unexplained. Data on five measures of hand use across four tool-use skills--ant-dipping, algae-scooping, pestle-pounding and nut-cracking--among the wild chimpanzees of Bossou, Guinea, West Africa, are presented here. This study aims to explore age- and sex-class effects, as well as the influence of task motor, cognitive and haptic demands, on the strength and directionality of hand preference within and across all five measures of hand use. Although there was no age- or sex-class effect on the directionality of hand preference, immature

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.

Preferences for Shared Decision Making in Older Adult Patients With Orthopedic Hand Conditions.

PubMed

Dardas, Agnes Z; Stockburger, Christopher; Boone, Sean; An, Tonya; Calfee, Ryan P

2016-10-01

The practice of medicine is shifting from a paternalistic doctor-patient relationship to a model in which the doctor and patient collaborate to decide optimal treatment. This study aims to determine whether the older orthopedic population desires a shared decision-making approach to care and to identify patient predictors for the preferred type of approach. This cross-sectional investigation enrolled 99 patients, minimum age 65 years, at a tertiary hand specialty practice between March and June 2015. All patients completed the Control Preferences Scale, a validated system that distinguishes among patient preferences for patient-directed, collaborative, or physician-directed decision making. Bivariate and logistic regression analyses assessed associations among demographic data; clinic encounter variables such as familiarity with provider, trauma, diagnosis, and treatment decision; and the primary outcome of Control Preferences Scale preferences. A total of 81% of patients analyzed preferred a more patient-directed role in decision making; 46% of the total cohort cited a collaborative approach as their most preferred treatment approach. Sixty-seven percent cited the most physician-directed approach as their least preferred model of decision making. In addition, 49% reported that spending more time with their physician to address questions and explain the diagnosis would be most useful when making a health care decision and 73% preferred additional written informational material. Familiarity with the provider was associated with being more likely to prefer a collaborative approach. Older adult patients with symptomatic upper-extremity conditions desire more patient-directed roles in treatment decision making. Given the limited amount of reliable information obtained independently outside the office visit, our data suggest that written decision aids offer an approach to shared decision making that is most consistent with the preferences of the older orthopedic patient. This study quantifies older adults' desire to participate in decision making when choosing among treatments for hand conditions. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

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.

Preferred neck-resting position predicts aggression in Caribbean flamingos (Phoenicopterus ruber).

PubMed

Anderson, Matthew J; Williams, Sarah A; Bono, Amanda J

2010-11-01

When flamingos rest, they typically lay their heads along their backs. In order to achieve this positioning they curve their necks to either the right or left of their midline. Previously we have shown both individual and flock-level laterality of preferred neck-resting direction, with most birds preferring to rest their necks to their right (Anderson, Williams, & O'Brien, 2009). As laterality has been shown to play a role in social cohesion (e.g., Rogers & Workman, 1989) and aggression (e.g., Vallortigara, Cozzutti, Tommasi, & Rogers, 2001), here we attempted to determine whether a flamingo's preferred neck-resting direction could be used to predict involvement in aggressive encounters. Results replicated the earlier flock-level preference for neck resting towards the right, and indicated that those flamingos preferring the left were more likely to be involved in aggressive encounters.

Estimating a just-noticeable difference for ocular comfort in contact lens wearers.

PubMed

Papas, Eric B; Keay, Lisa; Golebiowski, Blanka

2011-06-21

To estimate the just-noticeable difference (JND) in ocular comfort rating by human, contact lens-wearing subjects using 1 to 100 numerical scales. Ostensibly identical, new contact lenses were worn simultaneously in both eyes by 40 subjects who made individual comfort ratings for each eye using a 100-point numerical ratings scale (NRS). Concurrently, interocular preference was indicated on a five-point Likert scale (1 to 5: strongly prefer right, slightly prefer right, no preference, slightly prefer left, strongly prefer left, respectively). Differences in NRS comfort score (ΔC) between the right and left eyes were determined for each Likert scale preference criteria. The distribution of group ΔC scores was examined relative to alternative definitions of JND as a means of estimating its value. For Likert scores indicating the presence of a slight interocular preference, absolute ΔC ranged from 1 to 30 units with a mean of 7.4 ± 1.3 (95% confidence interval) across all lenses and trials. When there was no Likert scale preference expressed between the eyes, absolute ΔC did not exceed 5 units. For ratings of comfort using a 100-point numerical rating scale, the inter-ocular JND is unlikely to be less than 5 units. The estimate for the average value in the population was approximately 7 to 8 units. These numbers indicate the lowest level at which changes in comfort measured with such scales are likely to be clinically significant.

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.

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...

Elevated rates of atypical handedness in paedophilia: Theory and implications

PubMed Central

Fazio, Rachel L.; Lykins, Amy D.; Cantor, James M.

2014-01-01

Multiple factors determine handedness including genetics, prenatal stress and post-natal environmental conditions. Atypical handedness, whether manifest as increased sinistrality or decreased strength of lateral preference, has been noted in a wide variety of populations with neuropathology. Those with atypical sexual preferences, specifically paedophilia, also manifest reduced rates of right-handedness. This paper uses the largest sample of phallometrically assessed men to date to establish the pattern of atypical handedness in paedophilia. Specifically, whereas prior research has largely characterized participants dichotomously as right-handed or non-right-handed and/or used self-report of writing hand, this paper expands upon such reports by using the Edinburgh Handedness Inventory's laterality quotient. Participants' handedness and phallometrically assessed sexual preference were analyzed both as continuous and categorical variables, and the responses of those scoring in the range of ambiguous-handedness were evaluated to ascertain whether they were ambiguously handed or more accurately described as mixed-handed. Results indicated those producing scores in the range of ambiguous-handedness demonstrated response patterns consistent with ambiguous-handedness, rather than mixed-handedness. Paedophiles demonstrated high rates of non-right-handedness primarily manifested as sinistrality, whereas those who had a sexual preference for pubescent children evidenced increased ambiguous-handedness. Results support a view of ambiguous-handedness as less pathological than previously hypothesized, and of a neurodevelopmental origin of paraphilic sexual preferences. PMID:24666135

Elevated rates of atypical handedness in paedophilia: theory and implications.

PubMed

Fazio, Rachel L; Lykins, Amy D; Cantor, James M

2014-01-01

Multiple factors determine handedness including genetics, prenatal stress and post-natal environmental conditions. Atypical handedness, whether manifest as increased sinistrality or decreased strength of lateral preference, has been noted in a wide variety of populations with neuropathology. Those with atypical sexual preferences, specifically paedophilia, also manifest reduced rates of right-handedness. This paper uses the largest sample of phallometrically assessed men to date to establish the pattern of atypical handedness in paedophilia. Specifically, whereas prior research has largely characterized participants dichotomously as right-handed or non-right-handed and/or used self-report of writing hand, this paper expands upon such reports by using the Edinburgh Handedness Inventory's laterality quotient. Participants' handedness and phallometrically assessed sexual preference were analyzed both as continuous and categorical variables, and the responses of those scoring in the range of ambiguous-handedness were evaluated to ascertain whether they were ambiguously handed or more accurately described as mixed-handed. Results indicated those producing scores in the range of ambiguous-handedness demonstrated response patterns consistent with ambiguous-handedness, rather than mixed-handedness. Paedophiles demonstrated high rates of non-right-handedness primarily manifested as sinistrality, whereas those who had a sexual preference for pubescent children evidenced increased ambiguous-handedness. Results support a view of ambiguous-handedness as less pathological than previously hypothesized, and of a neurodevelopmental origin of paraphilic sexual preferences.

Surface-anchored poly(acryloyl-L(D)-valine) with enhanced chirality-selective effect on cellular uptake of gold nanoparticles

PubMed Central

Deng, Jun; Wu, Sai; Yao, Mengyun; Gao, Changyou

2016-01-01

Chirality is one of the ubiquitous phenomena in biological systems. The left handed (L-) amino acids and right handed (D-) sugars are normally found in proteins, and in RNAs and DNAs, respectively. The effect of chiral surfaces at the nanoscale on cellular uptake has, however, not been explored. This study reveals for the first time the molecular chirality on gold nanoparticles (AuNPs) functions as a direct regulator for cellular uptake. Monolayers of 2-mercaptoacetyl-L(D)-valine (L(D)-MAV) and poly(acryloyl-L(D)-valine (L(D)-PAV) chiral molecules were formed on AuNPs surface, respectively. The internalized amount of PAV-AuNPs was several times larger than that of MAV-AuNPs by A549 and HepG2 cells, regardless of the chirality difference. However, the D-PAV-AuNPs were internalized with significantly larger amount than the L-PAV-AuNPs. This chirality-dependent uptake effect is likely attributed to the preferable interaction between the L-phospholipid-based cell membrane and the D-enantiomers. PMID:27531648

Surface-anchored poly(acryloyl-L(D)-valine) with enhanced chirality-selective effect on cellular uptake of gold nanoparticles

NASA Astrophysics Data System (ADS)

Deng, Jun; Wu, Sai; Yao, Mengyun; Gao, Changyou

2016-08-01

Chirality is one of the ubiquitous phenomena in biological systems. The left handed (L-) amino acids and right handed (D-) sugars are normally found in proteins, and in RNAs and DNAs, respectively. The effect of chiral surfaces at the nanoscale on cellular uptake has, however, not been explored. This study reveals for the first time the molecular chirality on gold nanoparticles (AuNPs) functions as a direct regulator for cellular uptake. Monolayers of 2-mercaptoacetyl-L(D)-valine (L(D)-MAV) and poly(acryloyl-L(D)-valine (L(D)-PAV) chiral molecules were formed on AuNPs surface, respectively. The internalized amount of PAV-AuNPs was several times larger than that of MAV-AuNPs by A549 and HepG2 cells, regardless of the chirality difference. However, the D-PAV-AuNPs were internalized with significantly larger amount than the L-PAV-AuNPs. This chirality-dependent uptake effect is likely attributed to the preferable interaction between the L-phospholipid-based cell membrane and the D-enantiomers.

Surface-anchored poly(acryloyl-L(D)-valine) with enhanced chirality-selective effect on cellular uptake of gold nanoparticles.

PubMed

Deng, Jun; Wu, Sai; Yao, Mengyun; Gao, Changyou

2016-08-17

Chirality is one of the ubiquitous phenomena in biological systems. The left handed (L-) amino acids and right handed (D-) sugars are normally found in proteins, and in RNAs and DNAs, respectively. The effect of chiral surfaces at the nanoscale on cellular uptake has, however, not been explored. This study reveals for the first time the molecular chirality on gold nanoparticles (AuNPs) functions as a direct regulator for cellular uptake. Monolayers of 2-mercaptoacetyl-L(D)-valine (L(D)-MAV) and poly(acryloyl-L(D)-valine (L(D)-PAV) chiral molecules were formed on AuNPs surface, respectively. The internalized amount of PAV-AuNPs was several times larger than that of MAV-AuNPs by A549 and HepG2 cells, regardless of the chirality difference. However, the D-PAV-AuNPs were internalized with significantly larger amount than the L-PAV-AuNPs. This chirality-dependent uptake effect is likely attributed to the preferable interaction between the L-phospholipid-based cell membrane and the D-enantiomers.

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.

Cross-cultural variation in preference for replantation or revision amputation: Societal and surgeon views.

PubMed

Maroukis, Brianna L; Shauver, Melissa J; Nishizuka, Takanobu; Hirata, Hitoshi; Chung, Kevin C

2016-04-01

Treatment decisions after an injury like finger amputation are made based on injury and patient factors. However, decisions can also be influenced by provider and patient preferences. We compared hand surgeon and societal preferences and attitudes regarding finger amputation treatment in Japan and the US. We performed a cross-sectional survey with subjects derived from large tertiary care academic institutions in the US and Japan. We secured 100% participation of American hand surgeon members of the Finger Replantation and Amputation Multicenter Study and presenting hand surgeons at the 32nd Annual meeting of the Central Japanese Society for Surgery of the Hand. Societal preferences were gathered from volunteers at the 2 universities in the US and Japan. There were no significant differences in estimations of function, sensation, or appearance after replantation; American and Japanese societal participants preferred replantation compared to surgeons, although this was more pronounced in Japan. The Japanese society displayed more negative attitudes toward finger amputees than did Japanese surgeons. American respondents anticipated more public stigmatisation of amputees than did American surgeons. Societal preference for replantation was not caused by inflated expectations of outcomes after replantation. Japanese societal preference was likely driven by negative views of finger amputees. American society noted no decrease in physical health after amputation, but did note a quality of life decrease attributed to public stigmatisation. Japanese society and surgeons had a stronger preference for replantation than American society and surgeons, possibly attributed to cultural differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Free energy calculations of short peptide chains using Adaptively Biased Molecular Dynamics

NASA Astrophysics Data System (ADS)

Karpusenka, Vadzim; Babin, Volodymyr; Roland, Christopher; Sagui, Celeste

2008-10-01

We performed a computational study of monomer peptides composed of methionine, alanine, leucine, glutamate, lysine (all amino acids with a helix-forming propensities); and proline, glycine tyrosine, serine, arginine (which all have poor helix-forming propensities). The free energy landscapes as a function of the handedness and radius of gyration have been calculated using the recently introduced Adaptively Biased Molecular Dynamics (ABMD) method, combined with replica exchange, multiple walkers, and post-processing Umbrella Correction (UC). Minima that correspond to some of the left- and right-handed 310-, α- and π-helixes were identified by secondary structure assignment methods (DSSP, Stride). The resulting free energy surface (FES) and the subsequent steered molecular dynamics (SMD) simulation results are in agreement with the empirical evidence of preferred secondary structures for the peptide chains considered.

Hands on or hands off? Disgust sensitivity and preference for environmental education activities

Treesearch

Robert D. Bixler; Myron F. Floyd

1999-01-01

Detailed descriptions of barriers to enviromuental education (EE) can provide opportunities for educators to foresee potential problems in programs. High disgust sensitivity is an intrapersonal barrier that constrains preference for learning opportunities involving manipulation of some organic materials. Middle school students in Texas (N = 450)...

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.

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).

Laterality of suckling behaviour in three zebra species.

PubMed

Pluháček, Jan; Olléová, Michaela; Bartošová, Jitka; Pluháčková, Jana; Bartoš, Luděk

2013-01-01

Although side preference while suckling is an easily characterised lateralised behaviour, few studies have been conducted. We observed laterality in suckling behaviour in three captive zebra species to test two hypotheses: laterality affected by the foal (motor laterality) and laterality affected by the mother. In total we observed 35 foals of Grevy's, plains, and mountain zebra in two zoos and recorded 5128 successful suckling bouts and 9095 unsuccessful suckling attempts. At the population level the only factor affecting side preference of suckling bouts and attempts was the identity of the individual foal. Ten foals showed individual preferences: seven foals preferred suckling from the left side of the mother, three preferred suckling from the right side of the mother. The individual preferences increased with increasing age of the foal. Only one foal was refused more often from the opposite side than the preferred side used for suckling whereas three other foals were refused from the preferred side. Foals that preferred suckling either from left or right side were refused by the mare more often than foals which showed non-preference. Thus lateral preferences in suckling behaviour of zebra foals seem to be in line with the motor laterality hypotheses.

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.

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.

Adult Attachment Affects Neural Response to Preference-Inferring in Ambiguous Scenarios: Evidence From an fMRI Study

PubMed Central

Zhang, Xing; Ran, Guangming; Xu, Wenjian; Ma, Yuanxiao; Chen, Xu

2018-01-01

Humans are highly social animals, and the ability to cater to the preferences of other individuals is encouraged by society. Preference-inferring is an important aspect of the theory of mind (TOM). Many previous studies have shown that attachment style is closely related to TOM ability. However, little is known about the effects of adult attachment style on preferences inferring under different levels of certainty. Here, we investigated how adult attachment style affects neural activity underlying preferences inferred under different levels of certainty by using functional magnetic resonance imaging (fMRI). The fMRI results demonstrated that adult attachment influenced the activation of anterior insula (AI) and inferior parietal lobule (IPL) in response to ambiguous preference-inferring. More specifically, in the ambiguous preference condition, the avoidant attached groups exhibited a significantly enhanced activation than secure and anxious attached groups in left IPL; the anxious attached groups exhibited a significantly reduced activation secure attached group in left IPL. In addition, the anxious attached groups exhibited a significantly reduced activation than secure and avoidant attached groups in left AI. These results were also further confirmed by the subsequent PPI analysis. The results from current study suggest that, under ambiguous situations, the avoidant attached individuals show lower sensitivity to the preference of other individuals and need to invest more cognitive resources for preference-reasoning; while compared with avoidant attached group, the anxious attached individuals express high tolerance for uncertainty and a higher ToM proficiency. Results from the current study imply that differences in preference-inferring under ambiguous conditions associated with different levels of individual attachment may explain the differences in interpersonal interaction. PMID:29559932

Lateralization of ERPs to speech and handedness in the early development of Autism Spectrum Disorder.

PubMed

Finch, Kayla H; Seery, Anne M; Talbott, Meagan R; Nelson, Charles A; Tager-Flusberg, Helen

2017-01-01

Language is a highly lateralized function, with typically developing individuals showing left hemispheric specialization. Individuals with autism spectrum disorder (ASD) often show reduced or reversed hemispheric lateralization in response to language. However, it is unclear when this difference emerges and whether or not it can serve as an early ASD biomarker. Additionally, atypical language lateralization is not specific to ASD as it is also seen more frequently in individuals with mixed- and left-handedness. Here, we examined early asymmetry patterns measured through neural responses to speech sounds at 12 months and behavioral observations of handedness at 36 months in children with and without ASD. Three different groups of children participated in the study: low-risk controls (LRC), high risk for ASD (HRA; infants with older sibling with ASD) without ASD, and HRA infants who later receive a diagnosis of ASD (ASD). Event-related potentials (ERPs) to speech sounds were recorded at 12 months. Utilizing a novel observational approach, handedness was measured by hand preference on a variety of behaviors at 36 months. At 12 months, lateralization patterns of ERPs to speech stimuli differed across the groups with the ASD group showing reversed lateralization compared to the LRC group. At 36 months, factor analysis of behavioral observations of hand preferences indicated a one-factor model with medium to high factor loadings. A composite handedness score was derived; no group differences were observed. There was no association between lateralization to speech at 12 months and handedness at 36 months in the LRC and HRA groups. However, children with ASD did show an association such that infants with lateralization patterns more similar to the LRC group at 12 months were stronger right-handers at 36 months. These results highlight early developmental patterns that might be specific to ASD, including a potential early biomarker of reversed lateralization to speech stimuli at 12 months, and a relation between behavioral and neural asymmetries. Future investigations of early asymmetry patterns, especially atypical hemispheric specialization, may be informative in the early identification of ASD.

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.

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...

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.

Phase Transition and Texture Evolution in the Ni-Mn-Ga Ferromagnetic Shape-Memory Alloys Studied by a Neutron Diffraction Technique

NASA Astrophysics Data System (ADS)

Nie, Z. H.; Wang, Y. D.; Wang, G. Y.; Richardson, J. W.; Wang, G.; Liu, Y. D.; Liaw, P. K.; Zuo, L.

2008-12-01

The phase transition and influence of the applied stress on the texture evolution in the as-cast Ni-Mn-Ga ferromagnetic shape-memory alloys were studied by the time-of-flight (TOF) neutron diffraction technique. The neutron diffraction experiments were performed on the General Purpose Powder Diffractometer (Argonne National Laboratory). Inverse pole figures were determined from the neutron data for characterizing the orientation distributions and variant selections of polycrystalline Ni-Mn-Ga alloys subjected to different uniaxial compression deformations. Texture analyses reveal that the initial texture for the parent phase in the as-cast specimen was composed of {left\\{ {{text{001}}} right\\}}{left< {{text{100}}} rightrangle } , {left\\{ {{text{001}}} right\\}}{left< {{text{110}}} rightrangle } , {left\\{ {{text{011}}} right\\}}{left< {{text{100}}} rightrangle } , and {left\\{ {{text{011}}} right\\}}{left< {{text{110}}} rightrangle } , which was weakened after the compression deformation. Moreover, a strong preferred selection of martensitic-twin variants ( {left\\{ {{text{110}}} right\\}}{left< {{text{001}}} rightrangle } and {left\\{ {{text{100}}} right\\}}{left< {{text{001}}} rightrangle } ) was observed in the transformed martensite after a compression stress applied on the parent phase along the cyclindrical axis of the specimens. The preferred selection of variants can be well explained by considering the grain/variant-orientation-dependent Bain-distortion energy.

Accuracy of piezoelectric pedometer and accelerometer step counts.

PubMed

Cruz, Joana; Brooks, Dina; Marques, Alda

2017-04-01

This study aimed to assess step-count accuracy of a piezoeletric pedometer (Yamax PW/EX-510), when worn at different body parts, and a triaxial accelerometer (GT3X+), and to compare device accuracy; and identify the preferred location(s) to wear a pedometer. Sixty-three healthy adults (45.8±20.6 years old) wore 7 pedometers (neck, lateral right and left of the waist, front right and left of the waist, front pockets of the trousers) and 1 accelerometer (over the right hip), while walking 120 m at slow, self-preferred/normal and fast paces. Steps were recorded. Participants identified their preferred location(s) to wear the pedometer. Absolute percent error (APE) and Bland and Altman (BA) method were used to assess device accuracy (criterion measure: manual counts) and BA method for device comparisons. Pedometer APE was below 3% at normal and fast paces despite wearing location, but higher at slow pace (4.5-9.1%). Pedometers were more accurate at the front waist and inside the pockets. Accelerometer APE was higher than pedometer APE (P<0.05); nevertheless, limits of agreement between devices were relatively small. Preferred wearing locations were inside the front right (N.=25) and left (N.=20) pockets of the trousers. Yamax PW/EX-510 pedometers may be preferable than GT3X+ accelerometers to count steps, as they provide more accurate results. These pedometers should be worn at the front right or left positions of the waist or inside the front pockets of the trousers.

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

In a demanding task, three-handed manipulation is preferred to two-handed manipulation

NASA Astrophysics Data System (ADS)

Abdi, Elahe; Burdet, Etienne; Bouri, Mohamed; Himidan, Sharifa; Bleuler, Hannes

2016-02-01

Equipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm.

In a demanding task, three-handed manipulation is preferred to two-handed manipulation.

PubMed

Abdi, Elahe; Burdet, Etienne; Bouri, Mohamed; Himidan, Sharifa; Bleuler, Hannes

2016-02-25

Equipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm.

“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

Preference and compliance of waterless hand-hygiene products versus soap and water.

PubMed

Carr, Michele P; Sullivan, Stefanie; Gilmore, Jenny; Rashid, Robert G

2003-09-01

To compare handwashing using traditional antimicrobial soap and water with two antimicrobial waterless hand-hygiene products for personal preference and compliance. Fifty dental and dental hygiene students were randomly chosen to participate in the study. All subjects were anonymously observed prior to the introduction of the waterless products for handwashing compliance using soap and water for 1 week. All subjects were then instructed on the use of a waterless gel and foam for handwashing. Both waterless products were used for a period of 1 week and students again were anonymously observed. A questionnaire was distributed at the conclusion of the study to determine product preference. During handwashing with soap and water, the average time the soap was in contact with the hands was 7.0 seconds. The average contact time with the gel and foam was 15.3 seconds and 20.0 seconds, respectfully. Questionnaire results indicated that the foam was significantly preferred over the gel and soap and water (54%, 28% and 16%, respectively). The foam was also significantly preferred when evaluating fragrance (52%), kindness to the skin (66%), convenience (64%) and fastest drying time (54%). Results from this study indicate that the waterless foam product was significantly preferred over the waterless gel and traditional soap and water for handwashing procedures. Since handwashing guidelines, regardless of which product used, recommend a minimum of 15 seconds to minimize the number of transient microorganisms on the hands, compliance was found only with the foam and the gel.

How was the Turin Shroud Man crucified?

PubMed

Bevilacqua, M; Fanti, G; D'Arienzo, M; Porzionato, A; Macchi, V; De Caro, R

2014-12-01

As the literature is not exhaustive with reference to the way the Turin Shroud (TS) Man was crucified, and it is not easy to draw significant information from only a "photograph" of a man on a linen sheet, this study tries to add some detail on this issue based on both image processing of high resolution photos of the TS and on experimental tests on arms and legs of human cadavers. With regard to the TS Man hands, a first hypothesis states that the left hand of the TS Man was nailed twice at two different anatomical sites: the midcarpal joint medially to the pisiform between the lunate/pyramidal and capitate/uncinate bones (Destot's space) and the radiocarpal joint between the radio, lunate and scaphoid; also the right hand would have been nailed twice. A second hypothesis, preferred by the authors, states that the hands were nailed only once in the Destot's space with partial lesion of the ulnar nerve and flexion of the metacarpophalangeal joint of the thumbs. With regard to the TS Man feet, the imprint of the sole of the right foot leads to the conclusion that TS Man suffered a dislocation at the ankle just before the nailing. The entrance hole of the nail on the right foot is a few inches from the ankle, and excludes a double nailing. The nail has been driven between the tarsal bones. The TS Man suffered the following tortures during crucifixion: a very serious and widespread causalgia due to total paralysis of the upper right limb (paradoxical causalgia); a nailing of the left wrist with damage to the ulnar nerve; a similar nailing of the right wrist; and a nailing to both feet using one only nail that injured the plantaris medialis nerves. The respiratory limitation was probably not sufficient to cause death by asphyxiation. Also considering the hypovolemia produced by scourging and the many other tortures detectable on the TS, the principal cause of death can be attributed to a myocardial infarction. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Impedance hand controllers for increasing efficiency in teleoperations

NASA Technical Reports Server (NTRS)

Carignan, C.; Tarrant, J.

1989-01-01

An impedance hand controller with direct force feedback is examined as an alternative to bilateral force reflection in teleoperations involving force contact. Experimentation revealed an operator preference for direct force feedback which provided a better feel of contact with the environment. The advantages of variable arm impedance were also made clear in tracking tests where subjects preferred the larger hand controller inertias made possible by the acceleration feedback loop in the master arm. The ability to decouple the hand controller impedance from the slave arm dynamics is expected to be even more significant when the inertial properties of various payloads in the slave arm are considered.

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.

Lateral bias and temperament in the domestic cat (Felis silvestris).

PubMed

McDowell, Louise J; Wells, Deborah L; Hepper, Peter G; Dempster, Martin

2016-11-01

Research points to a relationship between lateralization and emotional functioning in humans and many species of animal. The present study explored the association between paw preferences and emotional functioning, specifically temperament, in a species thus far overlooked in this area, the domestic cat. Thirty left-pawed, 30 right-pawed, and 30 ambilateral pet cats were recruited following an assessment of their paw preferences using a food-reaching challenge. The animals' temperament was subsequently assessed using the Feline Temperament Profile (FTP). Cats' owners also completed a purpose-designed cat temperament (CAT) scale. Analysis revealed a significant relationship between lateral bias and FTP and CAT scale scores. Ambilateral cats had lower positive (FTP+) scores, and were perceived as less affectionate, obedient, friendly, and more aggressive, than left or right-pawed animals. Left and right pawed cats differed significantly on 1 trait on the CAT scale, namely playfulness. The strength of the cats' paw preferences was related to the animals' FTP and CAT scores. Cats with a greater strength of paw preference had higher FTP+ scores than those with a weaker strength of paw preference. Animals with stronger paw preferences were perceived as more confident, affectionate, active, and friendly than those with weaker paw preferences. Results suggest that motor laterality in the cat is strongly related to temperament and that the presence or absence of lateralization has greater implications for the expression of emotion in this species than the direction of the lateralized bias. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

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...