scholarly journals Individual Laterality in Ghost Crabs (Ocypode saratan) Influences Burrowing Behavior

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1512
Author(s):  
Reuven Yosef ◽  
Michal Daraby ◽  
Alexei Semionovikh ◽  
Jakub Z. Kosicki
Keyword(s):  
Natural Selection ◽  
Red Sea ◽  
Selection Pressure ◽  
Left Handed ◽  
Self Defense ◽  
Temporal Segregation ◽  
Ghost Crabs ◽  
Left And Right ◽  
Burrowing Behavior ◽  
The Right

Behavioral handedness is known to enhance an individual’s handling capabilities. However, the ecological advantages in brachyuran crustaceans remain unclear, despite the Ocypode species having been studied extensively. Thus, in this study, we analyzed the laterality of the endemic Red Sea ghost crab on one beach in Eilat, Israel. We successfully documented the laterality of the large cheliped in 125 crabs; in 60 (48.0%), the right cheliped was larger, and in 64 (51.2%), the left. We also observed temporal segregation between the right- and left-clawed crabs. The right-handed crabs start activity just after sunrise, while left-handed crabs appear ca. 40 min after it. Similarly, temporal segregations were also observed in the evening. The right-clawed crab activity peaked ca. 20 min before sunset, while the left-clawed crabs were active uniformly. Additionally, burrow entrances corresponded to the larger cheliped of the resident individual and is probably a self-defense-related behavior. We conclude that cheliped laterality in O. saratan populations should be considered as a bimodal trait, where left- and right-handedness is not under natural selection pressure.

Handedness affects Emotional Valence Asymmetry

1989 ◽  
Vol 68 (2) ◽  
pp. 435-441 ◽  
Author(s):  
Richard A. McFarland ◽  
Robert Kennison
Keyword(s):  
Negative Affect ◽  
Hemispheric Asymmetry ◽  
Emotional Responses ◽  
Emotional Valence ◽  
Left Handed ◽  
Two Factors ◽  
Left And Right ◽  
The Asymmetry ◽  
The Right ◽  
Cerebral Processing

Music was played monaurally to 80 right-handed and 80 left-handed subjects. Right-handers reported more positive and less negative affect if the music was to the right ear. Left-handers reported experiencing more positive and less negative affect during music to the left ear. The hand × ear interaction was significant. The valence of emotional responses to the music seems influenced by a combination of at least two factors, (1) differences between left- and right-handers in the cerebral processing of emotional valence and (2) differences in the processing of emotional valence within each handedness group depending upon which hemisphere was initially most strongly engaged by the music. These results partially corroborate and extend the findings of previous studies in which briefer stimuli were presented tachistoscopically or dichotically. It is concluded that, while there is hemispheric asymmetry in the processing of emotional valence, the direction of the asymmetry may be associated with the handedness of the subjects.

scholarly journals Handedness and gender influence blood pressure in young healthy men and women: A pilot study

2016 ◽  
Vol 50 (1) ◽  
pp. 10-15 ◽  
Author(s):  
I Rueda ◽  
I Banegas ◽  
I Prieto ◽  
R Wangensteen ◽  
AB Segarra ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Sex Hormones ◽  
Sex Steroids ◽  
Menstrual Phase ◽  
Men And Women ◽  
Left Handed ◽  
Gender Influence ◽  
Left And Right ◽  
And Gender ◽  
The Right

AbstractObjective. The type and level of sex steroids influence blood pressure (BP). It has been suggested that functional brain asymmetries may be influenced by sex hormones. In addition, there are inter-arm differences in BP not yet related with handedness. In this study, we hypothesize a possible association between sex hormones, handedness, and inter-arm differences in blood pressure.Methods. To analyze this hypothesis, we measured BP in the left and right arm of the left and right handed adult young men and women in menstrual and ovulatory phase and calculated their mean arterial pressure (MAP).Results. Significant differences depending on sex, arm, handedness or phase of the cycle were observed. MAP was mostly higher in men than in women. Remarkably, in women, the highest levels were observed in the left handed in menstrual phase. Interestingly, the level of handedness correlated negatively with MAP measured in the left arm of right-handed women in the ovulatory phase but positively with the MAP measured in the right arm of right-handed women in the menstrual phase.Conclusions. These results may reflect an asymmetrical modulatory influence of sex hormones in BP control.

Cerebral Lateralization of Global-Local Processing in Left- and Right-Handed People

2005 ◽  
Vol 100 (3) ◽  
pp. 734-742 ◽  
Author(s):  
Mohammad Ali Goodarzi ◽  
Mohammad Reza Taghavi ◽  
Mohammad Reza Zoughi
Keyword(s):  
Visual Field ◽  
Left Visual Field ◽  
Right Hemisphere ◽  
Local Processing ◽  
Cerebral Lateralization ◽  
Left Handed ◽  
Left And Right ◽  
The Right ◽  
Paradigm Analysis ◽  
Local Superiority

Cerebral lateralization of global-local processing of 70 left-handed and 70 right-handed students was compared using a computerized global-local task in a half-visual field paradigm. Analysis showed that left-handed individuals were slower than right-handed individuals in processing Globally Directed stimuli presented to the left visual field (right hemisphere). In addition, left-handed individuals showed smaller local superiority in the left hemisphere to the right-handed individuals. These findings are more consistent with Levy's prediction of spatial inferiority of left-handed individuals than Geschwind and Galaburda's or Annett's hypotheses.

Synchronization Error in Bilateral Simultaneous Flexion of Elbows

1975 ◽  
Vol 40 (2) ◽  
pp. 527-532 ◽  
Author(s):  
R. Nakamura ◽  
R. Taniguchi ◽  
Y. Oshima
Keyword(s):  
Warning Signal ◽  
Mirror Image ◽  
Sound Stimulus ◽  
Synchronization Error ◽  
Experimental Conditions ◽  
Synchronization Errors ◽  
Left Handed ◽  
Left And Right ◽  
The Difference ◽  
The Right

Using 7 left- and 7 right-handed subjects, the difference in time between left and right arms in the initiation of bilateral simultaneous flexion of elbows (synchronization error) was measured under three conditions: response to a sound stimulus with a warning signal, response to a sound stimulus without a warning signal, and self-initiated trial (option). The absolute value of synchronization errors depended upon experimental conditions. In conditions ‘with warning’ and ‘option’ the dominance shown in performance of left-handed subjects was the mirror-image of that shown by the right-handed subjects. The right biceps muscle responded faster in left-handed subjects and vice versa. Right-handed subjects showed rather a constant value in their dispersion of synchronization errors.

Rein tension in novice riders when riding a horse simulator

2017 ◽  
Vol 13 (4) ◽  
pp. 237-242 ◽  
Author(s):  
H.M. Clayton ◽  
B. Smith ◽  
A. Egenvall
Keyword(s):  
Mixed Models ◽  
Sagittal Plane ◽  
Sampling Rate ◽  
Dominant Hand ◽  
Left Handed ◽  
Maximal Tension ◽  
Left And Right ◽  
The Mean ◽  
The Right

This study reports tension in the left and right reins when riding a horse simulator that moved only in the sagittal plane. The objective was to determine whether asymmetries in rein tension of novice riders at the rising trot, canter, and halt were present, and if so, to investigate their relationship with the rider’s handedness. The experimental hypothesis was that rein tension would be higher on the side of the rider’s non-dominant hand. 22 novice riders (19 right-handed; 3 left-handed) rode a horse simulator at halt, rising trot and canter. Rein tension was recorded in both reins at a sampling rate of 1000 Hz for 8 s at each gait. The variables measured in rising trot and canter were minimal and maximal tension, the change between minimal and maximal values and mean tension per step at rising trot or per stride at canter. At halt only mean tension during the 8 s recording was measured. Comparisons between right and left reins and between right-handed and left-handed riders were made using mixed models. The results showed no asymmetries in mean tension at halt. In rising trot and canter all significant differences involved higher tension in the right rein regardless of handedness of the riders. During rising trot the minimum was higher in the right rein over all riders and both the mean and maximal values were higher in the right rein in left-handed riders. In canter left-handed riders had higher mean tension in the right rein. All recorded asymmetries had higher tension in the right rein compared with the left and they were more prevalent in left-handed riders which implies higher tension in the non-dominant hand. Rein tension patterns were not symmetrical on the left and right sides and asymmetries in left-handed riders were not mirrored in right-handed riders.

scholarly journals Handedness Side and Magnetization Transfer Ratio in the Primary Sensorimotor Cortex Central Sulcus

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Mario Mascalchi ◽  
Stefano Ciulli ◽  
Andrea Bianchi ◽  
Chiara Marzi ◽  
Stefano Orsolini ◽  
...  
Keyword(s):  
Magnetization Transfer ◽  
Magnetization Transfer Ratio ◽  
Precentral Gyrus ◽  
Central Sulcus ◽  
Left Handed ◽  
Significant Difference ◽  
Primary Sensorimotor Cortex ◽  
Variable Content ◽  
Left And Right ◽  
The Right

Left-handers show lower asymmetry in manual ability when compared to right-handers. Unlike right-handers, left-handers do not show larger deactivation of the ipsilateral primary sensorimotor (SM1) cortex on functional magnetic resonance imaging when moving their dominant than their nondominant hand. However, it should be noted that morphometric MRI studies have reported no differences between right-handers and left-handers in volume, thickness, or surface area of the SM1 cortex. In this regard, magnetization transfer (MT) imaging is a technique with the potential to provide information on microstructural organization and macromolecular content of tissue. In particular, MT ratio index of the brain gray matter is assumed to reflect the variable content of afferent or efferent myelinated fibers, with higher MT ratio values being associated with increased fibers number or degree of myelination. The aim of this study was hence to assess, for the first time, through quantitative MT ratio measurements, potential differences in microstructural organization/characteristics of SM1 cortex between left- and right-handers, which could underlay handedness side. Nine left-handed and 9 right-handed healthy subjects, as determined by the Edinburgh handedness inventory, were examined with T1-weighted and MT-weighted imaging on a 3 T scanner. The hands of subjects were kept still during all acquisitions. Using FreeSurfer suite and the automatic anatomical labeling parcellations defined by the Destrieux atlas, we measured MT ratio, as well as cortical thickness, in three regions of interests corresponding to the precentral gyrus, the central sulcus, and the postcentral gyrus in the bilateral SM1 cortex. No significant difference between left- and right-handers was revealed in the thickness of the three partitions of the SM1 cortex. However, left-handers showed a significantly (p = 0.007) lower MT ratio (31.92%  ± 0.96%) in the right SM1 central sulcus (i.e., the hand representation area for left-handers) as compared to right-handers (33.28%  ± 0.94%). The results of this preliminary study indicate that quantitative MT imaging, unlike conventional morphometric MRI measurements, can be a useful tool to reveal, in SM1 cortex, potential microstructural correlates of handedness side.

Involvement of the Primary Motor Cortex in Controlling Movements Executed with the Ipsilateral Hand Differs between Left- and Right-handers

2011 ◽  
Vol 23 (11) ◽  
pp. 3456-3469 ◽  
Author(s):  
Femke E. van den Berg ◽  
Stephan P. Swinnen ◽  
Nicole Wenderoth
Keyword(s):  
Motor Cortex ◽  
Left Hemisphere ◽  
Primary Motor Cortex ◽  
Movement Control ◽  
Motor Tasks ◽  
Left Hand ◽  
Left Handed ◽  
Virtual Lesion ◽  
Left And Right ◽  
The Right

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.

Differences between Left- and Right-Handers on a Measure of Creativity

1981 ◽  
Vol 53 (3) ◽  
pp. 787-792 ◽  
Author(s):  
G. Anthony Newland
Keyword(s):  
Multivariate Analysis ◽  
Creative Thinking ◽  
Creative Behavior ◽  
Left Handed ◽  
Left And Right ◽  
The Right ◽  
College Educated

The literature reports a number of differences both psychological and physiological between left- and right-handed individuals. Creativity was investigated as another dimension for which differences may exist, based on the belief that the left-handed are challenged by an environment mostly organized for the right-handed and make special adaptations that may signal creative behavior. A figural form of the Torrance Tests of Creative Thinking was used to measure creativity on 192 participants, 96 left-handed and 96 right-handed individuals. A multivariate analysis indicated that the left-handed demonstrated greater creativity than the right-handed on all four scales of the Torrance test; females scored higher than males, and college-educated subjects scored higher than those with no college.

A Dissociation between the Representation of Tool-use Skills and Hand Dominance: Insights from Left- and Right-handed Callosotomy Patients

2005 ◽  
Vol 17 (2) ◽  
pp. 262-272 ◽  
Author(s):  
Scott H. Frey ◽  
Margaret G. Funnell ◽  
Valerie E. Gerry ◽  
Michael S. Gazzaniga
Keyword(s):  
Left Hemisphere ◽  
Tool Use ◽  
Right Hemisphere ◽  
Hand Dominance ◽  
Conceptual Level ◽  
Left Hand ◽  
Left Handed ◽  
Contralateral Hand ◽  
Left And Right ◽  
The Right

The overwhelming majority of evidence indicates that the left cerebral hemisphere of right-handed humans is dominant both for manual control and the representation of acquired skills, including tool use. It is, however, unclear whether these functions involve common or dissociable mechanisms. Here we demonstrate that the disconnected left hemispheres of both right- and left-handed split-brain patients are specialized for representing acquired tool-use skills. When required to pantomime actions associated with familiar tools (Experiment 2), both patients show a right-hand (left hemisphere) advantage in response to tool names, pictures, and actual objects. Accuracy decreases as stimuli become increasingly symbolic when using the left hand (right hemisphere). Tested in isolation with lateralized pictures (Experiment 3), each patient's left hemisphere demonstrates a significant advantage over the right hemisphere for pantomiming tool-use actions with the contralateral hand. The fact that this asymmetry occurs even in a left-handed patient suggests that the left hemisphere specialization for representing praxis skills can be dissociated from mechanisms involved in hand dominance located in the right hemisphere. This effect is not attributable to differences at the conceptual level, as the left and right hemispheres are equally and highly competent at associating tools with observed pantomimes (Experiment 4).

Comparison of Vestibular Function Between Right and Left Handed Normal Population

2018 ◽  
Vol 16 (1) ◽  
pp. 28-31
Author(s):  
Sharma Bhandari ◽  
Sagun Shrestha ◽  
R.K. Saxena
Keyword(s):  
Normal Population ◽  
Vestibular Function ◽  
Hand Preference ◽  
Normal Subjects ◽  
Slow Phase ◽  
Canal Paresis ◽  
Slow Phase Velocity ◽  
Left Handed ◽  
Left And Right ◽  
The Right

Objective To identify the side of vestibular dominance in right handed & left handed people. Method A total of 50 normal subjects, aged between 15 - 45 years were included as Left handers (n = 25) and Right handers (n = 25). Handedness was confirmed by the Annett Hand Preference Questionnaire. Bithermal caloric testing was done which was recorded by Electronystagmography (ENG). Maximum Slow Phase Velocity (MSPV) was taken as the parameter of choice. Directional Preponderance (DP) and Canal Paresis (CP) were calculated in each group. Results Out of the 25 Left handed subjects, 8 had DP towards Left whereas 7 had DP towards the Right and the remaining 10 showed no DP to any side (normal) (p<0.001). Out of the 25 Right handed subjects, 4 had DP towards Right and none had DP towards the Left, remaining 21 showed no DP to any side (normal) (p<0.001). For CP, out of 25 Left handed subjects, 2 showed CP towards the Left and 1 towards the Right, the remaining 22 showed no CP (normal) at all. Similarly out of the 25 Right handed subjects, 2 showed CP towards the Left and 1 towards the Right, the remaining 22 showed no CP (normal) at all. Out of 25 Right handers, it was found that Right handers showed Right vestibular preference whereas vestibular preference was almost equally distributed to Left and Right side in Left handers. Conclusion On considering DP, it was found that Right handers showed Right vestibular preference whereas vestibular preference was almost equally distributed toLeft and Right side in Left handers (p<0.001).

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