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OBJECTIVES Calcaneal fractures often require contralateral, uninjured calcaneus radiographs as a template. The purpose of this study was to establish mean values for calcaneal radiographic parameters in an uninjured urban American population and perform side-by-side comparison with respect to age, sex, laterality, and radiograph obliquity. DESIGN Retrospective analysis of consecutive patients. SETTING 14-hospitals including1 Level I trauma center. PATIENTS/PARTICIPANTS Retrospective review of >800 uninjured patients with bilateral foot and calcaneus radiographs obtained between June and December 2019 was performed. Inclusion criteria were the following: age 18 to 89 without fracture, previous foot surgical procedures, radiographic evidence of arthrosis in ankle, hindfoot, or midfoot, osteomyelitis, tumor or foot deformities. INTERVENTION The lateral radiographs were independently reviewed by three observers, measuring Bohler's Angle (BA), Crucial Angle of Gissane (CAG), calcaneal length (CL), calcaneal height (CH), calcaneotalar ratio (CTR), and radiograph obliquity (XRO). MAIN OUTCOME MEASUREMENTS The mean values of BA, CAG, CL, CH, and CTR were established. Side-by-side comparisons were completed with respect to age, sex, laterality, and XRO. RESULTS There were no statistically significant differences in side-by-side measurements of the BA, CAG, CL, or CH. XRO had significant effects on the measurements of BA, CAG, CH, and CTR. Side-by-side comparisons showed greater inter-subject variability than within subject differences. CONCLUSIONS We did not observe any differences in commonly measured calcaneal radiographic parameters. CAG is not a reliable parameter for diagnostic and operative planning purposes. We conclude that the use of contralateral calcaneus radiographs as templates for calcaneus fractures is a valid technique. LEVEL OF EVIDENCE Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

INTRODUCTION: Lateralization in brain function has been associated with age and sex in previous work; however, there has been less focus on lateralization of functional networks during development. AIM: We aim to examine laterality in typical development; a clearer understanding of how and to what extent functional brain networks are lateralized in typical development may eventually prove to hold predictive information in psychopathology. MATERIAL AND METHODS: In this study, we examine the lateralization of resting-state networks assessed with a group-independent component analysis using resting-state functional magnetic resonance imaging from a large cohort consisting of 774 children, ages 6–10 years. This is an extension of our previous work on normal aging in adults, where we now assess whether there are similar patterns in children. RESULTS: Unlike the results from our study of healthy aging in adults, which showed a decrease in laterality with increasing age, in this study we found both decreases and increases in lateralization in multiple networks with development. For example, auditory and sensorimotor regions had greater bilateral connectivity with development, whereas regions including the dorsolateral frontal cortex (Brodmann area left 9 and left 46) showed an increase in left lateralization with development. CONCLUSION: Our findings support a complex, nonlinear association between laterality and age in school-age children, a time when brain function and structure are developing rapidly. We also found brain networks in which laterality was significantly associated with sex, handedness, and intelligence quotient, but we did not find any significant association with behavioral scores. IMPACT STATEMENT: Lateralization in brain function has been associated with age and sex in several previous studies; however, there has been less focus on lateralization of functional networks during development. A clearer understanding of how and to what extent functional brain networks are lateralized in typical development may eventually prove to hold predictive information in psychopathology. In this study, we examine the lateralization of resting-state networks assessed with a group-independent component analysis using resting-state functional magnetic resonance imaging from a large cohort consisting of 774 children, ages 6–10 years.

OBJECTIVE Prism adaptation was shown to modify auditory perception. Using a dichotic listening task, which assesses auditory divided attention, benefits of a rightward prism adaptation were demonstrated in neglect patients (i.e., a syndrome following right hemisphere brain damage) by reducing their left auditory extinction. It is currently unknown whether prism adaptation affects auditory divided attention in healthy subjects. In the present study, we investigated the aftereffects of prism adaptation on dichotic listening. METHOD A sample of 47 young adults performed a dichotic listening task, in which pairs of words were presented with two words sounded simultaneously, one in each ear. Three parameters were measured: The percentage of recalled words, the percentage of correctly recalled words, and the laterality index (LI). RESULTS Prism adaptation to a leftward optical deviation (L-PA) significantly increased the overall percentage of recalled words (p = .044) and that from the right ear (p = .002), and the overall LI (p = .049). CONCLUSIONS For the first time, these findings demonstrate that L-PA produced an orientation of the auditory divided attention in favor of the right ear in healthy participants. This asymmetrical aftereffect provides a new argument in favor of the cross-modal dimension of prism adaptation, although an acclimatization effect of the dichotic listening task is also discussed. Our study opens up a new avenue for using prism adaptation in the field of auditory rehabilitation requiring a modulation of auditory attention. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

PURPOSE : Successful orbital reconstruction relies on an accurate restoration of orbital volume (OV). The purpose of this study was to determine if the OV of African American (AA) subjects differs from that of Caucasian subjects. MATERIALS AND METHODS : The authors implemented a retrospective observational study of successive subjects who received a maxillofacial computed tomography (CT) scan at a level I trauma center between 2017 and 2020. The primary predictor variable was race (AA/Caucasian). The primary outcome variable was orbital volume. Two independent examiners calculated OV with an open access OsiriX MD software version 10.0.5 (Pixmeo, Switzerland). Inter-rater reliability was calculated. Differences between races, genders, and sides were tested using independent samples t-test with a significance of p RESULTS : Sixty subjects (120 orbits) were included in the study. The mean age was 36.7 (SD ±13.2) years with a range of 22 to 78 years. Gender distribution was equal with 30 male (50%) and 30 female (50%) subjects. Inter-examiner reliability was 0.973. The mean OV of AA and Caucasians was 22.38 and 23.23 cm3, respectively (p = 0.07). The mean OV of AA and Caucasian males was 23.92 and 24.17cm 3 , respectively (p = 0.71). The mean OV in AA and Caucasian females was 20.84 and 22.28cm 3 , respectively (p = 0.013). CONCLUSION : African-American female subjects appear to have a smaller OV when compared to Caucasians which may influence orbital reconstruction. Laterality does not appear to be associated with any differences in OV.

The primary sensory modality for probing spatial perception can vary among psychophysical paradigms. In the subjective visual vertical (SVV) task, the brain must account for the position of the eye within the orbit to generate an estimate of a visual line orientation, whereas in the subjective haptic vertical (SHV) task, the position of the hand is used to sense the orientation of a haptic bar. Here we investigated whether a hand sensory bias can affect SHV measurement. We measured SHV in 12 subjects (6 left-handed and 6 right-handed) with a forced-choice paradigm using their left and right hands separately. The SHV measurement was less accurate than the SVV measurements (-0.6 ± 0.7) and it was biased in the direction of the hand used in the task but was not affected by handedness; SHV left hand -6.8 ± 2.1° (left-handed -7.9 ± 3.6°, right-handed -5.8 ± 2.5°) and right hand 9.8 ± 1.5° (left-handed 7.4 ± 2.2°, right-handed 12.3 ± 1.8°). SHV measurement with the same hand was also affected by the haptic bar placement on the left or right side versus midline, showing a side effect (left vs midline -2.0 ± 1.3°, right vs midline 3.8 ± 1.7°). Midline SHV measures using the left and right hands were different, confirming a laterality effect (left hand -4.5 ± 1.7°, right hand 6.4 ± 2.0°). These results demonstrate a sensory bias in SHV measurement related to the effects of both hand-in-body (i.e., right vs left hand) and hand-in-space positions. Such modality-specific bias may result in disparity between SHV and SVV measurements, and therefore cannot be generalized to vertical or spatial perception.

When using a bimanual tool to strike an object, most people place their preferred hand closer to the striking end. In sports, a player is deemed to adopt a “right- or left-handed” stance depending on the hand that is lower on the club or bat. Research has suggested there is an advantage in going against this convention by placing the preferred hand at the top in a “reversed-stance”. This study aimed to establish if the reversed-stance advantage exists in golf, whether it is underpinned by the preferred hand or dominant eye, and why players adopt such a stance. We tested hand preference, eye dominance, and full swing stance in 150 golfers (30 for each handicap category) and conducted follow-up interviews with 12 reversed-stance players. Professional or category 1 golfers were 21.5 times more likely to adopt a reversed-stance. The advantage could not be explained by ambidexterity or the dominant eye but could be explained by the position of the preferred hand. Reversed-stance players cited a variety of reasons for adopting it and were more likely to display a left-hand preference. Findings offer initial evidence of a reversed-stance advantage in golf and can inform work identifying its origins and mechanisms.

Masturbation is a common human behaviour. Compared to other unimanual behaviours it has unique properties, including increased sexual and emotional arousal, and privacy. Self-reported hand preference for masturbation was examined in 104 left-handed and 103 right-handed women, and 100 left-handed and 99 right-handed men. Handedness (modified Edinburgh Handedness Inventory, EHI), footedness, eyedness, and cheek kissing preferences were also measured. Seventy nine percent used their dominant hand (always/usually) for masturbation, but left-handers (71.5%) were less consistently lateralized to use their dominant hand than right-handers (86.5%). Hand preference for masturbation correlated more strongly with handedness (EHI), than with footedness, eyedness, or cheek preference. There was no difference in masturbation frequency between left- and right-handers, but men masturbated more frequently than women, and more women (75%) than men (33%) masturbated with sex aids. For kissing the preferred cheek of an emotionally close person from the viewer's perspective, left-handers showed a left-cheek preference, and right-handers a weaker right-cheek preference. The results suggest that hemispheric asymmetries in emotion do not influence hand preference for masturbation but may promote a leftward shift in cheek kissing. In all, masturbation is lateralized in a similar way to other manual motor behaviours in left-handed and right-handed men and women.

Laterality patterns of resting state networks (RSN) change in various neuropsychiatric conditions. Multiple sclerosis (MS) causes neuro-cognitive symptoms involving dysfunctional large-scale brain networks. Yet, whether healthy laterality patterns of RSNs are maintained in MS and whether altered laterality patterns explain disease symptoms has not been explicitly investigated. We analysed functional MRI and diffusion tensor imaging data from 24 relapsing–remitting MS patients and 25 healthy participants. We performed group-level independent component analysis and used dual regression to estimate individual versions of well-established RSNs. Voxelwise laterality indices were calculated for each RSN. Group differences were assessed via a general linear model-based approach. The relationship between functional laterality and white matter microstructural asymmetry was assessed using Tract-Based Spatial Statistics. Spearman’s correlation was calculated between laterality indices and Brief International Cognitive Assessment for Multiple Sclerosis scores. Functional laterality of the dorsal attention network showed a significant leftward shift in the MS group in the posterior intraparietal sulcus (p

Background and ObjectivesTask fMRI is a clinical tool for language lateralization, but has limitations, and cannot provide information about network-level plasticity. Additional methods are needed to improve the precision of presurgical language mapping. We investigate language resting-state functional connectivity (RS fMRI; FC) in typically developing children (TD) and children with epilepsy. Our objectives were to (1) understand how FC components differ between TD children and those with epilepsy; (2) elucidate how the location of disease (frontal/temporal epilepsy foci) affects FC; and (3) investigate the relationship between age and FC.MethodsOur sample included 55 TD children (mean age 12 years, range 7–18) and 31 patients with focal epilepsy (mean age 13 years, range 7–18). All participants underwent RS fMRI. Using a bilateral canonical language map as target, vertex-wise intrahemispheric FC map and interhemispheric FC map for each participant were computed and thresholded at top 10% to compute an FC laterality index (FCLI; [(L – R)/(L + R)]) of the frontal and temporal regions for both integration (intrahemispheric FC; FCLIi) and segregation (interhemispheric FC; FCLIs) maps.ResultsWe found FC differences in the developing language network based on disease, seizure foci location, and age. Frontal and temporal FCLIi was different between groups (t[84] = 2.82, p < 0.01; t[84] = 4.68, p < 0.01, respectively). Frontal epilepsy foci had the largest differences from TD (Cohen d frontal FCLIi = 0.84, FCLIs = 0.51; temporal FCLIi = 1.29). Development and disease have opposing influences on the laterality of FC based on groups. In the frontal foci group, FCLIi decreased with age (r = −0.42), whereas in the temporal foci group, FCLIi increased with age (r = 0.40). Within the epilepsy group, increases in right frontal integration FCLI relates to increased right frontal task activation in our mostly left language dominant group (r = 0.52, p < 0.01). Language network connectivity is associated with higher verbal intelligence in children with epilepsy (r = 0.45, p < 0.05).DiscussionThese findings lend preliminary evidence that FC reflects network plasticity in the form of adaptation and compensation, or the ability to recruit support and reallocate resources within and outside of the traditional network to compensate for disease. FC expands on task-based fMRI and provides complementary and potentially useful information about the language network that is not captured using task-based fMRI alone.

OBJECTIVE: This study was undertaken to measure the duration of chronic electrocorticography (ECoG) needed to attain stable estimates of the seizure laterality ratio in patients with drug-resistant bilateral temporal lobe epilepsy (BTLE). METHODS: We studied 13 patients with drug-resistant BTLE who were implanted for at least 1 year with a responsive neurostimulation device (RNS System) that provides chronic ambulatory ECoG. Bootstrap analysis and nonlinear regression were applied to model the relationship between chronic ECoG duration and the probability of capturing at least one seizure. Laterality of electrographic seizures in chronic ECoG was compared with the seizure laterality ratio from Phase 1 scalp video-electroencephalographic (vEEG) monitoring. The Kaplan–Meier estimator was used to evaluate time to seizure laterality ratio convergence. RESULTS: Seizure laterality ratios from Phase 1 scalp vEEG monitoring correlated poorly with those from RNS chronic ECoG (r = .31, p = .30). Across the 13 patients, average electrographic seizure frequencies ranged from 1.4 seizures/month to 5.1 seizures/day. A 50% probability of recording at least one electrographic seizure required 9.1 days of chronic ECoG, and 90% probability required 44.3 days of chronic ECoG. A median recording duration of 150.9 days (5 months), corresponding to a median of 16 seizures, was needed before confidence intervals for the seizure laterality ratio reliably contained the long-term value. The median recording duration before the point estimate of the seizure laterality ratio converged to a stationary value was 236.8 days (7.9 months). SIGNIFICANCE: RNS chronic ECoG overcomes temporal sampling limitations intrinsic to inpatient Phase 1 vEEG evaluations. In patients with drug-resistant BTLE, approximately 8 months of chronic RNS ECoG are needed to precisely estimate the seizure laterality ratio, with 75% of people with BTLE achieving convergence after 1 year of RNS recording. For individuals who are candidates for unilateral resection based on seizure laterality, optimized recording duration may help avert morbidity associated with delay to definitive treatment.

Background and ObjectivesTo identify white matter fiber tracts that exhibit structural abnormality in patients with bottom-of-sulcus dysplasia (BOSD) and investigate their association with seizure activity.MethodsWhole-brain fixel-based analysis of diffusion MRI data was performed to identify white matter fiber tracts with significant reductions in fiber density and cross-section in patients with BOSD (n = 20) when compared to healthy control participants (n = 40). Results from whole-brain analysis were used to investigate the association of fiber tract abnormality with seizure frequency and epilepsy duration.ResultsDespite the focal nature of the dysplasia, patients with BOSD showed widespread abnormality in white matter fiber tracts, including the bilateral corticospinal, corticothalamic, and cerebellothalamic tracts, superior longitudinal fasciculi, corpus callosum (body), and the forceps major. This pattern of bilateral connectivity reduction was not related to the laterality of the lesion. Exploratory post hoc analyses showed that high seizure frequency was associated with greater reduction in fiber density at the forceps major, bilateral corticospinal, and cerebellothalamic tracts.DiscussionWe demonstrate evidence of a bilaterally distributed, specific white matter network that is vulnerable to disruption in BOSD. The degree of tract abnormality is partly related to seizure activity, but additional contributors such as the genetic background and effects of treatment or environment have not been excluded.

Purpose Functional MRI (fMRI) enables evaluation of language cortical organization and plays a central role in surgical planning. Diffusion Tensor Imaging (DTI) or Tractography, allows evaluation of the white matter fibers involved in language. Unlike fMRI, DTI does not rely on the patient's cooperation. In monolinguals, there is a good correlation between the lateralization of language on fMRI and on DTI. Our objective is to delineate the arcuate fasciculus (AF) in right- and left-handed trilinguals and determine if the AF laterality on DTI is correlated to language lateralization on fMRI.Methods 15 right and 15 left-handed trilingual volunteers underwent fMRI and DTI. Laterality Index was determined on fMRI (fMRI-LI). Mean Diffusivity, Fractional Anisotropy (FA), Number of Fibers, Fiber Length, Fiber Volume and Laterality Index (DTI-LI) of the AF were calculated on DTI.Results 28 of the 30 subjects presented a bilateral AF. Most subjects (52%) were found to have a bilateral language lateralization of the AF on DTI. Only 4 subjects had bilateral lateralization of language on fMRI. The right AF demonstrated lower diffusivity than the left AF in the total participants, the right-handed, and the left-handed subjects. FA, Volume and Length of the AF were not significantly different between the two hemispheres. No correlation was found between the DTI-LI of the AF and the fMRI-LI.Conclusion A prominent role of the right AF and a bilateral structural organization of the AF was present in our multilingual population regardless of their handedness. While in prior studies DTI was able to determine language lateralization in monolingual subjects, this was not possible in trilingual highly educated subjects.

There are psychoacoustic methods thought to measure gain reduction, which may be from the medial olivocochlear reflex (MOCR), a bilateral feedback loop that adjusts cochlear gain. Although studies have used ipsilateral and contralateral elicitors and have examined strength at different signal frequencies, these factors have not been examined within a single study. Therefore, basic questions about gain reduction, such as the relative strength of ipsilateral vs contralateral elicitation and the relative strength across signal frequency, are not known. In the current study, gain reduction from ipsilateral, contralateral, and bilateral elicitors was measured at 1-, 2-, and 4-kHz signal frequencies using forward masking paradigms at a range of elicitor levels in a repeated measures design. Ipsilateral and bilateral strengths were similar and significantly larger than contralateral strength across signal frequencies. Growth of gain reduction with precursor level tended to differ with signal frequency, although not significantly. Data from previous studies are considered in light of the results of this study. Behavioral results are also considered relative to anatomical and physiological data on the MOCR. These results indicate that, in humans, cochlear gain reduction is broad across frequencies and is robust for ipsilateral and bilateral elicitation but small for contralateral elicitation.

This study aimed to assess the zygomaticosphenoidal (ZS) angle in patients with reducted unilateral zygomatico-maxillary complex (ZMC) fracture and compare it with the normal control group. This study was performed on CT images of 60 cases and 60 controls with a mean age of 35.1 ± 14.6. The ZS angle was measured on axial images containing the equator of the eyeball. Moreover, the mean absolute difference value and asymmetry index were calculated. Chi-square test, independent-sample t test, 1-way ANOVA, paired-sample t test, and ROC curve analysis were applied. The mean ZS angle in the control group was 46.6° ± 3.5°. Considering laterality, the mean of ZS was not significant in the control group. However, after reduction of unilateral ZMC fracture, there was a significant difference between the mean ZS angle in right and left sides. The mean absolute difference between right and left ZS angles was significantly higher in the case group. A threshold number of 0.9° is established in the mean absolute difference value which is the difference between the right and left ZS angles in an individual for detecting asymmetry. The ZS angle can be a useful anatomical aid to guide surgeons in achieving facial symmetry in ZMC fractures.

Objective To determine if impairment in motor imagery processes is present in Achilles tendinopathy (AT), as demonstrated by a reduced ability to quickly and accurately identify the laterality (left-right judgement) of a pictured limb. Additionally, this study aimed to use a novel data pooling approach to combine data collected at 3 different sites via meta-analytical techniques that allow exploration of heterogeneity. Design Multi-site case-control study. Methods Three independent studies with similar protocols were conducted by separate research groups. Each study-site evaluated left/right judgement performance for images of feet and hands using Recognise© software and compared performance between people with AT and healthy controls. Results from each study-site were independently collated, then combined in a meta-analysis. Results In total, 126 participants (40 unilateral, 22 bilateral AT cases, 61 controls) were included. There were no differences between AT cases and controls for hand image accuracy and reaction time. Contrary to the hypothesis, there were no differences in performance between those with AT and controls for foot image reaction time, however there were conflicting findings for foot accuracy, based on four separate analyses. There were no differences between the affected and unaffected sides in people with unilateral AT. Conclusions Impairments in motor imagery performance for hands were not found in this study, and we found inconsistent results for foot accuracy. This contrasts to studies in persistent pain of limbs, face and knee osteoarthritis, and suggests that differences in pathoetiology or patient demographics may uniquely influence proprioceptive representation.

Decomposition of whole-brain functional connectivity patterns reveals a principal gradient that captures the separation of sensorimotor cortex from heteromodal regions in the default mode network (DMN). Functional homotopy is strongest in sensorimotor areas, and weakest in heteromodal cortices, suggesting there may be differences between the left and right hemispheres (LH/RH) in the principal gradient, especially towards its apex. This study characterised hemispheric differences in the position of large-scale cortical networks along the principal gradient, and their functional significance. We collected resting-state fMRI and semantic, working memory and non-verbal reasoning performance in 175 + healthy volunteers. We then extracted the principal gradient of connectivity for each participant, tested which networks showed significant hemispheric differences on the gradient, and regressed participants’ behavioural efficiency in tasks outside the scanner against interhemispheric gradient differences for each network. LH showed a higher overall principal gradient value, consistent with its role in heteromodal semantic cognition. One frontotemporal control subnetwork was linked to individual differences in semantic cognition: when it was nearer heteromodal DMN on the principal gradient in LH, participants showed more efficient semantic retrieval—and this network also showed a strong hemispheric difference in response to semantic demands but not working memory load in a separate study. In contrast, when a dorsal attention subnetwork was closer to the heteromodal end of the principal gradient in RH, participants showed better visual reasoning. Lateralization of function may reflect differences in connectivity between control and heteromodal regions in LH, and attention and visual regions in RH.

To investigate the mechanisms underlying the effect of repetitive transcranial magnetic stimulation (rTMS) on post-stroke hemiplegia, we assessed alterations in cerebral glucose metabolism. Five post-stroke hemiplegic patients (three targeted for upper limb impairment and two targeted for lower limb impairment) aged 62.6 ± 6.1 years (mean ± standard deviation) with a duration since stroke onset of 3.5 ± 3.8 years participated in this preliminary study. Cerebral glucose metabolism was measured twice—before and after rTMS with intensive rehabilitation—using positron emission tomography with [18F]fluorodeoxyglucose. The Asymmetry Index (AI) was calculated to assess laterality of metabolism between the lesional and contralesional motor areas. The alteration rates of AI (%ΔAI) were compared between participants in whom rTMS was effective and ineffective. Two of the three upper-limb-targeted patients and one of the two lower-limb-targeted patients showed motor function improvements following rTMS treatment. All three patients who responded to rTMS had improved laterality of cerebral glucose metabolism in motor areas, commonly in the precentral gyrus, with an %ΔAI of approximately 10%. In contrast, the two patients who did not respond to rTMS had no improvements in laterality. These results suggest for the first time that improved glucose metabolism is associated with improved motor function after a combination of rTMS and intensive rehabilitation.

PurposeColorectal cancer revealed over the last decades a remarkable shift with an increasing proportion of a right- compared to a left-sided tumor location. In the current study, we aimed to disclose clinicopathological differences between right- and left-sided colon cancer (rCC and lCC) with respect to mortality and outcome predictors.MethodsIn total, 417 patients with colon cancer stage I–IV were analyzed in the present retrospective single-center study. Survival rates were assessed using the Kaplan–Meier method and uni/multivariate analyses were performed with a Cox proportional hazards regression model.ResultsOur study showed no significant difference of the overall survival between rCC and lCC stage I–IV (p = 0.354). Multivariate analysis revealed in the rCC cohort the worst outcome for ASA (American Society of Anesthesiologists) score IV patients (hazard ratio [HR]: 16.0; CI 95%: 2.1–123.5), CEA (carcinoembryonic antigen) blood level > 100 µg/l (HR: 3.3; CI 95%: 1.2–9.0), increased lymph node ratio of 0.6–1.0 (HR: 5.3; CI 95%: 1.7–16.1), and grade 4 tumors (G4) (HR: 120.6; CI 95%: 6.7–2179.6) whereas in the lCC population, ASA score IV (HR: 8.9; CI 95%: 0.9–91.9), CEA blood level 20.1–100 µg/l (HR: 5.4; CI 95%: 2.4–12.4), conversion to laparotomy (HR: 14.1; CI 95%: 4.0–49.0), and severe surgical complications (Clavien-Dindo III–IV) (HR: 2.9; CI 95%: 1.5–5.5) were identified as predictors of a diminished overall survival.ConclusionLaterality disclosed no significant effect on the overall prognosis of colon cancer patients. However, group differences and distinct survival predictors could be identified in rCC and lCC patients.

Mice and rats are among the most common animal model species in both basic and clinical neuroscience. Despite their ubiquity as model species, many clinically relevant brain-behaviour relationships in rodents are not well understood. In particular, data on hemispheric asymmetries, an important organizational principle in the vertebrate brain, are conflicting as existing studies are often statistically underpowered due to small sample sizes. Paw preference is one of the most frequently investigated forms of hemispheric asymmetries on the behavioural level. Here, we used meta-analysis to statistically integrate findings on paw preferences in rats and mice. For both species, results indicate significant hemispheric asymmetries on the individual level. In mice, 81 % of animals showed a preference for either the left or the right paw, while 84 % of rats showed this preference. However, contrary to what has been reported in humans, population level asymmetries were not observed. These results are particularly significant as they point out that paying attention to potential individual hemispheric differences is important in both basic and clinical neuroscience.

Functional and anatomical hemispheric asymmetries abound in the neural language system, yet the relationship between them remains elusive. One attractive proposal is that structural interhemispheric differences reflect or even drive functional language laterality. However, studies on structure-function couplings either find that left and right language dominant individuals display similar leftward structural asymmetry or yield inconsistent results. The current study aimed to replicate and extend prior work by comparing structural asymmetries between neurologically healthy left-handers with right hemispheric language dominance (N = 24) and typically lateralized left-handed controls (N = 39). Based on structural MRI data, anatomical measures of six 'language-related' perisylvian structures were derived, including the surface area of five gray matter regions with known language functions and the FDC (combined fiber density and fiber-bundle cross-sectional area) of the arcuate fasciculus. Only the surface area of the pars triangularis and the anterior insula differed significantly between participant groups, being on average leftward asymmetric in those with typical dominance, but right lateralized in volunteers with atypical language specialization. However, these findings did not survive multiple testing correction and the asymmetry of these structures demonstrated much inter-individual variability in either subgroup. By integrating our findings with those reported previously we conclude that while some perisylvian anatomical asymmetries may differ subtly between typical and atypical speech dominants at the group level, they serve as poor participant-specific predictors of hemispheric language specialization.

Dancers are known to have specific limb preferences when they dance and commonly experience lower limb injury, especially early in their training. The primary aim of this study was to determine and examine the relationships between lateral limb bias, perceived turnout profile, and lower limb injury history in female pre-professional ballet dancers using current definitions of lateral bias, leg dominance, and the concept of "working" and "supporting" legs in dance. A cross-sectional survey design with retrospective recall of 12-month injury history was employed. An online questionnaire was distributed to female dancers between the ages of 16 and 21 years who were training in classical ballet at the pre-professional level in Australia. The questionnaire gathered information regarding laterality, perceived turnout asymmetry, and self-reported 12-month injury profile. Descriptive and correlation analyses were employed to describe dancer profiles and determine relationships between the three variables. Thirty-two dancers participated. The majority of participants (67%) had right-side dominance and most indicated the right leg as their preferred supporting leg (86.7%) and working leg (60%). A total of 17 participants (53.1%) reported at least one injury in the preceding 12-month period and the side injured was significantly correlated with leg dominance (rS = 0.595, p = 0.012), with the majority of injuries also affecting the preferred supporting and working leg. Dancer perceptions regarding turnout range were correlated with their perceptions of leg dominance (rS = 0.556, p = 0.001), but no statistically significant associations were found between perceptions of turnout range and injury side. In pre-professional dancers, the dominant and the preferred supporting or working leg tend to be the same leg, and the results suggest that the dominant and preferred supporting and working leg of dancers are at greatest risk of injury.

Background The right ear advantage (REA) observed for dichotic CV (DCV) testing in Indian languages is seen to be smaller compared with the observations in several studies in English and other languages. Purpose The present study aims to explore whether the differences in the temporal alignment of consonant–vowel (CV) stimuli used for the dichotic task is a contributing factor that can explain the smaller REAs observed in Indian languages. Research Design The study compared the laterality index (LI) values between DCV test results obtained using CV stimuli that were temporally aligned at the acoustic onset versus the burst onset, with 0 milliseconds lag between the right and left ears. Study Sample A total of 50 right-handed individuals (native speakers of Kannada language) in the age range of 17 to 30 years with normal hearing sensitivity participated in the study. Data Collection and Analysis The participants' responses to the two sets of DCV stimuli were recorded and compared. LI was calculated for the overall scores as well as for specific voiced and unvoiced segment combinations. To test the reliability of the findings, 10 of the participants were re-tested using the same stimuli and the data were checked for reliability. Results The overall LI was 15.1% for the stimuli temporally aligned at the burst onset, whereas it was 5.7% for the stimuli temporally aligned at the acoustic onset. The difference in LI was not significant between the alignment conditions for unvoiced–unvoiced and voiced–voiced CV combinations, but this difference was significant for the unvoiced–voiced and voiced–unvoiced CV combinations. Comparing test and re-test scores showed good reliability. Conclusion The results support our hypothesis that smaller REA observed in DCV task in Indian languages was due to the temporal alignment of CV stimuli. In the acoustic-onset-aligned condition, presenting pairs contrasting in the voicing feature tends to cancel out a relative ear advantage.

As a rare disease with genetic pathogenesis, observational study about familial CHD recurrence risk on CHD patients with laterality defects is lacking. This study aimed to investigate familial recurrence among families of patients with CHD and laterality defects, and compare them with CHD patients without laterality defects. A total of 184 patients with CHD and laterality defects treated in Cardiovascular Center, Children’s Hospital of Fudan University were observed from 2008 to 2019. A detailed family history was documented by trained staff using questionnaires, and information about the subtypes of CHD and laterality defects was also collected. In addition, positive family history information, including all three degrees relatives and all affected family members, was reconfirmed by trained medical staff through face-to-face interviews, telephone interviews, and letter return visits. Of the 184 included patients, 30 had at least one family member (from among three linear generations and distant relatives) with CHD. The familial recurrence rate of CHD in our cohort was 16.3% (30/184), which was higher than the 3.3% (67/2024) of patients with CHD without laterality defects. This result shows that the recurrence rate among the first-, second-, and third-degree relatives was 11.7% (11/94), 1.5% (3/204), and 3.1% (6/91) and that the recurrence rate among siblings (21.4%, 9/42) was higher than that among parents (3.8%, 2/52). The familial recurrence risk of CHD among patients with CHD and laterality defects is high, which is consistent with the previous study that reported a high familial recurrence of heterotaxy of 10%. First-degree relatives have a higher recurrence rate than second- and third-degree relatives, especially siblings. These findings have important significance for prenatal screening, intervention, and genetic counseling in the Chinese population, but may not be generalizable to other populations that may have different rates of familial and sporadic cases. Supplementary Information The online version contains supplementary material available at 10.1007/s00246-021-02656-4.

Objectives: To assess whether the order of permanent tooth eruption may be a useful indicator of motor function laterality. Methods: We conducted a cross-sectional study in schoolchildren aged 6–8 years old evaluated in the annual school-based routine dental health examinations conducted by the staff of the primary care centre of an urban district in Barcelona, Spain. We also evaluated hand, foot, eye, and auditory lateralities using a battery of simple exercises. Bivariate and multivariate analysis of data was performed. Results: The study sample included 388 children, 51.3% female, with a mean age of 6.5 years. Right laterality was the predominant side in every variable under study, especially in tooth eruption (310 children; 80%), handedness (349; 89.9%), and footedness (337; 86.8%). In the bivariate analysis, we found a statistically significant association of tooth eruption laterality with handedness and footedness, and of tooth eruption laterality with ocular and auditory lateralities (p

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is characterized by a range of motor and nonmotor symptoms, often with the motor dysfunction initiated unilaterally. Knowledge regarding disease‐related alterations in white matter pathways can effectively help improve the understanding of the disease and propose targeted treatment strategies. Microstructural imaging techniques, including diffusion tensor imaging (DTI), allows inspection of white matter integrity to study the pathogenesis of various neurological conditions. Previous voxel‐based analyses with DTI measures, such as fractional anisotropy and mean diffusivity have uncovered changes in brain regions that are associated with PD, but the conclusions were inconsistent, partially due to small patient cohorts and the lack of consideration for clinical laterality onset, particularly in early PD. Fixel‐based analysis (FBA) is a recent framework that offers tract‐specific insights regarding white matter health, but very few FBA studies on PD exist. We present a study that reveals strengthened and weakened white matter integrity that is subject to symptom laterality in a large drug‐naïve de novo PD cohort using complementary DTI and FBA measures. The findings suggest that the disease gives rise to tissue degeneration and potential re‐organization in the early stage., Parkinson's disease (PD) is a progressive neurodegenerative disorder that is characterized by a range of motor and nonmotor symptoms, often with the motor dysfunction initiated unilaterally. We present a study that reveals strengthened and weakened white matter integrity that is subject to symptom laterality in a large drug‐naïve de novo Parkinson's disease cohort using complementary DTI and FBA measures. The findings suggest that the disease gives rise to tissue degeneration and potential re‐organization in the early stage.

A goal of rehabilitation after stroke is to promote pre-stroke levels of arm use for every day, frequently bimanual, functional activities. We reasoned that, after a stroke, the choice to use one or both hands for bimanual tasks might depend not only on residual motor capacity, but also the specialized demands imposed by the task on the paretic hand. To capture spontaneous, task-specific choices, we covertly observed 50 pre-stroke right-handed chronic stroke survivors (25 each of left, LHD, and right-hemisphere damage, RHD) and 11 age-similar control adults and recorded their hand use strategies for two pairs of bimanual tasks with distinct demands: one with greater precision requirements (photo-album tasks), and another with greater stabilization requirements (letter-envelope tasks). The primary outcome was the choice to use one or both hands. Logistic regression was used to test the two hypotheses that the probability of choosing a bimanual strategy would be greater in those with less severe motor impairment and also in those with LHD. When collapsed across the four tasks, we found support for these hypotheses. Notably, however, the influence of these factors on bimanual choice varied based on task demands. For the photo–album pair, the probability of a bimanual strategy was greater for those with LHD compared to RHD, regardless of the degree of motor impairment. For the letter–envelope pair, we found a significant interaction between impairment and side of lesion in determining the likelihood of choosing both hands. Therefore, the manner in which side of lesion moderates the effect of impairment on hand use depends on the task.

Musical training is thought to be related to improved language skills, for example, understanding speech in background noise. Although studies have found that musicians and nonmusicians differed in morphology of bilateral arcuate fasciculus (AF), none has associated such white matter features with speech-in-noise (SIN) perception. Here, we tested both SIN and the diffusivity of bilateral AF segments in musicians and nonmusicians using diffusion tensor imaging. Compared with nonmusicians, musicians had higher fractional anisotropy (FA) in the right direct AF and lower radial diffusivity in the left anterior AF, which correlated with SIN performance. The FA-based laterality index showed stronger right lateralization of the direct AF and stronger left lateralization of the posterior AF in musicians than nonmusicians, with the posterior AF laterality predicting SIN accuracy. Furthermore, hemodynamic activity in right superior temporal gyrus obtained during a SIN task played a full mediation role in explaining the contribution of the right direct AF diffusivity on SIN performance, which therefore links training-related white matter plasticity, brain hemodynamics, and speech perception ability. Our findings provide direct evidence that differential microstructural plasticity of bilateral AF segments may serve as a neural foundation of the cross-domain transfer effect of musical experience to speech perception amid competing noise.

BACKGROUND: Previous studies have analysed the effect of wearing high-heeled shoes (HHS) on gait analysis, balance and its relation to health. However, further research is needed to study its effect on the difference of chain reactions in the transfer of body impacts from the lower to the upper limbs. OBJECTIVES: The aims of the present research were: (a) to compare the effects of wearing HHS on impacts across body joints during walking with sport shoes (SS) as a reference, and (b) to examine such effects at different speeds. METHODS: Seven well-trained women completed this study. Incremental treadmill walking test were performed with two different footwear: SS and HHS. Inertial devices were used to quantify the chain reactions at selected anatomical lower limbs and trunk locations. Statistical analysis included the Wilcoxon test with ranges and Cohen’s d effect size with percentage of differences. RESULTS: The highest values were found at the heel in both footwear and in both legs (SS: right =0.76 ± 0.27, left = 0.79 ± 0.27; HHS: right = 1.07 ± 0.38, left = 1.11 ± 0.41), while the lowest values were registered at lower and upper back. Furthermore, significant differences were found with the HHS load being higher at all locations (p< 0.05; %=𝑑𝑖𝑓𝑓 12.20–36.36%), influenced by the walking speed. In addition, a strong influence of footwear in the change of the laterality profile was found (p< 0.05). CONCLUSIONS: These findings suggest that the use of HHS increase the load on the lower limb and the trunk. Until reaching 5 km/h during walking, no significant differences were found between wearing HHS or SS in accelerometer load, producing exponential differences from this speed. The great between-subject variability implies that within-subject analysis is recommended, as it is more related to real clinical practice.

PURPOSE To identify risk factors for incorrect self-identification of the treatment eye before intravitreal injections. METHODS This prospective study included consecutive patients who were asked to designate the eye for which the intravitreal injection was intended and were subsequently divided into two groups according to whether or not they identified the correct eye. RESULTS Overall, 349 eyes (n = 349) were included, and 8.6% (n = 30) designated the incorrect eye or did not know which eye was intended for treatment. Incorrect designation was associated with diabetic macular edema (odds ratio [OR] = 0.33 [0.15-0.75]), first injection in the intended eye or ≥1 year since previous injection (OR = 0.34 [0.14-0.87]), Arabic native tongue (OR = 0.48 [0.22-1.01]), previous injection to the fellow eye (OR = 0.26 [0.10-0.64]), and concurrent treatment of both eyes (OR = 0.35 [0.16-0.74]). Multivariate analysis showed the first injection or ≥1 year since last injection in the treatment eye (R2 = 2.24%, P = 0.004, OR = 0.20 [0.07-0.57]) and previous injection in the fellow eye (R2 = 6.55%, P < 0.001, OR = 0.20 [0.07-0.52]) as significant independent predictors of incorrect identification. CONCLUSION Several factors are associated with a greater probability for incorrect patient's self-identification of the eye laterality intended for intravitreal injections. These findings may help identify patients with a higher risk of such potential errors.

In most vertebrates, camera-style eyes contain retinal ganglion cell neurons that project to visual centers on both sides of the brain. However, in fish, ganglion cells were thought to innervate only the contralateral side, suggesting that bilateral visual projections appeared in tetrapods. Here we show that bilateral visual projections exist in non-teleost fishes and that the appearance of ipsilateral projections does not correlate with terrestrial transition or predatory behavior. We also report that the developmental program that specifies visual system laterality differs between fishes and mammals, as the Zic2 transcription factor, which specifies ipsilateral retinal ganglion cells in tetrapods, appears to be absent from fish ganglion cells. However, overexpression of human ZIC2 induces ipsilateral visual projections in zebrafish. Therefore, the existence of bilateral visual projections likely preceded the emergence of binocular vision in tetrapods., This work was supported by Programme Investissements d’Avenir IHU FOReSIGHT (ANR-18-IAHU-01) (A.C. and F.D.B.), INSERM cross-cutting program HuDeCA 2018 (A.C.), NIH R01OD011116 (I.B.), and UQ Amplify Fellowship (R.S.)

Purpose To investigate the clinical features of strabismus in patients with congenital optic disc anomaly and compare and analyze the characteristics of patients who showed changes in the strabismus pattern with those who did not. Methods Medical records of the patients who were diagnosed with both strabismus and congenital optic disc anomaly and followed-up for ≥1 year were reviewed retrospectively. Clinical characteristics and ophthalmic features at the initial visit and final follow-up were assessed. Patients with a change in the direction of strabismus or a difference of g10 prism diopters in the deviation angle during the follow-up period were allocated to the changed group. The remaining patients were assigned to the unchanged group. The clinical characteristics of the two groups were compared. Results Twenty-eight patients (15 boys) were included (mean age, 39.0 months; range, 5-150 months). Three (10.7%) patients were born preterm and four (14.3%) had other underlying systemic disease. Sixteen (57.1%) patients had exotropia, and 12 (42.9%) had esotropia. Concurrent vertical strabismus was present in three (10.7%) patients. Strabismus features changed in 14 (50.0%, changed group) patients and remained unchanged in 14 (50.0%, unchanged group) patients. Age, sex, and laterality did not differ between groups. Preterm birth history (n = 3) and combined systemic disease (n = 4) were only observed in the changed group (p = 0.111 and p = 0.049, respectively). Conclusions Considering the possibility of changes in strabismic features, close monitoring of patients with strabismus combined with congenital disc anomaly is essential, particularly in those with preterm birth history or underlying systemic conditions.

Objective Unilateral manifestation of motor dysfunction is a prominent hallmark of Parkinson’s disease (PD). We investigated how the motor laterality of the disorder affects sleep neural asymmetry before and after Deep Brain Stimulation (DBS). Methods Twenty-seven PD patients of the akinetic-rigid subtype were studied; 11 with right dominant (RD) and 16 with left dominant (LD) motor symptoms. Neuronal sleep asymmetry was computed as the difference of sleep slow-wave energy (SWE) between left and right hemispheres. We used linear mixed models to assess the relationship between symptomatic profile and SWE asymmetry. Results LD PD patients exhibited frontal electroencephalographic (EEG) asymmetry and motor laterality pre-DBS with increased SWE contralateral to their affected body side, which diminished post-DBS. The RD group did not exhibit neither neural asymmetry nor motor laterality pre- and post-DBS. There was a significant negative correlation between the motor laterality and sleep EEG asymmetry. Conclusions Our results suggest evidence for a local use-dependent modulation of SWE as a result of the lateralized pathological motor profile. More bilateral motor symptoms and optimized treatment contribute to diminished sleep EEG asymmetry. Significance These novel findings about the association between symptomatic motor laterality and sleep neural asymmetry may provide targeted therapeutic insights.

Background The incidence of early‐onset colorectal cancer (EOCRC) is rising. Left‐sided colorectal cancer (LCC) is associated with better survival compared to right‐sided colon cancer (RCC) in metastatic disease. NCCN guidelines recommend the addition of EGFR inhibitors to KRAS/NRAS WT metastatic CRC originating from the left only. Whether laterality impacts survival in locoregional disease and EOCRC is of interest. Methods 65,940 CRC cases from the National VA Cancer Cube Registry (2001–2015) were studied. EOCRC (2096 cases) was defined as CRC diagnosed at, In EOCRC patients, LCC is associated with better OS than RCC only in patients with metastatic disease. In the overall population, LCC is associated with better OS in all stages except stage II, which might be due to the high incidence of MMRd tumors in this subpopulation.

Background Most previous studies compared survival between left-sided and right-sided colon cancer without adjustment for clinicopathological parameters. We investigated the effect of sidedness on survival among patients with early-stage colon cancer, using a propensity score matching method. Methods The 18 registry custom data within the SEER database were used to identify patients who were diagnosed with colon cancer between 2010 and 2014. A propensity score matching analysis was performed using the nearest neighbor method. Survival was estimated using the Kaplan–Meier method. A Cox proportional hazards model was applied to determine the prognostic factors. Results In the unmatched cohort, 25,094 (35.72%) patients were diagnosed with left-sided colon cancer and 45,156 (64.28%) with right-sided colon cancer. After propensity score matching, each cohort included 5118 patients, and the clinicopathological characteristics were well balanced. In the unmatched cohort, left-sided colon cancer had superior all-cause (χ2=315, Pχ2=43, Pχ2=0.7, P=0.4) and cancer-specific (χ2=0, P=0.96) survival between left and right colon cancer. The Cox model did not indicate sidedness as a prognostic factor. In the subgroup analysis, stage II right-sided colon cancer had a better survival outcome, while stage III left-sided tumors had a better survival outcome. Conclusions After adjusting for clinicopathological characteristics in this study, sidedness showed no impact on survival in early-stage colon cancer. However, sidedness was associated with prognostic differences in stages II and III early-stage colon cancer.

Objective Patients undergoing frontal lobectomy demonstrate lower seizure-freedom rates than patients undergoing temporal lobectomy and several other resective interventions. We attempted to utilize automated preoperative quantitative analysis of focal and global cortical volume loss to develop predictive volumetric indicators of seizure outcome after frontal lobectomy. Methods Ninety patients who underwent frontal lobectomy were stratified based on seizure freedom at a mean follow-up time of 3.5 (standard deviation [SD] 2.5) years. Automated quantitative analysis of cortical volume loss organized by distinct brain region and laterality was performed on preoperative T1-weighted magnetic resonance imaging (MRI) studies. Univariate statistical analysis was used to select potential predictors of seizure freedom. Backward variable selection and multivariate logistical regression were used to develop models to predict seizure freedom. Results Forty-eight of 90 (53.3%) patients were seizure-free at the last follow-up. Several frontal and extrafrontal brain regions demonstrated statistically significant differences in both volumetric cortical volume loss and volumetric asymmetry between the left and right sides in the seizure-free and non-seizure-free cohorts. A final multivariate logistic model utilizing only preoperative quantitative MRI data to predict seizure outcome was developed with a c-statistic of 0.846. Using both preoperative quantitative MRI data and previously validated clinical predictors of seizure outcomes, we developed a model with a c-statistic of 0.897. Significance This study demonstrates that preoperative cortical volume loss in both frontal and extrafrontal regions can be predictive of seizure outcome after frontal lobectomy, and models can be developed with excellent predictive capabilities using preoperative MRI data. Automated quantitative MRI analysis can be quickly and reliably performed in patients with frontal lobe epilepsy, and further studies may be developed for integration into preoperative risk stratification.

Background: Although the prognostic relevance of KRAS status in metastatic colorectal cancer (CRC) depends on tumor laterality, this relationship is largely unknown in non-metastatic CRC. Methods: Patients who underwent resection for non-metastatic CRC between 2000 and 2018 were identified from institutional databases at six academic tertiary centers in Europe and Japan. The prognostic relevance of KRAS status in patients with right-sided (RS), left-sided (LS), and rectal cancers was assessed. Results: Of the 1093 eligible patients, 378 had right-sided tumors and 715 had left-sided tumors. Among patients with RS tumors, the 5-year overall (OS) and recurrence-free survival (RFS) for patients with KRASmut versus wild-type tumors was not shown to differ significantly (82.2% vs. 83.2% and 72.1% vs. 76.7%, respectively, all p >.05). Among those with LS tumors, KRAS mutation was associated with shorter 5-year OS and RFS on both the univariable (OS: 79.4% vs. 86.1%, p =.004; RFS: 68.8% vs. 77.3%, p =.005) and multivariable analysis (OS: HR: 1.52, p =.019; RFS: HR: 1.32, p =.05). Conclusions: KRAS mutation status was independently prognostic among patients with LS tumors, but this association failed to reach statistical significance in RS and rectal tumors. These findings confirm reports in metastatic CRC and underline the possible biologic importance of tumor location.

PURPOSE: This study aimed to assess the effectiveness of the “modified graded motor imagery” (mGMI) protocol as a rehabilitative treatment of musician’s focal dystonia (MFD). METHODS: Six musicians with MFD (age 43.83±17.24 yrs) performed the home-based mGMI protocol (laterality training, imagined hand movements and visual mirror feedback) once a day for 4 weeks. The mMGI protocol was designed to sequentially activate cortical motor networks and improve cortical organization. Subjects were evaluated before and after treatment with the dystonia evaluation scale (DES), arm dystonia disability scale (ADDS), Tubiana-Chamagne scale (TCS), and performing scale (PS). RESULTS: All participants were compliant with the mGMI treatment protocol without any adverse events. A significant improvement was measured in ADDS (p=0.047) and TCS scores (p=0.014) but not in DES (p=0.157). The severity of MFD decreased from moderate to mild in four patients. After mGMI treatment, all musicians were able to play easy pieces (TCS: median 3.5, IR 3.5–4). CONCLUSION: The findings from this pilot study suggest that home-based mGMI treatment is a feasible and promising rehabilitative approach for patients with mild to moderate MFD.

The ability to detect environmental changes is essential to determine the appropriate reaction when facing potential threats. Both detection and reaction functions are critical to survival, and the superior performance of motor reaction for the dominant hand is well recognized in humans. However, it is not clear whether there exists laterality in sensitivity to detect external changes and whether the possible laterality is associated with sensory modality and stimulus intensity. Here, we tested whether the perceptual sensitivity and electrophysiological responses elicited by graded sensory stimuli (i.e., nociceptive somatosensory, non-nociceptive somatosensory, auditory, and visual) that were delivered on/near the left and right hands would be different for right-handed individuals. We observed that perceived intensities and most brain responses were significantly larger when nociceptive stimuli were delivered to the left side (i.e., the non-dominant hand) than to the right side (i.e., the dominant hand). No significant difference was observed between the two sides for other modalities. The higher sensitivity to detect nociceptive stimuli for the non-dominant hand would be important to provide a prompt reaction to noxious events, thus compensating for its worse motor performance. This laterality phenomenon should be considered when designing experiments for pain laboratory studies and evaluating regional sensory abnormalities for pain patients.

Previous studies have shown inconsistent findings regarding the contribution of the different prefrontal regions in emotion recognition. Moreover, the hemispheric lateralization hypothesis posits that the right hemisphere is dominant for processing all emotions regardless of affective valence, whereas the valence specificity hypothesis posits that the left hemisphere is specialized for processing positive emotions while the right hemisphere is specialized for negative emotions. However, recent findings suggest that the evidence for such lateralization has been less consistent. In this study, we investigated emotion recognition of fear, surprise, happiness, sadness, disgust, and anger in 30 patients with focal prefrontal cortex lesions and 30 control subjects. We also examined the impact of lesion laterality on recognition of the six basic emotions. The results showed that compared to control subjects, the frontal subgroups were impaired in recognition of three negative basic emotions of fear, sadness, and anger - regardless of the lesion laterality. Therefore, our findings did not establish that each hemisphere is specialized for processing specific emotions. Moreover, the voxel-based lesion symptom mapping analysis showed that recognition of fear, sadness, and anger draws on a partially common bilaterally distributed prefrontal network.

Lateralized alterations in hippocampal function in the resting-state have been demonstrated for patients with temporal lobe epilepsy (TLE). However, resting-state fMRI of the hippocampus has yet to be substantiated as an adjunct to standard pre-operative assessments of the seizure focus. Here we report the results of a systematic review of resting-state fMRI studies investigating laterality of hippocampal network connectivity in TLE patients. A search of the PubMed, SCOPUS, Web of Science, and Embase databases for full-length articles written in English was conducted through June 2020 using the following terms: ‘resting state fMRI,’ ‘hippocampus,’ ‘epilepsy,’ and ‘laterality.’ Our literature search yielded a total of 42 papers. After excluding studies that did not include patients with epilepsy, utilize resting-state fMRI, or explore the relationship between functional connectivity and disease lateralization, 20 publications were selected for inclusion. From these studies, a total of 528 patients, 258 with left TLE and 270 with right TLE, and 447 healthy controls were included. Of the 20 studies included, 18 found that patients with TLE demonstrated decreased hippocampal functional connectivity ipsilateral to the epileptogenic focus and 10 additionally reported increased hippocampal functional connectivity contralateral to the epileptogenic focus. Several studies demonstrated that the duration of disease was correlated with these changes in functional connectivity. This implies that a compensatory mechanism may be present in patients with treatment-refractory TLE. The consistency of this hippocampal connectivity pattern across multiple studies suggests resting-state fMRI may be useful as a non-invasive diagnostic tool for preoperative evaluation of TLE patients.