Search Results (30)

The demeanour of a human during an interaction with an animal may influence the animal’s emotional response. We investigated whether the emotional responses of laying hens to a threatening or neutral human and a novel environment were lateralised, from which their emotional state can be inferred. Twenty-five DeKalb white laying hens reared in furnished cages under environmentally controlled conditions were individually assessed for their responses to these stimuli. They were contained in a box before emerging into an arena with a threatening human, who attempted direct eye contact with the bird and had their hands raised towards it, or a neutral person, who had no eye contact and sat with their hands on their knees. When initially placed in the box adjacent to the test arena, birds that remained in the box used their left eye more than their right eye, and they showed evidence of nervousness, with many head changes, neck stretching, and vocalisation. Birds showed lateralised behaviour in both the box and arena. Birds entering the arena with the threatening person used their left eye (connected to the right brain hemisphere) more than their right eye, usually with their body less vertical, and were more likely to be standing than sitting, compared with those viewing the neutral person. This confirms the bird’s interpretation of the person as threatening, with left eye/right brain hemisphere processing of flight or fight situations. We conclude that lateralised responses of chickens suggest that a threatening person is viewed more fearfully than a neutral person. However, further investigation is required with a larger sample of birds to strengthen these findings and enhance the generalisability of behavioural responses. Full article

Late contact-era depictions of inter-group conflict in southern African rock art include references to the image-makers and their opponents, who must also have been able to view the images. Performance theory allows researchers to go beyond the conventional question about who made the images by also addressing for whom the images were made. This case study uses performance theory to explore several details of the well-known conflict scene at Ventershoek (Jammerberg, Free State Province, South Africa). In it, ‘San hunter-gatherers’ appear to contest the possession of cattle, traditionally the property of ‘Bantu agro-pastoralists’. It is argued that, in addition to depicting conflict, the image-makers painted allusions to their ritualised, spirit-world mediation of conflict, their opponent’s use of protective war medicine and, potentially, lateralised symbols of cattle ownership that would have been comprehensible to audiences on both sides. It is argued further, from performance theory and the painted details, that the Ventershoek conflict scene contributed to the image-makers’ social construction of reality concerning their relationships with other groups. Full article

In humans, certain functions such as language and spatial attention are lateralised, meaning they are predominantly or exclusively performed by one hemisphere. Intriguingly, a significant portion of individuals exhibit a mirrored pattern of asymmetry, which has been attributed to genes, environmental influences, or other factors. As lateralisation occurs across all major groups of vertebrates, literature in other species might provide valuable insights into these mechanisms. We reviewed current knowledge on the genetic and environmental factors underlying individual variability in lateralisation in non-human vertebrates. Evidence of a genetic basis for the direction, strength of asymmetries, or both has been reported in about a dozen species of fish and mammals. Nevertheless, a careful examination revealed that none of these studies can definitively exclude the influence of non-genetic factors. On the other hand, studies from the past decade have suggested that environmental factors can shape both the direction and strength of lateralisation in adaptive ways, aligning the individual’s phenotype with local environmental conditions. Overall, this review supports the potential role of both genetic differences and environmentally driven plasticity in shaping lateralisation variance while highlighting literature gaps that prevent a precise disentanglement of the roles of these factors. Full article

Background/Objectives: Endogenous oscillations reflect the spontaneous activity of brain networks involved in cognitive processes. In adults, endogenous activity across different bands correlates with, and can even predict, language and speech perception processing. However, it remains unclear how this activity develops in children with typical and atypical development. Methods: We investigated differences in resting-state EEG between preschoolers with developmental language disorder (DLD), their age-matched controls with typical language development (TLD), and a group of adults. Results: We observed significantly lower oscillatory power in adults than in children (p < 0.001 for all frequency bands), but no differences between the groups of children in power or hemispheric lateralisation, suggesting that oscillatory activity reflects differences in age, but not in language development. The only measure that differed between the children’s groups was theta/alpha band ratio (p = 0.004), which was significantly smaller in TLD than in DLD children, although this was an incidental finding. Behavioural results also did not fully align with previous research, as TLD children performed better in the filtered speech test (p = 0.01), but not in the speech-in-babble one, and behavioural test scores did not correlate with high-frequency oscillations, lateralisation indices, or band ratio measures. Conclusions: We discuss the suitability of these resting-state EEG measures to capture group-level differences between TLD/DLD preschoolers and the relevance of our findings for future studies investigating neural markers of typical and atypical language development. Full article

Cerebral lateralisation is a core organising principle of the brain that is characterised by a complex pattern of hemispheric specialisations and interhemispheric interactions. In various mental disorders, functional and/or structural hemispheric asymmetries are changed compared to healthy controls, and these alterations may contribute to the primary symptoms and cognitive impairments of a specific disorder. Since multiple genetic and epigenetic factors influence both the pathogenesis of mental illness and the development of brain asymmetries, it is likely that the neural developmental pathways overlap or are even causally intertwined, although the timing, magnitude, and direction of interactions may vary depending on the specific disorder. However, the underlying developmental steps and neuronal mechanisms are still unclear. In this review article, we briefly summarise what we know about structural, functional, and developmental relationships and outline hypothetical connections, which could be investigated in appropriate animal models. Altered cerebral asymmetries may causally contribute to the development of the structural and/or functional features of a disorder, as neural mechanisms that trigger neuropathogenesis are embedded in the asymmetrical organisation of the developing brain. Therefore, the occurrence and severity of impairments in neural processing and cognition probably cannot be understood independently of the development of the lateralised organisation of intra- and interhemispheric neuronal networks. Conversely, impaired cellular processes can also hinder favourable asymmetry development and lead to cognitive deficits in particular. Full article

Background. Incidentalomas have an increasing incidence all over the world due to a larger access to imaging assessments, and endocrine incidentalomas make no exception in this matter, including pituitary incidentalomas (PIs). Objective. Our objective was to analyse the dynamic changes amid a second computed tomography (CT) scan after adult patients were initially confirmed with a PI (non-functioning micro-adenoma). Methods. This was a multi-centric, longitudinal, retrospective study in adults (aged between 20 and 70 y) amid real-world data collection. We excluded patients who experienced baseline pituitary hormonal excess or deficiency or those with tumours larger than 1 cm. Results. A total of 117 adults were included (94.02% females) with a mean age of 43.86 ± 11.99 years, followed between 6 and 156 months with a median (M) of 40 months (Q1 Q3: 13.50, 72.00). At the time of PI diagnosis, the transverse diameter had a mean value of 0.53 ± 0.16 cm, the longitudinal mean diameter was 0.41 ± 0.13 cm, and the largest diameter was 0.55 ± 0.16 cm. No PI became functioning during follow-up, neither associated hypopituitarism nor increased >1 cm diameter. A total of 46/117 (39.32%) patients had a larger diameter during follow-up (increase group = IG) versus a non-increase group (non-IG; N = 71, 60.68%) that included the subjects with stationary or decreased diameters. IG had lower initial transverse, longitudinal, and largest diameter versus non-IG: 0.45 ± 0.12 versus 0.57 ± 0.17 (p < 0.0001), 0.36 ± 0.11 versus 0.43 ± 0.13 (p = 0.004), respectively, 0.46 ± 0.12 versus 0.6 ± 0.16 (p < 0.0001). IG versus non-IG had a larger period of surveillance: M (Q1, Q3) of 48 (24, 84) versus 32.5 (12, 72) months (p = 0.045) and showed similar age, pituitary hormone profile, and tumour lateralisation at baseline and displayed a median diameter change of +0.14 cm versus −0.03 cm (p < 0.0001). To conclude, a rather high percent of patients might experience PI diameter increase during a longer period of follow-up, including those with a smaller initial size, while the age at diagnosis does not predict the tumour growth. This might help practitioners with further long-term surveillance protocols. Full article

Structural and functional asymmetries are traceable in every form of life, and some lateralities are homologous. Functionally speaking, the division of labour between the two halves of the brain is a basic characteristic of the nervous system that arose even before the appearance of vertebrates. The most well-known expression of this specialisation in humans is hand dominance, also known as handedness. Even if hand/limb/paw dominance is far more commonly associated with the presence of a nervous system, it is also observed in its own form in aneural organisms, such as plants. To date, little is known regarding the possible functional significance of this dominance in plants, and many questions remain open (among them, whether it reflects a generalised behavioural asymmetry). Here, we propose a comparative approach to the study of handedness, including plants, by taking advantage of the experimental models and paradigms already used to study laterality in humans and various animal species. By taking this approach, we aim to enrich our knowledge of the concept of handedness across natural kingdoms. Full article

Purpose: To evaluate magnetic resonance image (MRI) findings in children and adolescents suffering from knee pain without traumatic or physical overload history and to identify potential anatomic risk factors. Material and Methods: A total of 507 MRIs of 6- to 20-year-old patients (251 males; 256 females) were evaluated with regard to detectable pathologies of the knee. The results were compared to a control group without pain (n = 73; 34 males; 39 females). A binary logistic regression model and t-tests for paired and unpaired samples were used to identify possible risk factors and significant anatomic differences of the study population. Results: In 348 patients (68.6%), at least one pathology was detected. The most commonly detected finding was chondromalacia of the patellofemoral (PF) joint (n = 205; 40.4%). Chondral lesions of the PF joint occurred significantly more often in knee pain patients than in the control group (40% vs. 11.0%; p = 0.001), especially in cases of a patella tilt angle > 5° (p ≤ 0.001), a bony sulcus angle > 150° (p = 0.002), a cartilaginous sulcus angle > 150° (p = 0.012), a lateral trochlear inclination < 11° (p ≤ 0.001), a lateralised patella (p = 0.023) and a Wiberg type II or III patella shape (p = 0.019). Moreover, a larger patella tilt angle (p = 0.021), a greater bony sulcus angle (p = 0.042), a larger cartilaginous sulcus angle (p = 0.038) and a lower value of the lateral trochlear inclination (p = 0.014) were detected in knee pain patients compared to the reference group. Conclusion: Chondromalacia of the PF joint is frequently observed in children and adolescents suffering from non-overload atraumatic knee pain, whereby a patella tilt angle > 5°, a bony sulcus angle > 150°, a cartilaginous sulcus angle > 150°, a lateral trochlear inclination < 11°, a lateralised patella and a Wiberg type II or III patella shape seem to represent anatomic risk factors. Full article

Traditionally, adult and neonatal cerebral perfusion have been presumed to be symmetrical. Contrary to this, our adult work shows that supra-aortic cerebral supply is systematically biased towards the left, in terms of both vessel geometry and blood flow volumes. Although this asymmetry is meaningfully related to hand preference, the developmental origins of this association remain unknown. Our detailed investigations of the cerebral vasculature confirm analogous asymmetries in term neonates. Specifically, we demonstrate that the structure and flow of neonatal middle cerebral vessels are consistently asymmetric and predominantly left-dominant. Building on our work from the same cohort, we now report further analyses of these new-found asymmetries. Namely, exploring for the first time, the relationship between arterial lateral biases and the neonatal head-turning response—a reliable early behavioural precursor of handedness that shows a systematic rightward bias in the population. Here, we demonstrate a contralateral relationship between vessel morphology and primitive expressions of lateralisation that predate the establishment of definitive handedness in the course of postnatal development. This relationship mimics patterns observed in adults and suggests that lateralising trends in angiogenesis may ultimately influence the emergence of human lateral preferences. Full article

Lateralised behavioural responses to environmental stressors have become more frequently used as indicators of social welfare in animals. These lateralised behavioural responses are under the control of asymmetrical brain functions as part of the primary functions of most vertebrates and assist in primary social and survival functions. Lateralised behavioural responses originating from the left hemisphere are responsible for processing familiar conditions, while the right hemisphere is responsible for responding to novel stimuli in the environment. The forced lateralisation and side preference tests have been used to determine the visual lateralised behavioural responses in livestock to environmental stressors. Limb preference during movement has also been used to determine motor lateralisation. Although behavioural investigations in livestock have recorded lateralised behavioural responses to environmental stressors, there are still limitations in the implication of lateralisation to other conditions, such as restraint and invasive procedures. Thus, it is important to have a non-invasive measure for these lateralised behavioural responses. Recently, lateralised behavioural responses have been correlated with the use of infrared temperature of external body surfaces, such as the eyes and coronary bands of limbs. This review summarised the different forms of the lateralised behavioural responses in livestock, especially cattle and horses, to environmental stressors, and the association between these responses and the relevant external body surfaces’ infrared temperature, with the purpose of improving the use of non-invasive measures in assessing welfare conditions in animals. The combination of the lateralised behavioural responses and infrared temperature of external body surfaces to environmental stressors could improve the assessment strategies of welfare conditions and the related additional husbandry interventions that could be applied to improve the welfare of farm animals. Full article

Self-directed behaviours (SDBs) are widely used as markers of emotional arousal in primates, and are commonly linked to negative arousal, or are used as indicators of stress or poor welfare. However, recent studies suggest that not all SDBs have the same function. Moreover, lateralisation in the production of these behaviours has been suggested to be associated with emotional processing. Hence, a better understanding of the production and the asymmetry of these displacement behaviours is needed in a wider range of species in order to confirm their reliability as indicators of emotional arousal. In the current study, we experimentally evaluated the production and asymmetry of SDBs in zoo-housed bonobos during two cognitive touchscreen tasks. Overall, nose wipes were most commonly observed, followed by gentle self-scratches, and rough self-scratches. The rates of nose wipes and rough self-scratches increased with incorrect responses, suggesting that these behaviours indicate arousal and possibly frustration. Rough self-scratching was additionally more directed towards the left hemispace after incorrect responses. In contrast, gentle self-scratching increased after correct responses in one study, possibly linking it with positive arousal. We also tested if left-handed bonobos showed greater behavioural reactivity towards incorrect responses, but found no evidence to confirm this hypothesis. Our results shed light on potential different mechanisms behind separate SDBs. We therefore provide nuance to the use of SDBs as indicator of emotional arousal in bonobos. Full article

The implications of combining structural and functional connectivity to quantify the most active brain regions in seizure onset remain unclear. This study tested a new model that may facilitate the incorporation of diffusion MRI (dMRI) in clinical practice. We obtained structural connectomes from dMRI and functional connectomes from electroencephalography (EEG) to assess whether high structure-function coupling corresponded with the seizure onset region. We mapped individual electrodes to their nearest cortical region to allow for a one-to-one comparison between the structural and functional connectomes. A seizure laterality score and expected onset zone were defined. The patients with well-lateralised seizures revealed high structure-function coupling consistent with the seizure onset zone. However, a lower seizure lateralisation score translated to reduced alignment between the high structure-function coupling regions and the seizure onset zone. We illustrate that dMRI, in combination with EEG, can improve the identification of the seizure onset zone. Our model may be valuable in enhancing ultra-long-term monitoring by indicating optimal, individualised electrode placement. Full article

Endothelial dysfunction is one of the earliest manifestations of atherosclerosis, contributing to its development and progression. Mental stress induces endothelial dysfunction through increased activity of the sympathetic nervous system, release of corticotropin-releasing hormone from the hypothalamus, inhibition of nitric oxide (NO) synthesis by cortisol, and increased levels of pro-inflammatory cytokines. Mental-stress-induced increased output of the sympathetic nervous system and concomitant withdrawal of the parasympathetic inflammatory reflex results in systemic inflammation and activation of a neural–hematopoietic–arterial axis. This includes the brainstem and subcortical regions network, bone marrow activation, release of leukocytes into the circulation and their migration to the arterial wall and atherosclerotic plaques. Low-grade, sterile inflammation is involved in all steps of atherogenesis, from coronary plaque formation to destabilisation and rupture. Increased sympathetic tone may cause arterial smooth-muscle-cell proliferation, resulting in vascular hypertrophy, thus contributing to the development of hypertension. Emotional events also cause instability of cardiac repolarisation due to brain lateralised imbalance of cardiac autonomic nervous stimulation, which may lead to asymmetric repolarisation and arrhythmia. Acute emotional stress can also provoke severe catecholamine release, leading to direct myocyte injury due to calcium overload, known as myocytolysis, coronary microvascular vasoconstriction, and an increase in left ventricular afterload. These changes can trigger a heart failure syndrome mimicking acute myocardial infarction, characterised by transient left ventricular dysfunction and apical ballooning, known as stress (Takotsubo) cardiomyopathy. Women are more prone than men to develop mental-stress-induced myocardial ischemia (MSIMI), probably reflecting gender differences in brain activation patterns during mental stress. Although guidelines on CV prevention recognise psychosocial factors as risk modifiers to improve risk prediction and decision making, the evidence that their assessment and treatment will prevent CAD needs further evaluation. Full article

Humans are the only species that can speak. Nonhuman primates, however, share some ‘domain-general’ cognitive properties that are essential to language processes. Whether these shared cognitive properties between humans and nonhuman primates are the results of a continuous evolution [homologies] or of a convergent evolution [analogies] remain difficult to demonstrate. However, comparing their respective underlying structure—the brain—to determinate their similarity or their divergence across species is critical to help increase the probability of either of the two hypotheses, respectively. Key areas associated with language processes are the Planum Temporale, Broca’s Area, the Arcuate Fasciculus, Cingulate Sulcus, The Insula, Superior Temporal Sulcus, the Inferior Parietal lobe, and the Central Sulcus. These structures share a fundamental feature: They are functionally and structurally specialised to one hemisphere. Interestingly, several nonhuman primate species, such as chimpanzees and baboons, show human-like structural brain asymmetries for areas homologous to key language regions. The question then arises: for what function did these asymmetries arise in non-linguistic primates, if not for language per se? In an attempt to provide some answers, we review the literature on the lateralisation of the gestural communication system, which may represent the missing behavioural link to brain asymmetries for language area’s homologues in our common ancestor. Full article

Recent fMRI and fTCD studies have found that functional modules for aspects of language, praxis, and visuo-spatial functioning, while typically left, left and right hemispheric respectively, frequently show atypical lateralisation. Studies with increasing numbers of modules and participants are finding increasing numbers of module combinations, which here are termed cerebral polymorphisms—qualitatively different lateral organisations of cognitive functions. Polymorphisms are more frequent in left-handers than right-handers, but it is far from the case that right-handers all show the lateral organisation of modules described in introductory textbooks. In computational terms, this paper extends the original, monogenic McManus DC (dextral-chance) model of handedness and language dominance to multiple functional modules, and to a polygenic DC model compatible with the molecular genetics of handedness, and with the biology of visceral asymmetries found in primary ciliary dyskinesia. Distributions of cerebral polymorphisms are calculated for families and twins, and consequences and implications of cerebral polymorphisms are explored for explaining aphasia due to cerebral damage, as well as possible talents and deficits arising from atypical inter- and intra-hemispheric modular connections. The model is set in the broader context of the testing of psychological theories, of issues of laterality measurement, of mutation-selection balance, and the evolution of brain and visceral asymmetries. Full article