(Re)organisation of the somatosensory system after early brain lesion: A lateralization index fMRI study

ObjectiveTo evaluate the relationship between neural (re)organization of the somatosensory cortex and impairment of sensory function (2-point discrimination [2PD]) in individuals with unilateral cerebral palsy.MethodsWe included 21 individuals with unilateral cerebral palsy. 2PD thresholds were evaluated on thumb pads, and activation of the somatosensory cortex was recorded by functional MRI (fMRI) during passive movements of the affected hand. A lateralization index (LI) was calculated for the primary sensory (S1) and secondary sensory (S2) cortices and the correlation between the LI and 2PD thresholds was analysed.ResultsWe found a significant negative correlation between the 2PD thresholds and the S2 LI (r = −0.5, one-tailed P-value = 0.01) and a trend towards a negative correlation with the S1 LI (r = −0.4, one-tailed P-value = 0.05).ConclusionHigh levels of activation in the contralesional hemisphere were associated with high levels of sensory impairment in individuals with unilateral cerebral palsy. The interhemispheric (re)organization of the somatosensory system may not effectively compensate for somatosensory impairment.     

Evolutionary and mechanistic drivers of laterality: A review and new synthesis

Laterality, best understood as asymmetries of bilateral structures or biases in behaviour, has been demonstrated in species from all major vertebrate classes, and in many invertebrates, showing a large degree of evolutionary conservation across vertebrate groups. Despite the establishment of this phenomenon in so many species, however, the evolutionary and mechanistic study of laterality is uneven with numerous areas in this field requiring greater attention. Here, I present a partial review of how far the study of laterality has come, outlining previous pioneering work, I discuss the hypothesized costs and benefits of a lateralized brain and the suggested path of the evolution of laterality for populations and individuals. I propose an expansion of laterality research into areas that have been touched upon in the past but require stronger evidence from which the field will greatly benefit. Namely, I suggest a continuation of the phylogenetic approach to investigating laterality to better understand its evolutionary path; and a further focus on mechanistic drivers, with special attention to genetic and environmental effects. Putting together the puzzle of laterality using as many pieces as possible will provide a stronger understanding of this field, allowing us to continue to expand the field in novel ways.     

五例患者韦伯偏振试验的局限性报道

正音叉检查早期是耳科学常用的听力检查手段,后来随着声导抗测试和耳声发射等相关技术的问世和临床普及,在临床的应用大幅度减少,有的学者甚至认为应该摒弃。尽管如此,仍有很多耳科学专家认为,对于一些检查结果存在交叉盲区的患者,音叉检查往往能起到一锤定音的作用。因此,许多耳科学医师建议将音叉检查保留,可作为其他听力检查     

Reward bias and lateralization in gambling behavior: behavioral activation system and alpha band analysis

The present research explored the main factors that can influence subjects’ choices in the case of decisions. In order to elucidate the individual differences that influence the decisional processes, making their strategies more or less advantageous, we tested the effect of a reward sensitivity in the behavioral activation system (BAS-Reward) constructed on the ability to distinguish between high- and low-risk decisions. Secondly, the lateralization effect, related to increased activation of the left (BAS-related) hemisphere, was explored. Thirty-one subjects were tested using the Iowa Gambling Task, and the BAS-Reward measure was applied to distinguish between high-BAS and low-BAS groups. Behavioral responses (gain/loss options) and alpha-band modulation were considered. It was found that high-BAS group increased their tendency to opt in favor of the immediate reward (loss strategy) rather than the long-term option (win strategy). Secondly, high-BAS subjects showed an increased left-hemisphere activation in response to losing (with immediate reward) choices in comparison with low-BAS subjects. A “reward bias” effect was supposed to explain both the bad strategy and the unbalanced hemispheric activation for high-BAS and more risk-taking subjects.     

Brain stimulation enables the solution of an inherently difficult problem

Certain problems are inherently difficult for the normal human mind. Yet paradoxically they can be effortless for those with an unusual mind. We discovered that an atypical protocol for non-invasive brain stimulation enabled the solution of a problem that was previously unsolvable. The majority of studies over the last century find that no participants can solve the nine-dot problem – a fact we confirmed. But with 10 min of right lateralising transcranial direct current stimulation (tDCS), more than 40% of participants did so. Specifically, whereas no participant solved this extremely difficult problem before stimulation or with sham stimulation, 14 out of 33 participants did so with cathodal stimulation of the left anterior temporal lobe together with anodal stimulation of the right anterior temporal lobe. This finding suggests that our stimulation paradigm might be helpful for mitigating cognitive biases or dealing with a broader class of tasks that, although deceptively simple, are nonetheless extremely difficult due to our cognitive makeup.     

Postural laterality in Iberian ibex Capra pyrenaica: Effects of age,sex and nursing suggest stress and social information

Most studies of lateralized behaviour have to date focused on active behaviour such as sensorial perception and locomotion and little is known about lateralized postures, such as lying, that can potentially magnify the effectiveness of lateralized perception and reaction. Moreover, the relative importance of factors such as sex, age and the stress associated with social status in laterality is now a subject of increasing interest. In this study, we assess the importance of sex, age and reproductive investment in females in lying laterality in the Iberian ibex (Capra pyrenaica). Using generalized additive models under an information-theoretic approach based on the Akaike information criterion, we analyzed lying laterality of 78 individually marked ibexes. Sex, age and nursing appeared as key factors associated, in interaction and non-linearly, with lying laterality. Beyond the benefits of studying laterality with non-linear models, our results highlight the fact that a combination of static factors such as sex, and dynamic factors such as age and stress associated with parental care, are associated with postural laterality.     

The face is the thing: Faces,not emotions,are responsible for chimeric perceptual asymmetry

ABSTRACT

We used factor analysis to examine relationships among tasks that have previously shown right hemispheric processing asymmetries. We were interested in whether processing emotion displayed by a face constitutes a distinct perceptual process from processing other facial characteristics. Interest in this topic arose after Boles [1991 Boles, D. B. (1991). Factor analysis and the cerebral hemispheres: Pilot study and parietal functions. Neuropsychologia, 29(1), 59–91. doi: 10.1016/0028-3932(91)90094-O[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]. Factor analysis and the cerebral hemispheres: Pilot study and parietal functions. Neuropsychologia, 29 Boles, D. B. (1991). Factor analysis and the cerebral hemispheres: Pilot study and parietal functions. Neuropsychologia, 29(1), 59–91. doi: 10.1016/0028-3932(91)90094-O[Crossref], [PubMed], [Web of Science ®] , [Google Scholar](1 Boles, D. B. (1991). Factor analysis and the cerebral hemispheres: Pilot study and parietal functions. Neuropsychologia, 29(1), 59–91. doi: 10.1016/0028-3932(91)90094-O[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), 59 Boles, D. B. (1991). Factor analysis and the cerebral hemispheres: Pilot study and parietal functions. Neuropsychologia, 29(1), 59–91. doi: 10.1016/0028-3932(91)90094-O[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]–91 Boles, D. B. (1991). Factor analysis and the cerebral hemispheres: Pilot study and parietal functions. Neuropsychologia, 29(1), 59–91. doi: 10.1016/0028-3932(91)90094-O[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]] found evidence of a common process underlying face processing and then Boles [1992 Boles, D. B. (1992). Factor analysis and the cerebral hemispheres: Temporal, occipital and frontal functions. Neuropsychologia, 30(11), 963–988. doi: 10.1016/0028-3932(92)90049-R[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]. Factor analysis and the cerebral hemispheres: Temporal, occipital and frontal functions. Neuropsychologia, 30 Boles, D. B. (1992). Factor analysis and the cerebral hemispheres: Temporal, occipital and frontal functions. Neuropsychologia, 30(11), 963–988. doi: 10.1016/0028-3932(92)90049-R[Crossref], [PubMed], [Web of Science ®] , [Google Scholar](11 Boles, D. B. (1992). Factor analysis and the cerebral hemispheres: Temporal, occipital and frontal functions. Neuropsychologia, 30(11), 963–988. doi: 10.1016/0028-3932(92)90049-R[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), 963 Boles, D. B. (1992). Factor analysis and the cerebral hemispheres: Temporal, occipital and frontal functions. Neuropsychologia, 30(11), 963–988. doi: 10.1016/0028-3932(92)90049-R[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]–988 Boles, D. B. (1992). Factor analysis and the cerebral hemispheres: Temporal, occipital and frontal functions. Neuropsychologia, 30(11), 963–988. doi: 10.1016/0028-3932(92)90049-R[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]] found evidence of a distinct process for the processing of the facial emotion. We used seven tasks that measured both face and non-face perception. Analysis of the asymmetries revealed measures from the five face tasks resulted in a single factor, thus failing to support the hypothesis that emotional face perception would involve a separate process from non-emotional face perception. A second factor revealed a separate process underlying enumeration, and a third factor revealed yet another process underlying line bisection. The results indicate that perceiving facial emotion results in right hemisphere processing, and faces as a whole are responsible for such processing.     

Hemispheric asymmetry in mid and long latency neuromagnetic responses to single clicks

We examine lateralization in the evoked magnetic field response to a click stimulus, observing that lateralization effects previously demonstrated for tones, noise, frequency modulated sweeps and certain syllables are also observed for (acoustically simpler) clicks. These effects include a difference in the peak latency of the M100 component of the evoked field waveform such that the peak consistently appears earlier in the right hemisphere, as well as rightward lateralization of field amplitude during the rise of the M100 component. Our review of previous findings on M100 lateralization, taken together with our data on the click-evoked response, leads to the hypothesis that these lateralization effects are elicited by stimuli containing a sharp sound energy onset or acoustic transition rather than specific types of stimuli. We argue that both the latency and the amplitude lateralization effects have a common origin, namely, hemispheric asymmetry in the amplitude of the magnetic field generated by one or more sources active during the M100 rise. While anatomical asymmetry cannot be excluded as the cause of the amplitude difference, we propose that the difference reflects a rightward asymmetry in the processing of sound energy onsets that potentially underlies the lateralization of several functions.     

Catecholamine plasma levels following immune stimulation with rabies vaccine in dogs selected for their paw preferences

Epinephrine and norepinephrine plasma levels were assessed in dogs in relation to paw preference following an immune challenge with rabies vaccine. The results showed that both catecholamines increased after the vaccine administration, confirming the main role of the sympathetic nervous system in the modulation activity between the brain and the immune system. Moreover, ambidextrous dogs showed a significantly higher increase of epinephrine levels 8 days after immunization with respect to right- and left-pawed dogs, suggesting that the biological activity of this molecule could be key for a different immune response with regard to laterality.