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Ecker, C., Marquand, A., Mourao-Miranda, J., Johnston, P., Daly, E. M., Brammer, M. J., et al. (2010). Describing the Brain in Autism in Five Dimensions--Magnetic Resonance Imaging-Assisted Diagnosis of Autism Spectrum Disorder Using a Multiparameter Classification Approach. J. Neurosci., 30(32), 10612–10623.
Abstract: Autism spectrum disorder (ASD) is a neurodevelopmental condition with multiple causes, comorbid conditions, and a wide range in the type and severity of symptoms expressed by different individuals. This makes the neuroanatomy of autism inherently difficult to describe. Here, we demonstrate how a multiparameter classification approach can be used to characterize the complex and subtle structural pattern of gray matter anatomy implicated in adults with ASD, and to reveal spatially distributed patterns of discriminating regions for a variety of parameters describing brain anatomy. A set of five morphological parameters including volumetric and geometric features at each spatial location on the cortical surface was used to discriminate between people with ASD and controls using a support vector machine (SVM) analytic approach, and to find a spatially distributed pattern of regions with maximal classification weights. On the basis of these patterns, SVM was able to identify individuals with ASD at a sensitivity and specificity of up to 90% and 80%, respectively. However, the ability of individual cortical features to discriminate between groups was highly variable, and the discriminating patterns of regions varied across parameters. The classification was specific to ASD rather than neurodevelopmental conditions in general (e.g., attention deficit hyperactivity disorder). Our results confirm the hypothesis that the neuroanatomy of autism is truly multidimensional, and affects multiple and most likely independent cortical features. The spatial patterns detected using SVM may help further exploration of the specific genetic and neuropathological underpinnings of ASD, and provide new insights into the most likely multifactorial etiology of the condition.
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Fraser, O. N., & Bugnyar, T. (2010). Do Ravens Show Consolation? Responses to Distressed Others. PLoS ONE, 5(5), e10605.
Abstract: <sec> <title>Background</title> <p>Bystander affiliation (post-conflict affiliation from an uninvolved bystander to the conflict victim) may represent an expression of empathy in which the bystander consoles the victim to alleviate the victim's distress (“consolation”). However, alternative hypotheses for the function of bystander affiliation also exist. Determining whether ravens spontaneously offer consolation to distressed partners may not only help us to understand how animals deal with the costs of aggressive conflict, but may also play an important role in the empathy debate.</p> </sec><sec> <title>Methodology/Principal findings</title> <p>This study investigates the post-conflict behavior of ravens, applying the predictive framework for the function of bystander affiliation for the first time in a non-ape species. We found weak evidence for reconciliation (post-conflict affiliation between former opponents), but strong evidence for both bystander affiliation and solicited bystander affiliation (post-conflict affiliation from the victim to a bystander). Bystanders involved in both interactions were likely to share a valuable relationship with the victim. Bystander affiliation offered to the victim was more likely to occur after intense conflicts. Renewed aggression was less likely to occur after the victim solicited affiliation from a bystander.</p> </sec><sec> <title>Conclusions/Significance</title> <p>Our findings suggest that in ravens, bystanders may console victims with whom they share a valuable relationship, thus alleviating the victims' post-conflict distress. Conversely victims may affiliate with bystanders after a conflict in order to reduce the likelihood of renewed aggression. These results stress the importance of relationship quality in determining the occurrence and function of post-conflict interactions, and show that ravens may be sensitive to the emotions of others.</p> </sec>
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Weisbecker, V., & Goswami, A. (2010). Brain size, life history, and metabolism at the marsupial/placental dichotomy. Proc. Natl. Acad. Sci. U.S.A., 107(37), 16216–16221.
Abstract: The evolution of mammalian brain size is directly linked with the evolution of the brain's unique structure and performance. Both maternal life history investment traits and basal metabolic rate (BMR) correlate with relative brain size, but current hypotheses regarding the details of these relationships are based largely on placental mammals. Using encephalization quotients, partial correlation analyses, and bivariate regressions relating brain size to maternal investment times and BMR, we provide a direct quantitative comparison of brain size evolution in marsupials and placentals, whose reproduction and metabolism differ extensively. Our results show that the misconception that marsupials are systematically smaller-brained than placentals is driven by the inclusion of one large-brained placental clade, Primates. Marsupial and placental brain size partial correlations differ in that marsupials lack a partial correlation of BMR with brain size. This contradicts hypotheses stating that the maintenance of relatively larger brains requires higher BMRs. We suggest that a positive BMR–brain size correlation is a placental trait related to the intimate physiological contact between mother and offspring during gestation. Marsupials instead achieve brain sizes comparable to placentals through extended lactation. Comparison with avian brain evolution suggests that placental brain size should be constrained due to placentals’ relative precociality, as has been hypothesized for precocial bird hatchlings. We propose that placentals circumvent this constraint because of their focus on gestation, as opposed to the marsupial emphasis on lactation. Marsupials represent a less constrained condition, demonstrating that hypotheses regarding placental brain size evolution cannot be generalized to all mammals.
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Frère, C. H., Krützen, M., Mann, J., Connor, R. C., Bejder, L., & Sherwin, W. B. (2010). Social and genetic interactions drive fitness variation in a free-living dolphin population. Proc. Natl. Acad. Sci. U.S.A., 107(46), 19949–19954.
Abstract: The evolutionary forces that drive fitness variation in species are of considerable interest. Despite this, the relative importance and interactions of genetic and social factors involved in the evolution of fitness traits in wild mammalian populations are largely unknown. To date, a few studies have demonstrated that fitness might be influenced by either social factors or genes in natural populations, but none have explored how the combined effect of social and genetic parameters might interact to influence fitness. Drawing from a long-term study of wild bottlenose dolphins in the eastern gulf of Shark Bay, Western Australia, we present a unique approach to understanding these interactions. Our study shows that female calving success depends on both genetic inheritance and social bonds. Moreover, we demonstrate that interactions between social and genetic factors also influence female fitness. Therefore, our study represents a major methodological advance, and provides critical insights into the interplay of genetic and social parameters of fitness.
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R Development Core Team. (2010). R: A Language and Environment for Statistical Computing [Computer software]. http://www.R-project.org. Available from http://www.R-project.org
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Lemasson, A., Koda, H., Kato, A., Oyakawa, C., Blois-Heulin, C., & Masataka, N. (2010). Influence of sound specificity and familiarity on Japanese macaques' (Macaca fuscata) auditory laterality. Behav. Brain. Res., 208(1), 286–289.
Abstract: Despite attempts to generalise the left hemisphere-speech association of humans to animal communication, the debate remains open. More studies on primates are needed to explore the potential effects of sound specificity and familiarity. Familiar and non-familiar nonhuman primate contact calls, bird calls and non-biological sounds were broadcast to Japanese macaques. Macaques turned their heads preferentially towards the left (right hemisphere) when hearing conspecific or familiar primates supporting hemispheric specialisation. Our results support the role of experience in brain organisation and the importance of social factors to understand laterality evolution.
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Siniscalchi, M., Sasso, R., Pepe, A. M., Vallortigara, G., & Quaranta, A. (2010). Dogs turn left to emotional stimuli. Behav. Brain. Res., 208(2), 516–521.
Abstract: During feeding behaviour, dogs were suddenly presented with 2D stimuli depicting the silhouette of a dog, a cat or a snake simultaneously into the left and right visual hemifields. A bias to turn the head towards the left rather than the right side was observed with the cat and snake stimulus but not with the dog stimulus. Latencies to react following stimulus presentation were lower for left than for right head turning, whereas times needed to resume feeding behaviour were higher after left rather than after right head turning. When stimuli were presented only to the left or right visual hemifields, dogs proved to be more responsive to left side presentation, irrespective of the type of stimulus. However, cat and snake stimuli produced shorter latencies to react and longer times to resume feeding following left rather than right monocular visual hemifield presentation. Results demonstrate striking lateralization in dogs, with the right side of the brain more responsive to threatening and alarming stimuli. Possible implications for animal welfare are discussed.
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Pillot, M. - H., & Deneubourg, J. - L. (2010). Collective movements, initiation and stops: Diversity of situations and law of parsimony. Behav. Process., 84(3), 657–661.
Abstract: The environment of animals is often heterogeneous, containing zones that may be dedicated specifically to resting, drinking or feeding. These functional zones may spread over a more or a less extensive area. Thus, mobile animals may have to move from one patch to another when resources are locally depleted or when they need to change activity. The mechanisms involved in collective movement appear simple at first glance, but a brief reflection shows the real difficulty of the problem in terms of the numerous environmental, physical, physiological and social parameters involved. This review is mainly concerned with collective movements, which are characterised by a directional and temporal coordination, where individuals mutually influence each other, meaning this coordination mainly depends on social interactions ([Huth and Wissel, 1992], [Warburton and Lazarus, 1991], [Couzin and Krause, 2003] and [Couzin et al., 2002]). In literature, two types of movement are discussed: large-scale movement and small-scale movement. First, we define these types of movement and then discuss the behavioural mechanisms involved. Secondly, we show that short and long movement but also moving and stopping may result from the outcome of parameters modulation underpinning collective decision-making.
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Rands, S. A. (2010). Group-movement [`]initiation' and state-dependent decision-making. Behav. Process., 84(3), 668–670.
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Conradt, L., & Roper, T. J. (2010). Deciding group movements: Where and when to go. Behav. Process., 84(3), 675–677.
Abstract: A group of animals can only move cohesively, if group members “somehow” reach a consensus about the timing (e.g., start) and the spatial direction/destination of the collective movement. Timing and spatial decisions usually differ with respect to the continuity of their cost/benefit distribution in such a way that, in principle, compromises are much more feasible in timing decision (e.g. median preferred time) than they are in spatial decisions. The consequence is that consensus costs connected to collective timing decisions are usually less skewed amongst group members than are consensus costs connected to spatial decisions. This, in turn, influences the evolution of decision sharing: sharing in timing decisions is most likely to evolve when conflicts are high relative to group cohesion benefits, while sharing in spatial decisions is most likely to evolve in the opposite situation. We discuss the implications of these differences for the study of collective movement decisions.
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