The emergence of consciousness: Research on animals yields insights into how,when and why consciousness evolved

Whether some animal species possess consciousness is no longer the question; rather how their environment and evolution shaped species‐specific forms of self‐awareness Subject Categories: Ecology, Neuroscience

Ever since humans acknowledged consciousness in themselves, they speculated whether animals could have a similar sentience or awareness of their internal and external existence. But although human philosophers had pondered on consciousness for centuries, it was not until 1927 when the American psychologist Harvey Carr laid the foundations for research on animal consciousness. He argued that awareness in animals could be only understood and measured when we had developed “an accurate and complete knowledge of its essential conditions in man” (Carr, 1927).This may have provided a springboard for the field, but a definition of the essential conditions of consciousness in Homo sapiens has proved elusive to this day—hence, research on animal consciousness has struggled to achieve a sound basis for formulating and evaluating testable hypotheses. However, there has been some progress in developing correlates of human consciousness that can be applied to study animals, while brain scanning and imaging has recently allowed comparative studies of human and animal neurological activity while performing mental tasks. It has also become possible to observe animal behaviour and communication in much greater depth and identify examples of activities—such as advance planning, or recognition of individuals through their vocalization—that can be associated with human consciousness. Overall, there is a growing consensus that this research has moved beyond merely questioning whether animals can be conscious or aware of themselves to defining different dimensions along which this can be assessed.

… research has moved beyond merely questioning whether animals can be conscious or aware of themselves to defining different dimensions along which this can be assessed.

     

Reconciling variability and optimal behaviour using multiple criteria in optimization models

A major objective in behavioural and evolutionary ecology is to understand how animals make decisions in complex environments. Examinations of animal behaviour typically use optimization models to predict the choices animals ought to make. The performance of animals under specific conditions is then compared against the predicted optimal strategy. This optimization approach has come into question because model predictions often do not match animal behaviour exactly. This has led to serious scepticism about the ability of animals to exhibit optimal behaviour in complex environments. We show that conventional approaches that compare observed animal behaviour with single optimal values may bias the way we view real-world variation in animal performance. Considerable insight into the abilities of animals to make optimal decisions can be gained by interpreting why variability in performance exists. We introduce a new theoretical framework, called multi-objective optimization, which allows us to examine decision-making in complex environments and interpret the meaning of variability in animal performance. A multi-objective approach defines the set of efficient choices animals may make in attempting to reach compromises among multiple conflicting demands. In a multi-objective framework, we may see variation in animal choices, but, unlike single-objective optimizations where there is one best solution, this variation may represent a range of adaptive compromises to conflicting objectives. An important feature of this approach is that, within the set of efficient alternatives, no choice can be considered to yield higher fitness, a priori, than any other choice. Thus, variability and optimal behaviour may be entirely consistent. We illustrate our point using selected examples from foraging theory where there is already an optimization program in place.     

Insights into plant consciousness from neuroscience,physics and mathematics: A role for quasicrystals?

There is considerable debate over whether plants are conscious and this, indeed, is an important question. Here I look at developments in neuroscience, physics and mathematics that may impact on this question. Two major concomitants of consciousness in animals are microtubule function and electrical gamma wave synchrony. Both these factors may also play a role in plant consciousness. I show that plants possess aperiodic quasicrystal structures composed of ribosomes that may enable quantum computing, which has been suggested to lie at the core of animal consciousness. Finally I look at whether a microtubule fractal suggests that electric current plays a part in conventional neurocomputing processes in plants.     

Scientific Approaches to Animal Consciousness

In a marked departure from past inhibitions about scientificconsideration of conscious mental states in animals, the otherpapers in this symposium review a variety of evidence aboutwhat the content of animal consciousness is likely to be. Althoughfully convincing evidence is not yet available, there are promisingopportunities to reduce our current ignorance of what life islike, subjectively, for various animals. For example, recentneurophysiological experiments provide objective evidence aboutwhat monkeys are, and are not, conscious of. Versatility ofbehavior when animals cope with novel and unpredictable challengesstrongly suggests simple conscious thinking about alternativeactions. Finally, animal communication provides direct and objective,though incomplete and imperfect, evidence about some of theirconscious thoughts and feelings.     

I research,therefore I am?: A purely scientific understanding of consciousness remains elusive,but the search for its neurological foundation continues

The exploration of consciousness—the most elusive characteristic of human nature—has long been left to philosophers and artists. Using modern research tools, scientists have finally begun to subject the human mind to empirical analysis.Consciousness is the heart of human existence, yet it has proven to be an elusive subject for scientific research and analysis. Its study has largely been left to philosophers, writers and artists who have spent centuries exploring the meaning of life. Existential questions such as ‘why am I me?'' are, by their nature, difficult to answer with empirical analysis. It is therefore perhaps unsurprising that natural science has found it difficult to add detail to René Descartes general principle: cognito ergo sum. From some quarters—particularly religious ones—there has also been resistance to the ‘profane'' tools of science probing the ‘sacred heart'' of human consciousness; Pope John Paul II is reported to have proclaimed during a conference at the Vatican in the 1980s, that while scientists can have the brain, the mind belongs to God (Lane, 2009).Existential questions such as ‘why am I me?'' are, by their nature, difficult to answer with empirical analysisThe separation of mind and brain is fundamental to the study of consciousness, and requires elucidation of the relationship between the biological mechanisms of brain function and the higher-level processes—such as emotion or reason—that are enabled by them. Although the ultimate meaning of human existence remains elusive—assuming that there is one—research has begun to unravel the physical mechanisms that enable consciousness, by using brain imaging techniques together with an increasing understanding of the neuronal architecture of the brain. This approach has informed the quest to identify the neural correlates of consciousness (Crick & Koch, 1990) that were first defined by Christof Koch, Professor of Biology and Engineering at the California Institute of Technology, and Francis Crick, who is better known for his codiscovery of the DNA double helix. These correlates are defined as the minimal set of neuronal mechanisms required for a particular conscious function or ability. Their identification would be useful for assessing levels of consciousness in animals, infants and adults with brain damage or disease, who are unable to express what they are feeling in words.Koch explained that although neuronal mechanisms are necessary for consciousness, it is the information that they transmit and integrate that actually brings it into being; an idea that was first advanced by Giulio Tononi (2004), to which Koch has contributed. This theory, according to Koch, states that consciousness depends on the ability to coherently integrate information, irrespective of the information type. This has important implications: that consciousness is independent of language, vision or any other specific form of information, and can exist in any system with the required structure. From this, Koch has concluded that consciousness is not limited to humans, but could exist in a machine and many animals—a view that has led him to become a vegetarian. According to this theory, aspects of recent human evolution and culture—including language—are products of consciousness, rather than requirements for it.According to Naomi Eilan, Director of the Consciousness and Self-Consciousness Research Centre at the University of Warwick, UK, the information flows and synchronization that enable consciousness are nevertheless dependent on the physical structure of the brain. “It''s mad to think that consciousness and the brain are independent [of one another],” she said. The extent of their interdependence, however, is hotly debated. According to Eilan, scientists generally take one of three positions on the subject: “[O]ne view [is that] the brain will tell us what consciousness is, but at the other [extreme] there''s the view that it''s neither here nor there and that the brain is one thing and consciousness quite another. I''m in the middle, where the brain presupposes consciousness but does not explain it. The brain will not tell you what consciousness is, but it does tell us how various aspects of it work.”…consciousness is independent of language, vision or any other specific form of information, and can exist in any system with the required structureIn evolutionary terms, consciousness is a phenotype with an underlying genotype. It is therefore subject to the pressures of natural selection, which act at the level of the genes encoding neurological structures. These structures probably first emerged in animals for specific functions and only later became integrated into a universal continuous consciousness, according to Antonio Damasio, Director of the Brain and Creativity Institute at the University of Southern California, Los Angeles, USA. “I believe most of the phenomena of consciousness emerged as a result of specific brain complexities which were required by an improved life regulation,” he said. “But once basic consciousness emerged, its adaptive value was so remarkable that natural selection made it prevail.”​Open in a separate window© MedicalRF.com/CorbisIt is now almost universally agreed that consciousness is linked to the coherence of the electrical states of different groups of neurons, but the mechanisms underlying this are still disputed. Some researchers, such as the American psychologist Stuart Hameroff, argue that quantum mechanics must be involved through a phenomenon known as quantum coherence, which would correlate the states of subatomic particles across the brain (Hameroff, 1994). This hypothesis is questioned by others, but consciousness does seem to be generated by synchronized oscillations in the electrical states of neurons in different areas of the brain, as detected by electroencephalography.…aspects of recent human evolution and culture—including language—are products of consciousness, rather than requirements for itFor electrical coherence to occur, structures that can synchronize disparate brain regions must have evolved at some stage. Prime candidates are the calcium-binding (calbindin) positive cells in the thalamus—a structure that relays signals relating to spatial and motor awareness between the cerebral cortex and midbrain, as well as regulating sleep and alertness. Calbindin proteins modulate the flow of calcium within neurons, affecting synaptic activity and neuronal activation. The calbindin positive cells in the thalamus can thereby facilitate high-frequency oscillations in different regions of the cortex (Joliot et al, 1994). According to Koch, such cells might be crucial messengers for consciousness, enabling effective interactions between different cortical regions. In support of this, when calbindin positive thalamic cells lose their ability to activate other neurons—as a result of injury or disease—these patients are in a vegetative state even when their cortical tissue is intact.The above observation is an example of how the study of brain-damaged patients can shed light on the underlying mechanisms of consciousness. It also led to the development of a possible treatment for such patients. Niko Schiff and colleagues found that deep-brain electrical stimulation of the central thalamus restored some behavioural responsiveness in a patient who had been minimally conscious for 6 years (Schiff et al, 2007).In evolutionary terms, consciousness is a phenotype with an underlying genotypeSudden recovery from prolonged states of minimal consciousness can also indicate which structures of the brain are required for normal states of awareness and activity. A study by Henning Voss and colleagues in New York and New Zealand found evidence that axonal regrowth led to the dramatic recovery of speech in a patient who had been in a minimally conscious state for 19 years after a road accident in 1984 (Voss et al, 2006). Axonal regrowth was shown by use of a new imaging technique, Diffusion Tensor Imaging (DTI), as the patient quickly regained the ability to talk with increasing fluency over a period of a few days. DTI is a form of magnetic resonance imaging (MRI) that forms images by observing the Brownian motion of water molecules. It showed axons sprouting from neurons in the intact part of the cortex. Further evidence came from positron emission tomography scans of the same brain areas, showing increased glucose metabolism that seemed to be linked with the neuronal regrowth, which would explain the patient''s recovery.Sudden recovery from prolonged states of minimal consciousness can also indicate which structures of the brain are required for normal states of awareness and activityKoch noted that this and other neuroimaging studies of vegetative state or minimally conscious patients have found that even a prolonged loss of consciousness can be reversed. Another important question is whether consciousness can be detected when patients are in a persistent vegetative state and cannot communicate verbally or by movement. Observing responses to stimuli in specific brain areas is not sufficient to assess the level of consciousness, as these reactions can occur without consciousness, as they do during sleep.To address this question, Adrian Owen and colleagues in the UK and Belgium conducted an ingenious experiment with a female patient who was incapable of responding to external stimuli. The researchers asked the patient to imagine playing tennis while they observed her in an MRI scanner. They found that the same cortical areas were activated as when normal individuals perform the same task (Owen et al, 2006). Koch points out that the task could not have been performed by unconscious processing of external stimuli, as the patient was only imagining the action.This result does not conclusively show that the patient was conscious, as the neural correlates of thought processes remain unclear. However, the above observation suggests that the patient might be more than minimally conscious, as she had been diagnosed. Owen''s colleague, Steven Laureys, has since been involved in several studies indicating that almost half of people with disorders of consciousness are wrongly diagnosed as being in a vegetative state. According to Laureys, these findings might indicate that some patients have had their life support turned off as a result of such misdiagnoses, even though they could have subsequently regained consciousness, to some extent.At present, this suggestion is controversial and does no more than provide a source of acute uncertainty for the families and doctors of such patients. In future, however, brain imaging could help clinicians to make more accurate diagnoses. In one of the most striking examples so far, Christine Ecker and colleagues at King''s College and University College, London, UK, have identified characteristic structural features of the brain that can be used to reliably diagnose autism spectrum disorder (ASD; Ecker et al, 2010). They used MRI to measure certain brain features in patients with ASD—such as the thickness and degree of folding in particular areas of the cortex—and combined this information to obtain a correlate picture of the brain changes that are unique to ASD. This was an important development, as ASD is complex and associated with many cortical features that have previously been difficult to categorize. By using this new approach, ASD can now be clearly distinguished from other conditions and accurate, rapid diagnosis in early life could make a notable difference for sufferers.“the study of consciousness is now moving from the domain of philosophy and metaphysics into the empirical domain of science”This work might also guide research on the genetic and neurological bases of ASD, by identifying the anatomical features and ultimately individual proteins that are implicated in the disorder. Some of the cortical regions involved seem to be unique, which resonates with more general research into various aspects of consciousness.This type of applied research into consciousness is at the opposite end of the spectrum to the ongoing attempts to unite the scientific and philosophical approaches to studying the subject. Indeed, as Koch noted, “the study of consciousness is now moving from the domain of philosophy and metaphysics into the empirical domain of science.”This move is creating the ultimate challenge for multidisciplinary research; it requires the interaction of two fields with little history or experience of collaboration. According to Bill Brewer, who specializes in the philosophy of perception at Warwick University, UK, “this is a massive philosophical question in itself: what is the relationship between philosophical and scientific approaches to mental phenomena in general and conscious experience in particular?” Brewer believes that such efforts will ultimately prove successful; “My own opinion, having been part of a number of interdisciplinary projects concerned with such matters, is that there is no general abstract recipe for fruitful collaboration. It requires long periods of open-minded mutual learning, teaching and open-ended discussion of very specific questions and issues in the various different fields until it eventually becomes clear that a good deal in the disciplinary boundaries is arbitrary and all parties are actually concerned with the same fundamental problems in ways that merge into a continuum of approaches.”Whether this will lead to a full understanding of consciousness and whether science has something to say about the ‘meaning'' of our existence remains to be seen.     

Exploring the influence of plant and animal item contexts on student response patterns to natural selection multiple choice items

Background

Research has shown that students have a variety of ideas about natural selection that may be context dependent. Prior analyses of student responses to open-ended evolution items have demonstrated that students apply more core ideas about natural selection when asked about animals, but respond with the same number of naive ideas for plant and animal items. Other research has shown that changing an item to ask about trait loss or gain shifted the types of naive ideas applied by students in their responses. In this paper, we take up both of these findings to determine if differences exist in the types of ideas students apply to similar items with either a plant or an animal in the item stem.

Results

In order to understand if students applied different ideas to plants or animals in distractor-driven multiple-choice questions, we analyzed high school biology students’ responses to matched-item pairs. Dichotomous scoring revealed that students chose the correct response more often for the animal items as compared to the plant items. Chi squared analyses revealed significant differences in the distribution of student responses to matched items. For example, more students chose responses that defined animal fitness as related to their strength and plants’ fitness related to its longevity.

Conclusions

These results suggest that varied context of plants or animals in item stems on diagnostic assessments can provide teachers with a more complete picture of their students’ ideas about natural selection prior to instruction. This is particularly important in assessments used prior to instruction; as teachers will gain greater insight into the variety of ways students think about natural selection across different types of plants and animals.

     

Identifying Social Learning in Animal Populations: A New ‘Option-Bias’ Method

Background

Studies of natural animal populations reveal widespread evidence for the diffusion of novel behaviour patterns, and for intra- and inter-population variation in behaviour. However, claims that these are manifestations of animal ‘culture’ remain controversial because alternative explanations to social learning remain difficult to refute. This inability to identify social learning in social settings has also contributed to the failure to test evolutionary hypotheses concerning the social learning strategies that animals deploy.

Methodology/Principal Findings

We present a solution to this problem, in the form of a new means of identifying social learning in animal populations. The method is based on the well-established premise of social learning research, that - when ecological and genetic differences are accounted for - social learning will generate greater homogeneity in behaviour between animals than expected in its absence. Our procedure compares the observed level of homogeneity to a sampling distribution generated utilizing randomization and other procedures, allowing claims of social learning to be evaluated according to consensual standards. We illustrate the method on data from groups of monkeys provided with novel two-option extractive foraging tasks, demonstrating that social learning can indeed be distinguished from unlearned processes and asocial learning, and revealing that the monkeys only employed social learning for the more difficult tasks. The method is further validated against published datasets and through simulation, and exhibits higher statistical power than conventional inferential statistics.

Conclusions/Significance

The method is potentially a significant technological development, which could prove of considerable value in assessing the validity of claims for culturally transmitted behaviour in animal groups. It will also be of value in enabling investigation of the social learning strategies deployed in captive and natural animal populations.     

Detecting number processing and mental calculation in patients with disorders of consciousness using a hybrid brain-computer interface system

Background

For patients with disorders of consciousness such as coma, a vegetative state or a minimally conscious state, one challenge is to detect and assess the residual cognitive functions in their brains. Number processing and mental calculation are important brain functions but are difficult to detect in patients with disorders of consciousness using motor response-based clinical assessment scales such as the Coma Recovery Scale-Revised due to the patients’ motor impairments and inability to provide sufficient motor responses for number- and calculation-based communication.

Methods

In this study, we presented a hybrid brain-computer interface that combines P300 and steady state visual evoked potentials to detect number processing and mental calculation in Han Chinese patients with disorders of consciousness. Eleven patients with disorders of consciousness who were in a vegetative state (n?=?6) or in a minimally conscious state (n?=?3) or who emerged from a minimally conscious state (n?=?2) participated in the brain-computer interface-based experiment. During the experiment, the patients with disorders of consciousness were instructed to perform three tasks, i.e., number recognition, number comparison, and mental calculation, including addition and subtraction. In each experimental trial, an arithmetic problem was first presented. Next, two number buttons, only one of which was the correct answer to the problem, flickered at different frequencies to evoke steady state visual evoked potentials, while the frames of the two buttons flashed in a random order to evoke P300 potentials. The patients needed to focus on the target number button (the correct answer). Finally, the brain-computer interface system detected P300 and steady state visual evoked potentials to determine the button to which the patients attended, further presenting the results as feedback.

Results

Two of the six patients who were in a vegetative state, one of the three patients who were in a minimally conscious state, and the two patients that emerged from a minimally conscious state achieved accuracies significantly greater than the chance level. Furthermore, P300 potentials and steady state visual evoked potentials were observed in the electroencephalography signals from the five patients.

Conclusions

Number processing and arithmetic abilities as well as command following were demonstrated in the five patients. Furthermore, our results suggested that through brain-computer interface systems, many cognitive experiments may be conducted in patients with disorders of consciousness, although they cannot provide sufficient behavioral responses.

     

Theories of Nomadic Movement: A New Theoretical Approach for Understanding the Movement Decisions of Nenets and Komi Reindeer Herders

It is known that the relationship between humans and their animals is important for understanding many aspects of nomadic pastoralist systems, including nomadic movement. However, to date, these complex human–animal relations have not been analyzed in a way that has led to an explanatory model of nomadic movement capable of producing testable hypotheses. Based on ethnographic material collected amongst Komi and Nenets nomadic reindeer herders of the Russian Arctic, we argue that nomadic movements can be best understood as a product of the interplay that exists between animal behaviour and the herders’ skilful actions to (a) maintain herd cohesion and (b) avoid hazards, whilst deploying the minimum amount of resources (i.e., human/animal effort and use of equipment) on rounding up the herd, stopping and turning it. Ecological factors affect movement through their influence on animal behaviour, whereas non-ecological factors do so by influencing the herders’ skilful actions. We demonstrate that, based on these assumptions, it is possible to build a testable model explaining the movement of some nomadic groups.

Towards a nonessentialist class consciousness

Conclusion This paper has presented a concept of class consciousness from the framework of nonessentialist Marxism. Class consciousness as class-expressive discourse is epistemologically and theoretically different from concepts of that consciousness both in and outside the Marxian and nonessentialist frameworks. The concept here was developed within and by means of that framework-through the process of conceptual juxtaposition.I have indicated that instead of viewing a lack of class consciousness as false or mystified consciousness, it is possible to analyze various class conscious discourses. Thus an individual's lack of a capitalist class consciousness is attributed not to his/her inability to perceive the essence of his/her being as a capitalist class member, but as the presence of (multiple and contradictory) class conscious discourses that are themselves determined by the various social and natural processes in society.From the theory of multiple class processes and nonessentialist epistemology, the complexity of class and class consciousness was explored. Neither consciousness nor class was reduced to each other. Rather, their overdetermined complexity was analyzed.Dr. Oakes is currently engaged in fieldwork in Granada under a Fulbright grant.     

Politics or metaphysics? On attributing psychological properties to animals

Following recent arguments that there is no logical problem with attributing mental or agential states to animals, I address the epistemological problem of how to go about making accurate attributions. I suggest that there is a two-part general method for determining whether a psychological property can be accurately attributed to a member of another species: folk expert opinion and functionality. This method is based on well-known assessments used to attribute mental states to humans who are unable to self-ascribe due to an early stage of development or impairment, and can be used to describe social and emotional development as well as personality. I describe how instruments such as the Child Behavior Checklist, which relies on intersubjective expert opinion, could be modified to assess other species subjects. The measures are validated via the accuracy of the predictions that are derived, which is an example of the functionality of attribution. I respond to theoretical criticisms against use of this method, and argue that if the method counts as good science for infant cognition research, then it should count as good science for animal cognition research as well. Correspondingly, if the method doesn’t count as good science for animal cognition research, then we must be very skeptical of its use with nonverbal humans.

Class consciousness and political action in Testour

Conclusion I began this article with an effort to see how the concept of consciousness could be operationalized within an anthropological framework. It is clear from the examination of the concept that to use it to label or to judge is misleading. Instead, consciousness must be dialectical to be meaningful. Political, social or class consciousness emerges from a heritage of culture and a particular social context; it forms an understanding of society and so it shapes action. The presumption is that a particular action is reflective of some kind of an understanding, some kind of awareness. Further, the pattern of action is in turn a prime determinant of the consciousness of the actors.Thus we can observe several different types of social situation from the point of view of determining whether politics is based on a consciousness of class: (1) where class is not a basis for action; (2) where class is a basis for action but the understanding of that situation by actors is in terms of another code, one furnished by religion or by a sense of corporatism, so that the class basis for action is disguised; (3) where class is the basis for social action, and is perceived as such. The difference between these last two cases is the gap that Marx referred to in his analysis of the fetishism of commidities, or that caused Lukacs to distinguish between consciousness and false consciousness. If the people act as though class were a consideration (whether or not they call it class) in situations which divide people along class lines, then a consciousness of class will probably emerge if it is not present already. Our interest here should not be in the individual but in the accepted definition of the situation, the code or the metaphor.I have attempted to extrapolate from the actions of politics to some hypotheses about consciousness. My conclusion is that the evidence for class consciousness is more indirect than direct. In the case of the zerda, consciousness of class is not reinforced, though there are elements of class organization present. The election is similar to the zerda in that interpersonal rivalry is important, but different in that it is explicitly political, and the State appears on the scene. The reaction to the flood also highlights relations between Testouris and the State, but there is also a new element in the form of a fairly open confrontation between two classes. While it would be difficult to impute class consciousness except in the last case, the presence of class relations suggests that the Testouri model of society may soon develop such a perception.One source of awareness of class is the relations of production within Testour's agrarian society. Many of the institutions of the town mask the full impact of these relations: the emphasis placed on interpersonal rivalry, the stress on genealogical and geographical origin, and the strong sense of being from the town. Nevertheless, an awareness of class sometimes complements a behavior determined along class lines, as in the reaction to the flood. A second source of class consciousness would be the power relations that exist between the State, as the instrument of the dominant class at the national level, and the various segments of Tunisian society. People are conscious of these as political relations rather than the political expression of class relations, and so here, too, some aspects of the social relationship are not recognized.The partially negative conclusion concerning class consciousness reflects the stage in the transition from precapitalist to capitalist society that Testour has reached. The complexity and subtlety of the real case should be a corrective to overhasty generalization as well as a contribution to the growing debate on the usefulness of consciousness as a concept in anthropology. As Lynch argues, it is one way to restore the problematic of meaning to a mechanistic interpretation of a particular social situation. The idea of consciousness provides a sense of movement in change and creates the possibility of a dialectical understanding of political action.Nicholas Hopkins is Chair of the Department of Anthropology, Sociology and Psychology at the American University in Cairo.

---

     

Scavengers on the Move: Behavioural Changes in Foraging Search Patterns during the Annual Cycle

Background

Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, simple Brownian random movement should be sufficient. Although very different groups of organisms exhibit Lévy motion, the shift from a Lévy to a Brownian search strategy has been suggested to depend on internal and external factors such as sex, prey density, or environmental context. However, animal response at the individual level has received little attention.

Methodology/Principal Findings

We used GPS satellite-telemetry data of Egyptian vultures Neophron percnopterus to examine movement patterns at the individual level during consecutive years, with particular interest in the variations in foraging search patterns during the different periods of the annual cycle (i.e. breeding vs. non-breeding). Our results show that vultures followed a Brownian search strategy in their wintering sojourn in Africa, whereas they exhibited a more complex foraging search pattern at breeding grounds in Europe, including Lévy motion. Interestingly, our results showed that individuals shifted between search strategies within the same period of the annual cycle in successive years.

Conclusions/Significance

Results could be primarily explained by the different environmental conditions in which foraging activities occur. However, the high degree of behavioural flexibility exhibited during the breeding period in contrast to the non-breeding period is challenging, suggesting that not only environmental conditions explain individuals'' behaviour but also individuals'' cognitive abilities (e.g., memory effects) could play an important role. Our results support the growing awareness about the role of behavioural flexibility at the individual level, adding new empirical evidence about how animals in general, and particularly scavengers, solve the problem of efficiently finding food resources.     

Dobutamine in Paediatric Population: A Systematic Review in Juvenile Animal Models

Objective

Although dobutamine is widely used in neonatal clinical practice, the evidence for its use in this specific population is not clear. We conducted a systematic review of the use of dobutamine in juvenile animals to determine whether the evidence from juvenile animal experiments with dobutamine supported the design of clinical trials in neonatal/paediatric population.

Methods

Studies were identified by searching MEDLINE (1946–2012) and EMBASE (1974–2012). Articles retrieved were independently reviewed by three authors and only those concerning efficacy and safety of the drug in juvenile animals were included. Only original articles published in English and Spanish were included.

Results

Following our literature search, 265 articles were retrieved and 24 studies were included in the review: 17 focused on neonatal models and 7 on young animal models. Although the aims and design of these studies, as well as the doses and ages analysed, were quite heterogeneous, the majority of authors agree that dobutamine infusion improves cardiac output in a dose dependent manner. Moreover, the cardiovascular effects of dobutamine are influenced by postnatal age, as well as by the dose used and the duration of the therapy. There is inadequate information about the effects of dobutamine on cerebral perfusion to draw conclusions.

Conclusion

There is enough preclinical evidence to ensure that dobutamine improves cardiac output, however to better understand its effects in peripheral organs, such as the brain, more specific and well designed studies are required to provide additional data to support the design of clinical trials in a paediatric population.     

Social transmission of fear in rats: the role of 22-kHz ultrasonic distress vocalization

Background

Social alarm calls alert animals to potential danger and thereby promote group survival. Adult laboratory rats in distress emit 22-kHz ultrasonic vocalization (USV) calls, but the question of whether these USV calls directly elicit defensive behavior in conspecifics is unresolved.

Methodology/Principal Findings

The present study investigated, in pair-housed male rats, whether and how the conditioned fear-induced 22-kHz USVs emitted by the ‘sender’ animal affect the behavior of its partner, the ‘receiver’ animal, when both are placed together in a novel chamber. The sender rats’ conditioned fear responses evoked significant freezing (an overt evidence of fear) in receiver rats that had previously experienced an aversive event but not in naïve receiver rats. Permanent lesions and reversible inactivations of the medial geniculate nucleus (MGN) of the thalamus effectively blocked the receivers’ freeezing response to the senders'' conditioned fear responses, and this occurred in absence of lesions/inactivations impeding the receiver animals'' ability to freeze and emit 22-kHz USVs to the aversive event per se.

Conclusions/Significance

These results—that prior experience of fear and intact auditory system are required for receiver rats to respond to their conspecifics'' conditioned fear responses—indicate that the 22-kHz USV is the main factor for social transmission of fear and that learning plays a crucial role in the development of social signaling of danger by USVs.     

Renal effects of angiotensin II in the newborn period: role of type 1 and type 2 receptors

Background

Evidence suggests a critical role for the renin-angiotensin system in regulating renal function during postnatal development. However, the physiological relevance of a highly elevated renin-angiotensin system early in life is not well understood, nor which angiotensin receptors might be involved. This study was designed to investigate the roles of angiotensin receptors type 1 (AT1R) and type 2 (AT2R) in regulating glomerular and tubular function during postnatal development.

Methods

The renal effects of the selective antagonist to AT1R, ZD 7155 and to AT2R, PD 1233319 were evaluated in two groups of conscious chronically instrumented lambs aged?~?one week (N?=?8) and?~?six weeks (N?=?10). Two experiments were carried out in each animal and consisted of the assessment of renal variables including glomerular and tubular function, for 30 min before (Control) and 60 min after infusion of ZD 7155 and PD 123319, respectively. Statistical significance was determined using parametric testing (Student t-test, analysis of variance ANOVA) as appropriate.

Results

ZD 7155 infusion was associated with a significant decrease in glomerular filtration rate and filtration fraction at one but not six weeks; urinary flow rate decreased significantly in older animals, whereas sodium excretion and free water clearance were not altered. There was an age-dependent effect on potassium handling along the nephron, potassium excretion decreasing after ZD 7155 infusion in younger but not in older lambs. PD 123319 had no significant effects on glomerular filtration rate and tubular function in either age group.

Conclusions

These results provide evidence to support an important role for AT1Rs in mediating the renal effects of angiotensin II during postnatal maturation in conscious developing animals. In contrast to a role for AT2Rs later in life, there appears to be no role for AT2Rs in influencing the renal effects of Angiotensin II in the postnatal period.

     

“Garden hunting” in the American tropics

Using faunal analysis, this article outlines a coastal mammalian harvesting pattern involving a few terrestrial mammals whose biomass appears to have been greater when associated with man than under natural conditions. Archeological evidence suggests that these animals fed regularly on cultivated crops and were hunted in house gardens and cultivated fields. By concentrating the supply of both carbohydrates and animal protein, garden hunting may have eliminated seasonality and scheduling problems. And because it artificially increased the biomass of selected animals, it may have functioned as a substitute for animal domestication.     

The social construction of unreality: The real American dilemma

Conclusion Before Marx took up the concept of consciousness it was damaged by the submissive theology of Hegel. Marx grounded consciousness in the nuts-and-bolts happenings of everyday life in a repressive society. From the predicament of a dominated mind arises false consciousness, a condition in which subject classes are cognitively incapable of identifying their own interests, historical role, and human potential. Mystification is the construction of a collective unreality in which myth displaces the real antagonisms of social life. Of all the ideologies that contribute to a state of false consciousness, individualism is the most significant in its relation to de-fusing a class struggle; it is the divide and conquer tactic par excellence. Taking a page from Marx, we have presented scenarios from everyday life that perpetuate the individual's image of him or herself as an isolated, privatized element in society. We have also followed Marx in the view, amply supported by the historical evidence, that the dominant class projects the standard cultural norms in capitalist society.Sociologists of a phenomenological persuasion have viewed the social world as a dialectic between mind and concrete environment. Reality as such is the end product of subjective definitions by individuals and groups. We have argued that perceptions of social reality are in large part engineered by a minority whose interest rests in creating images that effectively disguise their control of society's resources. Thus, Americans who have been thoroughly mystified by the ideology of individualism are capable of seeing their own lives as bright with promise, while their nation's fortunes decline. Such mental acrobatics are not explainable in terms of dissonance theory, which gives an ahistorical analysis, or particularization, which reduces false consciousness to the psychological level. False consciousness — whether it be evidenced by individualism, chauvinism, religious fanaticism, aestheticism, or nature worship — does not result from a random ordering of phenomena: It is the reflection of a conscious choice by dominating classes and their agents, i.e., distortion of reality to prevent communal actions threateningH.C. Greisman and Sharon S. Mayes are Assistant Professors in the Department of Sociology at the University of Maryland, College Park.