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A life filled with learning is advisable. Tasks involving some degree of cognitive complexity is desirable, but there is no reason to believe that certain forms of learning are better than others. What is critical is that the activity needs to be consistent and persistent. Involvement of cognitive activity at work is important and jobs that involve high stress, passive participation, and lack of complexity are associated with higher levels of cognitive impairment in later life. There is also no reason to believe that mental activities must be limited to the early years of life. People are able to learn at all ages and participation in learning is valuable for the brain throughout life. The concept of diversity refers as well to learning and mental activities. It is good to learn new things! Participation in cognitive activities throughout the lifespan both at home and at work and avoiding multi-tasking can help build cognitive reserve capacity. Cognitive activities directly impair disease processes. Being cognitively active and paying attention to the world helps to protect the brain from free radicals and toxins. Cognitive activities also assists in the management of stress.
Memory and cognition are critical parts of who we are. Our capacity for recall allows us to use past experience to guide our actions. Our cognitive abilities allow us to monitor events and evaluate plans for action. In aging there are varying degrees of decline in cognitive function which begin in the 30s and are quite common. They are not a disease and are accompanied by the growth of wisdom which can negate the influence of age-related memory changes. Memory losses with aging can be avoided with consideration of the importance of attention for memory. The role of forgetting as a normal activity of the brain is critical. It is necessary to realize that the influences of aging and age-related disease (such as Alzheimer’s) on brain function are not determined only on the processes of aging and disease -- the effect of these processes on our performance abilities depends upon our cognitive, physical, psychological, and social reserves. We all need to enhance these reserve capacities to decrease the influence of the aging process and developing brain disease on our function. This chapter reviews the functions of memory and how losses that accompany aging can best be managed.
Understanding of the magnificence and uniqueness of the brain is important for realizing the goals of aging. We must respect its central role in our lives and work to see what we must do to enhance its health throughout life. The brain is precisely responsive to activities and its structure is changed by learning. It is also uniquely sensitive to damage and has a limited capacity for repair, compared to other body parts. What we do changes the brain, and the nature of our mental activities modifies the ability of the brain to resist declines with aging and disease. Cognitive involvement in educational, occupational, and recreational tasks throughout life, as well as physical activities, helps to enhance resistance to decline with age and diseases such as Alzheimer’s. This chapter examines how the four reserves (cognitive, physical, psychological, and social) help to maintain brain function with age. Recent research has uncovered the influence of our partner microbes in the gut on learning, memory, and age-related diseases of the brain. These developments beautifully illustrate how there are things we can all do to maintain brain function with age.
Engaging Catherine Malabou's philosophical work on biological plasticity, this article combines microbiological and geopolitical analysis of the deadliest manifestations of childhood malnutrition. At the scale of microbiology, childhood malnutrition is a devastating condition and a mystery to which it seems microbiomes – the ecosystems of microbes in the gut – hold a key. At the scale of geopolitics, childhood malnutrition is a calamity generated by racial capitalism, poverty, and underdevelopment. What should we do with the plasticity that makes us? Malabou asks. Engaging philosophically with the plastic materiality of microbiomes in childhood malnutrition, the article focuses on destructive plasticity as an ontological alternative to what science on malnutrition pursues as a problem of causality. This leads to an argument that medicine, as well as humanitarian, security, and development interventions, must reckon with the destructive plasticity of what is in essence a political disease of annihilation. The article ends by speculating on resistance via the biological act of nurturing.
The main principles of plasticity theory are introduced. The collapse theorems are presented as one of the principal applications of plasticity theory in soil mechanics. Some special plasticity theories for soil (Cam-clay theory and Mohr–Coulomb applications) are also presented.
For species without parental care, such as sea turtles, nest site selection is particularly important for embryo development, hatchling survival and, ultimately, reproductive success. We conducted an 8-year (2012–2019) capture–mark–recapture study of the re-nesting behaviour of loggerhead turtles Caretta caretta to identify both inter- and intra-beach patterns of nest site selection. Our study site, Maio Island in the archipelago of Cabo Verde, hosts one of the largest loggerhead turtle nesting colonies globally. Of 1,060 females analysed, 77% laid repeated clutches within 15 km of their previous nesting sites both between and within nesting seasons. This site fidelity was particularly high (64–71%) for turtles nesting on the east coast of Maio Island. In two areas of the island (north-west and south-east) individual nesting zone consistency was extremely low (10–25%). In all cases extra-zone re-nesting events mainly occurred on the east coast. We also found that females avoided re-nesting near the shoreline, which is particularly relevant in the context of rising sea levels. Overall, loggerhead turtles nesting in Maio Island are philopatric but are using a bet-edging strategy to distribute nests amongst several beaches, choosing the safest area within each beach to maximize their reproductive success. This study highlights the priority sites for protection on Maio Island and could help to optimize capture–mark–recapture programmes. The data reveal the potential for adaptive responses to projected sea level rises.
A Primer to Theoretical Soil Mechanics is about adapting continuum mechanics to granular materials. The field of continuum mechanics offers many fruitful concepts and methods, however there is declining interest in the field due to its complex and fragmented nature. This book's purpose is therefore to facilitate the understanding of the theoretical principles of soil mechanics, as well as introducing the new theory of barodesy. This title argues for barodesy as a simple alternative to the plasticity theory used currently and provides a systematic insight into this new constitutive model for granular materials. This book therefore introduces a complex field from a fresh and innovative perspective using simple concepts, succinct equations and explanatory sketches. Intended for advanced undergraduates, graduates and PhD students, this title is also apt for researchers seeking advanced training on fundamental topics.
We provide a brief overview of current research on the behavioral ecology of learning in insects, emphasizing the function of learning in their ability to find food, locate hosts, avoid danger, and secure mates. In addition, we outline two important issues facing the current study of insect learning. One issue is the need, not only to recognize, but also to understand the role of plasticity and variation in the expression of learning, including the impacts of circadian rhythm, intraspecific and interspecific genetic differences, sex, development and environmental context. A second issue is the vexing question of homology versus homoplasy in the underlying mechanisms of learning in insects, other invertebrates and single-celled organisms.
The fossil record is scarce and incomplete by nature. Animals and ecological processes devour soft tissue and important bony details over time and, when the dust settles, we are faced with a patchy record full of variation. Fossil taxa are usually defined by craniodental characteristics, so unless postcranial bones are found associated with a skull, assignment to taxon is unstable. Naming a locomotor category based on fossil bone morphology by analogy to living hominoids is not uncommon, and when no single locomotor label fits, postcrania are often described as exhibiting a ‘mosaic’ of traits. Here, we contend that the unavoidable variation that characterises the fossil record can be described far more rigorously based on extensive work in human neurobiology and neuroanatomy, movement sciences and motor control and biomechanics research. In neurobiology, degeneracy is a natural mechanism of adaptation allowing system elements that are structurally different to perform the same function. This concept differs from redundancy as understood in engineering, where the same function is performed by identical elements. Assuming degeneracy, structurally different elements are able to produce different outputs in a range of environmental contexts, favouring ecological robusticity by enabling adaptations. Furthermore, as degeneracy extends to genome level, genetic variation is sustained, so that genes which might benefit an organism in a different environment remain part of the genome, favouring species’ evolvability.
During pregnancy in humans and rats, plasma osmolality is regulated at a level about 3% lower than in nonpregnant females (or males). This may be, in part, caused by reproduction-related hormonal changes. Late in gestation, fetal sheep show acute swallowing responses to some dipsogens, and the relevant CVOs in the brain appear to have full responsiveness to those dipsogens at this time. Postnatal development of independent drinking in rats shows that responses to hypovolemia are present and vigorous very soon after birth, whereas development of osmoregulatory drinking has a considerably slower ontogenetic trajectory. Further, this trajectory seems to be slower in mice than rats and requires further study. Some aspects of osmoregulatory drinking in rats, as well as food-associated drinking, appear to have an experiential component. Hypovolemia or other circulatory challenges before birth in rats cause alterations in the ontogenetic trajectory of drinking, although the limits and mechanisms of this phenotypic plasticity have not been fully elucidated.
The brain has the innate ability to undergo neuronal plasticity, which refers to changes in its structure and functions in response to continued changes in the environment. Although these concepts are well established in animal slice preparation models, their application to a large number of human subjects could only be achieved using noninvasive brain stimulation (NIBS) techniques. In this review, we discuss the mechanisms of plasticity induction using NIBS techniques including transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), random noise stimulation (RNS), transcranial ultrasound stimulation (TUS), vagus nerve stimulation (VNS), and galvanic vestibular stimulation (GVS). We briefly introduce these techniques, explain the stimulation parameters and potential clinical implications. Although their mechanisms are different, all these NIBS techniques can be used to induce plasticity at the systems level, to examine the neurophysiology of brain circuits and have potential therapeutic use in psychiatric and neurological disorders. TMS is the most established technique for the treatment of brain disorders, and repetitive TMS is an approved treatment for medication-resistant depression. Although the data on the clinical utility of the other modes of stimulation are more limited, the electrical stimulation techniques (tDCS, tACS, RNS, VNS, GVS) have the advantage of lower cost, portability, applicability at home, and can readily be combined with training or rehabilitation. Further research is needed to expand the clinical utility of NIBS and test the combination of different modes of NIBS to optimize neuromodulation induced clinical benefits.
Developmental biology is seemingly well understood, with development widely accepted as being a series of programmed changes through which an egg turns into an adult organism, or a seed matures into a plant. However, the picture is much more complex than that: is it all genetically controlled or does environment have an influence? Is the final adult stage the target of development and everything else just a build-up to that point? Are developmental strategies the same in plants as in animals? How do we consider development in single-celled organisms? In this concise, engaging volume, Alessandro Minelli, a leading developmental biologist, addresses these key questions. Using familiar examples and easy-to-follow arguments, he offers fresh alternatives to a number of preconceptions and stereotypes, awakening the reader to the disparity of developmental phenomena across all main branches of the tree of life.
The accumulation of nutrients during diapause preparation is crucial because any lack of nutrition will reduce the likelihood of insects completing diapause, thereby decreasing their chances of survival and reproduction. The fall webworm, Hyphantria cunea, diapause as overwintering pupae and their diapause incidence and diapause intensity are regulated by the photoperiod. In this study, we test the hypothesis that photoperiod influences energy reserve accumulation during diapause preparation in fall webworm. We found that the body size and mass, lipid and carbohydrate content of pupae with a short photoperiod during the diapause induction phase were significantly greater than those of pupae with a relatively short photoperiod, and the efficiency of converting digested food and ingested food into body matter was greater in the short-photoperiod diapause-destined larvae than the relatively short-photoperiod diapause-destined larvae. We also observed higher lipase and amylase activities in short-photoperiod diapause-destined larvae relative to the counterparts. However, no obvious difference was found in protein and protease in the pupae with a short photoperiod during the diapause induction phase and short-photoperiod diapause-destined larvae compared with the counterparts. Therefore, we conclude that the energy reserve patterns of diapausing fall webworm pupae are plastic and that short-photoperiod diapause-destined larvae increase their energy reserves by improving their feeding efficiency and increase their lipid and carbohydrate stores by increasing the lipase and amylase activities in the midgut.
While Aristotle located minerals, metals and other earth matter at the bottom of the hierarchical classification of beings, thus creating an insurmountable gap between the geological and animated ontologies, post-humanist approaches to the inorganic seek to bridge that gap and complicate the Aristotelian hierarchy of beings. Post-humanist approaches to the inorganic include thing-theory, object-oriented ontology, vital materialism and actor-network theory. I zoom onto Catherine Malabou’s concept of plasticity, which she develops in a post-humanist reading of Hegel, and which captures the capacity of organisms and objects to transform their internal parameters in response to the environment. I argue that Malabou’s ‘plasticity’ complicated and subverts the Aristotelian hierarchy of beings. Next, I apply these conceptual insights to ask about the place of non-human agency in collective and traumatic memory; through a close reading of Didi-Huberman’s Bark, I show that materiality and plasticity are aspects of mnemonic affordance
The classical pragmatists provided a clear set of leading ideas about what a habit is. This conception of “habit” is distinct from the behavioral conception of habit as a fixed disposition to respond to stimuli that has been enforced by the environment. This chapter focuses on developing a pragmatic account of habit based on leading ideas from Peirce and Dewey. It also argues that this account can play a useful role in the emerging account of cognition as culturally evolved and enculturated. The combined account demonstrates that the work of the classical pragmatists is as fresh and important now as it was a hundred years ago.
Natural selection has operated as strongly or more so on the early stages of the lifespan as on adulthood. One evolved feature of human childhood is high levels of behavioral, cognitive, and neural plasticity, permitting children to adapt to a wide range of physical and social environments. Taking an evolutionary perspective on infancy and childhood provides a better understanding of contemporary human development, predicting and understanding adult behavior, and explaining how changes in the early development of our ancestors produced contemporary Homo sapiens.
Chapter 5 returns to the question of the affordance and ductility of paper in Italian, Welsh and English literature. The use of paper in literary manuscripts is not just a question of production, but has implications for the reading of medieval literature itself. The interplay of Chaucer in Troilus and Criseyde and his sources in their comments on the material properties of writing-supports is evidence of paper’s wider cultural acceptance, as well as literary ingenuity. In the light of the foregoing chapters’ exploration of paper books as precisely defined and individually distinctive objects, with very specific properties and effects, this chapter explores the fascinating relationship between the material aspect of book production and the literary world of medieval authors to offer nuanced readings of their works.
In this article, I explore the relationship between performativity, as it appears in Judith Butler's work, and plasticity, as it appears in the work of Catherine Malabou. I argue that these concepts are isomorphic. Butler and Malabou both hold that resistance to contemporary forms of power, or “insubordination,” is contingent on a subject's ability to become other than what it is; Butler articulates this ability in terms of performativity, and Malabou articulates it in terms of plasticity. I reveal the social-constructivist dimension of Malabou's work while also making apparent the extent to which Butler's work, contrary to her own way of conceptualizing it, and hence surprisingly and uneasily, presupposes a biologically basic capacity for change. Plasticity is this biologically basic capacity. Both thinkers affirm the idea that insubordinate forms of transformation can be impeded by the discourse that conditions what a subject can think. I suggest that this is an insight that must be heeded, even as I seek to affirm a form of plasticity beyond discourse.
Life experiences have been associated with significant changes in brain structure and functioning. This experience-dependent plasticity is thought to reflect the capacity of our nervous systems to adapt to environmental demands, and ultimately shape cognition. This chapter focuses on how such experiences and environment can specifically impact the hippocampus, a structure important for learning, memory, and healthy cognition. The hippocampal memory system maintains a competitive relationship with other memory systems, in particular the caudate nucleus of the striatum, part of the basal ganglia. Specific types of behavior, such as spatial-based vs. response-based navigational strategies, can influence these memory systems both positively and negatively and lead to long-term neuroplastic changes. Overreliance on non-hippocampus dependent navigational strategies is associated with a reduction in hippocampus volume and activity across the lifespan. Emerging research is now pointing to the wide use of electronic devices – GPS, smartphones, and video games – as a contributing factor to greater reliance on non-hippocampus dependent memory. Given the limited, but concerning, evidence that reliance on electronic devices can interact with already established factors related to underuse of the hippocampal memory system, further study is needed to better understand how these imbalances occur and how they can be mitigated.