In his Arthur Holly Compton Memorial Lecture Sir Karl Popper tackles a problem raised by Compton himself in an earlier lecture. The problem is to understand how such abstract things as aims, purposes, rules, or agreements can influence or control the movements of men, and perhaps also of animals. To illustrate the problem Compton had remarked on the amazing faith and confidence shown by his audience and the lecture's organizer that he should arrive on the agreed date to give (...) the lecture, considering ‘the great physical improbability that their confidence was justified’. ForIn the meanwhile my work called me to the Rocky Mountains and across the ocean to sunny Italy. A phototropic organism [such as I happen to be, would not easily]... tear himself away from there to go to chilly New Haven. Considered as a physical event, the probability of meeting my engagement would have been fantastically small. (shrink)

A response to Via about the existence (or not) and role of plasticity genes in evolution.

The growing field of evo-devo is increasingly demonstrating the complexity of steps involved in genetic, intracellular regulatory, and extracellular environmental control of the development of phenotypes. A key result of such work is an account for the remarkable plasticity of organismal form in many species based on relatively minor changes in regulation of highly conserved genes and genetic processes. Accounting for behavioral plasticity is of similar potential interest but has received far less attention. Of particular interest is plasticity in (...) communication systems, where human language represents an ultimate target for research. The present paper considers plasticity of language capabilities in a comparative framework, focusing attention on examples of a remarkable fact: Whereas there exist design features of mature human language that have never been observed to occur in non-humans in the wild, many of these features can be developed to notable extents when non-humans are enculturated through human training. These examples of enculturated developmental plasticity across extremely diverse taxa suggest, consistent with the evo-devo theme of highly conserved processes in evolution, that human language is founded in part on cognitive capabilities that are indeed ancient and that even modern humans show self-organized emergence of many language capabilities in the context of rich enculturation, built on the special social/ecological history of the hominin line. Human culture can thus be seen as a regulatory system encouraging language development in the context of a cognitive background with many highly conserved features. (shrink)

The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behaviour against the volitional control of a goal-directed behaviour. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behaviour and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following two weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following two weeks of training; however this (...) increased speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions. (shrink)

Most discussions of neural plasticity in the context of the Molyneux question focus on changes in the visual cortex, early on during critical periods, or post-surgery after patients are given sight. There are good reasons, based on enactive approaches to perception to ask about plastic changes in the dorsal visual pathway and motor control areas. This essay explores the implications of such changes for the Molyneux question.

Imbalanced plasticity of neural networks in the brain is proposed to underlie deficits in the integration of efferent and afferent processes in schizophrenia. These deficits affect the priming of the behavior implementing systems by prior knowledge, and thus impair both controlled regulation and automatic activation of mental and motor processes. The sense of self as a distinct entity can consequently be undermined. In predominantly reality-distorting patients, hypo-plasticity of neural connectivity may cause the emergence of highly focused but inflexible patterns of (...) activation in their representation and response systems. This may lead to dominance of prepotent patterns of activity in these systems and a relative inability of higher control systems to bias lower level activity towards congruence with the ongoing cognitive and motor context. By contrast, predominantly disorganized patients are characterized by hyper-plastic connectivity. This leads to a weakening of prepotent response tendencies but also, as in reality-distorting patients, to less effective top-down contextual constraining. (shrink)

Studies comparing movement-related cortical potentials, post-excitatory inhibition after transcranial magnetic brain stimulation, and PET findings in normal controls and patients with cerebellar degeneration demonstrate plasticity of cerebro-cerebellar interactions and hereby support Thach's theory that the cerebellum has the ability to play a role in building behavioral context-response linkages and to build up appropriate responses from simpler constitutive elements, [THACH].

The spinal mechanisms of action of opioids under normal conditions are reasonably well understood. The spinal effects of opioids can be enhanced or reduced depending on pathology and activity in other segmental and nonsegmental pathways. This plasticity will be considered in relation to the control of different pain states using opioids. The complex and contradictory findings on the supraspinal actions of opioids are explicable in terms of heterogeneous descending pathways to different spinal targets using multiple transmitters and receptors – (...) therefore opioids can both increase and decrease activity in descending pathways. These pathways could exhibit considerable plasticity. There is increasing evidence that delta opioid receptor agonists have the potential to replace morphine as major analgesics with reduced side-effect profiles. The concept of preemptive analgesia, based on preventing the induction of some of the negative plastic influences on opioid controls and the detrimental effects of pain, is sound, but experimental verification in the clinical setting is difficult. For example, a delayed compensatory upregulation of inhibitory systems, particularly in inflammation, may counter persistent painful inputs. Combination therapy with opioids may be beneficial in many pain states where either negative influences are blocked or inhibitory controls are enhanced. Finally, developmental aspects of these systems are discussed in connection with the treatment of pain in young children, where inhibitory systems in the spinal cord are immature. (shrink)

Plastic changes in spinal cord function like neuronal wind-up and increased receptive field are too short-lived to explain chronic pain without structural changes. It is possible that learning could be a mechanism for longlasting changes in nociceptive regulation. A learning process localized to the spinal cord has been shown to be important for the development of tolerance to the analgetic effect of ethanol, suggesting that nociceptive control systems may be changed by learning. Long term potentiation (LTP) is regarded (...) as a useful model of learning and memory. LTP-like changes have been observed in invitro preparations from the spinal cord and in spinal cord field potentials. Recently a long term increase in spinal A-[beta] and C-fibre evoked responses after painful stimulation has been observed. [coderre & katz, dickenson, wiesenfeld-hallin et al.]. (shrink)

Single-sided deafness (SSD) or profound unilateral hearing loss obligates the only serviceable ear to capture all acoustic information. This loss of binaural function taxes cognitive resources for accurate listening performance, especially under adverse environments or challenging tasks. We hypothesized that adults with SSD would manifest both functional and structural brain plasticity compared to controls with normal binaural hearing. We evaluated functional alterations using magnetoencephalographic imaging (MEGI) of brain activation during performance of a moderately difficult auditory syllable sequence reproduction task and (...) assessed structural integrity using diffusion tensor magnetic resonance imaging (DTI). MEGI showed the SSD cohort to have increased induced oscillations in the theta band over the left superior temporal cortex and decreased induced gamma band oscillations over the frontal and parietal cortices between 175-475 ms following stimulus onset. DTI showed the SSD cohort to have extensive fractional anisotropy reduction in both auditory and non-auditory tracts and regions. Overlaying functional and structural changes revealed by the two imaging techniques demonstrated close registration of cortical areas and white matter tracts that expressed brain plasticity. Hence, complete loss of input from one ear in adulthood triggers both functional and structural alterations to dorsal temporal and frontal-parietal areas. (shrink)

Experience-dependent neural plasticity is high in the developing brain, presenting a unique window of opportunity for training. To optimize existing training programs and develop new interventions, it is important to understand what processes take place in the developing brain during training. Here, we systematically review MRI-based evidence of training-induced neural plasticity in children and adolescents. A total of 71 articles were included in the review. Significant changes in brain activation, structure, microstructure, and structural and functional connectivity were reported with different (...) types of trainings in the majority of the studies. Significant correlation of performance improvement with neural changes was reported in 51% of the studies. Yet, only 48% of the studies had a control condition. Overall, the review supports the hypothesized neural changes with training while at the same time charting empirical and methodological desiderata for future research. (shrink)

Short-term motor practice leads to plasticity in the primary motor cortex. The purpose of this study is to investigate the factors that determine the increase in corticospinal tract excitability after motor practice, with special focus on two factors; “the level of muscle activity” and “the presence/absence of a goal of keeping the activity level constant.” Fifteen healthy subjects performed four types of rapid thumb adduction in separate sessions. In the “comfortable task” and “forceful task”, the subjects adducted their thumb using (...) comfortable and strong forces. In the “comfortable with a goal task” and “forceful with a goal task”, subjects controlled the muscle activity at the same level as in the C and F, respectively, by adjusting the peak electromyographic amplitude within the target ranges. Paired associative stimulation, which combines peripheral nerve stimulation and transcranial magnetic stimulation, with an inter-stimulus interval of 25 ms was also done. Before and after the motor tasks and PAS25, TMS was applied to the M1. None of the four tasks showed any temporary changes in behavior, meaning no learning occurred. Motor-evoked potential amplitude increased only after the FG and it exhibited a positive correlation with the MEP increase after PAS25, suggesting that FG and PAS25 share at least similar plasticity mechanisms in the M1. Resting motor threshold decreased only after FG, suggesting that FG would also be associated with the membrane depolarization of M1 neurons. These results suggest task-dependent plasticity from the synergistic effect of forceful muscle activity and of setting a goal of keeping the activity level constant. (shrink)

A leading critic of the disruptive force of technology in education, Bernard Stiegler saw the counter-effects of artificial intelligence in undermining human agency, autonomy and individuality, rendering the role of education ever more critical. Stiegler believes that our goal is not to abandon technology but to focus our attention on its power and direction in a hypercapitalist economy. While he did not foresee the emergence of generative artificial intelligence (GAI), its rapid acceleration raises important issues for his notion of digital (...) writing as a pharmakon. In this essay, we examine Stiegler’s view on intelligence, digital writing, technological memory, and neuropower, focusing specifically on his Shanghai lecture and Nanjing Lectures. We compare Stiegler with Catherine Malabou, who examines the nature of intelligence primarily through the lens of neuroscience. We argue that Malabou’s view of neuroplasticity in human and artificial brains, and her critique of techno-narcissism in the control over technology, add an important dimension to Stiegler’s political critique of education. Finally, we examine how best to construe AI as part of a hyper-materialist epistemology that Stiegler espouses in the conclusion of his Nanjing Lectures, to bring about neganthropic knowledge through a therapeutics of care. (shrink)

Idealization is a reasoning strategy that biologists use to describe, model and explain that purposefully departs from features known to be present in nature. Similar to other strategies of scientific reasoning, idealization combines distinctive strengths alongside of latent weaknesses. The study of ontogeny in model organisms is usually executed by establishing a set of normal stages for embryonic development, which enables researchers in different laboratory contexts to have standardized comparisons of experimental results. Normal stages are a form of idealization because (...) they intentionally ignore known variation in development, including variation associated with phenotypic plasticity (e.g. via strict control of environmental variables). This is a tension between the phenomenon of plasticity and the practice of staging that has consequences for evolutionary developmental investigation because variation is conceptually removed as a part of rendering model organisms experimentally tractable. Two compensatory tactics for mitigating these consequences are discussed: employing a diversity of model organisms and adopting alternative periodizations. (shrink)

Cells in the basal metazoan phylum Cnidaria are characterized by remarkable plasticity in their differentiation capacity. The mechanism controlling asymmetric cell divisions is not understood in cnidarians or in any other animal group. PIWI proteins recently have been shown to be involved in maintaining the self‐renewal capacity of stem cells in organisms as diverse as ciliates, flies, worms and mammals. Seipel et al.1 find that, in the cnidarian Podocoryne carnea, the Piwi homolog Cniwi is transcriptionally upregulated when the polyp generates (...) buds, which will develop into medusae. Since transdifferentiation of striated muscle cells to smooth muscle cells also activated Cniwi expression, Cniwi appears to play a crucial role in differentiation events. The discovery should facilitate elucidation of the poorly understood factors that control asymmetric cell divisions at the beginning of animal evolution. BioEssays 26:929–931, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

The fate of root epidermal cells is controlled by a complex interplay of transcriptional regulators, generating a genetically determined, position‐biased arrangement of root hair cells. This pattern is altered during postembryonic development and in response to environmental signals to confer developmental plasticity that acclimates the plant to the prevailing conditions. Based on the hypothesis that events downstream of this initial mechanism can modulate the pattern installed during embryogenesis, we have developed a reaction diffusion model that reproduces the root hair patterning (...) previously observed experimentally. Under all growth conditions, an almost equal spacing between root hair forming cells was observed both in vitro and in silico, indicating that long‐range intercellular communication is crucial for the trichoblasts' decision to form a root hair. We assume that a hair growth promoter (HGP) is upregulated in root‐hair‐forming cells by a trichoblast‐specific component. Once established, HGP production is self‐enhancing. The autocatalytic regulation of HGP is antagonized by an HGP‐produced hair growth inhibitor (HGI). HGI is exported from trichoblasts and diffuses to neighboring cells, where it inhibits further HGP production and promotes the non‐hair cell fate. Under conditions of phosphate deficiency, we hypothesise that HGP production is increased and HGI diffusion rate is reduced, leading to a position‐independent formation of extra root hairs. BioEssays 30:75–81, 2008. © 2007 Wiley Periodicals, Inc. (shrink)

Advanced biological brains are by nature open-ended opportunistic controllers. Such controllers compute, pretty much on a moment-to-moment basis, what problem-solving resources are readily available and recruit them into temporary problem-solving wholes. Neural plasticity, exaggerated in our own species, makes it possible for such resources to become factored deep into both our cognitive and physical problem-solving routines. One way to think about this is to depict the biological brain as a master of what I shall dub ‘ecological control’. Ecological (...) class='Hi'>control is the kind of top-level control that does not micro-manage every detail, but rather encourages substantial devolvement of power and responsibility. This kind of control allows much of our skill at walking to reside in the linkages and elastic properties of muscles and tendons. And it allows much of our prowess at thought and reason to depend upon the robust and reliable operation, often in dense brain-involving loops, of a variety of non-biological problem-solving resources spread throughout our social and technological surround. Are the complex distributed systems that result in some sense ‘out of control’, beyond the reach of useful governance? I shall argue that they are not, although understanding them requires us to re-think some key ideas about control and the nature of the self. To make this case, I shall first examine some strategies for efficient, external opportunity exploiting control in simple systems. I shall then argue that many of the same lessons apply to the case of higher-level human problem-solving. (shrink)

How the formidable diversity of forms emerges from developmental and evolutionary processes is one of the most fascinating questions in biology. The homeodomain‐containing Hox proteins were recognized early on as major actors in diversifying animal body plans. The molecular mechanisms underlying how this transcription factor family controls a large array of context‐ and cell‐specific biological functions is, however, still poorly understood. Clues to functional diversity have emerged from studies exploring how Hox protein activity is controlled through interactions with PBC class (...) proteins, also evolutionary conserved HD‐containing proteins. Recent structural data and molecular dynamic simulations add further mechanistic insights into Hox protein mode of action, suggesting that flexible folding of protein motifs allows for plastic protein interaction. As we discuss in this review, these findings define a novel type of Hox‐PBC interaction, weak and dynamic instead of strong and static, hence providing novel clues to understanding Hox transcriptional specificity and diversity. (shrink)

In Anti-Oedipus, Deleuze and Guattari saw the difficulty of disentangling the question of Spinoza and, later, of Reich from the very limit of a system of representation by which they mean Oedipus. As A Thousand Plateaus would emphasize later, this limit brings out the question of the desire for democracy (‘democracies are majorities’). It desires Oedipus. In What Is Philosophy?, the limit question (Oedipus) gave way to the concept of a people to come. Fifty years since its publication, Anti-Oedipus remains (...) a relevant text (apropos of its ‘strategic adversary’ identified by Foucault) against the background of the social pathology of neofascism, populist politics, and the rise of the alt-right and neoconservative movements in recent years. The paper tries to locate this inflexion point where the desire for democracy modulates into the bi-univocal plasticity of Oedipal desire whose dangers people already seem to know. They have unmasked Oedipus’ double impasse and have escaped it. They no longer desire fascism; they desire fascists, neocons, and right-leaning mob rousers. Fifty years since its publication, Anti-Oedipus confronts a type of people who have learned to behave like the enemies of capitalism, too careful not to overload desire and destroy its bi-univocality, its great balancing act on the Body without organs. Incidentally, in ‘Postscript on the Societies of Control,’ Deleuze spoke about a people who know how to ‘surf’ replacing the ‘older sports.’ This applies to people who could become either schizoidal or regress to its more familiar inversion, the simulacra of Oedipus. (shrink)

This paper builds upon historico-epistemological analyses of plasticity across the nineteenth and twentieth centuries to distinguish among uses of this notion in contemporary epigenetics. By digging into this diachronic phase of plasticity thinking, we highlight a series of historically situated understandings and pragmatic dimensions of this notion. Specifically, our analysis describes four distinct phases in plasticity thinking across the nineteenth and twentieth centuries: plasticity as chemical modification of the body by its milieu; plasticity as explanandum for the modifications of life’s (...) ontogenetic and phylogenetic substrates; plasticity as mechanistic process in need of distinct explanations in ontogeny and phylogeny; and plasticity as responsive potential to perturbations of a complex genetic system of development. These four versions of plasticity provide, in turn, the opportunity to discern synchronically the uses of this notion in epigenetic biosciences. Fleshing out these historical ramifications animating the present, we argue, highlights a fundamental epistemological disagreement at the basis of the controversies around the definition, scope, and epistemic priorities of epigenetics: how to reconcile the contemporary epistemologies of plasticity that hold epigenetic marks capable of bearing the material impression of the environment with those grounded on a strong view of plasticity as operating under genetic control? Parallel to this analysis of the epistemic space of plasticity from the nineteenth century onward, we show how these distinct modes of understanding body–environment relationships also constituted conceptual, representational, and experimental resources for understanding the entanglement between life as a biological and socially situated phenomenon. These different traces of biosocial thinking ante litteram, we conclude, provide a blueprint to interrogate today’s assumptions, values, ontologies, and political leanings behind similar attempts to interpret the biosocial nexus that links our biology with its material, social, and cultural environments. (shrink)

In this address I discuss agricultural plastic use and plastic pollution mitigation strategies. I focus on agricultural plastic mulches, which offer many benefits to farmers, such as weed control, better moisture retention, and increased yield. The removal and disposal of widely used polyethylene plastic mulch, however, have detrimental environmental and health impacts. Are biodegradable plastic mulches a promising alternative? Biodegradable plastic mulches ideally offer the same benefits as PE plastic mulch, but biodegrade (...) in soil or composting environments. I describe social science research findings from a large USDA-funded project focused on the performance and adoptability of biodegradable plastic mulches for U.S. specialty crop production. I also provide agrifood scholars with ideas for future research on plastics. (shrink)

Over the last few years, oncolytic virus therapy has been recognised as a promising approach in cancer treatment, due to the potential of these viruses to induce systemic anti-tumour immunity and selectively killing tumour cells. However, the effectiveness of these viruses depends significantly on their interactions with the host immune responses, both innate and adaptive. In this article, we consider a mathematical approach to investigate the possible outcomes of the complex interactions between two extreme types of macrophages, effector $$\hbox {CD8}^{+}$$ (...) T cells and an oncolytic Vesicular Stomatitis Virus, on the growth/elimination of B16F10 melanoma. We discuss, in terms of VSV, $$\hbox {CD8}^{+}$$ and macrophages levels, two different types of immune responses which could ensure tumour control and eventual elimination. We show that both innate and adaptive anti-tumour immune responses, as well as the oncolytic virus, could be very important in delaying tumour relapse and eventually eliminating the tumour. Overall this study supports the use mathematical modelling to increase our understanding of the complex immune interaction following oncolytic virotherapies. However, the complexity of the model combined with a lack of sufficient data for model parametrisation has an impact on the possibility of making quantitative predictions. (shrink)

Previously published studies have reported that 150 min of short-term monocular deprivation temporarily changes perceptual eye dominance. However, the possible mechanisms underlying monocular deprivation-induced perceptual eye dominance plasticity remain unclear. Using a binocular phase and contrast co-measurement task and a multi-pathway contrast-gain control model, we studied the effect of 150 min of monocular pattern deprivation in normal adult subjects. The perceived phase and contrast varied significantly with the interocular contrast ratio, and after MPD, the patched eye became dominant. Most (...) importantly, we focused on the potential mechanisms of the deprivation effect. The data of an averaged subject was best fitted by a model, which assumed a monocular signal enhancement of the PE after the MPD. The present findings might have important implications for investigations of binocular vision in both normal and amblyopic populations. (shrink)

AbstractmRNA stability is increasingly recognized as being essential for controlling the expression of a wide variety of transcripts during neuronal development and synaptic plasticity. In this context, the role of AU‐rich elements (ARE) contained within the 3′ untranslated region (UTR) of transcripts has now emerged as key because of their high incidence in a large number of cellular mRNAs. This important regulatory element is known to significantly modulate the longevity of mRNAs by interacting with available stabilizing or destabilizing RNA‐binding proteins (...) (RBP). Thus, in parallel with the emergence of ARE, RBP are also gaining recognition for their pivotal role in regulating expression of a variety of mRNAs. In the nervous system, the member of the Hu family of ARE‐binding proteins known as HuD, has recently been implicated in multiple aspects of neuronal function including the commitment and differentiation of neuronal precursors as well as synaptic remodeling in mature neurons. Through its ability to interact with ARE and stabilize multiple transcripts, HuD has now emerged as an important regulator of mRNA expression in neurons. The present review is designed to provide a comprehensive and updated view of HuD as an RBP in the nervous system. Additionally, we highlight the role of HuD in multiple aspects of a neuron's life from early differentiation to changes in mature neurons during learning paradigms and in response to injury and regeneration. Finally, we describe the current state of knowledge concerning the molecular and cellular events regulating the expression and activity of HuD in neurons. BioEssays 28: 822–833, 2006. © 2006 Wiley Periodicals, Inc. (shrink)

In several experimental conditions, neuronal excitation at the perirhinal cortex (PC) does not propagate to the entorhinal cortex (EC) due to a “wall” of inhibition, which may help to create functional coupling and un‐coupling of the PC and EC in the medial temporal lobe. However, little is known regarding the coupling control process. Herein, we propose that the deep layer of area 35 in the PC plays a pivotal role in opening the gate for coupling, thus allowing the activity (...) in the PC to propagate to the EC. Using voltage‐sensitive dye imaging for the brain slices of rodents, we show that a slowly inactivating potassium conductance in this area is essential to induce excitation overtaking the inhibitory control. This coupling between the distinct neural circuits persists for at least 1 h. We elucidate further implications of this network‐level plastic behavior and its mechanism. (shrink)

Volatile compounds, such as nitric oxide and ethylene gas, play a vital role as signaling molecules in organisms. Ethylene is a plant hormone that regulates a wide range of plant growth, development, and responses to stress and is perceived by a family of ethylene receptors that localize in the endoplasmic reticulum. Constitutive Triple Response 1 (CTR1), a Raf‐like protein kinase and a key negative regulator for ethylene responses, tethers to the ethylene receptors, but undergoes nuclear translocation upon activation of ethylene (...) signaling. This ER‐to‐nucleus trafficking transforms CTR1 into a positive regulator for ethylene responses, significantly enhancing stress resilience to drought and salinity. The nuclear trafficking of CTR1 demonstrates that the spatiotemporal control of ethylene signaling is essential for stress adaptation. Understanding the mechanisms governing the spatiotemporal control of ethylene signaling elements is crucial for unraveling the system‐level regulatory mechanisms that collectively fine‐tune ethylene responses to optimize plant growth, development, and stress adaptation. (shrink)

Previous research has demonstrated that regular exercise modulates motor cortical plasticity and cognitive function, but the influence of short-term high-intensity interval training remains unclear. In the present study, the effect of short-term HIIT on neuroplasticity and executive function was assessed in 32 sedentary females. Half of the participants undertook 2 weeks of HIIT. Paired-pulse transcranial magnetic stimulation was used to measure motor cortical plasticity via short intracortical inhibition and intracortical facilitation. We further adapted the Stroop task using functional near-infrared spectroscopy (...) to evaluate executive function in the participants. The results indicated that, compared with the control group, the HIIT group exhibited decreased ICF. In the Stroop task, the HIIT group displayed greater activation in the left dorsolateral prefrontal cortex and left orbitofrontal cortex even though no significant difference in task performance was observed. These findings indicate that short-term HIIT may modulate motor cortical plasticity and executive function at the neural level. (shrink)

We criticize the synaptic theory of long-term memory and the inappropriate usage of physical notions such as in motor control theories. Motor control and motor memory hypotheses should be based on explicitly specified hypothetical control variables that are sound from both physiological and physical perspectives. [HOUK et al.; SMITH; THACH].

Advanced biological brains are by nature open-ended opportunistic controllers. Such controllers compute, pretty much on a moment-to-moment basis, what problem-solving resources are readily available and recruit them into temporary problem-solving wholes. Neural plasticity, exaggerated in our own species, makes it possible for such resources to become factored deep into both our cognitive and physical problem-solving routines. One way to think about this is to depict the biological brain as a master of what I shall dub ‘ecological control’. Ecological (...) class='Hi'>control is the kind of top-level control that does not micro-manage every detail, but rather encourages substantial devolvement of power and responsibility. This kind of control allows much of our skill at walking to reside in the linkages and elastic properties of muscles and tendons. And it allows much of our prowess at thought and reason to depend upon the robust and reliable operation, often in dense brain-involving loops, of a variety of non-biological problem-solving resources spread throughout our social and technological surround. Are the complex distributed systems that result in some sense ‘out of control’, beyond the reach of useful governance? I shall argue that they are not, although understanding them requires us to re-think some key ideas about control and the nature of the self. To make this case, I shall first examine some strategies for efficient, external opportunity exploiting control in simple systems. I shall then argue that many of the same lessons apply to the case of higher-level human problem-solving. (shrink)

The self-domestication hypothesis suggests that, like mammalian domesticates, humans have gone through a process of selection against aggression – a process that in the case of humans was self-induced. Here, we extend previous proposals and suggest that what underlies human social evolution is selection for socially mediated emotional control and plasticity. In the first part of the paper we highlight general features of human social evolution, which, we argue, is more similar to that of other social mammals than to (...) that of mammalian domesticates and is therefore incompatible with the notion of human self-domestication. In the second part, we discuss the unique aspects of human evolution and propose that emotional control and social motivation in humans evolved during two major, partially overlapping stages. The first stage, which followed the emergence of mimetic communication, the beginnings of musical engagement, and mimesis-related cognition, required socially mediated emotional plasticity and was accompanied by new social emotions. The second stage followed the emergence of language, when individuals began to instruct the imagination of their interlocutors, and to rely even more extensively on emotional plasticity and culturally learned emotional control. This account further illustrates the significant differences between humans and domesticates, thus challenging the notion of human self-domestication. (shrink)

The biology of trophoblast cell lineage development and placentation is characterized by the involvement of several known transcription factors. Central to the action of a subset of these transcriptional regulators is CBP‐p300 interacting transactivator with Glu/Asp‐rich carboxy‐terminal domain 2 (CITED2). CITED2 acts as a coregulator modulating transcription factor activities and affecting placental development and adaptations to physiological stressors. These actions of CITED2 on the trophoblast cell lineage and placentation are conserved across the mouse, rat, and human. Thus, aspects of CITED2 (...) biology in hemochorial placentation can be effectively modeled in the mouse and rat. In this review, we present information on the conserved role of CITED2 in the biology of placentation and discuss the use of CITED2 as a tool to discover new insights into regulatory mechanisms controlling placental development. (shrink)

The nature and value of autonomy has long been debated in diverse philosophical traditions, including moral and political philosophy. Although the notion dates back to ancient Greek philosophy, it was during the Age of Enlightenment that autonomy drew much attention. Thus, as may be known, moral philosophers tended to emphasize self-regulation, particularly one’s own will to abide by universal moral laws, as the term “autonomy” originates from the Greek words “self” (auto) and “rule” (nomos). In parallel, modern epistemologists supposedly espoused (...) the idea of intellectual autonomy as self-reliance. In this classical view, an intellectually autonomous explorer of knowledge must not depend on a belief that is obtained from another’s testimony, until one can justify it to oneself. However, accompanying the growing focus on the importance of social dimensions of acquiring knowledge and understanding, recent epistemologists have doubted the classical view and have since reconsidered intellectual autonomy from distinct approaches such as social and virtue epistemology. This paper propounds an interpersonal-epistemic approach to intellectual autonomy. First, it is argued that thinking through questioning both individually and with other epistemic peers is an interpersonal-epistemic practice. Second, it is demonstrated that with particular cognitive features inherent within us, an intellectually autonomous person must think through questioning in necessary situations. This interpersonal account of intellectual autonomy can conceptually enrich intellectual autonomy by considering its relationship with not only responsibility but also with vulnerability. Specifically, regarding responsibility, an intellectually autonomous person must be responsible for his or her own actions throughout questioning processes. Regarding vulnerability, our intellectual autonomy lies in retaining autonomy with vulnerability in the plastic control of the questioning processes. (shrink)

How learning a second language changes our brain has been an important question in neuroscience. Previous neuroimaging studies with different ages and language pairs spoken by bilinguals have consistently shown plastic changes in brain systems supporting executive control. One hypothesis posits that L2 experience-induced neural changes supporting cognitive control, which is responsible for the selection of a target language and minimization of interference from a non-target language. However, it remains poorly understood as to whether such cognitive advantage (...) is reflected as stronger controlled processing or increased automatic inhibition processing. In this study, using functional MRI we scanned 27 Chinese-English late bilinguals while they performed a Simon task. Results showed that bilinguals with higher L2 vocabulary proficiency performed better in the Simon task, and more importantly, higher L2 vocabulary proficiency was associated with weaker activation of brain regions that support more general cognitive control, including the right anterior cingulate cortex, left insula and left superior temporal gyrus. These results suggest that L2 experience may lead to a more automatic and efficient processing in the inhibitory control task. Our finding provides an insight into neural activity changes associated with inhibitory control as a function of L2 proficiency. (shrink)

The ability of using a large variety of tools is important in our daily life. Behind human tool-use abilities lays the brain capacity to incorporate tools into the body representation for action (Body Schema, BS), thought to rely mainly on proprioceptive information. Here we tested whether tool incorporation is possible in absence of proprioception by studying a patient with right upper-limb deafferentation. We adopted a paradigm sensitive to changes of the Body Schema and analysed the kinematics of free-hand movements before (...) and after tool-use, in three sessions over a period of two years. In the first session, before tool-use, the kinematics of the deafferented hand was disrupted. Similarly, the first movements with the tool (a mechanical grabber elongating the arm by ∼40cm) showed an abnormal profile that tended to normalize at the end of the session. Subsequent free-hand movements were also normalised. At session 2, 6 months later, the patient exhibited normal free-hand kinematic profiles, additionally showing changes in grasping kinematics after tool-use, but no sign of tool incorporation. A follow-up two years later, further confirmed the normalized kinematic profile but the absence of tool incorporation. This first description of tool-use in absence of proprioception shows the fundamental role of proprioception in the update of the Body Schema. These results provide an important further step in understanding human motor control and have implications for future development of rehabilitation programs for patients with sensory deficits. (shrink)

A modest dc electric field markedly reduced the tensile flow stress at high temperatures in three polycrystalline oxides, i.e. MgO, Al2O3 and yttria-stabilized tetragonal ZrO2 (Y-TZP). The reduction in flow stress ΔσE in Y-TZP consisted of three components: (i) ΔσT due to Joule heating, (ii) a rapid, reversible component obtained in on-off and electric field step tests and (iii) the cumulative effect of the field on microstructure. Only ΔσT and occurred in MgO and Al2O3. It is concluded that results from (...) a reduction in the electrochemical potential for the formation of vacancies corresponding to the diffusion of the rate-controlling ion in the space-charge at the grain boundary. The calculated magnitude of the space-charge zone width and its temperature and solute composition dependence are in accord with theory and experiment; is attributed mainly to the retardation of grain growth by the field. The retardation could be due to one or more of the following effects of the field on the space-charge zone: (i) an increase in the segregated solute ions, (ii) a decrease in grain boundary energy and (iii) a decrease in solute ion mobility. (shrink)

A vast network of cellular circadian clocks regulates 24‐hour rhythms of behavior and physiology in mammals. Complex environments are characterized by multiple, and often conflicting time signals demanding flexible mechanisms of adaptation of endogenous rhythms to external time. Traditionally this process of circadian entrainment has been conceptualized in a hierarchical scheme with a light‐reset master pacemaker residing in the hypothalamus that subsequently aligns subordinate peripheral clocks with each other and with external time. Here we review new experiments using conditional mouse (...) genetics suggesting that resetting of the circadian system occurs in a more “federated” and tissue‐specific fashion, which allows for increased noise resistance and plasticity of circadian timekeeping under natural conditions. (shrink)

Epigenetic control of gene expression by chromatin remodeling is critical for adult stem cell function. A decline in stem cell function is observed during aging, which is accompanied by changes in the chromatin structure that are currently unexplained. Here, we hypothesize that these epigenetic changes originate from the limited cellular capability to inherit epigenetic information. We suggest that spontaneous loss of histone modification, due to fluctuations over short time scales, gives rise to long‐term changes in DNA methylation and, accordingly, (...) in gene expression. These changes are assumed to impair stem cell function and, thus, to contribute to aging. We discuss cell replication as a major source of fluctuations in histone modification patterns. Gene silencing by our proposed mechanism can be interpreted as a manifestation of the conflict between the stem cell plasticity required for tissue regeneration and the permanent silencing of potentially deleterious genomic sequences. (shrink)

This paper will critically assess Popper’s evolutionary philosophy. There exists a rich literature on the topic with which we have many reservations. We believe that Popper’s evolutionary philosophy should be assessed in light of the intriguing theoretical insights offered, during the last 10 years or so, by the philosophy of biology, evolutionary biology and molecular biology. We will argue that, when analysed in this manner, Popper’s ideas concerning the nature of selection, Lamarckism and the theoretical limits of neo-Darwinism can be (...) appreciated in their full biological and philosophical value. (shrink)

In this article, we hypothesize that individuals with autism spectrum disorder (ASD) are born with a deficit in invariance detection, which is a learning process whereby people and animals come to attend the relatively stable patterns or structural regularities in the changing stimulus array. This paper synthesizes a substantial body of research which suggests that a deficit in the domain-general perceptual learning process of invariant detection in ASD can lead to a cascade of consequences in different developmental domains. We will (...) outline how this deficit in invariant detection can cause uncertainty, unpredictability, and a lack of control for individuals with ASD and how varying degrees of impairments in this learning process can account for the heterogeneity of the ASD phenotype. We also describe how differences in neural plasticity in ASD underlie the impairments in perceptual learning. The present account offers an alternative to prior theories and contributes to the challenge of understanding the developmental trajectories that result in the variety of autistic behaviors. (shrink)

An item that stands out (is isolated) from its context is better remembered than an item consistent with the context. This isolation effect cannot be accounted for by increased attention, because it occurs when the isolated item is presented as the first item, or by impoverished memory of nonisolated items, because the isolated item is better remembered than a control list consisting of equally different items. The isolation effect is seldom experimentally or theoretically related to the primacy or the (...) recency effects—that is, the improved performance on the first few and last items, respectively, on the serial position curve. The primacy effect cannot easily be accounted for by rehearsal in short‐term memory because it occurs when rehearsal is eliminated. This article suggests that the primacy, the recency, and the isolation effects can be accounted for by experience‐dependent synaptic plasticity in neural cells. Neurological empirical data suggest that the threshold that determines whether cells will show long‐term potentiation (LTP) or long‐term depression (LTD) varies as a function of recent postsynaptic activity and that synaptic plasticity is bounded. By implementing an adaptive LTP‐LTD threshold in an artificial neural network, the various aspects of the isolation, the primacy, and the recency effects are accounted for, whereas none of these phenomena are accounted for if the threshold is constant. This theory suggests a possible link between the cognitive and the neurological levels. (shrink)

Cells and tissues are continuously exposed to a changing microenvironment, hence the necessity of a flexible modulation of gene expression that in complex organism have been achieved through specialized chromatin mechanisms. Chromatin-based cell memory enables cells to maintain their identity by fixing lineage specific transcriptional programs, ensuring their faithful transmission through cell division; in particular PcG-based memory system evolved to maintain the silenced state of developmental and cell cycle genes. In evolution the complexity of this system have increased, particularly in (...) vertebrates, indicating combinatorial and dynamic properties of Polycomb proteins, in some cases even overflowing outside the cell nucleus. Therefore, their function may not be limited to the imposition of rigid states of genetic programs, but on the ability to recognize signals and allow plastic transcriptional changes in response to different stimuli. Here, we discuss the most novel PcG mediated memory functions in facing and responding to the challenges posed by a fluctuating environment. Cellular microenvironment can regularly change, hence the need for a dynamic modulation of transcriptional programs by the epigenome. In the current review, we highlight novel emerging aspects of epigenetic memory controlled by PcG proteins and the evolution of specialized functions to convey plasticity and adaptability to environmental changes. (shrink)

Many sensory processing regions of the central brain undergo critical periods of experience‐dependent plasticity. During this time ethologically relevant information shapes circuit structure and function. The mechanisms that control critical period timing and duration are poorly understood, and this is of special importance for those later periods of development, which often give rise to complex cognitive functions such as social behavior. Here, we review recent findings in Drosophila, an organism that has some unique experimental advantages, and introduce novel views (...) for manipulating plasticity in the post‐embryonic brain. Critical periods in larval and young adult flies resemble classic vertebrate models with distinct onset and termination, display clear connections with complex behaviors, and provide opportunities to control the time course of plasticity. These findings may extend our knowledge about mechanisms underlying extension and reopening of critical periods, a concept that has great relevance to many human neurodevelopmental disorders. (shrink)