Ontogenetic Perspective Research Articles

Exploration and refinement of migratory routes in long-lived birds.

In Focus: Campioni L., Dias M. P., Granadeiro J. P., & Catry P. (2019). An ontogenetic perspective on migratory strategy of a long-lived pelagic seabird: Timings and destinations change progressively during maturation. Journal of Animal Ecology, 89, 29-43. https://doi.org/10.1111/1365-2656.13044 How migration routes develop in long-lived migratory animals remains poorly understood. Campioni et al. (2019) tracked the migration of immature and breeding Cory's shearwaters and found that the timings and routes gradually changed with age. Young birds followed more exploratory routes at first, but gradually shortened and defined them as they matured, and they returned to the breeding grounds progressively earlier. These findings suggest that long-lived species start by exploring potentially suitable areas for the non-breeding season and progressively refine their migration route as they age.

An ontogenetic perspective on migratory strategy of a long‐lived pelagic seabird: Timings and destinations change progressively during maturation

The processes that drive the ontogeny of migratory strategies in long-lived animals with slow maturation remain enigmatic. While some short-lived migrants are known or believed to repeat the same migratory patterns throughout their lives, little is known on the time required for immature long-lived migrants to progressively acquire adult-like migratory behaviours, or which aspects take longer to refine during the maturation process. Here, we studied the ontogeny of long-distance migratory strategies and related patterns of spatial distribution in a long-lived seabird species during the annual cycle. To do so, we deployed light-level geolocators on 4- to 9-year-old immature Cory's shearwaters (Calonectris borealis) and on breeding adults. We revealed that migratory timings and destinations of young shearwaters progressively changed with age. The effect of ageing was remarkably evident on spring migratory performance and phenology. Birds gradually shortened the duration of the non-breeding period by advancing departure date and reducing travelling time, which resulted in a sequential arrival at the colony of the various age contingents. Ageing immatures gradually changed from a more exploratory strategy to a more conservative way of exploiting resources, reducing both their year-round spatial spread across oceanic domains and the total distance travelled. Immatures always performed a trans-equatorial migration to the Southern Hemisphere, contrasting with 17% of the adults which remained in the North Atlantic year-round. Finally, during the breeding season immatures were widely dispersed through the North Atlantic reducing their overlap with breeding adults. Our long-term study provides empirical support to the hypothesis that in long-lived species, the refinement of migratory behaviour and year-round spatial distribution is a progressive process mediated by age and experience, where life stage constraints and competition for resources may also play a role. The emerging pattern suggests that for some avian taxa, the ontogeny of migratory strategy is a prolonged, complex and dynamic process.

Age-related differences in the acute pain facial expression during infancy.

The ontogenetic perspective on the development of emotional expressions in infants holds that infants' facial and vocal expressions evolved to serve crucial communicative functions in infancy and contribute to infants' survival. Infants' facial expressions should be contextualized by their own developmental stage rather than presuppositions from verbal populations. The overall aim of this paper was to examine age differences in the temporal patterning of elucidated facial expressions in the first minute following vaccination injections. One hundred infants were videotaped longitudinally (2, 4, 6 and 12 months) from 2007-2012during their routine vaccination appointment over the first year of life and five major negative facial configurations were identified using BabyFACS. In the current study, facial configurations were graphed in 5-s epochs for 1-min post-vaccination and subsequently analysed for facial expression by time effects using Repeated Measures ANOVAs at each age. Clear differences in temporal patterns were displayed as infants aged. ANOVA analyses indicated significant facial expression by time interactions at each age. Facial expressions illustrating intense/moderate distress and sensory overload were prominent in the first 15s at the 2-, 4- and 6-month vaccination. However, expressions showing regulation of distress occurred progressively earlier over 1min post-needle in older infants, suggesting a significant shift in regulatory capacity of pain-related distress occurs after 6-months of age. An important developmental milestone was identified in infants' ability to regulate distress at 6months. Supporting parents' infant pain management is particularly critical in the first months of life as infants' initial facial expressions appear to be more reflective of an organism overwhelmed by distress.

Ontogeny of Orbit Orientation in Primates.

Orbit orientation in primates has been linked to adaptive factors related to activity pattern and size-related variation in structural influences on orbit position. Although differences in circumorbital form between anthropoids and strepsirrhines appear to be related to interspecific disparities in levels of orbital convergence and orbital frontation, there is considerable overlap in convergence between suborders. Unfortunately, putative links between convergence and frontation across primates, and consequent arguments about primate and anthropoid origins, are likely to be influenced by allometry, the size range of a respective sample, and adaptive influences on encephalization and activity patterns. Such a multifarious system is less amenable to interspecific treatment across higher-level clades. An ontogenetic perspective is one way to evaluate transformations from one character state to another, especially as they pertain to allometric effects on phenotypic variation. We characterized the ontogeny of orbital convergence and frontation in 13 anthropoid and strepsirrhine species. In each suborder, correlation and regression analyses were used to test hypotheses regarding the allometric bases of variation in orbital orientation. Growth trajectories were analyzed intra- and inter-specifically. Frontation decreased postnatally in all taxa due to the negative scaling of brain vs. skull size. Further, interspecific variation in relative levels of frontation was linked to corresponding ontogenetic transpositions in encephalization that differed within both suborders. In strepsirrhines, postnatal increases in convergence were largely due to the negative allometry of orbit vs. skull size. In contrast, convergence in anthropoids varied little during growth, being unrelated to ontogenetic variation in either relative orbit or interorbit size. Anat Rec, 302:2093-2104, 2019. © 2019 American Association for Anatomy.

Patterned Vascularization of Embryonic Mouse Forebrain, and Neuromeric Topology of Major Human Subarachnoidal Arterial Branches: A Prosomeric Mapping.

The prosomeric brain model contemplates progressive regionalization of the central nervous system (CNS) from a molecular and morphological ontogenetic perspective. It defines the forebrain axis relative to the notochord, and contemplates intersecting longitudinal (zonal, columnar) and transversal (neuromeric) patterning mechanisms. A checkboard pattern of histogenetic units of the neural wall results, where each unit is differentially fated by an unique profile of active genes. These natural neural units later expand their radial dimension during neurogenesis, histogenesis, and correlative differential morphogenesis. This fundamental topologic framework is shared by all vertebrates, as a Bauplan, each lineage varying in some subtle aspects. So far the prosomeric model has been applied only to neural structures, but we attempt here a prosomeric analysis of the hypothesis that major vessels invade the brain wall in patterns that are congruent with its intrinsic natural developmental units, as postulated in the prosomeric model. Anatomic and embryologic studies of brain blood vessels have classically recorded a conserved pattern of branches (thus the conventional terminology), and clinical experience has discovered a standard topography of many brain arterial terminal fields. Such results were described under assumptions of the columnar model of the forebrain, prevalent during the last century, but this is found insufficient in depth and explanatory power in the modern molecular scenario. We have thus explored the possibility that brain vascularization in rodents and humans may relate systematically to genoarchitectonic forebrain subdivisions contemplated in the prosomeric model. Specifically, we examined first whether early vascular invasion of some molecularly characterized prosomeric domains shows heterochrony. We indeed found a heterochronic pattern of vascular invasion that distinguishes between adjacent brain areas with differential molecular profiles. We next mapped topologically on the prosomeric model the major arterial branches serving the human brain. The results of this approach bear on the possibility of a developmentally-based modern arterial terminology.

Éducation sentimentale? Rethinking emotional intelligence with Michel Henry: from incarnation to education

ABSTRACTIn this paper we explore the possibility of rethinking the concept of emotional intelligence within the context of education. By developing a pedagogical dialogue with Michel Henry’s phenomenology of incarnation, we try to move beyond existing models of emotional intelligence by shifting the emphasis from the intellectual significance of emotion to a more original incarnate affectivity within intelligence, understood as lived sense-making. We claim that this ontological and ontogenetic perspective on emotion puts it at the heart of education. Yet only because it evokes an understanding of education which is expressly non-functionalist: a disruptive, even dreadful event that marks the threshold and tension between what Henry terms Life (interiority) and World (exteriority). More than simply learning us to manage our emotions or recognize the value of experiences, emotional intelligence is about the very making of World out of Life, a Life that is at once radically subjective and communal.

Alone with oneself: Solitude and Loneliness

Рассматривается соотношение понятий «уединение» и «одиночество» в религиозном, философском и психологическом контекстах. Авторы сосредотачиваются на теоретическом анализе уединения как самостоятельного феномена. В религиозных традициях уединение создает условия для размышлений в тишине, медитации, молитвы, обращения к совести, помогает приблизиться к Богу, достичь мудрости и обрести способность к состраданию. Однако в уединении человек может также переживать одиночество, уныние, пребывать под влиянием самообмана, а при длительном отсутствии общения с людьми — дойти до безумия. В философской и психологической литературе термины «уединение» и «одиночество» не имеют однозначных определений, более того — отмечается небрежность в их употреблении. Вместе с тем в истории мысли возможно дифференцировать одиночество и уединение как разные феномены. Анализ понятий в основных психологических подходах (психоаналитический, гуманистический, когнитивно-поведенческий, экзистенциальный) позволяет отстоять право уединения на независимый от одиночества статус. Как в культурно-исторической, так и в онтогенетической перспективе виден вектор дифференциации рассматриваемых понятий: зрелая личность в уединении не страдает от одиночества; личностное развитие связано с принятием уединения и раскрытием его творческого потенциала. Уединение — это ситуация аутокоммуникации, которая открыта позитивным и негативным переживаниям, связана с развитием рефлексии «Я», а также содержит потенциал для осознания и трансформации внутренних отношений личности с миром. Одиночество — это негативное переживание, при котором аутокоммуникация либо отсутствует, либо препятствует реализации человеком желаемого стремления к своему «Я», другим людям или к миру.

CASE REPORT: HUMAN DIGASTRIC SARTORIUS MUSCLE WITH AN EVO‐DEVO APPROACH

INTRODUCTIONHox genes are essential in the fixation of the anteroposterior axes in symmetrical individuals. During mammal evolution of the musculoskeletal system's paired appendages there has been expresión HOX genes; for example, Tbx4 genes determine the identity of hind limbs when paired paraxial mesoderm originates hypaxial and epaxial muscles. From an ontogenetic perspective, muscle embryology has myogenic hierarchical control genes such as Myf5, MyoD, myogenin and MRF4, when linked with diversity controlling genes like Kdm5, Med13, Tcfap4 Atrophin1, Rere, Elongin‐B, ZBTB20, AF10/AF17, Kdm2, Sin3A justify muscular morphological diversity, loss or duplication. Once this is understood trough an evolutionary perspective, one may understand sartorius muscle diversity in mammals. In the case of ruminants, this muscle has a morphology with two superior heads. Interestingly enough, the same sartorius morphology has been documented in humans like an anatomical variant. The present case aims to describe this anatomical variant with an EVO‐DEVO approach.REPORT CASEDuring the course of a second year anatomy class, at La Universidad de La Sabana, the class professor, when exploring the corpse of a 40 year old male, noticed a digastric belly sartorius muscle on the left lower limb, while also noticing an uncommonly thick sartorium on the right lower limb. [Figure 1]. When it came to the digastric sartorius muscle, both bellies ran parallel to each another, however they were covered by different fascia. The medial head originated from the superior border of the anterior superior iliac crest. The lateral head had its classical origin. Both heads had the classical muscular insertion.DiscussionIn natural populations, there are reports of morphological left – right differences, however, reports of individuals with asymmetric morphologies are rare, suggesting the possibility that asymmetric individuals might arise as a result of imperfect development. This may be reflected by the genome's instability due to interactions with environmental factors or “noise”. The stability of the genome is an intrinsic capacity of an organism to resist external disturbances that may occur during natural development and growth. In this case report, the obvious sartorius muscles asymmetry is evidence that invites us to consider the Evo‐Devo perspective. Such idea suggests the possibility that any disturbance during early ontogeny of the lower limb might have occurred as consequence of the genome's lack of buffer capacity. This reminds us, that myogenic control and diversity genes define an individual's symmetry when they are buffered.ConclusionA molecular Evo‐Devo approach should be started in ontogenical manner in order to explain the asymmetry cases that might be found.Support or Funding InformationPROSEIMThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Individual differences in perceptual sensitivity and representation of facial signals of trustworthiness.

One of the most important sources of social information is the human face, on whose appearance we easily form social judgments: Adults tend to attribute a certain personality to a stranger based on minimal facial cues, and after a short exposure time. Previous studies shed light on the cognitive and neural mechanisms underlying the ability to discriminate facial properties conveying social signals, but the underlying processes supporting individual differences remain poorly understood. In the current study, we explored whether differences in sensitivity to facial cues to trustworthiness and in representing such cues in a multidimensional space are associated with individual variability in social attitude, as measured by the extraversion/introversion dimension. Participants performed a task where they assessed the similarity between faces that varied in the level of trustworthiness, and multidimensional scaling analyses were performed to describe perceptual similarity in a multidimensional representational space. Extraversion scores impacted RTs, but not accuracy or face representation, making less extraverted individuals slower in detecting similarity of faces based on physical cues to trustworthiness. These findings are discussed from an ontogenetic perspective, where reduced social motivation might constrain perceptual attunement to social cues from faces, without affecting the structuring of the face representational space. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The Silence of Movement

The kinetic silence of movement has formidable powers. Observations of a film critic, poet, professor of political history, and medical doctor attest to the fact that that silence is replete with meanings. Those meanings in turn testify to a movement-anchored corporeal semiotics that resounds not merely functionally but experientially in animate forms of life. It does so consistently and directly in kinesthesia, the ever-present sense modality by which we experience the qualitative dynamics of movement and synergies of meaningful movement. Phylogenetic and ontogenetic perspectives attest to these dynamics and synergies. So also does Aristotle’s description of movement as a sensu communis. Because a movement-anchored corporeal semiotics discovers and describes what is existentially meaningful in the lives of animate organisms, such a semiotics is the foundation of a cognitive semiotics. It is so in a number of everyday ways, most notably in terms of thinking in movement and of cognition itself.

Aparición y desarrollo del lenguaje humano

I will introduce the topic of this paper by demarcating the notion of “language”, as a necessary first step in order to know what we mean when dealing with its appearance and development in the human species. In a first approximation, I’ll highlight the fact of being a human capacity with an intermediary function between a physical signal (i.e., sounds) and an intentional state of the individual (i.e., meanings). Such an intermediary function and its associated features (arbitrariness, symbolism, compositionality, productivity, systematicity) require a multidisciplinary treatment with different levels of explanation (linguistic, psychological, neurobiological) that give rise to corresponding models of that human language capacity. I’ll then review those models and make them converge into the appropriate frame of reference –characteristic of the cognitive science– for dealing with the main topic of this paper. It will be pursued along two sections, one devoted to the acquisition of language by the individual and its development from an ontogenetic perspective; and the other just devoted to language appearance in the evolutionary history of the species and, hence, to its phylogenetic development. I’ll conclude by underlining the natural (innate for its most part) and specialized character of the human faculty of language, together with its specificity as a unique property of the human species, which points to its relatively sudden appearance and to the possibility of facing a genuine example of evolutionary discontinuity.

Natural reference: A phylo- and ontogenetic perspective on the comprehension of iconic gestures and vocalizations.

The recognition of iconic correspondence between signal and referent has been argued to bootstrap the acquisition and emergence of language. Here, we study the ontogeny, and to some extent the phylogeny, of the ability to spontaneously relate iconic signals, gestures, and/or vocalizations, to previous experience. Children at 18, 24, and 36months of age (N=216) and great apes (N=13) interacted with two apparatuses, each comprising a distinct action and sound. Subsequently, an experimenter mimicked either the action, the sound, or both in combination to refer to one of the apparatuses. Experiments 1 and 2 found no spontaneous comprehension in great apes and in 18-month-old children. At 24months of age, children were successful with a composite vocalization-gesture signal but not with either vocalization or gesture alone. At 36months, children succeeded both with a composite vocalization-gesture signal and with gesture alone, but not with vocalization alone. In general, gestures were understood better compared to vocalizations. Experiment 4 showed that gestures were understood irrespective of how children learned about the corresponding action (through observation or self-experience). This pattern of results demonstrates that iconic signals can be a powerful way to establish reference in the absence of language, but they are not trivial for children to comprehend and not all iconic signals are created equal.

The pirarucu net: Artefact, animism and the technical object

This article explores the decision of a group of Amazonian lake fishermen to ban the use of nets to catch the pirarucu fish as part of an official agreement. It discusses the approach to artefacts found in the agentive turn and in recent explorations of Amazonian animism in Anthropology. It adopts the concept of technical object influenced by the anthropological approach to technology and in line with the ontogenetic perspective of Gilbert Simondon. The main focus is the way in which the fishermen compare the different modes of existence of the harpoon and the net. For them, the pirarucu net is a poor way to catch fish since it captures by itself, which is a form of cowardice in relation to the fish and drives them away. The ethnography centres on the operation of these objects and the way in which different properties of the fishermen and fish emerge through these processes.

A Sociocultural Psychological Approach to Religion.

Sociocultural psychology can contribute to the understanding of religion, as it examines the dynamics by which the social and cultural world creates the conditions for the lives of unique people. This approach focuses especially on semiotic dynamics, by which religion can both guide practices and sense-making, but also become an object of shared representations. Drawing on a series of past studies, I first adopt an ontogenetic perspective, to explore early development into a sociocultural environment in which religion is present, and then to address young adults' religious bricolage. I especially show people's creativity in using various symbolic resources, linked to religious elements or not. Second, I consider more sociogenetic dynamics: boundary making processes taking place in intergroup dynamics. This leads me, third, to consider the resonances between social discourses on religion and more subjective experiences: I especially show how public discourses may create confusing fields of meaning which find deep resonances in emotional experiences, which may have dramatic consequences, both at the individual and collective levels. For each point, I try to show how such this theoretical perspective and empirical evidence may illuminate contemporary issues and debates.

Syntactical regularities of action sequences in the infant brain: when structure matters.

Throughout life, actions and language are inherent to social interactions. A long-standing research question in cognitive neuroscience concerns the interrelation between verbal and non-verbal forms of social interactions, that is, language and action. Perceiving how actions are performed and why they are performed in a certain way is crucial for the observer to anticipate the actor's goal and to prepare an appropriate response. It is suggested that predicting upcoming events in a given action sequence can be compared to the way we process the language information flow. Goal-directed actions can be sequenced in small units, which are organized according to a hierarchical plan, resembling the hierarchical organization of language. Research on adults suggests that manipulating the action structure (i.e., action syntax) leads to analogous cortical signatures as a similar manipulation of a sentence structure (i.e., language syntax). Whereas in adults language and action knowledge are based on life-time experience, in infants both domains are still developing. The current study examined the neural processing of structural violations of observed goal-directed action sequences in infants at 6-7 months, using event-related potentials (ERPs). Results showed that a structural violation of the action sequence elicited bilateral frontal positivity effects. This suggests that infants capture structural regularities, and it adds a crucial element to the understanding of general syntactic regularities and their violation from an ontogenetic perspective.

“What Just Happened?”

The author discusses experiences in analysis during the formation of an object relationship, which can give rise to a phase of experiential “wholeness” when a particular piece of unconscious analytic work has been completed. The question of wholeness is also considered from an ontogenetic perspective. The difficulties in achieving a good object relationship are considered, including with those who have had little or no experience of a good internal object. Three stages in the formation of a good internal object relationship are proposed.

Pathways to Consensual Popularity and Mating Opportunities in Ontogenetic Perspective

Pathways to Consensual Popularity and Mating Opportunities in Ontogenetic Perspective

What triggers puberty?

Puberty is defined as the transient phase between childhood and adulthood. During this stage the second growth spurt occurs, genital organs gradually mature, reproductive function is attained, and major physiological and psychological changes happen. Primates other than homo sapiens also experience the similar developmental phase. However we know little about the control and onset of puberty. For this reason, Science listed “What triggers puberty?” as one of the 125 questions (25 “Big Questions” along with 100 smaller ones) posed on its 125th Anniversary Issue. Existing research findings show that the timing of puberty is a complex phenomenon involving evolution, genetics, development, and many other fields. Phylogenesis and ontogenesis are thought to be the two major perspectives for understanding the phenomenon. From the phylogenetic point of view, puberty is the survival strategy chosen by species. The emergence of puberty indicates that individuals will spend a relatively long time on developing and preparing for reproduction. Such a developmental pattern promotes the physical, behavioral, and cognitive development of individuals. This is a long-term result of adaptation to the environment, which promises a higher survival rate of the offspring. Meanwhile the ontogenetic perspective focuses on neuroendocrine mechanisms of the puberty onset. Researches show that puberty starts from the activation of the hypothalamic-pituitary-gonadal (HPG) axis. Kisspeptin, which is secreted by hypothalamic arcuate nucleus neurons, is the first signal of the whole chain reaction. Kisspeptin initiates the pulsatile release of gonadotropin releasing hormone (GnRH) so that adenohypophysis synthesizes and releases follicle stimulating hormone (FSH) and luteinizing hormone (LH). Both FSH and LH can stimulate gonads to release sex hormones, which leads to the development of secondary sex characteristics and the maturation of sexual organs. Additionally, some neuroendocrine factors involving in reproductive regulation and metabolism are also shown to influence the onset of puberty by regulating the process of releasing GnRH in the upstream through the dual effects of excitation and inhibition. In brief, the pulsatile secreted GnRH in the HPG system together with other neurohormones and neurotransmitters trigger the onset of puberty, which regulate the reproductive functions in species. The timing when puberty occurs is also influenced by environmental resources. In general, the onset of puberty occurs earlier and earlier with the development of human society. Individuals living in impoverished areas reach puberty later than their counterparts living in developed areas. The body composition of individuals can also have an impact on the starting time of puberty. The body fat rate suggest the body has stored enough energy to support reproduction. In consistent with the evolutionary model, the adjustment of maturation time is also a reaction towards environmental stressors. In addition, studies on precocious or delayed puberty and the underlying genetic factors can also help us understand the reasons for the onset of puberty, especially the mechanisms related to neuroendocrine processes. In summary, the onset of puberty is a complex phenomenon regulated by genetic, environmental, endocrine and many other factors. Although accumulated data has explained the possible processes of puberty initiation on the physiological level, only some descriptions of the phenomenon are available when it comes to the psychological and environmental factors. Further research is needed to investigate how these various factors have independent and interactive effects on the onset of puberty.

Ontogenetic Changes in the Bacterial Symbiont Community of the Tropical Demosponge Amphimedon queenslandica: Metamorphosis Is a New Beginning

Vertical transmission of bacterial symbionts, which is known in many species of sponge (Porifera), is expected to promote strong fidelity between the partners. Combining 16S rRNA gene amplicon sequencing and electron microscopy, we have assayed the relative abundance of vertically-inherited bacterial symbionts in several stages of the life cycle of Amphimedon queenslandica, a tropical coral reef sponge. We reveal that adult A. queenslandica house a low diversity microbiome dominated by just three proteobacterial OTUs, with a single gammaprotebacterium clearly dominant through much of the life cycle. This ontogenetic perspective has revealed that, although vertical transmission occurs very early in development, the inherited symbionts do not maintain proportional dominance of the bacterial community at every developmental stage. A reproductive bottleneck in the A. queenslandica life cycle is larval settlement, when a free-swimming pelagic larva settles out of the water column onto the benthos and completes metamorphoses into the sessile body plan within just 3 to 4 days. During this dramatic life cycle transition, an influx of environmentally-derived bacteria leads to a major reorganization of the microbiome, potentially challenging the fidelity and persistence of the vertically-inherited symbiotic relationships. However, dominance of the primary, vertically-inherited symbionts is restored in adult sponges. The mechanisms underlying ontogenetic changes in the bacterial community are unknown, including how the dominance of the primary symbionts is restored in the adult sponge – does the host or symbiont regulate this process? Using high-resolution transcriptional profiling in multiple stages of the A. queenslandica life cycle combined with this natural perturbation of the microbiome immediately following larval settlement, we are beginning to identify candidate host genes associated with animal-bacterial crosstalk. Among the sponge host genes upregulated during the times of active microbiome assembly, there is an enrichment of genes potentially involved in innate immunity, including scavenger receptors, and of genes containing eukaryote-like domains, which have elsewhere been implicated in host-symbiont interactions. Intriguingly, we also see an enrichment of sponge genes arising from ancient horizontal transfer events from bacteria, which raises the possibility that host-bacterial associations in the evolutionary past may help to regulate host-bacterial associations in the ecological present.

Aging promotes acquisition of naive-like CD8+ memory T cell traits and enhanced functionalities.

Protective T cell memory is an acquired trait that is contingent upon the preservation of its constituents and therefore vulnerable to the potentially deleterious effects of organismal aging. Here, however, we have found that long-term T cell memory in a natural murine host-pathogen system can substantially improve over time. Comprehensive molecular, phenotypic, and functional profiling of aging antiviral CD8+ memory T cells (CD8+ TM) revealed a pervasive remodeling process that promotes the gradual acquisition of distinct molecular signatures, of increasingly homogeneous phenotypes, and of diversified functionalities that combine to confer a CD8+ TM-autonomous capacity for enhanced recall responses and immune protection. Notably, the process of CD8+ TM aging is characterized by a progressive harmonization of memory and naive T cell traits, is broadly amenable to experimental acceleration or retardation, and serves as a constitutional component for the "rebound model" of memory T cell maturation. By casting CD8+ TM populations within the temporal framework of their slowly evolving properties, this model establishes a simple ontogenetic perspective on the principal organization of CD8+ T cell memory that may directly inform the development of improved diagnostic, prophylactic, and therapeutic modalities.