Do humans (Homo sapiens) and fish (Pterophyllum scalare) make similar numerosity judgments?

Numerous studies have shown that many animal species can be trained to discriminate between stimuli differing in numerosity. However, in the absence of generalization tests with untrained numerosities, what decision criterion was used by subjects remains unclear: the subjects may succeed by selecting a specific number of items (a criterion over absolute numerosities), or by applying a more general relative numerosity rule, for example, selecting the larger/smaller quantity of items. The latter case may require more powerful representations, supporting judgments of order ("more/less") beyond simple "same/different" judgments, but a relative numerosity rule may also be more adaptive. In previous research, we showed that guppies (Poecilia reticulata) spontaneously prefer relative numerosity rules. To date it is unclear whether this preference is shared by other fish and, more broadly, other species. Here we compared the performance of angelfish (Pterophyllum scalare) with that of human adults (Homo sapiens) in a task in which subjects were initially trained to select arrays containing 10 dots (either in 5 vs. 10 or 10 vs. 20 comparisons). Subsequently they were tested with the previously trained numerosity and a novel numerosity (respectively, 20 or 5). In the absence of explicit instructions, both species spontaneously favored a relative rule, selecting the novel numerosity. These similarities demonstrate that, beyond shared representations for numerical quantities, vertebrate species may also share a system for taking decisions about quantities. (PsycINFO Database Record

MODELLI CHIMICI DEL VIVENTE LE ORIGINI DEL CENCETTO DI «MACCHINA CHIMICA¼.

The concept of "chemical machine" is currently very much in use in studies of the physiology of living bodies especially at the level of their intimate structure. Its appearance, however, has a long history that begins as early as the sixteenth century, when it became apparent that the living body was the abode of complex and fundamental chemical processes. When this awareness met the equally widespread idea that living bodies could be described as "machinery", the problem emerged of reconciling the two approaches, which gave origin to the concept of "chemical machine."

Proximal metatarsal articular surface shape and the evolution of a rigid lateral foot in hominins.

This study quantifies the proximal articular surface shape of metatarsal (MT) 4 and MT 5 using three-dimensional morphometrics. Humans and apes are compared to test whether they have significantly different shapes that are skeletal correlates to comparative lateral foot function. In addition, shod and unshod humans are compared to test for significant differences in surface shape. The MT 4 fossils OH 8, Stw 628, and AL 333-160, and the MT 5 fossils AL 333-13, AL 333-78, OH 8, and Stw 114/115 are compared with humans and apes to assess whether they bear greater similarities to humans, which would imply a relatively stable lateral foot, or to apes, which would imply a flexible foot with a midfoot break. Apes have a convex curved MT 4 surface, and humans have a flat surface. The MT 4 fossils show greater similarity to unshod humans, suggesting a stable lateral foot. Unshod humans have a relatively flatter MT 4 surface compared with shod humans. There is much overlap in MT 5 shape between humans and apes, with more similarity between humans and Gorilla. The fossil MT 5 surfaces are generally flat, most similar to humans and Gorilla. Because of the high degree of shape overlap between humans and apes, one must use caution in interpreting lateral foot function from the proximal MT 5 surface alone.

Paleogenomics of archaic hominins.

In order to understand the genetic basis for the evolutionary success of modern humans, it is necessary to compare their genetic makeup to that of closely related species. Unfortunately, our closest living relatives, the chimpanzees, are evolutionarily quite distant. With the advent of ancient DNA study and more recently paleogenomics - the study of the genomes of ancient organisms - it has become possible to compare human genomes to those of much more closely related groups. Our closest known relatives are the Neanderthals, which evolved and lived in Europe and Western Asia, from about 600,000 years ago until their disappearance around 30,000 years ago following the expansion of anatomically modern humans into their range. The closely related Denisovans are only known by virtue of their DNA, which has been extracted from bone fragments dating around 30,000 to 50,000 years ago found in a single Siberian cave. Analyses of Neanderthal and Denisovan nuclear and mitochondrial genomes have revealed surprising insights into these archaic humans as well as our own species. The genomes provide a preliminary catalogue of derived amino acids that are specific to all extant modern humans, thus offering insights into the functional differences between the three lineages. In addition, the genomes provide evidence of gene flow between the three lineages after anatomically modern humans left Africa, drastically changing our view of human evolution.

A comparative study of working memory: immediate serial spatial recall in baboons (Papio papio) and humans.

Two experiments assessed if non-human primates can be meaningfully compared to humans in a non-verbal test of serial recall. A procedure was used that was derived from variations of the Corsi test, designed to test the effects of sequence structure and movement path length in humans. Two baboons were tested in Experiment 1. The monkeys showed several attributes of human serial recall. These included an easier recall of sequences with a shorter number of items and of sequences characterized by a shorter path length when the number of items was kept constant. However, the accuracy and speed of processing did not indicate that the monkeys were able to benefit from the spatiotemporal structure of sequences. Humans tested in Experiment 2 showed a quantitatively longer memory span, and, in contrast with monkeys, benefitted from sequence structure. The results are discussed in relation to differences in how human and non-human primates segment complex visual patterns.

Proyectos Fisioma / Physione projects

Los proyectos fisioma están siendo desarrollados por diversa organizaciones y comunidades internacionales. Proponen innovadores enfoques investigativos, formas de organización y utilización de recursos para comprender integralmente, como sistemas, al ser humano y otros eucariotas, desde la concepción hasta la muerte, desde los genes hasta los organismos, a través de multiples escalas de espacio (rango: 10 elevado a 9 en la escala métrica), tiempo (rango: 3 x 10 elevado a 15 en segundos) y organización (moléculas, células, tejidos, organos, organismos). Se pone gran énfasis en el uso de modelos matemáticos/computacionales como herramientas para la integración del conocimiento, la experimentación virtual in sílico, el trabajo colaborativo de numerosos grupos multidisciplinarios internacionales, la creación de grandes bases de datos, ontologías, lenguajes estandarizados, metodologías, infraestructura, repositorios de instrumentos de trabajo; el entrenamiento de nuevos investigadores interdisciplinarios, el desarrollo de organizaciones y comunidades para obtener apoyo financiero, considerar aspectos éticos y legales, validar los modelos, facilitar la aplicación de resultados en la clínica, en la industria, en la enseñanza de los profesionales y en la educación del público, con el fin de maximizar los beneficios sociales. Presentamos el proyecto Fisioma de la Union Internacional de Ciencias Fisiológicas (UICF), y el "Humano Fisiológico Virtual", Eurofisioma, apoyado por la Union Europea. Mencionamos otros proyectos relacionados.

Physiome projects are being developed by several international organizations and communities. They propose innovative approaches to research, organization and resourse allocation aiming to fully understand, as systems, the human being and other eukaryotes, from conception to death, from genes to organisms, through multiple scales of space, time and organization (molecules, cells, tissues, organs, organisms). Great emphasis is placed in the of mathematical/computational modeling, in silico experimentation, international collaborative multidisciplinary work; the creation and share of large data bases, antologies standard languages, methodologies. infrastructures, tools; the training of new interdisciplinary investigators. New organizations are being developed to get funding, to consider ethical and legal aspects, to validate models, to facilitate the application of results from basic research to clinical practice, industry and education of professionals and the general public, in order to maximize social benefits. We will consider the Physiome Projects of the International Union Physiological Sciences (IUPS) and the Virtual Physiological Human (VPH), Europhysiome, supported by the European Union. Other related projects are mentioned.

Evaluación de los efectos de diversas intensidades de estimulación nerviosa sobre la amplitud de la respuesta en diferentes especies / Evaluation of the effects of various intensities of nerve stimulation on the scale of the response in different species

El comportamiento nervioso a la estimulación eléctrica ha sido ampliamente estudiado desde 1840, época en la que se comienza a entender las características de la amplitud de respuesta nerviosa y velocidades de conducción en nervios de animales. La amplitud de respuesta en segmentos de nervios es producto de los potenciales de acción compuestos resultantes a la estimulación eléctrica. En esta investigación se estudió el comportamiento nervioso a potenciales evocados in vivo en humanos (nervio ulnar) e in vitro como nervio aislado en Bufus marinus. Durante la estimulación de los nervios se encontró respuesta de comportamiento cualitativo creciente y heterogéneo intra e ínter-especie. El análisis de las respuestas y mecanismos que participan en estos resultados se discuten.

Nervous behaviour by electrical stimulation has been widely studied since 1840, times that initiated the comprehension of the conduction velocity and nerve's amplitude responses in animals. The amplitude response in nerve segments electrically stimulated is generated by the result of composed action potentials. This research pretended to study the nerve responses to evoked potentials in human in vivo (ulnar nerve) and in vitro in animals (Bufus marinus) in sciatic nerve. Electrical stimulation resulted in rising responses of heterogeneous quality inter and intra-species. Mechanisms involved in each response are examined.

Abnormal body perception and neural activity in the insula in depression: an fMRI study of the depressed "material me".

OBJECTIVES: In addition to affective-cognitive symptoms, patients with major depressive disorder (MDD) suffer from somato-vegetative symptoms, suggesting abnormal interoceptive awareness of their "material me". While recent imaging studies have extensively investigated affective-cognitive symptoms in MDD, the neural correlates of somato-vegetative symptoms and abnormal interoception remain unclear. Since the "material me" has been especially associated with the anterior insula in healthy subjects, we hypothesized abnormalities in this region during interoceptive awareness in MDD. METHODS: We therefore investigated behavioural and neural correlates of interoception in healthy and depressed subjects using the Body Perception Questionnaire (BPQ) and a well established heartbeat perception task in fMRI. RESULTS: MDD patients showed significantly higher scores in the BPQ and reduced neural activity during rest periods, particularly in the bilateral anterior insula. In contrast to healthy subjects, BPQ scores no longer correlated with activity during rest periods in the anterior insula. Both BPQ scores and left anterior insula signal changes correlated with depression severity. CONCLUSIONS: We demonstrate for the first time abnormal body perception and altered activity in the insula during rest in MDD. Our results suggest that these behavioural and neural abnormalities are closely related to these patients' somato-vegetative abnormalities and their abnormal "material me".

The kinematics of load carrying in humans and great apes: implications for the evolution of human bipedalism.

We present a comparison of loaded and unloaded carrying kinematics in humans, common chimpanzees (Pan troglodytes), bonobos (Pan paniscus), western lowland gorillas (Gorilla gorilla gorilla) and Bornean and Sumatran orang-utans (Pongo pygmaeus and Pongo abelii). Human hindlimb joint and segment angles were collected during treadmill locomotion using infrared motion analysis cameras. Non-human primate fore- and hindlimb joint and segment angles were collected at zoos during free-ranging locomotion using a standard video camera. In quadrupedal locomotion there were small but potentially important changes associated with load carriage leading to a more upright trunk and a shift in shoulder excursion. These changes were exacerbated as locomotion shifts from quadrupedal to tripedal and bipedal gaits when carrying more awkward loads suggesting a possible adaptive sequence. However, food carrying may favour a highly flexed bent-hip bent-knee bipedal gait since it allows simultaneous foraging and hoarding. In bipedal humans no changes in limb kinematics were seen associated with type of load, although asymmetric loads may lead to lateral postural shifts. Carrying may therefore be an important component of the evolutionary shift to habitual bipedalism, although further work is needed to understand the full biomechanical implications.

The paranasal sinuses: the last frontier in craniofacial biology.

This special issue of the Anatomical Record explores the presence and diversity of paranasal sinuses in distinct vertebrate groups. The following topics are addressed in particular: dinosaur physiology; development; physiology; adaptation; imaging; and primate systematics. A variety of approaches and techniques are used to examine and characterize the diversity of paranasal sinus pneumatization in a wide spectrum of vertebrates. These range from dissection to histology, from plain X-rays to computer tomography, from comparative anatomy to natural experimental settings, from mathematical computation to computer model simulation, and 2D to 3D reconstructions. The articles in this issue are a combination of literature review and new, hypothesis-driven anatomical research that highlights the complexities of paranasal sinus growth and development; ontogenetic and disease processes; physiology; paleontology; primate systematics; and human evolution. The issue incorporates a wide variety of vertebrates, encompassing a period of over 65 million years, in an effort to offer insight into the diversity of the paranasal sinus complexes through time and space, and thereby providing a greater understanding and appreciation of these special spaces within the cranium.

Towards a fuller understanding of mosquito behaviour: use of electrocuting grids to compare the odour-orientated responses of Anopheles arabiensis and An. quadriannulatus in the field.

The epidemiological role of and control options for any mosquito species depend on its degree of 'anthropophily'. However, the behavioural basis of this term is poorly understood. Accordingly, studies in Zimbabwe quantified the effects of natural odours from cattle and humans, and synthetic components of these odours, on the attraction, entry and landing responses of Anopheles arabiensis Giles (Diptera: Culicidae) and Anopheles quadriannulatus Theobald. The numbers of mosquitoes attracted to human or cattle odour were compared using electrocuting nets (E-nets), and entry responses were gauged by the catch from an odour-baited entry trap (OBET) relative to that from an odour-baited E-net. Landing responses were estimated by comparing the catches from E-nets and cloth targets covered with an electrocuting grid. For An. arabiensis, E-nets baited with odour from a single ox or a single man caught similar numbers, and increasing the dose of human odour from one to three men increased the catch four-fold. For An. quadriannulatus, catches from E-nets increased up to six-fold in the progression: man, three men, ox, and man + ox, with catch being correlated with bait mass. Entry responses of An. arabiensis were stronger with human odour (entry response 62%) than with ox odour (6%) or a mixture of cattle and human odours (15%). For An. quadriannulatus, the entry response was low (< 2%) with both cattle and human odour. Anopheles arabiensis did not exhibit a strong entry response to carbon dioxide (CO2) (0.2-2 L/min). The trends observed using OBETs and E-nets also applied to mosquitoes approaching and entering a hut. Catches from an electrocuting target baited with either CO2 or a blend of acetone, 1-octen-3-ol, 4-methylphenol and 3-n-propylphenol - components of natural ox odour - showed that virtually all mosquitoes arriving there alighted on it. The propensity of An. arabiensis to enter human habitation seemed to be mediated by odours other than CO2 alone. Characterizing 'anthropophily' by comparing the numbers of mosquitoes caught by traps baited with different host odours can lead to spurious conclusions; OBETs baited with human odour caught around two to four times more An. arabiensis than cattle-baited OBETs, whereas a human-baited E-net caught less ( approximately 0.7) An. arabiensis than a cattle-baited E-net. Similar caution is warranted for other species of mosquito vectors. A fuller understanding of how to exploit mosquito behaviour for control and surveys requires wider approaches and more use of appropriate tools.

The lumbar spine in Neanderthals shows natural kyphosis.

Nowadays, lumbar spondylosis is one of the most frequent causes of lower back pain. In order to improve our understanding of the lumbar spine anatomy and functionality over time, we compared the lumbar vertebrae of Neanderthals with those of anatomically modern humans. The fossil record reports on only two Neanderthal skeletons (i.e., Kebara 2 and Shanidar 3, both predating the appearance of modern humans) with full preservation of the entire lumbar spine. Examination of these early hominids showed that they display natural lumbar kyphosis, with only mild degenerative changes of the lumbar spine (ages at death: 30-35 years, Kebara 2; and 35-50 years, Shanidar 3). This finding is highly unexpected since Neanderthals are known to have had extraordinary physical activity due to demanding living conditions. The adult lumbar spines discussed here therefore show no correlation between high physical activity and degenerative spine disease as known from recent times. We speculate that both the kyphosis itself and the massive and heavily muscled skeleton of Neanderthals are causative for the minimal bone degeneration. We conclude that a kyphotic lumbar spine is the natural anatomy in these two Neanderthal individuals. Future research will reveal if this holds true for the entire Neanderthal species.