Transcriptomic Analysis of Planarians under Simulated Microgravity or 8 g Demonstrates That Alteration of Gravity Induces Genomic and Cellular Alterations That Could Facilitate Tumoral Transformation.

The possibility of humans to live outside of Earth on another planet has attracted the attention of numerous scientists around the world. One of the greatest difficulties is that humans cannot live in an extra-Earth environment without proper equipment. In addition, the consequences of chronic gravity alterations in human body are not known. Here, we used planarians as a model system to test how gravity fluctuations could affect complex organisms. Planarians are an ideal system, since they can regenerate any missing part and they are continuously renewing their tissues. We performed a transcriptomic analysis of animals submitted to simulated microgravity (Random Positioning Machine, RPM) (s-µg) and hypergravity (8 g), and we observed that the transcriptional levels of several genes are affected. Surprisingly, we found the major differences in the s-µg group. The results obtained in the transcriptomic analysis were validated, demonstrating that our transcriptomic data is reliable. We also found that, in a sensitive environment, as under Hippo signaling silencing, gravity fluctuations potentiate the increase in cell proliferation. Our data revealed that changes in gravity severely affect genetic transcription and that these alterations potentiate molecular disorders that could promote the development of multiple diseases such as cancer.

Culture: The Driving Force of Human Cognition.

It is often, though sometimes only implicitly, assumed that biological/genetic evolution sets neural substrates, that neural substrates fix cognitive abilities, and that cognitive abilities determine the spectrum of cultural practices exhibited by a biological species. We label this view as the "bottom-up-only" view. In this paper we will show that such a "chain of dependence" is much looser than usually assumed, especially as far as recent periods (the last 800,000 years vs. the last 7 million years or more) are considered. We will provide evidence and arguments supporting the idea that cultural innovation may have direct and ascertainable effects both on the cognitive capabilities of populations of hominins (via what we call "cultural exaptation") and on the neural substrates of the individuals in those populations (via what we call "cultural neural reuse"). Together, cultural exaptation and cultural neural reuse may give raise to a plausible general mechanism for cognitive evolution in which culture is the driving force, thus offering a "top-down-also" view of human evolution.

The concreteness of abstract language: an ancient issue and a new perspective.

This paper addresses the debated issue of abstract language in the framework of embodiment. First, we discuss the notion of abstractness in the light of the Western philosophical thought, with a focus on the English empiricist tradition. Second, we review the most relevant psychological models and neuroscientific empirical findings on abstract language. It turns out that abstract words are not such, because their meaning is "far from experience", but, because of the high complexity of the attached experiential clusters. Finally, we spell out the consequences of this understanding of abstractness in relation to the neural mechanisms subserving abstract language processing. If abstract words, as compared to concrete ones, imply an increasing complexity of the associated experiential clusters, then the processing of abstract language relies on the recruitment of several neural substrates coding for those experiences. We forward that, at the neural level, this complexity is coded by means of three main mechanisms: (1) the recruitment of the motor representations of different biological effectors (abstract meaning as effector-unspecific); (2) the recruitment of different systems, including sensory, motor, and emotional ones (abstract meaning as multi-systemic); (3) the recruitment of neural substrates coding for social contexts and levels of self-relatedness (abstract meaning as dynamic). As compared to the current approaches in the literature on abstract language that combine embodiment with some a-modal aspects, our proposal is fully embodied and rules out additional aspects. Our proposal may spur future empirical research on abstract language in the embodied approach.

From number sense to number symbols. An archaeological perspective.

How and when did hominins move from the numerical cognition that we share with the rest of the animal world to number symbols? Objects with sequential markings have been used to store and retrieve numerical information since the beginning of the European Upper Palaeolithic (42 ka). An increase in the number of markings and complexity of coding is observed towards the end of this period. The application of new analytical techniques to a 44-42 ka old notched baboon fibula from Border Cave, South Africa, shows that notches were added to this bone at different times, suggesting that devices to store numerical information were in use before the Upper Palaeolithic. Analysis of a set of incisions on a 72-60 ka old hyena femur from the Les Pradelles Mousterian site, France, indicates, by comparison with markings produced by modern subjects under similar constraints, that the incisions on the Les Pradelles bone may have been produced to record, in a single session, homologous units of numerical information. This finding supports the view that numerical notations were in use among archaic hominins. Based on these findings, a testable five-stage scenario is proposed to establish how prehistoric cultures have moved from number sense to the use of number symbols.This article is part of a discussion meeting issue 'The origins of numerical abilities'.

Grounding meaning in experience: A broad perspective on embodied language.

This work reviews key behavioural, neurophysiological and neuroimaging data on the neural substrates for processing the meaning of linguistic material, and tries to articulate the picture emerging from those findings with the notion of meaning coming from specific approaches in philosophy of language (the "internalist" view) and linguistics (words point at experiential clusters). The reviewed findings provide evidence in favour of a causal role of brain neural structures responsible for sensory, motor and even emotional experiences in attributing meaning to words expressing those experiences and, consequently, lend substantial support to an embodied and "internalist" conception of linguistic meaning. Key evidence concern verbs, nouns and adjectives with a concrete content, but the challenge that abstract domains pose to the embodied approach to language is also discussed. This work finally suggests that the most fundamental role of embodiment might be that of establishing commonalities among individual experiences of different members of a linguistic community, and that those experiences ground shared linguistic meanings.