Wednesday, January 23, 2019

Raising mice in an enriched environment (better opportunities for social interaction, voluntary physical exercise & explorative behaviour) boosts cortical plasticity & now ocular dominance plasticity

Transgenerational transmission of enhanced ocular dominance plasticity from enriched mice to their non-enriched offspring. Evgenia Kalogeraki, Rashad Yusifov and Siegrid Löwel. eNeuro January 21 2019, ENEURO.0252-18.2018;

Abstract: In recent years, evidence has accumulated that non-Mendelian transgenerational inheritance of qualities acquired through experience is possible. In particular, it has been shown that raising rodents in a so-called enriched environment (EE) can not only modify the animals’ behaviour and increase their susceptibility to activity-dependent neuronal network changes, but also influences both behaviour and neuronal plasticity of the non-enriched offspring. Here, we tested whether such a transgenerational transmission can also be observed in the primary visual cortex (V1) using ocular dominance (OD) plasticity after monocular deprivation (MD) as a paradigm. While OD-plasticity after 7 days of MD is absent in standard-cage (SC) raised mice beyond postnatal day (P) 110, it is present lifelong in EE-raised mice. Using intrinsic signal optical imaging to visualize cortical activity, we confirm these previous observations and additionally show that OD-plasticity is not only preserved in adult EE-mice but also in their adult non-enriched offspring: mice born to enriched parents, but raised in SCs at least until P110 displayed similar OD-shifts towards the open eye after 7 days of MD as age-matched EE-raised animals. Furthermore, testing the offspring of EE-female versus EE-males with SC-mating partners revealed that only pups of EE-females, but not of EE-males, preserved OD-plasticity into adulthood, suggesting that the life experiences of the mother have a greater impact on the continued V1-plasticity of the offspring. The OD-plasticity of the non-enriched pups of EE-mothers was, however, mechanistically different from that of non-enriched pups of EE-parents or EE-mice.

Significance statement:  Recently evidence is accumulating that life experiences and thus acquired qualities of parents can be transmitted across generations in a non-Mendelian fashion and have a significant impact on the fitness of offspring. Raising mice in a so-called enriched environment with enhanced opportunities for social interaction, voluntary physical exercise and explorative behaviour has been shown to boost cortical plasticity. Our results now show that the plasticity-promoting effect of enrichment on ocular dominance plasticity, a well-established plasticity paradigm in a primary sensory cortex, can also be transmitted from enriched parents to their non-enriched offspring. Thus cortical plasticity is not only influenced by an animal’s life experiences but can also be modified by the life experiences of its parents.

Fake News & Ideological (a)symmetries in Perceptions of Media Legitimacy: Partisans are motivated to believe fake news & dismiss true news that contradicts their position as fake news

Harper, Craig A., and Thom Baguley. 2019. ““you Are Fake News”: Ideological (a)symmetries in Perceptions of Media Legitimacy” PsyArXiv. January 23. doi:10.31234/

Abstract: The concept of ‘fake news’ has exploded into the public’s consciousness since the election of Donald Trump to the US presidency in late 2016. Since then, this phrase has witnessed a more than 350% increase in its popular usage, and was named Collins Dictionary’s word of the year for 2017. However, the concept of fake news has received surprisingly little attention within the social psychological literature. We present three well-powered studies (combined N = 2,275) using American and British samples to establish whether liberal and conservative partisans are motivated to believe fake news (Study 1; n = 722) or dismiss true news that contradicts their position as being fake (Study 2; n = 570). We found support for both of these hypotheses. Further, these effects were asymmetrically moderated by collective narcissism, need for cognition, and faith in intuition (Study 3; n = 983). Together, our findings suggest that partisans of both sides of the political spectrum engage with the ‘fake news’ label (and perceive media story legitimacy) in a way that is consistent with a motivated reasoning approach, though these motivations appear to differ between-groups. Theoretical and practical implications are discussed, particularly in relation to growing levels of political polarization and incivility in modern Western democracies.

There were to Neanderthals two effective methods of minimizing C vitamin loss and prevent scurvy: eating meat raw (fresh or frozen); and eating the meat after it has been putrefied

Neanderthals, vitamin C, and scurvy. John D.Speth. Quaternary International,

Abstract: This paper explores the role of vitamin C (ascorbic acid) in the foodways of hunter-gatherers—both ethnohistoric and Paleolithic—whose diet seasonally or over much of the year, of necessity, was comprised largely of animal foods. In order to stave off scurvy, such foragers had to obtain a minimum of about 10 mg per day of vitamin C. However, there is little to no vitamin C in muscle meat, being concentrated instead in various internal organs and brain. Even ruminant stomach contents, despite the abundance of partially digested plants, contains almost none. Moreover, many of the “meatiest” anatomical units in a carcass, such as the thigh muscles or “hams” associated with the femur, are extremely lean in most wild ungulates, making them nutritionally much less valuable to northern foragers than archaeologists commonly assume (for example, Inuit and other indigenous peoples of the arctic and subarctic commonly use the thigh meat as dog food). Vitamin C is also the most unstable vitamin, rapidly degrading or disappearing when exposed to water, air, light, heat, and pH levels above about 4.0. As a consequence, common methods of preparing meat for storage and consumption (e.g., drying, roasting, boiling) may lead to significant loss of vitamin C. There are two effective methods of minimizing such loss: (1) eating meat raw (fresh or frozen); and (2) eating the meat after it has been putrefied. Putrefaction has distinct advantages that make it a common, if not essential, way of preparing and preserving meat among northern latitude foragers and, for the same reasons, very likely also among Paleolithic foragers in the colder climes of Pleistocene Eurasia. Putrefaction “pre-digests” the meat (including the organs), making it much less costly to ingest and metabolize than raw meat; and it lowers the pH, greatly increasing the stability of vitamin C. These observations offer insights into critical nutritional constraints that likely had to be addressed by Neanderthals and later hominins in any context where their diet was heavily meat-based for a substantial part of the year.


Many animals show evidence of culture (innovations in multiple domains whose frequencies are influenced by social learning), but only humans show strong evidence of complex, cumulative culture. Why?

Teaching and curiosity: sequential drivers of cumulative cultural evolution in the hominin lineage. Carel P. van Schaik, Gauri R. Pradhan, Claudio Tennie. Behavioral Ecology and Sociobiology, January 2019, 73:2,

Abstract: Many animals, and in particular great apes, show evidence of culture, in the sense of having multiple innovations in multiple domains whose frequencies are influenced by social learning. But only humans show strong evidence of complex, cumulative culture, which is the product of copying and the resulting effect of cumulative cultural evolution. The reasons for this increase in complexity have recently become the subject of extensive debate. Here, we examine these reasons, relying on both comparative and paleoarcheological data. The currently best-supported inference is that culture began to be truly cumulative (and so, outside the primate range) around 500,000 years ago. We suggest that the best explanation for its onset is the emergence of verbal teaching, which not only requires language and thus probably coevolved with the latter’s evolution but also reflects the overall increase in proactive cooperation due to extensive allomaternal care. A subsequent steep increase in cumulative culture, roughly 75 ka, may reflect the rise of active novelty seeking (curiosity), which led to a dramatic range expansion and steep increase in the diversity and complexity of material culture. A final, and continuing, period of acceleration began with the Neolithic (agricultural) revolution.

Keywords: Cumulative culture Stone tools Out of Africa Imitation Verbal instruction Teaching

Short periods of unoccupied waking rest can facilitate consolidation in a manner similar to that proposed to occur during sleep

Memory Consolidation during Waking Rest. Erin J. Wamsley. Trends in Cognitive Sciences,

Abstract: Recent studies show that brief periods of rest after learning facilitate consolidation of new memories. This effect is associated with memory-related brain activity during quiet rest and suggests that in our daily lives, moments of unoccupied rest may serve an essential cognitive function.

In fact, a growing body of evidence suggests that short periods of unoccupied waking rest can facilitate consolidation in a manner similar to that proposed to occur during sleep [1–3,5,6] (quiet wake conditions, Figure 1). Our group and others have demonstrated that a 15min period of eyes-closed rest following encoding enhances memory for both procedural [5] and declarative [1,2] memory tasks, compared to an equivalent period spent completing a distractor task. Other recent studies have demonstrated that post-learning rest enhances subsequent memory for spatial and temporal information [7] , facilitates insight into a complex problem [3] , and enhances auditory statistical learning [6]. These memory effects can be maintained for a week or more after the rest intervention [2,7]. Together, these observations suggest that even during wakefulness, memory is preferentially consolidated during offline states characterized by reduced attentional demands.

Thus, the fundamental insight yielded by these new studies of waking rest is not so much that consolidation can occur during wakefulness but that consolidation is not uniformly distributed throughout all of wakefulness. Instead, memory is preferentially facilitated during periods of unoccupied time in which attentional and cognitive demands are reduced [1,2,5]. This insight helps us to understand the necessary and sufficient conditions for consolidation to occur. Increasingly, it appears that for many forms of consolidation, sleep-specific neural mechanisms may not be strictly required. Instead, both sleep and other of fl ine states share common neurobiological features essential for consolidation to take place.

Indeed, many of the same neurobiological mechanisms thought to underlie sleep’s effect on memory are shared in common by waking rest. First, cellular-level memory ‘reactivation’ occurs during quiescent waking rest in the hippocampus as well as in other brain regions. During this process, sequences of neuronal fi ring representing recent experience are reiterated of fl ine. Blocking these reactivations impairs learning and memory [8]. In humans, a growing number of neuroimaging studies demonstrate memory-related brain activity during periods of post-training rest that predicts subsequent memory. For example, fMRI has been used to demonstrate that patterns of hippocampal activity characterizing encoding persist into post-learning rest and that this predicts subsequent memory [9]. Our own group has meanwhile reported that low-frequency electroencephalogram oscillations thought to support consolidation during sleep similarly predict memory retention across quiet waking rest [1]. And the neuromodulatory environment during quiet rest is also well own group has meanwhile reported that low-frequency electroencephalogram oscillations thought to support consolidation during sleep similarly predict memory retention across quiet waking rest [1]. And the neuromodulatory environment during quiet rest is also well suited to facilitate consolidation; in both sleep and quiet rest, acetylcholine levels are substantially reduced from active waking levels, thought to promote hippocampal-cortical communication dynamics that benefit consolidation, as opposed to new learning. Thus, converging lines of evidence suggest that like sleep, rest benefits memory by enabling an active process of consolidation, facilitated by the offline reactivation and synaptic plasticity.