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- Cordero, Gerardo A., et al.
(author)
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Physiological plasticity in lizard embryos exposed to high-altitude hypoxia
- 2017
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In: JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY. - : Wiley. - 2471-5646 .- 2471-5638. ; 327:7, s. 423-432
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Journal article (peer-reviewed)abstract
- Coping with novel environments may be facilitated by plastic physiological responses that enable survival during environmentally sensitive life stages. We tested the capacity for embryos of the common wall lizard (Podarcis muralis) from low altitude to cope with low-oxygen partial pressure (hypoxia) in an alpine environment. Developing embryos subjected to hypoxic atmospheric conditions (15-16% O-2 sea-level equivalent) at 2,877m above sea level exhibited responses common to vertebrates acclimatized to or evolutionarily adapted to high altitude: suppressed metabolism, cardiac hypertrophy, and hyperventilation. These responses might have contributed to the unaltered incubation duration and hatching success relative to the ancestral, low-altitude, condition. Even so, hypoxia constrained egg energy utilization such that larger eggs produced hatchlings with relatively low mass. These findings highlight the role of physiological plasticity in maintaining fitness-relevant phenotypes in high-altitude environments, providing impetus to further explore altitudinal limits to ecological diversification in ectothermic vertebrates.
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| 2. |
- Grassini, Simone, et al.
(author)
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Pattern matters : Snakes exhibiting triangular and diamond-shaped skin patterns modulate electrophysiological activity in human visual cortex
- 2019
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In: Neuropsychologia. - : Elsevier. - 0028-3932 .- 1873-3514. ; 131, s. 62-72
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Journal article (peer-reviewed)abstract
- The neural and perceptual mechanisms that support the efficient visual detection of snakes in humans are still not fully understood. According to the Snake Detection Theory, selection pressures posed by snakes on early primates have shaped the development of the visual system. Previous studies in humans have investigated early visual electrophysiological activity in response to snake images vs. various alternative dangerous or non-dangerous stimuli. These studies have shown that the Early Posterior Negativity (EPN) component is selectively elicited by snake or snake-like images. Recent findings yielded the complementary/alternative hypothesis that early humans (and possibly other primates) evolved an aversion especially for potentially harmful triangular shapes, such as teeth, claws or spikes. In the present study we investigated the effect of triangular and diamond-shaped patterns in snake skins on the ERP correlates of visual processing in humans. In the first experiment, we employed pictures of snakes displaying either triangular/diamond-shaped patterns or no particular pattern on their skins, and pictures of frogs as control. Participants observed a random visual presentation of these pictures. Consistent with previous studies, snakes elicited an enhanced negativity between 225 and 300 ms (EPN) compared to frogs. However, snakes featuring triangular/diamond-shaped patterns on their skin produced an enhanced EPN compared to the snakes that did not display such patterns. In a second experiment we used pictures displaying only skin patterns of snakes and frogs. Results from the second experiment confirmed the results of the first experiment, suggesting that triangular snake-skin patterns modulate the activity in human visual cortex. Taken together, our results constitute an important contribution to the snake detection theory.
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