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https://www.readbyqxmd.com/read/27922638/enhancing-dopaminergic-signaling-and-histone-acetylation-promotes-long-term-rescue-of-deficient-fear-extinction
#1
N Whittle, V Maurer, C Murphy, J Rainer, D Bindreither, M Hauschild, A Scharinger, M Oberhauser, T Keil, C Brehm, T Valovka, J Striessnig, N Singewald
Extinction-based exposure therapy is used to treat anxiety- and trauma-related disorders; however, there is the need to improve its limited efficacy in individuals with impaired fear extinction learning and to promote greater protection against return-of-fear phenomena. Here, using 129S1/SvImJ mice, which display impaired fear extinction acquisition and extinction consolidation, we revealed that persistent and context-independent rescue of deficient fear extinction in these mice was associated with enhanced expression of dopamine-related genes, such as dopamine D1 (Drd1a) and -D2 (Drd2) receptor genes in the medial prefrontal cortex (mPFC) and amygdala, but not hippocampus...
December 6, 2016: Translational Psychiatry
https://www.readbyqxmd.com/read/27922320/discrimination-between-safe-and-unsafe-stimuli-mediates-the-relationship-between-trait-anxiety-and-return-of-fear
#2
Lindsay K Staples-Bradley, Michael Treanor, Michelle G Craske
Individuals with anxiety disorders show deficits in the discrimination between a cue that predicts an aversive outcome and a safe stimulus that predicts the absence of that outcome. This impairment has been linked to increased spontaneous recovery of fear following extinction, however it is unknown if there is a link between discrimination and return of fear in a novel context (i.e. context renewal). It is also unknown if impaired discrimination mediates the relationship between trait anxiety and either spontaneous recovery or context renewal...
December 6, 2016: Cognition & Emotion
https://www.readbyqxmd.com/read/27922064/ancient-tortoise-hunting-in-the-southwest-pacific
#3
Stuart Hawkins, Trevor H Worthy, Stuart Bedford, Matthew Spriggs, Geoffrey Clark, Geoff Irwin, Simon Best, Patrick Kirch
We report the unprecedented Lapita exploitation and subsequent extinction of large megafauna tortoises (?Meiolania damelipi) on tropical islands during the late Holocene over a 281,000 km(2) region of the southwest Pacific spanning from the Vanuatu archipelago to Viti Levu in Fiji. Zooarchaeological analyses have identified seven early archaeological sites with the remains of this distinctive hornless tortoise, unlike the Gondwanan horned meiolaniid radiation to the southwest. These large tortoise radiations in the Pacific may have contributed to the rapid dispersal of early mobile Neolithic hunters throughout southwest Melanesia and on to western Polynesia...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27921363/morphomechanics-and-developmental-constraints-in-the-evolution-of-ammonites-shell-form
#4
Alexander Erlich, Derek E Moulton, Alain Goriely, Regis Chirat
The idea that physical processes involved in biological development underlie morphogenetic rules and channel morphological evolution has been central to the rise of evolutionary developmental biology. Here, we explore this idea in the context of seashell morphogenesis. We show that a morphomechanical model predicts the effects of variations in shell shape on the ornamental pattern in ammonites, a now extinct group of cephalopods with external chambered shell. Our model shows that several seemingly unrelated characteristics of synchronous, ontogenetic, intraspecific, and evolutionary variations in ornamental patterns among various ammonite species may all be understood from the fact that the mechanical forces underlying the oscillatory behavior of the shell secreting system scale with the cross-sectional curvature of the shell aperture...
December 6, 2016: Journal of Experimental Zoology. Part B, Molecular and Developmental Evolution
https://www.readbyqxmd.com/read/27921349/repeated-trauma-exposure-does-not-impair-distress-reduction-during-imaginal-exposure-for-posttraumatic-stress-disorder
#5
Alissa B Jerud, Frank J Farach, Michele Bedard-Gilligan, Hillary Smith, Lori A Zoellner, Norah C Feeny
BACKGROUND: Based on experimental research on threat extinction, individuals exposed to repeated traumatic events may have impaired outcome in exposure therapy compared to those who have experienced a single trauma (Lang & McTeague, ). This study examined whether repeated trauma exposure predicts smaller changes in self-reported distress during imaginal exposure and worse outcomes for patients with posttraumatic stress disorder (PTSD). METHODS: Adults (N = 116) with chronic PTSD received up to 10 sessions of prolonged exposure (PE) therapy...
December 6, 2016: Depression and Anxiety
https://www.readbyqxmd.com/read/27921340/brain-activation-during-fear-extinction-predicts-exposure-success
#6
Tali Manber Ball, Sarah E Knapp, Martin P Paulus, Murray B Stein
BACKGROUND: Exposure therapy, a gold-standard treatment for anxiety disorders, is assumed to work via extinction learning, but this has never been tested. Anxious individuals demonstrate extinction learning deficits, likely related to less ventromedial prefrontal cortex (vmPFC) and more amygdala activation, but the relationship between these deficits and exposure outcome is unknown. We tested whether anxious individuals who demonstrate better extinction learning report greater anxiety reduction following brief exposure...
December 6, 2016: Depression and Anxiety
https://www.readbyqxmd.com/read/27920788/vegetative-and-adaptive-traits-predict-different-outcomes-for-restoration-using-hybrids
#7
Philip A Crystal, Nathanael I Lichti, Keith E Woeste, Douglass F Jacobs
Hybridization has been implicated as a driver of speciation, extinction, and invasiveness, but can also provide resistant breeding stock following epidemics. However, evaluating the appropriateness of hybrids for use in restoration programs is difficult. Past the F1 generation, the proportion of a progenitor's genome can vary widely, as can the combinations of parental genomes. Detailed genetic analysis can reveal this information, but cannot expose phenotypic alterations due to heterosis, transgressive traits, or changes in metabolism or development...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/27920390/life-history-trade-offs-the-intensity-of-competition-and-coexistence-in-novel-and-evolving-communities-under-climate-change
#8
Lesley T Lancaster, Gavin Morrison, Robert N Fitt
The consequences of climate change for local biodiversity are little understood in process or mechanism, but these changes are likely to reflect both changing regional species pools and changing competitive interactions. Previous empirical work largely supports the idea that competition will intensify under climate change, promoting competitive exclusions and local extinctions, while theory and conceptual work indicate that relaxed competition may in fact buffer communities from biodiversity losses that are typically witnessed at broader spatial scales...
January 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/27920385/sublethal-streptomycin-concentrations-and-lytic-bacteriophage-together-promote-resistance-evolution
#9
Johannes Cairns, Lutz Becks, Matti Jalasvuori, Teppo Hiltunen
Sub-minimum inhibiting concentrations (sub-MICs) of antibiotics frequently occur in natural environments owing to wide-spread antibiotic leakage by human action. Even though the concentrations are very low, these sub-MICs have recently been shown to alter bacterial populations by selecting for antibiotic resistance and increasing the rate of adaptive evolution. However, studies are lacking on how these effects reverberate into key ecological interactions, such as bacteria-phage interactions. Previously, co-selection of bacteria by phages and antibiotic concentrations exceeding MICs has been hypothesized to decrease the rate of resistance evolution because of fitness costs associated with resistance mutations...
January 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/27920376/invasions-and-extinctions-through-the-looking-glass-of-evolutionary-ecology
#10
REVIEW
Robert I Colautti, Jake M Alexander, Katrina M Dlugosch, Stephen R Keller, Sonia E Sultan
Invasive and endangered species reflect opposite ends of a spectrum of ecological success, yet they experience many similar eco-evolutionary challenges including demographic bottlenecks, hybridization and novel environments. Despite these similarities, important differences exist. Demographic bottlenecks are more transient in invasive species, which (i) maintains ecologically relevant genetic variation, (ii) reduces mutation load, and (iii) increases the efficiency of natural selection relative to genetic drift...
January 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/27920231/bayesian-morphological-clock-methods-resurrect-placoderm-monophyly-and-reveal-rapid-early-evolution-in-jawed-vertebrates
#11
Benedict King, Tuo Qiao, Michael S Y Lee, Min Zhu, John A Long
The phylogeny of early gnathostomes provides an important framework for understanding one of the most significant evolutionary events, the origin and diversification of jawed vertebrates. A series of recent cladistic analyses have suggested that the placoderms, an extinct group of armoured fish, form a paraphyletic group basal to all other jawed vertebrates. We revised and expanded this morphological data set, most notably by sampling autapomorphies in a similar way to parsimony-informative traits, thus ensuring this data (unlike most existing morphological data sets) satisfied an important assumption of Bayesian tip-dated morphological clock approaches...
December 5, 2016: Systematic Biology
https://www.readbyqxmd.com/read/27919830/newly-acquired-and-reactivated-contextual-fear-memories-are-more-intense-and-prone-to-generalize-after-activation-of-prelimbic-cortex-nmda-receptors
#12
Ana C Vanvossen, Marina A M Portes, Rafael Scoz-Silva, Hugo B Reichmann, Cristina A J Stern, Leandro J Bertoglio
Activity in the rodent prelimbic (PL) cortex contributes to consolidation, retrieval and reconsolidation of learned fear. The PL cortex is considered homologous to the primate dorsal anterior cingulate cortex (dACC). In patients with post-traumatic stress disorder (PTSD), the dACC is often reported to be hyperactive after acquisition and/or around the retrieval of the traumatic memory. It is still unknown, however, whether there is a relationship between altered dACC functioning at these time points and PTSD-associated behavioral outcomes, such as fear overgeneralization...
December 2, 2016: Neurobiology of Learning and Memory
https://www.readbyqxmd.com/read/27918284/context-specificity-of-both-acquisition-and-extinction-of-a-pavlovian-conditioned-response
#13
Sarah Starosta, Metin Uengoer, Isabelle Bartetzko, Sara Lucke, Onur Güntürkün, Maik C Stüttgen
It is widely held that the extinction of a conditioned response is more context specific than its initial acquisition. One proposed explanation is that context serves to disambiguate the meaning of a stimulus. Using a procedure that equated the learning histories of the contexts, we show that the memory of an appetitive Pavlovian association can be highly context specific despite being unambiguous. This result is inconsistent with predictions of the Rescorla-Wagner model of learning but in line with configural accounts of contextual control of behavior...
November 2016: Learning & Memory
https://www.readbyqxmd.com/read/27918282/conditioned-object-preference-an-alternative-approach-to-measuring-reward-learning-in-rats
#14
Bruce C Kennedy, Maulika Kohli, Jamie J Maertens, Paulina S Marell, Jonathan C Gewirtz
Pavlovian conditioned approach behavior can be directed as much toward discrete cues as it is toward the environmental contexts in which those cues are encountered. The current experiments characterized a tendency of rats to approach object cues whose prior exposure had been paired with reward (conditioned object preference, COP). To demonstrate the phenomenon, rats were conditioned to associate cocaine or saline with two different objects. Rats acquired a preference, assessed using investigation times directed toward each object, for the cocaine-paired object following conditioning...
November 2016: Learning & Memory
https://www.readbyqxmd.com/read/27918278/pi3-kinase-cascade-has-a-differential-role-in-acquisition-and-extinction-of-conditioned-fear-memory-in-juvenile-and-adult-rats
#15
Ilana Slouzkey, Mouna Maroun
The basolateral amygdala (BLA), medial prefrontal cortex (mPFC) circuit, plays a crucial role in acquisition and extinction of fear memory. Extinction of aversive memories is mediated, at least in part, by the phosphoinositide-3 kinase (PI3K)/Akt pathway in adult rats. There is recent interest in the neural mechanisms that mediate fear and extinction in juvenile animals and whether these mechanisms are distinctive from those in adult animals. In the present study, we examined (1) changes in phosphorylation of Akt in the BLA and mPFC after fear conditioning and extinction in juvenile and adult rats and (2) the effect of BLA and mPFC localized inhibition of the PI3K following acquisition and extinction of contextual fear memory...
December 2016: Learning & Memory
https://www.readbyqxmd.com/read/27918275/behavioral-mechanisms-of-context-fear-generalization-in-mice
#16
Kylie A Huckleberry, Laura B Ferguson, Michael R Drew
There is growing interest in generalization of learned contextual fear, driven in part by the hypothesis that mood and anxiety disorders stem from impaired hippocampal mechanisms of fear generalization and discrimination. However, there has been relatively little investigation of the behavioral and procedural mechanisms that might control generalization of contextual fear. We assessed the relative contribution of different contextual features to context fear generalization and characterized how two common conditioning protocols-foreground (uncued) and background (cued) contextual fear conditioning-affected context fear generalization...
December 2016: Learning & Memory
https://www.readbyqxmd.com/read/27918273/neural-circuits-via-which-single-prolonged-stress-exposure-leads-to-fear-extinction-retention-deficits
#17
Dayan Knox, Briana R Stanfield, Jennifer M Staib, Nina P David, Samantha M Keller, Thomas DePietro
Single prolonged stress (SPS) has been used to examine mechanisms via which stress exposure leads to post-traumatic stress disorder symptoms. SPS induces fear extinction retention deficits, but neural circuits critical for mediating these deficits are unknown. To address this gap, we examined the effect of SPS on neural activity in brain regions critical for extinction retention (i.e., fear extinction circuit). These were the ventral hippocampus (vHipp), dorsal hippocampus (dHipp), basolateral amygdala (BLA), prelimbic cortex (PL), and infralimbic cortex (IL)...
December 2016: Learning & Memory
https://www.readbyqxmd.com/read/27917952/biodiversity-in-models-of-cyclic-dominance-is-preserved-by-heterogeneity-in-site-specific-invasion-rates
#18
Attila Szolnoki, Matjaž Perc
Global, population-wide oscillations in models of cyclic dominance may result in the collapse of biodiversity due to the accidental extinction of one species in the loop. Previous research has shown that such oscillations can emerge if the interaction network has small-world properties, and more generally, because of long-range interactions among individuals or because of mobility. But although these features are all common in nature, global oscillations are rarely observed in actual biological systems. This begets the question what is the missing ingredient that would prevent local oscillations to synchronize across the population to form global oscillations...
December 5, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27917060/antarctotrechus-balli-sp-n-carabidae-trechini-the-first-ground-beetle-from-antarctica
#19
Allan C Ashworth, Terry L Erwin
Fossil elytra of a small trechine carabid are reported from the Oliver Bluffs on the Beardmore Glacier at lat. 85°S. They were compared with counterparts from the extant genera Trechisibus, Tasmanorites, Oxytrechus and Pseudocnides. The fossils share some characters but are sufficiently different to be described as a new genus and species. We named the new species Antarctotrechus balli in honour of George E. Ball who made major contributions to the study of carabids through his own research and the training of students while at the University of Alberta, Edmonton, Alberta, Canada...
2016: ZooKeys
https://www.readbyqxmd.com/read/27916139/effects-of-an-ethanol-paired-cs-on-responding-for-ethanol-and-food-comparisons-with-a-stimulus-in-a-truly-random-control-group-and-to-a-food-paired-cs-on-responding-for-food
#20
R J Lamb, Brett C Ginsburg, Charles W Schindler
Motivational increases due to exposure to alcohol-paired Conditioned Stimuli (CS) are central to some accounts of alcoholism. However, few studies isolate a stimulus's function as a CS from its other potential functions. Pavlovian-Instrumental-Transfer (PIT) procedures isolate a stimulus's function as a CS from its other functions. Though there are several relevant studies using PIT, knowledge gaps exist. Particularly, it is not clear that an alcohol-paired CS will increase alcohol seeking compared to the same stimulus in a Truly-Random-Control group, nor whether such increases are specific to alcohol seeking...
December 2016: Alcohol
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