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Are extinction opinions extinct?

ABSTRACT: Extinction models vary in the information they require, the simplest considering the rate of certain sightings only. More complicated methods include uncertain sightings and allow for variation in the reliability of uncertain sightings. Generally extinction models require expert opinion, either as a prior belief that a species is extinct, or to establish the quality of a sighting record, or both. Is this subjectivity necessary? We present two models to explore whether the individual quality of sightings, judged by experts, is strongly informative of the probability of extinction: the 'quality breakpoint method' and the 'quality as variance method'. For the first method we use the Barbary lion as an exemplar. For the second method we use the Barbary lion, Alaotra grebe, Jamaican petrel and Pohnpei starling as exemplars. The 'quality breakpoint method' uses certain and uncertain sighting records, and the quality of uncertain records, to establish whether a change point in the rate of sightings can be established using a simultaneous Bayesian optimisation with a non-informative prior. For the Barbary lion, there is a change in subjective quality of sightings around 1930. Unexpectedly sighting quality increases after this date. This suggests that including quality scores from experts can lead to irregular effects and may not offer reliable results. As an alternative, we use quality as a measure of variance around the sightings, not a change in quality. This leads to predictions with larger standard deviations, however the results remain consistent across any prior belief of extinction. Nonetheless, replacing actual quality scores with random quality scores showed little difference, inferring that the quality scores from experts are superfluous. Therefore, we deem the expensive process of obtaining pooled expert estimates as unnecessary, and even when used we recommend that sighting data should have minimal input from experts in terms of assessing the sighting quality at a fine scale. Rather, sightings should be classed as certain or uncertain, using a framework that is as independent of human bias as possible.

SUBMITTER: Lee TE

PROVIDER: S-EPMC5555291 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Are extinction opinions extinct?

Lee Tamsin E TE Bowman Clive C Roberts David L DL

PeerJ 20170811

Extinction models vary in the information they require, the simplest considering the rate of certain sightings only. More complicated methods include uncertain sightings and allow for variation in the reliability of uncertain sightings. Generally extinction models require expert opinion, either as a prior belief that a species is extinct, or to establish the quality of a sighting record, or both. Is this subjectivity necessary? We present two models to explore whether the individual quality of s ...[more]

PMID: 28828259

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Project description:BackgroundSecond medical opinions have become commonplace and even mandatory in some health-care systems, as variations in diagnosis, treatment or prognosis may emerge among physicians.ObjectiveTo evaluate whether physicians' judgment is affected by another medical opinion given to a patient.DesignOrthopedic surgeons and neurologists filled out questionnaires presenting eight hypothetical clinical scenarios with suggested treatments. One group of physicians (in each specialty) was told what the other physician's opinion was (study group), and the other group was not told what it was (control group).ParticipantsA convenience sample of 332 physicians in Israel: 172 orthopedic surgeons (45.9% of their population) and 160 neurologists (64.0% of their population).MeasurementsScoring was by choice of less or more interventional treatment in the scenarios. We used ?(2) tests and repeated measures ANOVA to compare these scores between the two groups. We also fitted a cumulative ordinal regression to account for the dependence within each physician's responses.ResultsOrthopedic surgeons in the study group chose a more interventionist treatment when the other physician suggested an intervention than those in the control group [F (1, 170)?=4.6, p=0.03; OR=1.437, 95% CI 1.115-1.852]. Evaluating this effect separately in each scenario showed that in four out of the eight scenarios, they chose a more interventional treatment when the other physician suggested an intervention (scenario 1, p=0.039; scenario 2, p<0.001; scenario 3, p=0.033; scenario 6, p<0.001). These effects were insignificant among the neurologists [F (1,158)?=0.44, p=0.51; OR=1.087, 95% CI 0.811-1.458]. In both specialties there were no differences in responses by level of clinical experience [orthopedic surgeons: F (2, 166)?=0.752, p=0.473; neurologists: F (2,154)?=1.951, p=0.146].ConclusionsThe exploratory survey showed that in some cases physicians' judgments may be affected by other physicians' opinions, but unaffected in other cases. Weighing previous opinions may yield a more informed clinical decision, yet physicians may be unintentionally influenced by previous opinions. Second opinion has the potential to improve the clinical decision-making processes, and mechanisms are needed to reconcile discrepant opinions.

Project description:Extinction learning refers to the phenomenon that a previously learned response to an environmental stimulus, for example the expression of an aversive behavior upon exposure to a specific context, is reduced when the stimulus is repeatedly presented in the absence of a previously paired aversive event. Extinction of fear memories has been implicated with the treatment of anxiety disease but the molecular processes that underlie fear extinctionare only beginning to emerge. Here we show that fear extinction initiates up-regulation of hippocampal insulin-growth factor 2 (Igf2) and down-regulation of insulin-growth factor binding protein 7 (Igfbp7). In line with this observation we demonstrate that IGF2 facilitates fear extinction, while IGFBP7 impairs fear extinction in an IGF2-dependent manner. Furthermore, we identify one cellular substrate of altered IGF2-signaling during fear extinction. To this end we show that fear extinction-induced IGF2/IGFBP7-signaling promotes the survival of 17-19 day-old newborn hippocampal neurons. In conclusion, our data suggests that therapeutic strategies that enhance IGF2-signaling and adult neurogenesis might be suitable to treat disease linked to excessive fear memory. We employed mice to investigate fear extinction in the hippocampus-dependent contextual fear conditioning paradigm. To this end, male C57BL/6J mice were exposed to the fear conditioning box (context) followed by an electric foot-shock which elicits the acquisition of conditioned contextual fear. For extinction training animals were repeatedly reexposed to the conditioned context on consecutive days (24h interval) without receiving the footshockagain (extinction trial, E). This procedure eventually results in the decline of the aversive freezing behavior. Mice that were exposed to the conditioning context without receiving fear conditioning training served as control groups. To gain a better understanding of the molecular processes underlying fear extinction we performed a genome-wide analysis of the hippocampal transcriptome during fear extinction. In the employed paradigm fear extinction is a gradual process. To capture the longitudinal course of fear extinction we decided to perform hippocampal microarray analysis at two time points: (1) After the first extinction trial (E1) when animals display high levels of aversive freezing behavior and (2) at the extinction trial on which the freezing behavior was significantly reduced when compared to E1. This extinction trial, in the case of this experiment E5, we termed “extinction trial low freezing” (ELF). Mice that were exposed to the conditioning context without receiving fear conditioning training served as control groups (3). For all three groups we hybridized 5 samples (biological replicates).

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Are extinction opinions extinct?

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Are extinction opinions extinct?

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