38,954 research outputs found
Three-year monitoring of potential insect vectors of “flavescence dorée” in Trentino vineyards through use of chromotropic traps
5openopenGelmetti, A.; Ghidoni, F.; Zapponi, L.; Mazzoni, V.; Bottura, M.Gelmetti, A.; Ghidoni, F.; Zapponi, L.; Mazzoni, V.; Bottura, M
A biophysical observation model for field potentials of networks of leaky integrate-and-fire neurons
We present a biophysical approach for the coupling of neural network activity
as resulting from proper dipole currents of cortical pyramidal neurons to the
electric field in extracellular fluid. Starting from a reduced threecompartment
model of a single pyramidal neuron, we derive an observation model for
dendritic dipole currents in extracellular space and thereby for the dendritic
field potential that contributes to the local field potential of a neural
population. This work aligns and satisfies the widespread dipole assumption
that is motivated by the "open-field" configuration of the dendritic field
potential around cortical pyramidal cells. Our reduced three-compartment scheme
allows to derive networks of leaky integrate-and-fire models, which facilitates
comparison with existing neural network and observation models. In particular,
by means of numerical simulations we compare our approach with an ad hoc model
by Mazzoni et al. [Mazzoni, A., S. Panzeri, N. K. Logothetis, and N. Brunel
(2008). Encoding of naturalistic stimuli by local field potential spectra in
networks of excitatory and inhibitory neurons. PLoS Computational Biology 4
(12), e1000239], and conclude that our biophysically motivated approach yields
substantial improvement.Comment: 31 pages, 4 figure
On the existence and implications of nonbelieved memories
In this article, we review the state of knowledge about a previously-assumed-to-be-rare memory phenomenon called nonbelieved memories. Nonbelieved memories are a counterintuitive phenomenon in which vivid autobiographical memories are no longer believed to have happened even though vivid recollective features remain present. Such memories stand in contrast to the more typical situation that when events are recollected they are also believed to have genuinely occurred. We review data on the frequency, characteristics, and factors that contribute to the development of naturally occurring and laboratory-induced nonbelieved memories and discuss the relationships of nonbelieved memories with theories of autobiographical remembering and the study of remembering in applied domains
Hypnosis and memory: two hundred years of adventures and still going!
One of the most persistent beliefs about hypnosis is its ability to transcend mnemonic abilities. This belief has paved the way to the use of hypnosis in the clinical and legal arenas. The authors review the phenomena of hypnotic hypermnesia, pseudo-memories, and amnesia in light of current knowledge of hypnosis and memory. The investigation of the relation between hypnosis and memory processes has played an important role in our understanding of memory in action. Hypnosis provides a fertile field to explore the social, neuropsychological, and cognitive variables at play when individuals are asked to remember or to forget their past. We suggest promising avenues of research that may further our knowledge of the building blocks of memories and the mechanisms that leads to forgetfulness
Believing Does Not Equal Remembering: The Effects of Social Feedback and Objective False Evidence on Belief in Occurrence, Belief in Accuracy, and Recollection
We examined the impact of social feedback and objective false evidence on belief in occurrence, belief in accuracy, and recollection of an autobiographical experience. Participants viewed six virtual scenes (e.g., park) and were tested on their belief/recollection. After 1-week, participants were randomly assigned to four groups. One group received social feedback that one scene was not experienced. A second group received objective false evidence that one of the scenes was not shown. A third group received both social feedback and objective false evidence and the control group did not receive any manipulation. Belief in occurrence dropped considerably in the social feedback group and in the combined group. Also, nonbelieved memories were most likely to occur in participants receiving both social feedback and objective false evidence. We show that social feedback and objective false evidence undermine belief in occurrence, but that they leave belief in accuracy and recollection unaffected
Hypothesis: is yeast a clock model to study the onset of humans aging phenotypes?
In this paper we report the growth and aging of yeast colonies derived from single cells isolated by micromanipulation and seeded one by one on separated plates to avoid growth interference by surrounding colonies. We named this procedure clonal life span, and it could represent a third way of studying aging together with the replicative life span and chronological life span. In this study we observed over time the formation of cell mass similar to the human "senile warts" (seborrheic keratoses), the skin lesions that often appear after 30 years of life and increase in number and size over the years. We observed that similar signs of aging appear in yeast colonies after about 27 days of growth and increase during aging. In this respect we hypothesize to use yeast as a clock to study the onset of human aging phenotypes
Increased levels of RNA oxidation enhance the reversion frequency in aging pro-apoptotic yeast mutants
Despite recent advances in understanding the complexity of RNA processes, regulation of the metabolism of oxidized cellular RNAs and the mechanisms through which oxidized ribonucleotides affect mRNA translation, and consequently cell viability, are not well characterized. We show here that the level of oxidized RNAs is markedly increased in a yeast decapping Kllsm4Δ1 mutant, which accumulates mRNAs, ages much faster that the wild type strain and undergoes regulated-cell-death. We also found that in Kllsm4Δ1 cells the mutation rate increases during chronological life span indicating that the capacity to han- dle oxidized RNAs in yeast declines with aging. Lowering intracellular ROS levels by antioxidants recovers the wild- type phenotype of mutant cells, including reduced amount of oxidized RNAs and lower mutation rate. Since mRNA oxidation was reported to occur in different neurodegen- erative diseases, decapping-deficient cells may represent a useful tool for deciphering molecular mechanisms of cell response to such conditions, providing new insights into RNA modification-based pathogenesis
Automatic and ironic behavior are both mediated by changes in the self-concept
Recent accounts suggest that prime-to-behavior effects are mediated by changes to the active self-concept. Likewise, recent reports of post-suppression behavioral rebound have attributed changes to behavior to changes in the self-concept. According to such accounts, whenever an activated trait or stereotype can be easily incorporated into the active self, behavioral assimilation (i.e., behavior consistent with the activated concept) is likely to ensue. Yet, little evidence has emerged to directly support the mediating role of changes to the self-concept. The present research was designed to examine whether changes to the active self-concept are responsible for changes in behavior following stereotype suppression and priming. Participants who suppressed or were primed with stereotypes of the elderly were more likely to endorse stereotypic traits as self-descriptive and to behave in stereotypic ways. Critically, the former effect significantly mediated the latter. Implications for theories of concept activation and behavior are discussed. (C) 2011 Elsevier Inc. All rights reserved
Manipulating Memory Associations Changes Decision-making Preferences in a Preconditioning Task
Memories of past experiences can guide our decisions. Thus, if memories are undermined or distorted, decision making should be affected. Nevertheless, little empirical research has been done to examine the role of memory in reinforcement decision-making . We hypothesized that if memories guide choices in a conditioning decision-making task, then manipulating these memories would result in a change of decision preferences to gain reward. We manipulated participants’ memories by providing false feedback that their memory associations were wrong before they made decisions that could lead them to win money . Participants’ memory ratings decreased significantly after receiving false feedback. More importantly, we found that false feedback led participants’ decision bias to disappear after their memory associations were undermined . Our results suggest that reinforcement decision-making can be altered by fasle feedback on memories . The results are discussed using memory mechanisms such as spreading activation theories
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