311 research outputs found
Modelling decision-making biases
Biases are a fundamental aspect of everyday life decision-making. A variety of modelling approaches have been suggested to capture decision-making biases. Statistical models are a means to describe the data, but the results are usually interpreted according to a verbal theory. This can lead to an ambiguous interpretation of the data. Mathematical cognitive models of decision-making outline the structure of the decision process with formal assumptions, providing advantages in terms of prediction, simulation, and interpretability compared to statistical models. We compare studies that used both signal detection theory and evidence accumulation models as models of decision-making biases, concluding that the latter provides a more comprehensive account of the decision-making phenomena by including response time behavior. We conclude by reviewing recent studies investigating attention and expectation biases with evidence accumulation models. Previous findings, reporting an exclusive influence of attention on the speed of evidence accumulation and prior probability on starting point, are challenged by novel results suggesting an additional effect of attention on non-decision time and prior probability on drift rate
The representation of abstract task rules in the human prefrontal cortex
We have previously reported sustained activation in the ventral
prefrontal cortex while participants prepared to perform 1 of 2 tasks
as instructed. But there are studies that have reported activation
reflecting task rules elsewhere in prefrontal cortex, and this is true in
particular when it was left to the participants to decide which rule to
obey. The aim of the present experiment was to use functional
magnetic resonance imaging (fMRI) to find whether there was
activation in common, irrespective of the way that the task rules
were established. On each trial, we presented a word after a variable
delay, and participants had to decide either whether the word was
abstract or concrete or whether it had 2 syllables. The participants
either decided before the delay which task they would perform or
were instructed by written cues. Comparing the self-generated with
the instructed trials, there was early task set activation during the
delay in the middle frontal gyrus. On the other hand, a conjunction
analysis revealed sustained activation in the ventral prefrontal and
polar cortex for both conditions. We argue that the ventral prefrontal
cortex is specialized for handling conditional rules regardless of how
the task rules were established
Catching wandering minds with tapping fingers: neural and behavioral insights into task-unrelated cognition
Charting human subcortical maturation across the adult lifespan with in vivo 7 T MRI
The human subcortex comprises hundreds of unique structures. Subcortical functioning is crucial for behavior, and disrupted function is observed in common neurodegenerative diseases. Despite their importance, human subcortical structures continue to be difficult to study in vivo. Here we provide a detailed account of 17 prominent subcortical structures and ventricles, describing their approximate iron and myelin contents, morphometry, and their age-related changes across the normal adult lifespan. The results provide compelling insights into the heterogeneity and intricate age-related alterations of these structures. They also show that the locations of many structures shift across the lifespan, which is of direct relevance for the use of standard magnetic resonance imaging atlases. The results further our understanding of subcortical morphometry and neuroimaging properties, and of normal aging processes which ultimately can improve our understanding of neurodegeneration
Optical Properties of Crystals with Spatial Dispersion: Josephson Plasma Resonance in Layered Superconductors
We derive the transmission coefficient, , for grazing incidence of
crystals with spatial dispersion accounting for the excitation of multiple
modes with different wave vectors for a given frequency . The
generalization of the Fresnel formulas contains the refraction indices of these
modes as determined by the dielectric function . Near
frequencies , where the group velocity vanishes, depends
also on an additional parameter determined by the crystal microstructure. The
transmission is significantly suppressed, if one of the excited modes is
decaying into the crystal. We derive these features microscopically for the
Josephson plasma resonance in layered superconductors.Comment: 4 pages, 2 figures, epl.cls style file, minor change
Individual differences in heart rate variability predict the degree of slowing during response inhibition and initiation in the presence of emotional stimuli
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