Biology subjects

Diederich, A.

Publications and source records attributed to Diederich, A..

7 recordsLinked to original sources

bioRxiv2025

Effect of dependency and tail behavior on a probability inequality occurring in modeling cognitive processes

A central idea in modeling performance in cognitive tasks is dynamic competition among processes in separate channels, known as "race model". This model implies a certain inequality between associated probability distributions under rather general conditions. The inequality represents an important empirical test of the race model, but its usefulness is limited since it requires the assumption of stochastic independence between the channels. Using the stop signal paradigm as reference, we investigate more general forms of stochastic dependence that still imply the inequality using the concepts of copula and heavy-tailed marginal distributions.

neuroscience↗

bioRxiv2025

Mixture-models for stimulus-selective stopping

Stimulus-selective stopping extends the standard stop signal task by occasionally presenting an ignore signal instead of a stop signal, in which case participants are instructed to continue responding to the go signal. Here we present several model classes that are based on the idea that responses observed under an ignore signal are the result of a probabilistic mixture from the processing distributions of the go and the ignore signal. Earlier work ensures that the mixture hypothesis is statistically testable. We derive quantitative predictions and parameter estimation for model classes that differ in the way the mixture is introduced. The results are illustrated with an application to a published dataset for stimulus-selective stopping.

neuroscience↗

bioRxiv2025

Predicting the Sound-Induced Flash Illusion: A Time-Window-of-Integration Approach

The sound-induced flash illusion (SIFI) refers to the observation that pairing a single flash with 2 auditory beeps leads to the illusory perception of 2 visual stimuli (fission illusion). Susceptibility to the illusion depends on many factors like exact physical stimulus parameters, participants expectations, attention, age, and clinical/non-clinical population membership. While there exist many experimental studies, very few models have been proposed to account for the phenomenon. Here we suggest a formal model (SIFI-TWIN) based on the notion of a temporal binding window that predicts the occurrence of illusory flashes as a function of the temporal and physical stimulus arrangement. The models performance is illustrated on a study investigating differences in SIFI performance between elderly hearing aid users and those with the same degree of mild hearing loss who were not using hearing aids. The results suggests that the higher incidence of reporting an illusory flash for hearing-aid users is due to both a larger temporal window of integration and a larger bias to report the illusion. The SIFI-TWIN model will help to better understand the diverse results from clinical and non-clinical studies as well as the cognitive foundations of the SIFI.

neuroscience↗

bioRxiv2024

The NAPstar family of NADP redox state sensors highlights glutathione as the primary mediator of anti-oxidative electron flux

The NADPH/NADP+ redox couple is central to metabolism and redox signalling. NADP redox state is differentially regulated by distinct enzymatic machineries at the subcellular compartment level. Nonetheless, a detailed understanding of subcellular NADP redox dynamics is limited by the availability of appropriate tools. Here, we introduce NAPstars, a family of genetically encoded, fluorescent protein-based NADP redox state biosensors. NAPstars offer real-time, specific, pH-resistant measurements, across a broad-range of NADP redox states, with subcellular resolution. We establish NAPstar measurements in yeast, plants and mammalian cell models, revealing a conserved robustness of cytosolic NADP redox homeostasis. NAPstars uncovered NADP redox oscillations linked to the cell cycle in yeast and illumination- and hypoxia-dependent NADP redox changes in plant leaves. By selectively impairing the glutathione and thioredoxin anti-oxidative pathways under acute oxidative challenge, NAPstars demonstrated an unexpected role for the glutathione system as the primary mediator of anti-oxidative electron flux that is conserved across eukaryotic kingdoms.

biochemistry↗

bioRxiv2020

A two-stage diffusion modeling approach to the compelled-response task

The issue of how perception and motor planning interact to generate a given choice between actions is a fundamental question in both psychology and neuroscience. Salinas and colleagues have developed a behavioral paradigm, the compelled-response task, where the signal that instructs the subject to make an eye movement is given before the cue that indicates which of two possible target choices is the correct one. When the cue is given rather late, the participant must guess and make an uninformed random choice. Perceptual performance can be tracked as a function of the amount of time during which sensory information is available. In Salinas accelerated race-to-threshold model, two variables race against each other to a threshold, at which a saccade is initiated. The source of random variability is in the initial state of information buildup across trials. This implies that incorrect decisions are due to the inertia of the racing variables that have, at the start, sampled a constant buildup in the "wrong" direction. Here we suggest an alternative, non-time-homogeneous two-stage-diffusion model that is able to predict both response time distributions and choice probabilities with a few easy-to-interpret parameters and without assuming cross-trial parameter variability. It is falsifiable at the level of qualitative features already, e.g. predicting bimodal RT distributions for particular gap times. It connects the compelled-response paradigm with an approach to decision making that has been uniquely successful in describing both behavioral and neural data in a variety of experimental settings for the last 40 years.

neuroscience↗

bioRxiv2018

Multisensory perception reflects individual differences in processing temporal correlations

Sensory signals originating from a single event, such as audiovisual speech, are temporally correlated. Correlated signals are known to facilitate multisensory integration and binding. We sought to further elucidate the nature of this relationship, hypothesizing that multisensory perception will vary with the strength of audiovisual correlation. Human participants detected near-threshold amplitude modulations in auditory and/or visual stimuli. During audiovisual trials, the frequency and phase of auditory modulations were varied, producing signals with a range of correlations. After accounting for individual differences which likely reflect relative temporal processing abilities of participants auditory and visual systems, we found that multisensory perception varied linearly with strength of correlation. Diffusion modelling confirmed this and revealed that correlation is supplied to the decisional system as sensory evidence. These data implicate correlation as an important cue in audiovisual feature integration and binding and suggest correlational strength as an important factor for flexibility in these processes.

neuroscience↗

bioRxiv2017

Race Model for the Stop Signal Paradigm Revisited: Perfect Negative Dependence

The ability to inhibit our responses voluntarily is an important case of cognitive control. The stop-signal paradigm is a popular tool to study response inhibition. Participants perform a response time task (go task) and, occasionally, the go stimulus is followed by a stop signal after a variable delay, indicating subjects to withhold their response (stop task). The main interest of modeling is in estimating the unobservable stop-signal processing time, that is, the covert latency of the stopping process as a characterization of the response inhibition mechanism. In the independent race model the stop-signal task is represented as a race between stochastically independent go and stop processes. Without making any specific distributional assumptions about the processing times, the model allows to estimate the mean time to cancel a response. However, neurophysiological studies on countermanding saccadic eye movements have shown that neural correlates of go and stop processes consist of networks of mutually interacting gaze-shifting and gaze-holding neurons. This poses a major challenge in formulating linking propositions between the behavioral and neural findings. Here we propose a dependent race model that postulates perfect negative stochastic dependence between go and stop activations. The model is consistent with the concept of interacting processes while retaining the simplicity and elegance of the distribution-free independent race model. For mean data, the dependent models predictions remain identical to those of the independent model. The resolution of this apparent paradox advances the understanding of mechanisms of response inhibition and paves the way for modeling more complex situations.

neuroscience↗