Biology subjects

Lukinova, E.

Publications and source records attributed to Lukinova, E..

3 recordsLinked to original sources

bioRxiv2025

Intertemporal choice across short and long time horizons: an fMRI study

This preregistered fMRI study investigates the neural mechanisms underlying intertemporal choices involving waiting and postponing. On a behavioral level, choices made regarding rewards available in seconds that require waiting compared to choices about rewards postponed to a number days are surprisingly similar. The explanation to this short/long time scales gap is lacking even after considering time perception and external factors, such as stress. To address that this study is the first to examine the overlapping and distinct neural circuitry involved in the intertemporal choices over seconds and days, and the waiting period within subject. Our results revealed considerable overlap in brain activation during choices that consider seconds and days delays to reward in the executive control (dACC, dlPFC) and prospection (PCC/precuneus, dmPFC) networks, but not in the valuation network. Consistent with existent literature we found the valuation network activation (both vmPFC and ventral striatum) being parametrically modulated by individual subjective values of delayed rewards. Overall, the key network determined through representational similarity and decoding analyses was prospection accounting for similarity in activation during decision making across time scales of delays and discriminating between waiting and postponing the reward. These findings enhance our understanding of the neural underpinnings of intertemporal choices and their implications for real-life decisions occurring across varying time horizons, such as paying to skip advertisements while watching videos or deciding on the next-day delivery service.

neuroscience↗

bioRxiv2021

Does endogenous variation in stress modulate risk and time preferences?

Stress is a normal part of our everyday lives. It alerts us to changes in our environment working as an early warning system. However, when stress is prolonged, it can become harmful. The deleterious effects of stress on brain function are well established: chronic stress significantly impairs cognitive function reducing our ability to solve problems and to regulate behavior and, therefore, may lead to more challenges that can further exacerbate stress. An important class of decisions that may be made under stress includes those between rewards delivered immediately vs. those delivered in the future. Not considering or devaluing future outcomes (delay discounting) can result in adverse outcomes such as not buying health insurance, gambling or drug use. To date, however, little is known about how chronic stress influences economic decisions that differ in the time of outcome delivery. A handful of studies suggest that increased stress may lead to more impulsive choices in subjects of average socioeconomic status and stress levels. Here, we addressed this gap by using a longitudinal design to determine whether chronic stress measures (via questionnaires, saliva and hair samples) are associated with the economic choices under different time scales within subject (N = 34). We found that the degree to which people think it is worth waiting, i.e. individuals discount factor, over seconds, but not over days, varied reliably with endogenous stress. These results are imperative to studying stress in a variety of contexts: e.g., the variation in consumers impulse purchases could be attributed to the variation in individual stress responses to the environment, even in healthy adults.

animal behavior and cognition↗

bioRxiv2018

Time preferences are reliable across time-horizons and verbal vs. experiential tasks

Individual differences in delay-discounting correlate with important real world outcomes, e.g. education, income, drug use, & criminality. As such, delay-discounting has been extensively studied by economists, psychologists and neuroscientists to reveal its behavioral and biological mechanisms in both human and non-human animal models. However, two major methodological differences hinder comparing results across species. Human studies present long time-horizon options verbally, whereas animal studies employ experiential cues and short delays. To bridge these divides, we developed a novel language-free experiential task inspired by animal decision-making studies. We find that subjects time-preferences are reliable across both verbal/experiential differences and also second/day differences. When we examined whether discount factors shifted or scaled across the tasks, we found a surprisingly strong effect of temporal context. Taken together, this indicates that subjects have a stable, but context-dependent, time-preference that can be reliably assessed using different methods; thereby, providing a foundation to bridge studies of time-preferences across species.

animal behavior and cognition↗