Biology subjects

Modak, P.

Publications and source records attributed to Modak, P..

4 recordsLinked to original sources

bioRxiv2026

Motivationally objective versus subjective decision-making: Neural correlates, behavior, and self-report

In this study, we investigated the neural and behavioral basis of motivationally objective versus subjective value-based decisions. Using a within-subject fMRI design, healthy participants performed a risky decision-making task that elicited different levels of subjectivity in decision-making in two task conditions. In the Best or objective condition, choices were rewarded only when they were objectively best on a given trial, incentivizing decisions based on externally specified per-trial point maximization. In the Choice or subjective condition, participants received the reward associated with the chosen option, irrespective of how it compared to the unchosen option, allowing greater freedom to exercise subjective preferences in decision policy. Behaviorally, participants relied more on objectively optimal policy in the Best than the Choice condition. There was also a greater consensus across participants in behaviorally displayed and self-reported policies in the Best condition as well as a greater commitment to a single policy by individual participants in this condition, further confirming more objective behavior in the Best condition, compared to Choice. Moreover, behavioral inferences showed a greater agreement with self-report in the Best condition. Our fMRI results showed that the decision-making in Choice, relative to the Best condition, was associated with greater BOLD response in mid-cingulum/posterior cingulate cortex and dorsal anterior cingulate cortex, suggesting their involvement in less externally constrained, or motivationally subjective, decision-making.

neuroscience↗

bioRxiv2026

Neural correlates of the subjective experience of free-will during value-based risky decisions: a pilot study

Underlying the very notion of choice is the fundamental idea of free-will, which is challenged by decision-neuroscience aiming to explain and predict choices as outcomes of neural processes embedded within an ongoing chain of physical causes. The question of whether any choice is truly a free-choice and born out of free-will has long been a subject of philosophical debate. In this work, we do not take a position on this debate; rather we investigate the subjective experience of free-will, whose existence is more universally accepted. We had healthy participants report the level of their experienced free-will while performing a value-based risky decision-making task during an fMRI session to find the neural and behavioral correlates of this experience. We identified regions in mid-cingulum and middle frontal gyrus showing positive association with self-reported free-will as well as a region in hippocampus and parahippocampal gyrus showing a negative association. The requirement to report the experience of free-will was associated at a trend-level with a higher BOLD signal in striatum during decision-making. Behaviorally, we found a positive trend between RT and free-will. While our sample size is small, these results help form hypotheses for further studies with larger cohorts and provide a proof-of-concept for the investigations of neural and behavioral mechanisms of the subjective experience of free-will in decision research.

neuroscience↗

bioRxiv2024

Temporal interference electrical neurostimulation yields fMRI BOLD activation in humans

Temporal interference electrical neurostimulation (TI) is a relatively new method of non-invasive neurostimulation that may be able to stimulate deep brain regions without stimulating the overlying superficial regions. Despite studies in rodents, almost no studies have investigated its effects on human brain activity along with safety and tolerability profiles. We performed simultaneous TI stimulation and fMRI to investigate the effects of TI on human BOLD signals. Here we show that TI can induce increased BOLD activation in humans, with good safety and tolerability profiles. We also show the limits of spatial precision and explore the nature and causes of additional off target effects. TI may be a promising approach for addressing questions about the causal role of deep brain structures in human cognition and may also afford new clinical treatments.

neuroscience↗

bioRxiv2021

Neural bases of risky decisions involving nicotine vapor versus monetary reward

Substantial effort has gone into neuroimaging studies of neural mechanisms underlying addiction. Human studies of smoking typically either give monetary reward during an fMRI task or else allow subjects to smoke outside the scanner, after the session. This raises a fundamental issue of construct validity, as it is unclear whether the same neural mechanisms process decisions about nicotine that process decisions about money. To address this, we developed a novel MR-compatible nicotine vaping device, such that access to nicotine vapor could be controlled and monitored. We recruited heavy smokers to perform a gambling task with nicotine and monetary reward on separate days. This allowed a direct comparison between the neural mechanisms of choosing and receiving immediate drug vs. monetary reward. We found substantial differences in the neural mechanisms that underlie risky choices about money vs. drug reward, including a reversal of the well-known error effects in the medial prefrontal cortex.

neuroscience↗