Investigating Mediodorsal Thalamus Representations Underlying Human Cognitive Flexibility
Kai Hwang
Summary
The goal of this basic experimental research study is to examine how the human thalamus supports flexible thinking and behavior. Specifically, the research aims to elucidate how the mediodorsal (MD) thalamus encodes and updates "context"-the mental framework that determines which rules or actions are relevant in a given situation. This work may contribute to understanding why certain psychiatric conditions, such as schizophrenia and ADHD, involve difficulties with cognitive flexibility and control. The primary research questions are: Does the MD thalamus represent the context that organizes how working memory guides task selection? Does the MD thalamus signal when context needs to be updated after a change in task demands? Do these thalamic representations support generalization to new situations or rules? Participants will complete cognitive tasks while undergoing high-resolution brain imaging using 7-Tesla MRI. The investigators will combine behavioral data, computational modeling, and advanced neuroimaging analyses to examine how the thalamus interacts with the cortex during flexible decision-making.
Description
The human brain's ability to learn and execute behaviors tailored to environmental contingencies is crucial for adaptive cognition. Central to this capacity are neural representations of context, which organize the associations between sensory features and behavioral utility. Despite their significance, the neural mechanisms underlying the encoding and updating of context representations remain poorly understood. This gap in knowledge is particularly relevant for understanding cognitive deficits in psychiatric disorders such as schizophrenia and ADHD. This research study proposes to test the…
Eligibility
- Age range
- 18–35 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: * No history of any neurological, psychiatric, or medical condition that could affect cognition * No use of benzodiazepines, long-acting opioids, or other psychotropic drugs that could alter cognitive performance * Normal or corrected-to-normal vision (visual acuity) * Normal color perception (Farnsworth-Munsell 100 Hue Test) * Fluent in English * No metal implants (including aneurysm clip, cardiac pacemaker, ICD, IUD, neurostimulation system, spinal cord stimulator, internal electrodes or wires, bone stimulator, ear implant, insulin or other infusion pump or device, prost…
Interventions
- OtherHigh-resolution fMRI during working memory, cognitive control, and decision-making tasks
Participants will perform a set of computerized cognitive tasks designed to test working memory, cognitive control, and decision-making while undergoing high-resolution 7-Tesla functional MRI. These tasks require participants to maintain and update contextual information, switch between rules, and make value-based choices under changing conditions. The intervention is distinguished by its integration of advanced neuroimaging with computational modeling to identify how the mediodorsal thalamus and prefrontal cortex represent, update, and generalize context. This approach allows precise mapping of thalamocortical mechanisms that support flexible cognition and goal-directed behavior.
Location
- The University of IowaIowa City, Iowa