NCT07217652 · Kai Hwang
Investigating Mediodorsal Thalamus Representations Underlying Human Cognitive Flexibility
What this study is about
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.
View original scientific description
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.
Interventions
OTHER
High-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.
Primary outcome measures
Decoding of context representations in the medial dorsal thalamus from 7 T MRI data
Time frame: Measured throughout the MRI session (approximately 90 minutes per participant).
This outcome measure will quantify the extent to which multivariate patterns of brain activity in the MD thalamus encode task context. High-resolution 7-Tesla fMRI data will be analyzed using computational modeling and multivariate pattern analysis (MVPA) techniques. The primary metric will be decoding accuracy, expressed as a percentage ranging from 0% to 100%. Decoding accuracy reflects how well task contexts for working memory, cognitive control, and decision-making can be predicted from MD thalamic activity patterns. A value of 0% indicates chance-level or poor performance, while 100% indicates perfect prediction accuracy. For each participant, decoding accuracy will be computed as a single value using the same unit of measure (percentage accuracy). This value will reflect the overall ability to decode task context from MD activity and thus serves as the primary measure of this research study.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
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, prosthesis, artificial or prosthetic limb, shunt, vascular access port or catheter, thermodilution catheter, medication patch, radiation seeds or implants, wire mesh implant, tissue expander, surgical staples or clips or sutures, joint replacement, joint/bone pin/screw/nail/wire/plate, dentures, or non-removable hearing aid)
- No exposure to shrapnel or other-related MR contraindications
- No non-removable body piercing jewelry
- No non-removable makeup
- No history of claustrophobia
- No history of breathing problems
- Not currently pregnant or trying to get pregnant (this will be determined via self report and no records will be kept).
Exclusion criteria
- Has a history of any neurological, psychiatric, or medical condition that could affect cognition
- Use of benzodiazepines, long-acting opioids, or other psychotropic drugs that could alter cognitive performance
- Not fluent in English
- Known 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, prosthesis, artificial or prosthetic limb, shunt, vascular access port or catheter, thermodilution catheter, medication patch, radiation seeds or implants, wire mesh implant, tissue expander, surgical staples or clips or sutures, joint replacement, joint/bone pin/screw/nail/wire/plate, dentures, or non-removable hearing aid)
- History of claustrophobia
- Currently pregnant or trying to get pregnant (this will be determined via self report and no records will be kept).
Where
- Iowa City, Iowa
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 13, 2026 · Source of record for eligibility and locations