Visual Features for Neural Representations of Location

Overseen By Emily Machniak

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: University of California, Santa Barbara

Disqualifiers: Neurological disease, Implanted devices, Pregnancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 3

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how the brain identifies important features in a scene, such as color or motion, to focus attention. Researchers use brain scans (fMRI) to observe how different brain areas respond when participants view visual stimuli, like moving colored dots, and perform tasks based on these features. The goal is to understand how the brain's feature maps process visual information and guide attention. Individuals with normal or corrected-to-normal vision and no history of neurological disease are suitable for this trial. As an unphased trial, this study allows participants to contribute to foundational research that enhances understanding of visual processing and attention.

Do I need to stop my current medications for this trial?

The trial information does not specify whether you need to stop taking your current medications.

What prior data suggests that this protocol is safe?

Research has shown that certain parts of the brain help focus on different parts of a scene by recognizing features like color and movement. These brain areas create maps to highlight important spots based on these features.

Regarding safety, the study involves viewing visual images while undergoing a brain scan using fMRI, a type of imaging. No negative effects have been reported from this process, as fMRI is non-invasive and generally easy for participants to handle.

For those considering joining this study, the procedures are safe and have been used in similar research without major issues. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores how visual features like color and motion direction can influence our brain's representation of location. Unlike standard cognitive tasks that focus on static imagery or sole color differentiation, this study manipulates task demands using dynamic stimuli—dots moving in specific directions and colored differently. By altering cues at fixation, researchers aim to uncover how these visual properties affect cognitive processing, potentially opening new avenues for enhancing spatial awareness and decision-making in complex environments.

What evidence suggests that this trial's treatments could be effective?

Research shows that different brain regions specialize in perceiving various elements, such as color and movement. These regions create 'maps' that help the brain focus on important scene details. Studies have found that these areas become more active depending on the task. For example, when focusing on color, the brain areas responsible for color perception work harder. This adaptability allows the brain to adjust to different visual tasks by concentrating on key details. These findings could enhance understanding of how the brain processes complex visual scenes and directs attention.

In this trial, participants will encounter manipulations of task demands, such as viewing a single stimulus with dots moving in different directions and colors, to study how these visual features influence neural representations of location. ^{6 7 8 9 10}

Who Is on the Research Team?

Tommy C Sprague

Principal Investigator

University of California, Santa Barbara

Are You a Good Fit for This Trial?

This trial is for healthy individuals interested in how the brain processes visual information. Participants should be willing to undergo fMRI scans and perform visual tasks that involve discriminating colors or motion of stimuli. Specific eligibility criteria are not provided, but typically participants would need to have no contraindications to fMRI.

Inclusion Criteria

My vision is normal or corrected to normal with glasses or contacts.

Exclusion Criteria

Non-removable metallic piercings

Pregnant or have a chance of being pregnant (if female)

Implanted medical devices (e.g., cardiac pacemaker; metallic aneurism clip)

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Anatomical & Retinotopic Mapping

Participants undergo anatomical and retinotopic mapping to identify brain regions for further analysis

2 hours

1 visit (in-person)

Experimental fMRI Sessions

Participants engage in visual attention tasks during fMRI scanning to study feature dimension maps

3-4 hours

2 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after the experimental sessions

2 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Stimulus properties: task-defining feature

Trial Overview The study examines how certain brain regions process and prioritize visual features like color or motion when performing a task. Using advanced imaging (fMRI) and analysis techniques, researchers will track how these regions create 'feature dimension maps' that guide attention in complex scenes.

How Is the Trial Designed?

Group I: Manipulations of task demands (Expt 2.1) Experimental Treatment 1 Intervention

Participants will view a single stimulus containing dots moving in one of two directions (clock-wise or counterclockwise) and drawn in one of two colors (orange and cyan). To complete the correct task for a trial, a cue at fixation will be manipulated.

Who Is Running the Clinical Trial?

University of California, Santa Barbara

Lead Sponsor

Trials

33

Recruited

3,100+

National Eye Institute (NEI)

Collaborator

Trials

572

Recruited

1,320,000+

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/39829822/

ATTENTION MODULATES STIMULUS REPRESENTATIONS ... These results suggest feature-selective cortical regions support 'neural feature dimension maps': spatial maps of different visual features that ...

2. elifesciences.org elifesciences.org/reviewed-preprints/107356

Task structure tailors the geometry of neural ... eLife Assessment. This study presents a valuable finding on the representational structure of task encoding in the prefrontal cortex.

3. sciencedirect.com sciencedirect.com/science/article/pii/S0896627325004386

Representations of stimulus features in the ventral ... Discriminating and categorizing the meaning of environmental stimuli and responding accordingly are essential for survival.

4. nature.com nature.com/articles/s41467-024-54336-5

The neural link between stimulus duration and spatial ... We investigated how and where the processing and the representation of a visual stimulus duration is linked to that of its spatial location.

5. biorxiv.org biorxiv.org/content/10.1101/2025.01.10.632497v1.full

Attention Modulates Stimulus Representations in Neural ... This analysis determined how task demands and feature selectivity uniquely modulated responses between regions at each location. Next, we ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/40644362/

Attention Modulates Stimulus Representations in Neural ... These results suggest feature-selective cortical regions support "neural feature dimension maps": spatial maps of different visual features ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7241310/

Learning task-state representations - PMC In this Perspective, we summarize our recent research into the computational and neural underpinnings of “representation learning” — how humans (and other ...

8. jneurosci.org jneurosci.org/content/43/2/282

Lingering Neural Representations of Past Task Features ... The formation of conjunctive representations of specific task contexts, stimuli, and actions in the brain can indeed adversely affect future behavior.

9. sciencedirect.com sciencedirect.com/science/article/pii/S0042698924001834

Task-modulated neural responses in scene-selective ... We performed a model-based RSA defining responses to each stimulus under each task as separate conditions to examine the activity patterns in scene ...

10. nature.com nature.com/articles/s41467-023-38709-w

Task state representations in vmPFC mediate relevant and ... We show that multivariate vmPFC signals contain a rich representation that includes the current task state or context (motion/color), the associated expected ...