NCT06281457

Probing the Role of Feature Dimension Maps in Visual Cognition: Impact of Task Demands (Expt 2.1)

ENROLLING BY INVITATION NA Last updated 21 August 2024

What this trial tests

NA trial testing Stimulus properties: task-defining feature in Basic Science: Visual Attention in Healthy Participants in 10 participants. Enrolling by invitation.

Timeline

1 April 2024

Primary endpoint
31 December 2024

30 June 2025

Quick facts

Lead sponsor	University of California, Santa Barbara
Phase	NA
Status	ENROLLING BY INVITATION
Study type	INTERVENTIONAL
Allocation	na
Design	single group
Masking	none
Primary purpose	basic science
Enrollment	10
Start date	1 April 2024
Primary completion	31 December 2024
Estimated completion	30 June 2025
Sites	1 location across United States

Drugs / interventions tested

• Stimulus properties: task-defining feature

Conditions studied

• Basic Science: Visual Attention in Healthy Participants — all drugs for Basic Science: Visual Attention in Healthy Participants →
• Basic Science: Neural Representations of Location — all drugs for Basic Science: Neural Representations of Location →

Sponsor

University of California, Santa Barbara

Who can join

Adults 18 to 55, any sex, with Basic Science: Visual Attention in Healthy Participants or Basic Science: Neural Representations of Location. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

How does one know what to look at in a scene? Imagine a "Where's Waldo" game - it's challenging to find Waldo because there are many 'salient' locations in the picture, each vying for one's attention. One can only attend to a small location on the picture at a given moment, so to find Waldo, one needs to direct their attention to different locations. One prominent theory about how one accomplishes this claims that important locations are identified based on distinct feature types (for example, motion or color), with locations most unique compared to the background most likely to be attended. An important component of this theory is that individual feature dimensions (again, color or motion) are computed within their own 'feature maps', which are thought to be implemented in specific brain regions. However, whether and how specific brain regions contribute to these feature maps remains unknown.

The goal of this study is to determine how brain regions that respond strongly to different feature types (color and motion) and which encode spatial locations of visual stimuli transform 'feature dimension maps' based on stimulus properties as a function of task instructions. The investigators hypothesize that feature-selective brain regions act as neural feature dimension maps, and thus encode representations of relevant location(s) based on their preferred feature dimension, such that the stimulus representation in the most relevant feature map is up-regulated to support adaptive behavior. The investigators will scan healthy human participants using functional MRI (fMRI) in a repeated-measures design while they view visual stimuli made relevant based on a cued feature dimension (e.g., color or motion). The investigators will employ state-of-the-art multivariate analysis techniques that allow them to reconstruct an 'image' of the stimulus representation encoded by each brain region to dissect how neural tissue identifies salient locations. Each participant will perform a challenging discrimination task based on the cued feature (report motion direction or color of stimulus dots) of a stimulus presented in the periphery, which are identical across trial types. Across trials the investigators will manipulate the attended feature value (color, motion, or fixation point). This manipulation will help the investigators fully understand these critical relevance computations in the healthy human visual system.

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

1. Attention Modulates Stimulus Representations in Neural Feature Dimension Maps.
   Thayer DD, Sprague TC. · · 2025 · PMID 40644362 · DOI 10.1162/jocn.a.74