Probing the Role of Feature Dimension Maps in Visual Cognition: Impact of Task Demands and Spatial Attention (Expt 2.2)

Part of paid clinical trials in Santa Barbara, California.

Sponsor
University of California, Santa Barbara
Study ID
NCT07572630
Status
Enrolling By Invitation

Conditions

  • Basic Science: Neural Representations of Location
  • Basic Science: Visual Attention in Healthy Participants

Eligibility Criteria

Sex
ALL
Age
18 Years - 55 Years
Healthy Volunteers
Accepted

Interventions

  • Stimulus properties: task-defining feature — OTHER
    The feature used to determine which stimulus feature to attend to will be varied across trials using a letter cue (M = motion-attend, C = color-attend, F = fixation-attend)

Study Details

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 either a single stimulus presented in the periphery, which are identical across trial types, or multiple simultaneously-presented stimuli. Across trials the investigators will manipulate the attended feature value (color, motion, or fixation point) and number of attended stimuli (attend 1 stimulus, attend 2 stimuli). These manipulations will help the investigators fully understand these critical relevance computations in the healthy human visual system.

Key Dates

Start date
Jan 22, 2026
Status verified
May 2026
Primary completion
Sep 15, 2026
Completion
Sep 15, 2026

Study Design

Enrollment
12 participants (estimated)
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE

Arms

  • Experimental: Manipulations of task demands and attended location(s) (Expt 2.2)
    Participants will view one or two peripheral stimuli containing dots moving in one of two directions (clock-wise or counterclockwise) and drawn in one of two colors (orange and cyan). A cue at fixation will indicate the relevant feature and stimulus/stimuli for task completion

Primary Outcome Measure

Strength of stimulus representation quantified by map activation at stimulus location(s) derived from multivariate analysis of functional MRI data [ Time Frame: During each fMRI scanning session throughout enrollment (sessions will be scheduled to occur within 1-2 weeks of enrollment). ]

Locations (1)

FacilityCityStateZIPSite coordinators
University of California, Santa BarbaraSanta BarbaraCalifornia93117-

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University of California, Santa Barbara· Santa Barbara, CA

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