Probing the Role of Feature Dimension Maps in Visual Cognition: Impact of Salience Level (Expt 1.1)
Completed · Not applicable
Conditions studied: Basic Science: Visual Attention in Healthy Participants, Basic Science: Neural Representations of Location, Attention
In brief
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 extract 'feature dimension maps' based on stimulus properties, including feature contrast. The investigators hypothesize that feature-selective brain regions act as neural feature dimension maps, and thus encode representations of salient location(s) based on their preferred feature dimension. The investigators will scan healthy human participants using functional MRI (fMRI) in a repeated-measures design while they view visual stimuli made salient based on different combinations of feature dimensions. 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 task at the center of the screen to ensure they keep their eyes still and ignore the stimuli presented in the periphery, which are used to gauge how the visual system automatically extracts important locations without confounding factors like eye movements. Across trials and experiments the investigators will manipulate 1) the 'strength' of the salient locations based on how different the salient stimulus is compared to the background, 2) the number of salient locations, and 3) the feature value(s) used to make each location salient. Altogether, these manipulations will help the investigators fully understand these critical salience computations in the healthy human visual system.
Key facts
- Study ID
- NCT06175312
- Run by
- University of California, Santa Barbara
- People needed
- 10
- Starts
- 2024-04-25
- Expected to finish
- 2025-01-31
- Last updated by the study team
- 2025-05-23
Who can join
Age: 18 and older, up to 55. Sex: any. Healthy volunteers: accepted.
You may qualify if…
- between 18 and 55 years of age
- normal or corrected-to-normal vision
You may not qualify if…
- neurological disease based on self-report
- implanted medical devices (e.g., cardiac pacemaker; metallic aneurism clip)
- non-removable metallic piercings
- metal fragments in the body (e.g., from welding)
- pregnant and have a chance of being pregnant (if female)
- history of claustrophobia
- history of hearing loss/damage
Where it is running
- University of California, Santa Barbara — Santa Barbara, California, United States
Full record on ClinicalTrials.gov
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