Attention, Basic Science: Visual Attention in Healthy Participants
Conditions
Brief summary
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 collect eye-tracking data while participants view visual stimuli made salient based on different combinations of feature dimensions. From the eye-tracking data, the investigators will construct fixation heat maps on the feature dimensions for all levels of salience, allowing them to connect behavioral data to the latter fMRI dataset. Each participant will freely view the stimuli as they appear on the computer display. Across trials, 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.
Interventions
The feature used to define a salient location will be varied across trials (checkerboard contrast; motion direction; color hue)
The magnitude of the salient location will be varied across trials independently from salience-defining feature (based on feature contrast)
Sponsors
University of California, Santa Barbara
National Eye Institute (NEI)
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Masking description
Participants will typically be unaware of the conditions presented, though because these involve manipulations of stimuli or task demands, they may be aware of the manipulation. This is not expected to impact the primary outcome measures (e.g., behavioral performance).
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
* between 18 and 55 years of age * normal or corrected-to-normal vision
Exclusion criteria
* N/A
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Gaze Position - Probability of Fixation at Salient Position | Through study completion, an average of one week | For each condition, we compute the probability that participants instructed to free-view the display fixate the salient location on the screen (reported for highest contrast condition) |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORTommy Sprague
University of California, Santa Barbara
Participant flow
Recruitment details
Participants recruited from local UCSB community via IRB-approved advertisements (flyers; email lists)
Pre-assignment details
Random effects study, so all participants engaged with all conditions
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 20 Participants |
| Sex: Female, Male Female | 16 Participants |
| Sex: Female, Male Male | 4 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 20 |
| other Total, other adverse events | 0 / 20 |
| serious Total, serious adverse events | 0 / 20 |
Outcome results
None listed