Systematic Psychophysical (Visuallearning)

Systematic Psychophysical Investigation of Visual Learning

The purpose of this study is to investigate how our performance changes after our perceptual system is trained in a certain way ("perceptual learning"). In addition, investigators are interested in identifying and characterizing relationships between such changes and neuroimaging signals recorded from the human brain.

Study Overview

• Status: Recruiting
• Conditions: Perceptual Learning
• Intervention / Treatment: Behavioral: Visual Training

Detailed Description

The long-term goal of the proposed project is to elucidate the underlying mechanisms of visual perceptual learning (VPL) for artificial and natural stimuli, which will be instrumental in developing rehabilitation programs aimed at enhancing damaged or deteriorating vision. The specificity of VPL to the feature and location of the trained visual stimulus is a fundamental characteristic of VPL. To investigate the specificity, one effective way is to use an artificial stimulus such as a Gabor patch as the trained stimulus, as it has been widely used to investigate basic visual processing. Simultaneously, to create an impactful rehabilitation program, the resulting improvements must be generalized to untrained features and locations in visual stimuli encountered in everyday life, including natural scenes (NS). However, it remains uncertain whether the same mechanisms underlie the generalization and specificity in VPL for artificial and NS stimuli. In Specific Aim (SA) 1, investigators aim to examine basic mechanism of the specificity using a Gabor patch. According to a prevailing theory, early visual processing (e.g., 0 to 150ms after the stimulus onset) primarily involves input-level feedforward signals. In contrast, late processing (e.g.,150-300ms after the stimulus onset) involves recurrent processing. To better understand the mechanism of the specificity of VPL it is crucial to clarify whether early or late processing is involved. Additionally, it remains unclear whether the specificity of VPL involves excitation on the trained feature and location or inhibition on untrained features and locations. Therefore, investigators will test Hypothesis 1 (H1): Late processing (H1-a) or early processing (H1-b) plays a role in the specificity of VPL, and H2: Excitatory signals (H2-a) or inhibitory signals (H2-b) are involved in inducing the specificity of VPL. investigators will employ two methods. The backward masking (BM) is used to disrupts and reveal roles of late processing. In preliminary results, BM applied to the trained orientation eliminated the orientation specificity in VPL, supporting H1-a. A Rhythmic Synchronization Orientation Decoding Change (RSDC) method is a novel method that examines at which band(s) of rhythmic synchronization from electroencephalogram (EEG) the decoding performances of trained and untrained features and locations change after VPL training. Preliminary results suggest that trained orientation signals are enhanced at both trained and untrained locations during early processing, while those at untrained locations are inhibited during late processing, leading to the location specificity. In SA2, investigators will examine the specificity and generalizability of VPL for NS. Our first step is to test H3: VPL for the dominant orientation in NS is specific (H3-a) or generalized (H3-b) to other orientations. Preliminary results support H3-b. If true, investigators will further investigate the aspects in NS that induce the generalization of VPL. Preliminary result suggests that higher-order statistics, involving correlations between different orientation and spatial frequency channels derived from NS, play a role in the generalization of VPL for NS. Investigators further aim to test H1 and H2 for NS images, using both the BM and RSDC methods.

• Study Type: Interventional
• Enrollment (Estimated): 400
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Research Assistant; Phone Number: 401-863-5186; Email: akiko_norton@brown.edu
• Study Contact Backup: Name: Takeo Watanabe; Phone Number: 401-863-6916; Email: takeo_watanabe@brown.edu

Study Locations

• United States
  • Rhode Island
    • Providence, Rhode Island, United States, 02912
      • Recruiting
      • Brown University
      • Contact: Academic Department Manager; Phone Number: 401-863-2702; Email: reinette_sousa@brown.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Ages 18 - 60,
• Normal or corrected-to-normal vision

Exclusion Criteria:

• Eye disorders (cataracts, age related macular degeneration, diabetic retinopathy, glaucoma)
• Drug use (psychoactive drugs, neuroleptic medications, prescription medications that might affect cognitive and motor performance)
• Sleep disorders (sleep apnea, insomnia)
• Magnetically or mechanically activated implants (such as cardiac pacemakers)
• clips on blood vessels in the brain
• intrauterine devices
• dentures
• pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Parallel Assignment
• Masking: Single

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Behavioral measure	Changes in rates of correct detection or discrimination in behavioral visual tasks after training are measured.	From enrollment to the end of treatment at 2 weeks.

Collaborators and Investigators

• Sponsor: Brown University
• Collaborators: National Eye Institute (NEI)

Study record dates

Study Major Dates

• Study Start (Actual): July 22, 2025
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): January 1, 2029

Study Registration Dates

• First Submitted: May 2, 2025
• First Submitted That Met QC Criteria: May 2, 2025
• First Posted (Actual): May 11, 2025

Study Record Updates

• Last Update Posted (Actual): November 19, 2025
• Last Update Submitted That Met QC Criteria: November 17, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Behavioral
• Additional Relevant MeSH Terms: Behavior
• Other Study ID Numbers: 1203000582-02; R01EY019466 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The types of data to be produced in the current project will be behavioral data and participants' demographic information will also be collected. All data will be de-identified before receipt by the repository. Programs for visual stimuli and data analyses will be produced in the project.
• IPD Sharing Supporting Information Type: ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No