InformationSeekingMesolimbicEngagementStudy2

The Influence of Mesolimbic-hippocampal Interactions on Episodic Memory During Active Information Seeking

Participants will complete a treasure task during neuroimaging where they have to learn which keys open a treasure chest, and then they are tested on the contents of the treasure chest.

Study Overview

• Status: Recruiting
• Conditions: Motivation
• Intervention / Treatment: Behavioral: Task Instructions

Detailed Description

Study 2 will use a treasure task (employed in C.2.1.1), in which participants select amongst 3 keys to learn which feature of keys unlocks the treasure chest, revealing a trial unique object image (Fig. 8b). On each encoding trial participants view three multi-featural keys and a treasure chest. Each key varies on three dimensions: color (red, blue, yellow), shape of the handle (square, circle, triangle), and number of ridges (one, two, three). On each trial, all 9 dimensions of the keys are represented, but the dimensions represented on each key are randomized across trials. During hypothesis testing runs, participants are instructed to find the feature of a key that opens the treasure chest to reveal a trial-unique image. Critically, there is one target feature of a key that deterministically opens the treasure chest. The target feature of the key randomly changes after participants successfully open the chest 4 consecutive times. This design manipulates goal-oriented exploration by allowing participants to resolve uncertainty until they identify the target feature of the key. Uncertainty resolution is the greatest after the target features switches and incrementally reduces via individuals' active hypothesis testing. During control runs, participants will be instructed to select specific keys, and key selection and outcomes will be yolked to prior hypothesis testing runs. Participants will complete 3 runs of hypothesis testing runs and 3 control runs. Trial number for each run is determined by participant behavior, in that hypothesis testing runs end when participants complete 4 rule switches (~30 trials). Encoding is incidental in this task. Following encoding, participants will complete an immediate and delayed item memory test. On each trial, participants will view objects from the hypothesis testing and control conditions as well as new foil objects. Memory will be tested for half the stimuli immediately and at a 24-hour delay. These memory measures will be related to uncertainty resolution estimated by reinforcement learning, to determine how prior knowledge during information seeking has subsequent effects on memory.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Vishnu Murty, PhD; Phone Number: 7406328932; Email: vishnu.murty@temple.edu

Study Locations

• United States
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19122
      • Recruiting
      • Temple University
      • Contact: Vishnu P Murty; Phone Number: 7406328932; Email: vishnu.murty@temple.edu
      • Principal Investigator: Vishnu P Murty, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 20/40 far acuity (either corrected or uncorrected)
• In good medical health

Exclusion Criteria:

• History of head injury
• History of illness with Central Nervous Systems implications
• On Medications that Affect blood flow response and alertness
• Consumption of smoking and/or coffee 30 minutes prior to laboratory testing
• Placement of a device contraindicated for magnetic resonance imaging including cardia pacemaker, aneurysm clip, cochlear implants, pregnancy, intra-uterine device, shrapnel, metal fragments in the eyes, neurostimulators
• Weight > 250lbs
• Claustrophobia

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Motivation; Trials in which participants are motivated by hypothesis testing or not.	Behavioral: Task Instructions; Participants will be given cued instructions as to whether they are in a high or low motivation condition

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mesolimbic Hippocampal Interactions	Functional Magnetic Resonance Imaging Activation characterizing Mesolimbic-Hippocampal Interactions	During Procedure
Episodic Memory	Item and Associative Memory for memoranda shown during the task	24-hours After Procedure

Collaborators and Investigators

• Sponsor: Temple University

Study record dates

Study Major Dates

• Study Start (Actual): October 24, 2023
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: January 31, 2024
• First Submitted That Met QC Criteria: February 12, 2024
• First Posted (Actual): February 14, 2024

Study Record Updates

• Last Update Posted (Estimated): September 5, 2025
• Last Update Submitted That Met QC Criteria: August 28, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: R01DA055259-2; R01DA055259 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Deidentified data will be shared on the open science framework.
• IPD Sharing Time Frame: Data will be shared within 1 year of study completion, and it will be available for at least 10 years.
• 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
• product manufactured in and exported from the U.S.: No