fMRI Analysis of Aging and Awareness in Conditioning

Functional Magnetic Resonance Imaging (fMRI) Analysis of Aging and Awareness in Conditioning

Cathodal Transcranial direct current stimulation (tDCS) was administered to the right parietal region in order to determine if this stimulation could disrupt awareness of the conditioned stimulus (CS) - unconditioned stimulus (US) relationship in a classical conditioning experiment.

Study Overview

• Status: Active, not recruiting
• Conditions: Transcranial Direct Current Stimulation
• Intervention / Treatment: Device: sham transcranial direct current stimulation; Device: transcranial direct current stimulation

• Study Type: Interventional
• Enrollment (Estimated): 16
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 30 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Educational attainment of at least eight years and English as the native language
• Mini-Mental State Examination (MMSE) score of 26
• Normal episodic memory (i.e., CERAD word List Recall > 5)
• Informed consent; 5) age of 20-30

Exclusion Criteria:

• Disturbed consciousness
• Other neurological or systemic disorder which can cause dementia or cognitive dysfunction
• Prior history of a major psychiatric disorder
• History of definite stroke
• Focal lesion on MRI exam
• Use of anxiolytic, antidepressant, neuroleptic, or sedative medication
• Predominately left-handed
• Has MRI contraindication such as pacemaker, implanted pumps, shrapnel, etc. (full MRI screening form will be filled out).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: sham tDCS; tDCS delivered for only 30 sec to replicate tingling sensation and blind subject	Device: sham transcranial direct current stimulation; transcranial direct current stimulation applied at 2 mA over the right parietal region for 30 sec
Experimental: cathodal tDCS; cathodal tDCS, 2 milliamps (mA), delivered to right parietal region	Device: transcranial direct current stimulation; transcranial direct current stimulation applied at 2 mA over the right parietal region for 20 min

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
CS-US Awareness	To assess CS-US awareness, we used a questionnaire The questionnaire consists of 7 true/false questions about the sequence and co-occurrence of the conditioned stimulus (CS, a 1000 Hz tone) and unconditioned stimulus (US, a 100 ms puff of air to the eye). The score can thus range from 0 to 7. Higher score values indicate better awareness of the sequence and co-occurrence of the CS and US	recorded immediately after the 20 minutes of tDCS stimulation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Line bisection test of left-hemifield neglect	The subject is given a sheet of paper with a number of horizontal lines on it. The subject is instructed to cut each line in half by drawing a small pencil mark through each line. The test is scored by measuring the percent deviation, which is calculated by the following formula: Percent deviation=100 x (measured left half - true half)/true half This yields positive numbers for marks placed to the right of center, and negative numbers for marks placed to the left of center. Patients with right hemisphere damage and contralateral neglect show higher positive line bisection scores compared to healthy controls or patients without right hemisphere damage and vice versa.	recorded immediately after primary awareness questionnaire
Eyeblink conditioned responding	Eyeblink conditioning is recorded while the subject watches a silent movie. For conditioning, the conditioned stimulus (CS) is a 1350 ms 1000 Hz tone. This tone co-terminates with a 100 ms left corneal airpuff (5 psi). 30 CS-US presentations are delivered at an average rate of one every 18 sec. Conditioned responses (CRs) are defined as follows: the difference between the maximum and minimum responses in a 500 ms pre-US time window must exceed four times the standard deviation of the mean of the baseline period (250 ms pre-CS presentation). The 500 ms pre-US time window was selected to minimize the inclusion of voluntary and alpha responses as CRs. Performance is expressed as % CRs, that is, the percent of trials in which a CR occurred. Greater numbers indicate greater amounts of learning.	recorded during the tDCS administration

Collaborators and Investigators

• Sponsor: Johns Hopkins University
• Collaborators: National Institute on Aging (NIA)
• Investigators: Principal Investigator: John Desmond, Johns Hopkins University

Study record dates

Study Major Dates

• Study Start (Actual): November 9, 2010
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: August 30, 2018
• First Submitted That Met QC Criteria: August 30, 2018
• First Posted (Actual): August 31, 2018

Study Record Updates

• Last Update Posted (Actual): December 11, 2025
• Last Update Submitted That Met QC Criteria: December 4, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Therapeutics; Behavioral Disciplines and Activities; Electric Stimulation Therapy; Convulsive Therapy; Psychiatric Somatic Therapies; Electroshock; Psychological Techniques; Transcranial Direct Current Stimulation
• Other Study ID Numbers: NA_00045404; R01AG021501 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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