Frontopolar Cortex and Motivation in Healthy Older Adults

Causal Role of Frontopolar Cortex for Motivation in Healthy Older Adults: a Transcranial Direct Current Stimulation Study

Motivation represents a core aspect of goal-directed behavior as it determines how much effort individuals are willing to invest to reach their goals. While research on effort-based decision-making focuses mainly on effort preferences in younger adults, loss of motivation might be a key component of the apathetic tendencies frequently seen in older adults. However, an open question refers to which brain mechanisms underlie motivational processes in older adults. The investigators have recently shown that the frontopolar cortex plays a crucial in motivating the exertion of rewarded effort in younger adults. The goal of the current study is to determine whether frontopolar cortex plays a crucial role for motivation also in older adults and may thus be a promising target for improving the motivation deficits in healthy aging. Participants perform computer-based experimental tasks measuring the propensity to exert cognitive or physical effort for monetary rewards. During task performance, participants receive anodal or sham transcranial direct current stimulation (tDCS) over their frontopolar cortex. The study tests whether tDCS over frontopolar cortex allows modulating participants' motivation to engage in rewarded effort.

Study Overview

• Status: Completed
• Conditions: Motivation in Healthy Older Adults
• Intervention / Treatment: Device: transcranial direct current stimulation

Detailed Description

Motivation represents a core aspect of goal-directed behavior as it determines how much effort individuals are willing to invest to reach their goals. While research on effort-based decision-making focuses mainly on effort preferences in younger adults, loss of motivation might be a key component of the apathetic tendencies frequently seen in older adults. However, an open question refers to which brain mechanisms underlie motivational processes in older adults. The investigators have recently shown that the frontopolar cortex plays a crucial in motivating the exertion of rewarded effort in younger adults (Soutschek et al., 2018, Biological Psychiatry). The goal of the current study is to determine whether frontopolar cortex plays a crucial role for motivation also in older adults and may thus be a promising target for improving the motivation deficits in healthy aging. 30 older participants (65-80 years) perform computer-based experimental tasks measuring the propensity to exert cognitive or physical effort for monetary rewards. During task performance, participants receive 1 mA anodal or sham transcranial direct current stimulation (tDCS) over their frontopolar cortex. The study tests whether tDCS over frontopolar cortex allows modulating participants' motivation to engage in rewarded effort.

• Study Type: Interventional
• Enrollment (Actual): 26
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Zürich, Switzerland, 8006
    • University of Zurich

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years to 80 years (OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 65-80 years
• Informed consent as documented by signature
• Normal or corrected-to-normal vision
• Cognitive and language ability to understand study content and procedure
• Normal cognitive functioning (assessed by MMST)
• BDI-II score < 20

Exclusion Criteria:

• Negative response to TMS/tDCS in past
• History of seizure
• History of stroke or heart attack
• History of head injury
• Psychiatric or neurological disorder
• Metal in body/head
• Implanted medical products like pacemaker, medical pumps, heart catheter
• Headache
• Tinnitus
• Currently taking medication affecting the central nervous system
• Insufficient sleep in preceding night
• Excessive consumption of alcohol within last 24 hours

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: anodal transcranial direct current stimulation; anodal transcranial direct current stimulation (current strength: 1 mA, duration: 20 min) over the frontopolar cortex	Device: transcranial direct current stimulation; Participants receive anodal or sham transcranial direct current stimulation while performing effort-based decision tasks.
SHAM_COMPARATOR: sham transcranial direct current stimulation; sham transcranial direct current stimulation (current strength: 1 mA, duration: 0.5 min) over the frontopolar cortex	Device: transcranial direct current stimulation; Participants receive anodal or sham transcranial direct current stimulation while performing effort-based decision tasks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
participants' decisions to exert cognitive or physical effort for monetary rewards	The project seeks to test the causal role of FPC in discounting of cognitive and physical effort in healthy older adults. For that purpose, participants perform a task on a computer which requires the participants to decide whether the participants are willing to exert cognitive or physical effort for a monetary reward. Participants perform this task both under anodal and under sham stimulation. It is tested whether anodal, relative to sham, stimulation increases participants' willingness to engage in rewarded cognitive or physical effort.	All participants perform this decision-making task in both experimental sessions (i.e., both the anodal and the sham stimulation session) for 20 min while receiving anodal or sham stimulation.

Collaborators and Investigators

• Sponsor: University of Zurich
• Investigators: Principal Investigator: Philippe N Tobler, Prof., University of Zurich

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 16, 2018
• Primary Completion (ACTUAL): June 30, 2020
• Study Completion (ACTUAL): June 30, 2020

Study Registration Dates

• First Submitted: June 20, 2017
• First Submitted That Met QC Criteria: June 21, 2017
• First Posted (ACTUAL): June 23, 2017

Study Record Updates

• Last Update Posted (ACTUAL): April 29, 2021
• Last Update Submitted That Met QC Criteria: April 27, 2021
• Last Verified: April 1, 2021

More Information

Terms related to this study

• Other Study ID Numbers: FPC-17-AGING-01

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