Imaging During Subliminal Perception

Functional Imaging During Subliminal Perception

Subliminal perception of visual stimuli can be studied with functional brain imaging, e.g. with functional magnetic resonance imaging (fMRI). However, it is unclear how subliminal perception affects connectivity in the brain.

Further, it is not known if real-time (rt) fMRI neurofeedback of brain areas involved in subliminal perception can lead to supra-threshold perception.

For attention tasks, the investigators hypothesize that functional connectivity strength is mediated by the insular cortex during both supra-threshold and subliminal perception.

Additionally, the investigators hypothesize that rt-fMRI neurofeedback training should alter neuronal and behavioral responses.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Other: real-time fMRI

Detailed Description

In this project, using healthy adults, the investigators have 2 aims:

1. Apply electroencephalography (EEG) and fMRI before and after rt-fMRI neurofeedback during attention tasks to identify brain regions involved in subliminal and supraliminal perception.
2. Apply functional connectivity analyses during these tasks.

• Study Type: Observational
• Enrollment (Actual): 70

Contacts and Locations

Study Locations

• Switzerland
  • Zürich, Switzerland
    • University of Zurich

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Healthy adults

Description

Inclusion Criteria:

• Healthy adults (> 18 < 80 years), which can read and sign the informed consent form
• Male and female
• Right-handed

Exclusion Criteria:

• metallic items in the body (i.e. eye splinter, MR incompatible implants)
• pacemaker
• claustrophobia
• pregnant participants
• participants suffering from a degenerative disorder of the Central Nervous System, such as Stroke, Multiple Sclerosis, Parkinson's Disease, Alzheimer's Disease and Huntington's Disease and with major psychiatric disorders such as schizophrenia, depression, or anxiety disorder
• Drug intake (psychopharmaca)

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
active group 1; This group will train the insular cortex by real-time fMRI	Other: real-time fMRI; Brain regions can be trained, i.e. fMRI activity can be actively modulated online by humans, using rt-fMRI (Bruhl, Scherpiet et al. 2014, Bruhl 2015, Emmert, Kopel et al. 2016).
active group 2; This group will train the visual cortex by real-time fMRI	Other: real-time fMRI; Brain regions can be trained, i.e. fMRI activity can be actively modulated online by humans, using rt-fMRI (Bruhl, Scherpiet et al. 2014, Bruhl 2015, Emmert, Kopel et al. 2016).
sham; This group will only train the insula by a particular strategy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
fMRI during supra-threshold and subliminal perception		2020 - 2022
rt-fMRI activity	rt-fMRI activity: fMRI signal changes during repetitive real time fMRI based training	2020 - 2022

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional connectivity	Examination of fMRI signal dependencies (coherence) between brain regions.	2020 - 2022
EEG activity	EEG activity: Event related potentials and spectral band power for different trial types	2020 - 2022
fMRI task performance	Reaction time and accuracy	2020 - 2022

Collaborators and Investigators

• Sponsor: University of Zurich
• Collaborators: Swiss National Science Foundation
• Investigators: Principal Investigator: Lars Michels, PhD, University Hospital, Zürich

Publications and helpful links

Helpful Links

• SNF database

Study record dates

Study Major Dates

• Study Start (Actual): March 15, 2020
• Primary Completion (Actual): December 1, 2021
• Study Completion (Actual): December 1, 2022

Study Registration Dates

• First Submitted: November 16, 2020
• First Submitted That Met QC Criteria: November 24, 2020
• First Posted (Actual): November 25, 2020

Study Record Updates

• Last Update Posted (Actual): June 13, 2023
• Last Update Submitted That Met QC Criteria: June 12, 2023
• Last Verified: June 1, 2023

More Information

Terms related to this study

• Keywords: neurofeedback; functional MRI; EEG; attention; subliminal perception
• Other Study ID Numbers: 2017-00483

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Raw imaging data can be shared with other groups (outside of the USZ), e.g. for replication purpose.

Drug and device information, study documents

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