Imaging During Subliminal Perception

Completed

• Conditions: Healthy
• Interventions: Other: real-time fMRI

• Registration Number: NCT04643340
• Lead Sponsor: University of Zurich

Brief Summary

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.

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 Timeline

• Study Start: 2020-03-15
• Study First Submitted: 2020-11-16
• Study First Submitted QC: 2020-11-24
• Study First Posted: 2020-11-25
• Primary Completion: 2021-12-01
• Study Completion: 2022-12-01
• Status Verified: 2023-06
• Last Update Submitted: 2023-06-12
• Last Update Posted: 2023-06-13

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 70

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 & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
active group 1	real-time fMRI	This group will train the insular cortex by real-time fMRI
active group 2	real-time fMRI	This group will train the visual cortex by real-time fMRI

Primary Outcome Measures

Name	Time	Method
fMRI during supra-threshold and subliminal perception	2020 - 2022
rt-fMRI activity	2020 - 2022	rt-fMRI activity: fMRI signal changes during repetitive real time fMRI based training

Secondary Outcome Measures

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

Trial Locations

Locations (1)

University of Zurich; 🇨🇭 Zürich, Switzerland