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Healthy VolunteerNEURO-ISNCT07885020

NEURO-IS: Neurophysiology of Inner Speech Across Neurotypical Participants.

A study testing Inner Experience Induction Tasks and hdEEG in people with Healthy Volunteer, run by University of Liege at 1 site in Belgium.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

The purpose of this study is to investigate the brain activity associated with two common inner experiences: visual mental imagery (mentally seeing objects or actions) and inner speech (experiencing language without speaking out loud). Read more about this study

Who is it for?
Ages 18 to 70 yearsHealthy volunteers can take part
Conditions the study is for
Healthy Volunteer
What is being tested?
Inner Experience Induction Tasks and hdEEG
Could I receive a placebo?
No, everyone receives an active treatment
How many people
35 participants
Where
1 siteBelgium
Study dates
5 Oct 2026to 31 Oct 2027
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 70 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Be aged 18 to 70.
  • Have French as a native language.

Who cannot join

  • Presence of a neurological or psychiatric disorder.
  • Presence of an uncorrected sensory deficit.
  • Use of medications acting on the central nervous system.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Olivia Gosseries, PhD contact

+32 4 323 36 14

ogosseries@uliege.be

Anaïs Gillet, Master contact

+32 4 323 36 14

agillet@uliege.be

Belgium1 site, 1 recruiting
  • Université de Liège - GIGA Institute (Coma Science Group)

    Liège, Wallonia, 4020

    Olivia Gosseries, PhD, +32 4 323 36 14, ogosseries@uliege.be

    Anaïs Gillet, Master, +32 4 323 36 14, agillet@uliege.be

    Recruiting

Other trials in Belgium

About this study

Official title: Tracking Inner Experiences: Neuronal and Behavioral Perspectives in Conscious Neurotypical Participants.

The purpose of this study is to investigate the brain activity associated with two common inner experiences: visual mental imagery (mentally seeing objects or actions) and inner speech (experiencing language without speaking out loud). Researchers aim to identify the most effective tasks to generate robust and detectable brain signals (EEG biomarkers) for these experiences in healthy adults. Participants will complete questionnaires and perform specific mental tasks, such as silently repeating words or imagining movements and faces, while their brain activity is recorded using high-density electroencephalography (hdEEG). These tasks will be compared to resting and passive listening conditions to better understand the relationship between inner experiences, self-awareness, and neurophysiology.

Read the detailed description

Background and scientific rationale :

The most frequently reported subjective experiences in the general population are visual mental imagery (VMI) and inner speech (IS). VMI refers to the ability to mentally "see" objects or actions in their physical absence, while IS is defined as the subjective experience of language without overt articulation. IS presents several phenomenological aspects, such as condensation, evaluative aspects, dialogic properties, and the involvement of others. It has been associated with high-level consciousness, self-reflection, and metacognition. Previous studies have identified EEG biomarkers reflecting the induction of both IS (e.g., N400, theta, beta, and gamma bands) and VMI (e.g., alpha band desynchronization, anterior negativity). The primary objective of this study is to determine which neurophysiological biomarkers resulting from the induction of these inner experience tasks are the most robust.

Study hypotheses :

The research is driven by three main hypotheses:

  1. Mentally reciting a word will provide robust EEG biomarkers of IS (stable modulations in the beta and gamma bands), particularly in comparison with the passive listening of that same word.
  2. A lower reflective consciousness will be associated with an overall reduction in the use of IS.
  3. The condensation dimension of IS will be negatively correlated with reflective consciousness, whereas the dialogic dimension will be positively associated with levels of reflective consciousness.

General experimental plan :

The study will enroll neurotypical conscious adult participants. The experimental session involves both behavioral and neurophysiological assessments. First, participants will complete validated questionnaires evaluating self-consciousness and inner experiences, including the Short French Meta-Cognitions Questionnaire (MCQ-30), the Rumination-Reflection Questionnaire (RRQ), the Varieties of Inner Speech Questionnaire-Revised (VISQ-R), and the Vividness of Visual Imagery Questionnaire (VVIQ).

Following a training phase, participants will undergo high-density electroencephalography (hdEEG) recording during resting state and experimental tasks. The paradigms consist of four mental imagery conditions:

  • IS (auditory presentation): Mentally repeating a word heard orally.
  • IS (visual presentation): Mentally repeating a written word presented on a screen.
  • VMI (hand movement): Mentally visualizing opening and closing the right hand.
  • VMI (face imagery): Mentally visualizing a face. These tasks are designed to isolate specific cognitive constraints, with strictly controlled trials composed of a stimulus presentation followed by an action phase. A 5 minute passive listening period of an audio story comprising the target words will serve as a control condition to capture baseline electrophysiological activity during passive semantic processing.

After each main task block, participants will retrospectively evaluate their subjective experiences using visual analog scales (VAS) to assess task success, modality used, generated content, perceived difficulty, and modality mixing.

Data analyses will investigate behavioral measures and neurophysiological signatures (such as beta and gamma bands for IS, and alpha band for VMI) using standard statistical approaches. In an exploratory approach, a deep learning model based on a Convolutional Neural Network (CNN) will also be tested to classify EEG signals reflecting IS or VMI.

Clinical perspectives :

The investigation of these inner experiences and their biomarkers opens long-term clinical applications. For patients with aphasia, these tools could help determine if IS is preserved despite the loss of overt speech, and explore its potential impact on anosognosia. Additionally, for patients with disorders of consciousness, these neurophysiological tools could offer the opportunity to investigate "hidden cognition", ultimately contributing to reducing clinical diagnostic errors.

Being tested
Inner Experience Induction Tasks and hdEEG
Keywords
Inner Speech, Visual Mental Imagery, Electroencephalography, Metacognition, Inner Experiences

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Inner Experience Induction Tasks and hdEEGBehavioural

    The intervention consists of performing specific mental tasks to induce inner speech (mentally repeating heard or read words) and visual mental imagery (mentally visualizing a hand movement or a loved one's face). These tasks are performed while high-density EEG (hdEEG) is recorded. The protocol also includes a resting state period, a passive listening control condition, and the completion of psychological questionnaires (MCQ-30, RRQ, VISQ-R, VVIQ).

Study groups in NCT07885020
Study groupRoleWhat they receive
Healthy VolunteersExperimentalParticipants undergo a single experimental session. They first complete behavioral questionnaires evaluating self-consciousness and inner experiences (MCQ-30, RRQ, VISQ-R, VVIQ). Following a training phase, their brain activity is recorded using high-density electroencephalography (hdEEG). During the EEG recording, they perform cognitive tasks designed to induce inner speech (auditory and visual presentation of words) and visual mental imagery (imagining hand movements and familiar faces). Resting state and passive listening conditions are also recorded as baselines. Finally, they evaluate their subjective experience using visual analog scales.
Receives: Behavioral: Inner Experience Induction Tasks and hdEEG

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Modulation of EEG spectral power (Alpha, Beta, and Gamma bands)

    The primary evaluation relies on the analysis of high-density EEG signals in response to the induction of inner experiences. Specifically, the analysis will focus on identifying the most robust paradigms by examining specific EEG characteristics: modulation in the beta and gamma frequency bands for Inner Speech (IS), and alpha band desynchronization for Visual Mental Imagery (VMI). The goal is to identify the most appropriate and effective tasks to generate these detectable biomarkers.

    Measured: Day 1

Secondary outcomes (2)
  1. Difference in EEG biomarkers between passive listening and active mental repetition

    Investigating the neurophysiological correlates of the passive listening of words in comparison with their silent repetition (Inner Speech). This involves a comparative analysis of EEG biomarkers between these different tasks to determine the specific electrophysiological signatures of active mental generation versus passive semantic processing.

    Measured: Day 1

  2. Correlation between self-consciousness scores and phenomenological dimensions of inner speech

    To better understand the links between self-consciousness and the phenomenological components of inner speech. Self-consciousness will be evaluated using the Short French Meta-Cognitions Questionnaire (MCQ-30) and the Rumination-Reflection Questionnaire (RRQ). These scores will be correlated with the detailed profile of inner experiences obtained through the Varieties of Inner Speech Questionnaire-Revised (VISQ-R) and the Vividness of Visual Imagery Questionnaire (VVIQ). A specific aim is to evaluate whether increased reflective consciousness is positively correlated with the dialogic and evaluative/critical dimensions of inner speech.

    Measured: Day 1

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted21 Oct 2026
  2. Study start5 Oct 2026 (estimated)
  3. Primary completion31 Oct 2027 (estimated)
  4. Study completion31 Oct 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
35 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07885020
Sponsor's protocol ID
2026-429
Other IDs
B7072026000097, CE2026-429
Acronym
NEURO-IS
Status last verified
Oct 2026
First submitted
13 Oct 2026
Last updated
26 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided: In accordance with the study protocol and the informed consent form approved by the local Ethics Committee, access to the data is strictly restricted to the authorized researchers of the GIGA-Consciousness research unit directly involved in this study. To ensure strict participant confidentiality and full compliance with the European General Data Protection Regulation (GDPR), individual participant data (IPD) might not be shared with external researchers or third parties.

Publications

  • Whitford TJ, Spencer KM, Godwin M, Hirano Y, Chung LK, Vodovozov W, Griffiths O, Harris AWF, Le Pelley ME, Jack BN. Gamma and Theta/Alpha-Band Oscillations in the Electroencephalogram Distinguish the Content of Inner Speech. eNeuro. 2025 Feb 10;12(2):ENEURO.0297-24.2025. doi: 10.1523/ENEURO.0297-24.2025. Print 2025 Feb.

    PubMed 39843220
  • Stephan F, Saalbach H, Rossi S. The Brain Differentially Prepares Inner and Overt Speech Production: Electrophysiological and Vascular Evidence. Brain Sci. 2020 Mar 4;10(3):148. doi: 10.3390/brainsci10030148.

    PubMed 32143405
  • Fama ME, Turkeltaub PE. Inner Speech in Aphasia: Current Evidence, Clinical Implications, and Future Directions. Am J Speech Lang Pathol. 2020 Feb 21;29(1S):560-573. doi: 10.1044/2019_AJSLP-CAC48-18-0212. Epub 2019 Sep 13.

    PubMed 31518502
  • Schendan HE, Ganis G. Electrophysiological potentials reveal cortical mechanisms for mental imagery, mental simulation, and grounded (embodied) cognition. Front Psychol. 2012 Sep 14;3:329. doi: 10.3389/fpsyg.2012.00329. eCollection 2012.

    PubMed 23049515
  • Villena-Gonzalez M, Palacios-Garcia I, Rodriguez E, Lopez V. Beta Oscillations Distinguish Between Two Forms of Mental Imagery While Gamma and Theta Activity Reflects Auditory Attention. Front Hum Neurosci. 2018 Sep 25;12:389. doi: 10.3389/fnhum.2018.00389. eCollection 2018.

    PubMed 30337865
  • van der Stelt CM, Fama ME, Mccall JD, Snider SF, Turkeltaub PE. Intellectual awareness of naming abilities in people with chronic post-stroke aphasia. Neuropsychologia. 2021 Sep 17;160:107961. doi: 10.1016/j.neuropsychologia.2021.107961. Epub 2021 Jul 16.

    PubMed 34274379
  • Trapnell PD, Campbell JD. Private self-consciousness and the five-factor model of personality: distinguishing rumination from reflection. J Pers Soc Psychol. 1999 Feb;76(2):284-304. doi: 10.1037//0022-3514.76.2.284.

    PubMed 10074710
  • Thut G, Nietzel A, Brandt SA, Pascual-Leone A. Alpha-band electroencephalographic activity over occipital cortex indexes visuospatial attention bias and predicts visual target detection. J Neurosci. 2006 Sep 13;26(37):9494-502. doi: 10.1523/JNEUROSCI.0875-06.2006.

    PubMed 16971533
  • Skipper JI. A voice without a mouth no more: The neurobiology of language and consciousness. Neurosci Biobehav Rev. 2022 Sep;140:104772. doi: 10.1016/j.neubiorev.2022.104772. Epub 2022 Jul 11.

    PubMed 35835286
  • Raij TT, Riekki TJJ. Dorsomedial prefontal cortex supports spontaneous thinking per se. Hum Brain Mapp. 2017 Jun;38(6):3277-3288. doi: 10.1002/hbm.23589. Epub 2017 Mar 31.

    PubMed 28370735
  • Proverbio AM, Tacchini M, Jiang K. What do you have in mind? ERP markers of visual and auditory imagery. Brain Cogn. 2023 Mar;166:105954. doi: 10.1016/j.bandc.2023.105954. Epub 2023 Jan 17.

    PubMed 36657242
  • Pratts J, Pobric G, Yao B. Bridging phenomenology and neural mechanisms of inner speech: ALE meta-analysis on egocentricity and spontaneity in a dual-mechanistic framework. Neuroimage. 2023 Nov 15;282:120399. doi: 10.1016/j.neuroimage.2023.120399. Epub 2023 Oct 11.

    PubMed 37827205
  • Papathanassiou D, Etard O, Mellet E, Zago L, Mazoyer B, Tzourio-Mazoyer N. A common language network for comprehension and production: a contribution to the definition of language epicenters with PET. Neuroimage. 2000 Apr;11(4):347-57. doi: 10.1006/nimg.2000.0546.

    PubMed 10725191
  • Morin A. Levels of consciousness and self-awareness: A comparison and integration of various neurocognitive views. Conscious Cogn. 2006 Jun;15(2):358-71. doi: 10.1016/j.concog.2005.09.006. Epub 2005 Nov 2.

    PubMed 16260154
  • Lee SH, Lee M, Lee SW. Neural Decoding of Imagined Speech and Visual Imagery as Intuitive Paradigms for BCI Communication. IEEE Trans Neural Syst Rehabil Eng. 2020 Dec;28(12):2647-2659. doi: 10.1109/TNSRE.2020.3040289. Epub 2021 Jan 28.

    PubMed 33232243

Questions about this trial

What is this clinical trial studying?

A study testing Inner Experience Induction Tasks and hdEEG in people with Healthy Volunteer, run by University of Liege at 1 site in Belgium.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 26 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Olivia Gosseries, PhD (+32 4 323 36 14, ogosseries@uliege.be), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Modulation of EEG spectral power (Alpha, Beta, and Gamma bands) (time frame: Day 1). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07885020, which also lists 26 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Oct 2026.

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