Brain Networks Involved in Inner World Control

Summary

Inner speech (the "little voice" in our heads) plays a central role in our ability to perform complex cognitive tasks such as problem solving, reading, writing, thinking, and self awareness. It is estimated that at least a quarter of our lives is accompanied by inner speech, whether deliberate (mentally making a list) or more spontaneous (mind wandering). Although central to human life, its neural bases remain poorly understood. It has been recently discovered a single region in the human prefrontal cortex absent in nonhuman primates, the prefrontal operculum (PFO), which shows a pattern of functional connectivity with the rest of the brain that could give it a role in controlling inner speech. The aim of this research is to understand how the brain generates and controls inner speech using functional magnetic resonance imaging (fMRI). Dysfunctions of inner speech, especially when spontaneous and wandering, can lead to severe mental disorders (anxiety disorders, depression, verbal auditory hallucinations). It is therefore crucial to identify the role of the PFO and the networks that involve it, particularly the precuneus, in controlling inner speech across its different manifestations. The first hypothesis is that the PFO and the networks that include it play a key role in the cognitive control of inner speech in participants who experience inner speech. The second hypothesis is that the PFO is hyperactive in participants who lack inner speech (so called aphantasics), preventing the production of inner speech. To test these hypotheses, participants will complete a battery of well established questionnaires to determine whether they can produce inner speech (control participants with typical inner speech) or not (aphantasic participants). These participants will take part in an fMRI study contrasting tasks that recruit inner speech that do or do not require cognitive control. The third hypothesis is that the extent of inner speech depends on the capacity for self representation, and thus on the interaction between the PFO and the precuneus. The investigator hypothesize a positive correlation between inner speech ability and self representation capacity, associated with stronger functional connectivity between the PFO and the precuneus. The investigator predict reduced self representation in aphantasic participants. To test this, participants will complete a battery of well established questionnaires. The investigator will compute correlations between 1) behavioral performance on inner speech tasks and questionnaire scores, and 2) the network measures identified in fMRI (task activation and connectivity) and questionnaire scores.

Conditions

• Neurosciences

Interventions

BEHAVIORAL

Neuropsychological evaluation, questionnaires, and training on the tasks that will be performed in the MRI.

The neuropsychological/questionnaires evaluation is a 3 hour visit during which participants will complete a battery of neuropsychological tests and respond to questionnaires assessing their capacity for inner speech and self representation. In a second 30 minute visit, they will be trained on the tasks (inner speech tasks and control tasks) that they will perform in the MRI.

OTHER

MRI visits

There will be two 2 hour MRI visits. During the first visit, participants will perform the learned task conditions designed to test the control of inner speech; during the second visit, they will perform the control conditions and an anatomical MRI will be acquired, as well as a resting state fMRI scan to study functional connectivity and a DTI scan to study structural connectivity

Sponsors & Collaborators

• Hospices Civils de Lyon

  lead OTHER

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

20 Years

Max Age

45 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-05-01

Primary Completion

2028-05-01

Completion

2028-05-01

Countries

• France

Study Locations