Skip to main content
OpenTrials
Completed

NCT Number: NCT05603780

DEEPTIME: Human Adaptation in Time Underground Isolation

The objectives of this scientific expedition are: a/ Evaluation of temporal cognitive perception and collective synchronization in a temporally anomalous universe (underground environment), b/ Influence of group living on the endogenous circadian rhythmicity of the central biological clock and peripheral clocks in a "free-running" situation (absence of light/natural darkness), c/Evaluation of cognitive and physiological performance in response to exposure to an extreme environment in a natural underground cavity (cave) without access to a time indicator for 40 days, d/Correlation of cognitive, behavioral, psychological, social, neurophysiological and physiological parameters, e/ Determination of adaptation or maladaptation criteria (biological, genetic, physiological, neurophysiological, psychological and cognitive) in an isolation environment (underground) f/ Study of the evolution of collective organization, decision making and leadership in an extreme isolation and management situation.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Physiological Stress Cognition Disorders Cognitive Dysfunction Mental Disorders Neurocognitive Disorders Sleep

Age range

25 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

CHU CAEN

Caen, France

About this study

This exceptional period has shown a significant desynchronization and loss of notion of time in a large number of people as well as important questions about human abilities to live in confined conditions. It is partly for this reason, but also to answer more fundamental questions on the perception of time that the extraordinary research expedition Deep Time was conceived: 40 days underground to know the links of our brain to time and synchronization within a group. A fundamental need for our future. This scientific expedition will take place entirely in France to ensure the feasibility and safety of the subjects and experimenters, under the direction of Christian Clot and the Institute of Human Adaptation, placed under the high patronage of the Ministry of Education, Research and Innovation.

The project addresses the fundamental question of human adaptation to the physical environment and the crucial role of the brain's neuroplasticity properties.

The present "Deep-Time" protocol naturally echoes the "out-of-time" isolation experiments conducted by the speleologist Michel Siffre starting in 1962 and its various components in the years that followed.

These "out of time" experiments led to certain conclusions. As curious as it may seem, in the absence of the time givers (synchronizers or Zeitgebers in German) that are the social rhythms and the day-night alternations, the spontaneous rhythm would settle on a rhythm of about 25 hours.

However, these experiments remained limited to isolated individuals, in conditions of spatial unity (no displacement outside of the work camps), leaving a whole field of research and questioning that the year 2021 has strongly emphasized.

The objectives of this scientific expedition are: a/ Evaluation of temporal cognitive perception and collective synchronization in a temporally anomalous universe (underground environment), b/ Influence of group living on the endogenous circadian rhythmicity of the central biological clock and peripheral clocks in a "free-running" situation (absence of light/natural darkness), c/Evaluation of cognitive and physiological performance in response to exposure to an extreme environment in a natural underground cavity (cave) without access to a time indicator for 40 days, d/Correlation of cognitive, behavioral, psychological, social, neurophysiological and physiological parameters, e/ Determination of adaptation or maladaptation criteria (biological, genetic, physiological, neurophysiological, psychological and cognitive) in an isolation environment (underground) f/ Study of the evolution of collective organization, decision making and leadership in an extreme isolation and management situation.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Strictly right-handed Good health without any medical and psychiatric diseases No contraindications to MRI French or European nationality Not to be included in another biomedical protocol

Exclusion criteria

Being pregnant Minor, under guardianship or curatorship

Treatment and study plan

exploratory protocol

Behavioral

physiological and cognitive evaluations

Primary outcomes

  1. Time

    Time frame: every ten days up to 40 days

    • Evaluation of time perception perceived by subjects (minute and days) every 10 days up to 40 days

  2. chronobiology

    Time frame: every 5 days up to 40 days

    -Influence of group living on the endogenous circadian rhythmicity of the central biological clock and peripheral clocks in a "free-running" situation (absence of light / natural darkness): measurments of body core temperature, cortisol and melatonine salivary concentration circadian rythms

  3. Human Factors: ethological measurments with video 24/24, actimetric circadian rythms

    Time frame: all along the cavern experiment for 40 days

    • Evaluation of the capacity of a group to find a synchronicity and a way of life in a new context, extreme in its environmental and temporal dimensions and out of the initial competences of each group member. Measurments of social interaction, comparison of actimetric circadien rythm

  4. Physiology

    Time frame: every ten days up to 40 days

    Physiological parameters (HRV, lean and fat mass by impedancemtry, weight in kg, core body temperature) in response to exposure to an extreme environment in a natural underground cave for 40 days.

  5. Cognition, Emotion and personnality

    Time frame: every ten to 15 days up to 40 days

    Evaluation of cognitive (taking decision, emotion, spatial cognition) through differents paradigms displayed on screen of Headset in 2D and 3D virtual reality.

    Mesurements of time reaction, risk score, number of strategy or procedural errors, time to achieve the tasks.

    Questionnaires (STAI, POMS, big five inventory, IP9)

Sponsors and collaborators

Lead sponsor

University Hospital, Caen

Other

Registry information

Official study title

Cognitive, Emotional, Physiological, Chronobiological and Genetic Effects of a Time Underground Isolation

Acronym: DEEPTIME

Important dates

Study start
2021
Primary completion
2021
Study completion
2022
First posted
Nov 3, 2022
Registry last updated
Apr 2, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.