Evidence map›Paper›PMID 33828471›Full record

ArticleFrontiers in human neuroscience2021

Brain Entropy During Aging Through a Free Energy Principle Approach.

Filippo Cieri, Xiaowei Zhuang, Jessica Z K Caldwell, Dietmar Cordes

Abstract read
In one paragraph

Article in Frontiers in human neuroscience, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 31 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
31citing papers in PubMed, 1 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

31 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
  2. Entropy of the resting state cortex in epilepsy.Biomedical physics & engineering express · 2026
    Article
  3. The entropic brain today.Brain : a journal of neurology · 2026
    Review
  4. Article
  5. Article
  6. Article
  7. Article
  8. Article
  9. Article
  10. Article
  11. Article
  12. Structured Dynamics in the Algorithmic Agent.Entropy (Basel, Switzerland) · 2025
    Article
  13. Article
  14. Article
  15. Review
  16. The brain entropy dynamics in resting state.Frontiers in neuroscience · 2024
    Article
  17. Dissociable Effects of Alzheimer's Disease-Related Cognitive Dysfunction and Aging on Functional Brain Network Segregation.The Journal of neuroscience : the official journal of the Society for Neuroscience · 2023
    Article
  18. Article
  19. Article
  20. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Filippo CieriDepartment of Neurology, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States.
Xiaowei ZhuangDepartment of Neurology, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States.
Jessica Z K CaldwellDepartment of Neurology, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States.
Dietmar CordesDepartment of Neurology, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, United States.

Funding

Renewal of Centers of Biomedical Research Excellence (COBRE) (Phase 2) CNTN - ResubmissionP20GM109025 · NIGMS · CLEVELAND CLINIC FOUNDATION · PI JESSICA KIRKLAND CALDWELL · 2015 to 2026
$22.8M
Machine and deep learning for finding multimodal imaging biomarkers in prodromal ADRF1AG071566 · NIA · CLEVELAND CLINIC LERNER COM-CWRU · PI CORDES, DIETMAR, LOWE, MARK J · 2021 to 2021
$2.3M
Interactions of Sex and Gender Factors in Risk for Alzheimers Disease: Links Between Stress, Neural Activity, Inflammation, and MemoryR01AG074392 · NIA · CLEVELAND CLINIC LERNER COM-CWRU · PI KIRKLAND CALDWELL, JESSICA · 2021 to 2024
$1.8M
NIA NIH HHS R01 AG074392NIA NIH HHS RF1 AG071566NIGMS NIH HHS P20 GM109025
6 · The paper itself

Abstract

Neural complexity and brain entropy (BEN) have gained greater interest in recent years. The dynamics of neural signals and their relations with information processing continue to be investigated through different measures in a variety of noteworthy studies. The BEN of spontaneous neural activity decreases during states of reduced consciousness. This evidence has been showed in primary consciousness states, such as psychedelic states, under the name of "the entropic brain hypothesis." In this manuscript we propose an extension of this hypothesis to physiological and pathological aging. We review this particular facet of the complexity of the brain, mentioning studies that have investigated BEN in primary consciousness states, and extending this view to the field of neuroaging with a focus on resting-state functional Magnetic Resonance Imaging. We first introduce historic and conceptual ideas about entropy and neural complexity, treating the mindbrain as a complex nonlinear dynamic adaptive system, in light of the free energy principle. Then, we review the studies in this field, analyzing the idea that the aim of the neurocognitive system is to maintain a dynamic state of balance between order and chaos, both in terms of dynamics of neural signals and functional connectivity. In our exploration we will review studies both on acute psychedelic states and more chronic psychotic states and traits, such as those in schizophrenia, in order to show the increase of entropy in those states. Then we extend our exploration to physiological and pathological aging, where BEN is reduced. Finally, we propose an interpretation of these results, defining a general trend of BEN in primary states and cognitive aging.

Indexed as

agingAlzheimerbrain entropyentropic brainfMRIfree energyneuroaging

Identifiers

PMID33828471
PMCPMC8019811

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.