Near-death experiences (NDEs) have intrigued humanity for centuries, provoking questions about consciousness, the nature of existence, and the mysteries of the afterlife. The vivid, often transformative experiences described by individuals who have faced life-threatening situations have sparked countless theories, ranging from spiritual interpretations to psychological and neurobiological explanations. However, in recent years, a growing body of scientific research has begun to provide a more cohesive understanding of NDEs, with one groundbreaking study leading the way: a unified neuroscientific model proposed by a multidisciplinary team from the University of Liège. This model, drawing on empirical findings across neurobiology, psychology, and evolutionary theory, sheds light on the mechanisms that may explain these extraordinary phenomena.
What is a Near-Death Experience?
A near-death experience is typically described as a profound psychological event that occurs when a person perceives they are close to death or when they are facing a life-threatening situation. While the experiences themselves are highly variable, many individuals report strikingly similar themes and elements. These commonly reported phenomena include:
- Out-of-body experiences (OBEs): A sensation of leaving the physical body and observing it from an external perspective.
- Distorted awareness of time: A feeling that time has either slowed down, stopped, or accelerated.
- A sense of peace and calm: Many individuals report an overwhelming sense of tranquility and emotional well-being, sometimes described as a state of bliss or serenity.
- Life review: Some individuals experience a rapid, vivid recollection of key moments from their lives, sometimes described as a “life flashing before their eyes.”
- Bright lights, tunnels, and spiritual encounters: These can include visions of bright lights, long tunnels, or encounters with deceased relatives, mystical figures, or perceived spiritual beings.
However, the field of NDE research is not limited to the more positive or mystical accounts. While the majority of NDEs reported in popular culture fit a pattern of awe and wonder, there are also less frequently mentioned experiences that are darker, nightmarish, or simply nonsensical. For example, some people report feelings of fear, anxiety, or a lack of meaning in their experiences. These less-discussed accounts challenge the idea that NDEs are inherently positive or universally transformative, pointing to the complexity of consciousness and the influence of personal psychology on these events.
Interestingly, NDE-like experiences can also occur in non-life-threatening contexts, such as during fainting, drug use, or sleep paralysis. This suggests that NDEs may not be uniquely tied to the proximity of death but rather to altered states of consciousness, which can be induced by various physiological or psychological triggers.
The New Unified Neuroscientific Model
In the review article titled “A neuroscientific model of near-death experiences,” published in Nature Reviews Neurology, a research team from the University of Liège presents a unified model based on converging evidence from various scientific fields. The researchers draw upon data from neurobiology, animal studies, psychedelic research, and clinical observations to offer a comprehensive explanation of how NDEs may emerge in response to physiological stressors such as oxygen deprivation, carbon dioxide buildup, and disruptions in brain energy metabolism.
At the core of this model is the idea that NDEs are triggered by specific physiological processes that occur during critical moments of survival, such as during cardiac arrest, traumatic injury, or near-drowning. These events initiate a cascade of neurological responses, leading to alterations in consciousness. The key factors identified in this model include:
- Oxygen Deprivation (Hypoxia): Reduced blood flow to the brain, often a result of cardiac arrest or traumatic injury, leads to hypoxia, a state in which the brain is deprived of oxygen. Hypoxia has been linked to vivid visual and emotional experiences, including hallucinations and feelings of euphoria, which are commonly reported during NDEs.
- Increased Carbon Dioxide (Hypercapnia): When oxygen levels drop, carbon dioxide levels in the blood tend to rise. Hypercapnia can result in feelings of confusion, disorientation, and a sense of altered reality, which may contribute to the disembodied sensations often reported in NDEs.
- Disruption in Brain Energy Metabolism: The brain requires a constant supply of glucose and oxygen to maintain its functions. During extreme stress or trauma, this metabolic balance is disrupted, leading to a breakdown in the brain’s normal electrical activity. This can give rise to altered states of consciousness, ranging from dissociation to intense perceptual experiences.
Physiological Mechanisms Behind NDEs
One of the critical insights provided by this unified neuroscientific model is the physiological breakdown that occurs during life-threatening events. The research team synthesized findings from human studies, animal experiments, and neuroimaging data from critically ill patients to identify consistent patterns of brain activity associated with NDEs. These studies show that when cerebral blood flow is reduced during cardiac arrest or other critical conditions, the brain experiences a shortage of oxygen and a buildup of carbon dioxide. These factors can lead to a variety of symptoms, including confusion, hallucinations, and even the feeling of being outside one’s body.
Research also suggests that these physiological disruptions may trigger the brain’s survival mechanisms. For instance, hypoxia can lead to the activation of neural circuits responsible for creating a sense of calm or detachment from the physical body. These responses may be adaptive, helping individuals cope with extreme stress or trauma. Additionally, the brain’s propensity to produce vivid imagery in response to metabolic imbalance could explain the bright lights, tunnels, and spiritual encounters reported by some individuals during NDEs.
The involvement of altered brain activity is further supported by studies of psychedelic substances, which can induce similar states of consciousness to those described in NDEs. Psychedelics, such as DMT and psilocybin, often result in visual hallucinations, a sense of unity with the universe, and encounters with mystical beings. These substances influence brain regions associated with self-awareness, perception, and emotional regulation—regions that are also implicated in NDEs.
The Evolutionary Perspective: NDEs as a Survival Mechanism?
In addition to the neurobiological and psychological explanations, the researchers also consider an evolutionary perspective on NDEs. The idea is that the brain’s response to life-threatening situations may have evolved as an adaptive mechanism designed to enhance survival. For instance, the feeling of peace and calm reported by many individuals during NDEs could serve as a way to reduce panic and anxiety in the face of imminent danger, allowing individuals to remain focused and better cope with extreme stress.
The phenomenon of life review, in which individuals experience a rapid recall of memories, may also have an evolutionary function. Some researchers speculate that this “life flashing before your eyes” could be a form of cognitive rehearsal that helps individuals assess their actions and decisions, potentially leading to better decision-making in future situations.
The Role of the Individual’s Psychological State
The neuroscientific model also emphasizes the role of psychological factors in shaping the content and interpretation of NDEs. The experiences reported during NDEs are not solely the result of physiological changes but are also influenced by the individual’s mindset, cultural background, and personal beliefs. For example, a person with a deeply spiritual worldview may interpret a bright light and a sense of peace as a visit to the afterlife, while someone with a more secular perspective may perceive the same experience as a natural consequence of brain activity.
Moreover, an individual’s mental state before the event can play a crucial role in determining the emotional tone of the NDE. People with a history of anxiety or trauma may be more likely to report distressing or nightmarish experiences, while those with a more optimistic or peaceful disposition may be more inclined to report positive, uplifting experiences.
The Future of NDE Research
The unified neuroscientific model of NDEs presented by the University of Liège team represents a significant step forward in understanding this enigmatic phenomenon. By synthesizing data from various disciplines, the researchers provide a more comprehensive framework that takes into account both the brain’s physiological responses and the individual’s psychological experiences. This model offers a promising avenue for future research, which could ultimately help to bridge the gap between scientific explanations and the deeply personal, subjective nature of NDEs.
As we continue to explore the complexities of consciousness, the study of NDEs offers valuable insights into the ways in which our brains respond to extreme stress and the nature of our perception of reality. Whether viewed as a neurological event or a profound spiritual experience, near-death experiences remain a powerful reminder of the mysteries that still surround the human mind, consciousness, and the potential for new forms of exploration into the nature of existence.
Reference: Charlotte Martial et al, A neuroscientific model of near-death experiences, Nature Reviews Neurology (2025). DOI: 10.1038/s41582-025-01072-z