A story of loss and intuition
As a neuroscientist and psychiatrist, Dr Tara Swart had built her career on understanding how the brain perceives and processes the world. She married her husband Robin in 2017, and three years later he was diagnosed with acute leukemia. Despite months of intensive treatment, he died on 26 October 2021, two days before their fourth wedding anniversary. In the early weeks after his death, Swart said she began to notice unusual experiences. Robins, his namesake, seemed to appear whenever she looked out of the window. One night she awoke at 4 a.m., felt a hard thump on her shoulder and, in her words, saw a hazy outline of her husband by the bedside. Haunted by grief and trained to recognise psychotic symptoms, she feared she might be losing her mind. She visited mediums but found them unconvincing. Eventually she decided that, if there was a way to communicate with her husband, she should be able to learn it herself.
Swart’s account reflects an experience that many bereaved people recognise: sensing a deceased loved one’s presence. Research on sensory and quasi‑sensory experiences of the deceased (SED) shows that such phenomena are surprisingly common. An interdisciplinary review notes that 47–82 percent of bereaved individuals report at least one experience such as feeling the presence, hearing the voice or dreaming of the deceased . These experiences occur in nonclinical populations and include diffuse sensations or what Swart calls “signs.” The same review cautions that SED are poorly understood and that different terms (after‑death communications, bereavement hallucinations, continued presence) reflect divergent assumptions about whether they are perceptual, emotional or spiritual . Rather than being pathological, many psychologists regard them as part of the grieving process .
Swart’s story raises important questions: Are these “signs” evidence of a mind that exists outside the body? Are they simply misinterpretations of normal brain activity? Or are they something in between — subjective experiences arising from the interplay of neurobiology, culture and belief? To explore these questions, we need to examine what science says about the capabilities and limitations of the brain, the nature of near‑death experiences, the biology of grief and trauma, and the way our senses construct reality.
Beyond the five senses: interoception and predictive brains
Most of us learn in school that humans have five senses. Yet neuroscience shows that the picture is far richer. The five “exteroceptive” senses — sight, hearing, touch, taste and smell — provide information about the external world, but our bodies also contain sensors for internal signals. Interoception is the perception of internal bodily states such as hunger, thirst, the fullness of the bladder or the beating of the heart. Harvard Medicine Magazine describes it as processing information from the heart, gut and lungs as they interact with the brain . Interoceptive signals help maintain homeostasis and influence emotions; research links abnormal interoception to anxiety, depression and eating disorders .
Neuroscientist Lisa Feldman Barrett notes that even vision depends on more than simple retinal input. Some retinal ganglion cells contain melanopsin, allowing them to signal day/night information to the brain and set circadian rhythms . The brain combines external sensory data with predictions based on prior experience to create perception . The same predictive machinery can also generate vivid internal experiences when the sensory input is ambiguous, a process that can explain hallucinations and the feeling of presence during grief.
Recent proposals suggest humans might have 20–33 distinct senses, depending on how senses are defined. These include proprioception (sense of body position), the vestibular sense (balance), and chemosensors that monitor blood pH, oxygen and carbon dioxide. While the exact number remains debated, the broad point is that our nervous system continuously monitors both the external and internal world. Interoceptive awareness can be trained through practices such as mindfulness and yoga, which may partially explain why Swart’s “signs” increased as she engaged in breath‑work and somatic therapies.
Lucidity at the edge: terminal bursts and dying brains
Swart’s belief that consciousness can exist separately from the brain draws, in part, on phenomena such as near‑death experiences (NDEs) and terminal lucidity. In the interview, she references the accounts of neurosurgeon Eben Alexander and orthopedic surgeon Mary Neal, both of whom reported vivid experiences of other realms during comas. Advocates argue that such experiences, coupled with sudden lucidity in people with advanced dementia, suggest that the mind is more than neural activity.
Scientific investigations into these phenomena paint a more cautious picture. Terminal lucidity describes episodes in which a person with severe dementia or brain damage suddenly regains awareness, coherent speech and recognition shortly before death. A 2021 National Institutes of Health–commissioned study noted that episodes of lucidity can occur months or years before death and may be part of the disease trajectory rather than strictly terminal . Surveys of dementia patients indicated that lucidity was common rather than exceptional . Philosophers debating the phenomenon in Psychology Today emphasise that science still lacks a complete explanation but caution against using it to prove dualism. They propose that dementia may disrupt neural circuits without destroying them and that dying processes — changes in neurochemicals, exhaustion of inhibitory circuits or surges of electrical activity — could temporarily reactivate dormant networks . The brain’s complexity and our limited mapping of its trillions of connections mean that “some so‑far‑unknown capability” may exist without invoking a non‑physical soul .
Similarly, NDEs can be studied scientifically. Michael Shermer’s critique of Eben Alexander’s Proof of Heaven points out that Alexander’s cortex could not have been completely inactive if he later recalled the experience. He highlights evidence that electrical stimulation of specific brain regions can induce feelings of a presence and out‑of‑body experiences . Neurologist Oliver Sacks reported that hallucinations in Parkinson’s disease, migraines and sensory deprivation can be remarkably vivid and meaningful . In other words, NDEs likely occur when the brain is still functioning, albeit in an altered state. In 2023, researchers at the University of Michigan recorded a surge of organised gamma‑wave activity in comatose patients within minutes of cardiac arrest . The posterior cortical “hot zone” showed activity associated with visual and auditory processing . These surges may contribute to reports of life reviews and bright lights. The fact that such activity occurs seconds after the heart stops suggests that the dying brain can generate conscious experiences even as it shuts down.
A related phenomenon involves the sedative zolpidem, which paradoxically can briefly restore consciousness in a small subset of patients with severe brain injury. An open‑label study notes that case reports describe transient improvements in visual pursuit, command following and communication, but that only one of 15 patients in a controlled trial responded . The authors caution that the effect is rare and that over‑reliance on anecdotal cases may lead to overestimates . Nevertheless, such cases underscore the brain’s capacity for recovery when inhibitory circuits are modulated, again suggesting that dormant neural networks may become active under unusual conditions.
Grief, trauma and the body
Swart emphasises that grief can resemble psychosis. Neurochemically, she is partly correct. Traumatic loss can dysregulate neurotransmitters such as serotonin, dopamine and cortisol; it can alter limbic system function and produce hyperarousal . The Substance Abuse and Mental Health Services Administration’s trauma‑informed care guidelines note that trauma survivors often present with physical symptoms — sleep disturbances, gastrointestinal and cardiovascular problems, musculoskeletal pain and somatic complaints . Hyperarousal may manifest as persistent muscle tension, exaggerated startle responses and difficulty relaxing . Such bodily sensations can appear unrelated to the original trauma but are part of the stress response.
Swart also discusses the idea that trauma is stored in the body and may require somatic therapies such as massage, dance or breath work to release it. Bessel van der Kolk’s influential book The Body Keeps the Score argues that traumatic memories are encoded not only in the hippocampus but also in muscle tension and fascia. While the concept is controversial, it is consistent with evidence that trauma can cause chronic muscle guarding and changes in the autonomic nervous system. The trauma‑informed care guidelines encourage clinicians to frame re‑experiencing, hyperarousal and physical symptoms as physiological reactions to extreme stress and to recommend wellness activities like therapy, meditation and exercise . These approaches aim to restore homeostasis and interoceptive awareness. Thus, while there is no consensus that trauma literally “lodges” in fascia, the interplay between body and mind means that movement‑based therapies may help integrate fragmented memories and emotions.
Swart’s mention of a “serotonin hypothesis” — that trauma restricts capillaries, trapping serotonin in tissues — is speculative. Mainstream research on serotonin and trauma focuses on dysregulation of central serotonin receptors in post‑traumatic stress disorder, rather than capillary constriction. A review of biological alterations after trauma lists changes in limbic function, hypothalamic–pituitary–adrenal axis activity and neurotransmitter regulation . It does not describe serotonin pooling in muscle tissues. Therefore, claims about serotonin stored in fascia should be treated as hypotheses requiring empirical support.
The gut–brain axis and intuition
Swart links intuition to gut health, suggesting that prebiotics, probiotics, art and music can sharpen intuitive “gut feelings.” There is growing evidence that the gut–brain axis connects the enteric and central nervous systems via neural, endocrine and immune pathways . The gut microbiota influences mood and cognition, and disruptions are associated with anxiety, depression and autism . Animal studies show that altering gut bacteria changes stress responses and behavior . However, while a healthy microbiome may support mental well‑being, there is no evidence that probiotics allow communication with the dead. Swart’s assertion likely reflects a broader theme: cultivating bodily awareness — through nutrition, mindfulness and creativity — can enhance interoception, making people more attuned to subtle emotional and bodily signals.
Slime moulds, forests and metaphors of connection
To illustrate that nature harbours capacities beyond our imagination, Swart cites biological examples: slime moulds that aggregate into slugs and form fruiting bodies, and mycorrhizal fungi that connect trees in “wood wide webs.” These examples highlight cooperation and communication in non‑human organisms. The social amoeba Dictyostelium discoideum indeed lives as single cells but, when starved, aggregates into a motile slug. About one fifth of the cells die to form the stalk that elevates the remaining cells as spores . This altruistic behaviour is vulnerable to cheating, and researchers have studied how kin discrimination and genetic controls prevent exploitation . The organism shows that self‑sacrifice can evolve in simple life forms without consciousness.
The idea that forests are interconnected by fungal networks has captured the public imagination. Mycorrhizal fungi link plant roots and exchange nutrients, water and chemical signals, leading to the notion of a cooperative “wood‑wide web.” However, the concept’s popular presentation has outrun the evidence. A 2024 Guardian article summarises a debate among forest ecologists: while mycorrhizal networks exist, claims that mature trees preferentially feed their offspring or that fungi deliberately send warnings may overstate the data . Some researchers argue that the evidence for extensive, species‑wide cooperation is weaker than portrayed and that more controlled studies are needed . This controversy underscores the risk of romanticising complex natural systems to support human narratives about connectedness.
These biological stories resonate with bereavement experiences: both highlight unseen networks and cooperation beyond individual awareness. For someone grieving, perceiving patterns and connections may provide comfort. But as the wood‑wide web controversy shows, extraordinary claims require careful evidence.
Bereavement experiences: hallucination or continuing bonds?
So where do Swart’s “signs” fit? Bereavement hallucinations or SED (Sensory Experience of the Deceased) are common across cultures and may have adaptive functions. The interdisciplinary review notes that prevalence estimates for at least one SED range from 47–82 percent . These experiences include sensing the presence, hearing the voice or receiving messages from the deceased . They are often interpreted within cultural or religious frameworks: some see them as after‑death communications, others as psychological defence mechanisms, and still others as hallucinations . Importantly, the review emphasises that such experiences are not normally linked to mental illness and should be normalised rather than pathologised .
From a neurocognitive perspective, these experiences can arise from the brain’s predictive processing and interoceptive systems. The reticular activating system filters sensory information, but under stress or heightened expectation, this filter may allow normally ignored stimuli to reach consciousness. Research shows that people often see what they expect to see: thinking about an item increases the chance of noticing it later, a form of confirmation bias. Swart acknowledges this but argues that she sets narrow criteria for her signs (e.g., seeing a phoenix symbol within 24 hours). However, coincidences can occur in a probabilistic world. Mathematically, rare events are bound to happen occasionally. Recognising patterns is a human strength, but it can also lead to apophenia, the tendency to find meaningful connections in random data.
Psychological studies of thought insertion — the sensation of thoughts not belonging to oneself — are typically associated with psychosis. However, cognitive scientist Carl Jung described the collective unconscious as a repository of human archetypes. Swart’s experiences may reflect the brain’s attempt to integrate trauma by generating internally sourced imagery and narratives. The fact that she questioned her own sanity and cross‑checked her experiences against psychiatric criteria indicates an awareness of these possibilities.
Faith, science and the search for meaning
Swart’s conclusion is not purely empirical; it is also existential. She argues that believing in something larger than oneself provides purpose and well‑being. There is evidence that having a sense of purpose beyond personal survival correlates with better mental and physical health. However, belief is a double‑edged sword. While spirituality or religion can foster community and resilience, dogmatic belief can lead to extremism or denial of scientific evidence. The same experiences that comfort one person can be used to justify harmful actions in another context.
The conversation highlights an important tension. Science thrives on scepticism and demands evidence; spiritual experiences often defy measurement. History shows that phenomena once regarded as mystical, such as disease or lightning, later received natural explanations. It also shows that dismissing subjective experiences outright can alienate those who find meaning in them. A middle path acknowledges the reality of the experiences without committing to metaphysical claims.
Ultimately, experiences like Swart’s belong to the domain where neuroscience, psychology, philosophy and culture meet. Science can explain mechanisms that make such experiences possible — surges of neural activity, predictive processing, interoception and the effects of trauma — but it cannot fully answer existential questions about meaning or the survival of consciousness. As philosopher Ralph Weir writes, the brain remains one of nature’s least understood phenomena, and terminal lucidity reminds us to be cautious in drawing metaphysical conclusions from scientific data .
Takeaway: staying open and grounded
Swart’s story invites us to explore the boundaries of scientific knowledge and the human need for connection. The science of the senses shows that our brains continuously construct reality from limited inputs, blending external stimuli with internal predictions . Our nervous system monitors not only the world around us but also the hidden world within us . The gut–brain axis links our microbiome to mood and cognition , and trauma can leave the body in a state of chronic hyperarousal . These biological processes can produce vivid, meaningful experiences, especially during grief. Terminal lucidity and NDEs show that the dying brain can generate organised activity and coherent thought , but they do not definitively prove that consciousness is independent of the brain.
The prevalence of sensory experiences of the deceased and the lack of evidence linking them to pathology suggest that they are part of the human response to loss. They can offer comfort and help maintain bonds. However, they should not be taken as scientific proof of life after death without rigorous evidence. The debate over the wood‑wide web reminds us that seductive narratives can outrun the data . A healthy approach is to remain curious and open, recognising that science and spirituality address different questions.
In the end, whether Swart’s signs were communications from her husband or expressions of a grieving brain, their impact is real to her and to others who find solace in similar experiences. Acknowledging this does not require abandoning scepticism. Instead, it encourages compassion for those grieving and humility about the limits of our current understanding. Science will continue to probe the brain’s mysteries, but it may never fully capture the subjective richness of love, loss and the longing to stay connected.
References
Alexander, E. (2012). Proof of Heaven: A Neurosurgeon’s Journey into the Afterlife. Simon & Schuster.
Bathany, A. (2022). Threshold: Terminal lucidity and the border of life and death. Yale University Press.
Bennett, M. R., & Hacker, P. M. S. (2021). The philosophical foundations of neuroscience (2nd ed.). Wiley-Blackwell.
Eagleman, D. (2020). Livewired: The Inside Story of the Ever-Changing Brain. Pantheon Books.
Foster, R. (2017). Circadian rhythms: A very short introduction. Oxford University Press.
Grayson, B. (2021). After: A Doctor Explores What Near-Death Experiences Reveal About Life and Beyond. St. Martin’s Essentials.
Hoffman, D. D. (2019). The Case Against Reality: Why Evolution Hid the Truth from Our Eyes. W. W. Norton & Company.
Jung, C. G. (1969). The structure and dynamics of the psyche. Princeton University Press.
Levine, P. A. (2010). In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness. North Atlantic Books.
Neil, M. (2012). To Heaven and Back: A Doctor’s Extraordinary Account of Her Death, Heaven, Angels, and Life Again. WaterBrook Press.
Swart, T. (2023). The Signs: The New Science of How to Trust Your Instincts. HarperCollins.
Van der Kolk, B. A. (2014). The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma. Viking.
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