If Freud had known…

Neurology and psychiatry maintain a complicated relationship (Drouin et al., 2022), which continues to question the fundamental interaction between mind and matter. How does the brain manufacture the mind? The nature of consciousness has been an enigma for millennia, challenging philosophers, physicians, and scientists alike. New research suggests that the brain functions as a confederation of independent modules working together in a layered architecture. Understanding how consciousness emerges from such an organization requires reverting to the fundamentals of physics. It also necessitates examining the transition from inanimate matter to living systems if we are to bridge the divide between brain and mind (Gazzaniga, 2022). As John Searle aptly noted, studying the brain without studying consciousness would be like studying the stomach without studying digestion (Searle, 2000).At the center of this question stands the figure of Sigmund Freud (1856Freud ( -1939)). His career illustrates the transition from a conception of mental disorders as purely organic to a psychodynamic approach based on the hypothesis of an unconscious. Originally trained as a neurologist in the clinical anatomical tradition of the 19th century, Freud progressively developed a theory of the unconscious. This theory moved him away from the medical materialism of his time. Importantly, Freud was not a dualist who defended the idea that psychic life exists outside our brains. Rather, he sought different explanatory frameworks when the neuroscience of his era proved insufficient.More than a century after the emergence of psychoanalysis, advances in neuroimaging and modern physics invite us to reconsider the perceived separation between the organic and the psychic. The connectome, defined as the comprehensive mapping of neural connections in the brain (Kruper et al., 2024), can now be visualized through diffusion MRI. This technology reveals structural modifications in various psychiatric pathologies. Simultaneously, contemporary physics such as quantum physics or relativity has opened new perspectives on the nature of consciousness. This has occurred particularly through concepts like the AdS/CFT duality (Anti-de Sitter/Conformal Field Theory), which establishes a mathematical correspondence between gravitational theories and quantum theories (Awret, 2022).These developments prompt us to ask: should Freudian thought be revisited in light of these new discoveries? Our aim is not to "rehabilitate" Freud but rather to examine how the physical and neuroscientific frameworks of our time might provide new interpretations of his key insights on the functioning of the psyche. This article offers an examination of this question by first briefly retracing Freud's shift from neurology to psychoanalysis. Second, we analyze how modern neuroscience illuminates certain Freudian concepts while revealing their neurobiological underpinnings. Third, we critically examine aspects of Freudian theory requiring substantial revision. Fourth, we explore how concepts from physics could enlighten our understanding of consciousness and some Freudian concepts, before proposing an integrative approach to these complex phenomena.We will see how the traditional separation between mental processes and physical brain function--commonly referred to as the mind-body dichotomy---tends to become less relevant in light of contemporary scientific frameworks. This perspective would perhaps not have surprised Freud himself. Despite his apparent distancing from neurology, Freud never completely excluded the possibility of a future biological understanding of the phenomena he described: "Given the intimate dependence that exists between the things that we divide into corporeal and psychic, we can foresee that a day will come when the paths will open to knowledge and also, hopefully, to practice, leading from biology organs and chemistry in the field of manifestations of neuroses" (Freud, 1926, translation by the authors). What he could not imagine was that physics itself would also provide avenues for rethinking the relationships between matter and consciousness.Freud's intellectual journey from neurology to psychoanalysis represents a significant epistemological shift in the history of medicine and psychology. In October 1885, Freud, then aggregated to neurology, arrived in Paris. He spent several months working in the service of Professor Jean-Martin Charcot (1825-1893) at La Salpêtrière. Freud was particularly drawn to Charcot's unconventional approach of using hypnosis to study hysteria. This condition was largely dismissed by the Viennese medical community, which adhered strictly to organic explanations of mental disorders (Drouin et al., 2023).The transition in Freud's thinking is particularly evident in his 1893 article published in the Archives of Neurology. In this work, he compares organic and hysterical paralysis. Initially approaching the topic from a neurological perspective, Freud progressively introduces the need for a psychological explanation: "Hysteria acts in its paralysis and other manifestations as if anatomy did not exist, or as if it did not have any consciousness" (Freud, 1893). This statement marks a crucial turning point in his thinking. He then asks permission to "enter the field of psychology" to explain how "there can be functional alteration without concurrent organic lesion" (Freud, 1893).In suggesting that hysteria behaves as if anatomy does not exist, Freud established a theoretical foundation for exploring psychological processes independently of their neurological substrates. However, this should not be misinterpreted as a complete rejection of the biological basis of mental phenomena.This departure from strictly neurological explanations represented a break with the medical thought of his time. It paved the way for a new conception of mental disorders where the psyche was not merely subordinate to anatomy but constituted a full field of investigation in its own right. Nevertheless, Freud maintained that the apparent independence of psychological processes from their neurological basis was a matter of current scientific limitations rather than an inherent dualism. As he would state in 1939: "the psychic topics of psychoanalytic theory have nothing to do with the anatomy of the brain" (Naccache, 2022). This statement reflected the methodological separation he established rather than an ontological claim about the independence of mind from brain.Freud's shift from neurology to psychoanalysis thus established a conceptual foundation that would allow for the exploration of psychological phenomena on their own terms. This foundation now serves as a productive starting point for examining how contemporary neuroscience might bridge the gap between psychological and neurobiological explanations of mental phenomena.The Connectome: Mapping Neural Connectivity Recent advances in neuroscience and neuroimaging provide new perspectives on the functional/organic duality that Freud grappled with. The concept of the connectome-the comprehensive mapping of neural connections within the brain-has emerged as a crucial framework for understanding brain function and dysfunction (Kruper et al., 2024). Modern connectomics aims to establish the complete "wiring diagram" of the human brain using diffusion MRI (dMRI) to trace white matter fibers (tractography) and functional MRI to map connectivity patterns.The emergence of diffusion MRI has been particularly revolutionary in revealing alterations to white matter organization in psychiatric pathologies (Le Bihan, 2003). Unlike molecular biology, which sometimes identifies the genetic origins of certain psychiatric disorders, neuroimaging targets structural anomalies that could underpin the phenotypic expression of numerous mental disorders.Comparative multimodal meta-analyses have identified specific white matter abnormalities across various psychiatric conditions. For instance, both schizophrenia and bipolar disorder share anomalies in the corpus callosum, indicating a common deficit in connectivity, though these abnormalities are more severe in schizophrenia (Zhao et al., 2022). As we will see later, this is also the case for pathologies closer to Freud's interests, such as post-traumatic stress disorder or conversion disorders. These findings provide tangible evidence of structural differences underlying diverse psychiatric presentations, offering a neurobiological dimension to conditions that Freud approached from a psychological perspective.Perhaps most remarkable is the emerging evidence that psychotherapeutic interventions can lead to measurable changes in brain architecture.A recent comprehensive meta-analysis by Cera et al. (2022) examining neural correlates of different psychotherapeutic approaches through fMRI provides strong empirical support for these observations. Analyzing 38 studies with a total sample of 1,688 subjects, they found that all forms of psychological intervention influenced brain function, with consistent changes in frontal, prefrontal regions, insular cortex, and superior and inferior frontal gyri. Importantly, their analysis revealed that psychodynamic approaches were distinctively associated with changes in the right superior and inferior frontal gyri and putamen, suggesting unique neurobiological mechanisms compared to CBT (Cognitive Behavioural Therapy) and mindfulness-based interventions. These findings align with the theoretical foundations of psychodynamic therapy, which emphasizes work with memory, space-time navigation, and representation-functions associated with these specific neural regions (Cera et al., 2022).Similarly, electroconvulsive therapy for depression has been shown to modify white matter microstructure, with measurable improvements in neural fiber organization and connectivity following treatment. These changes were followed by relative "remyelination" under treatment, confirming the plasticity of white matter in response to therapeutic intervention, both psychotherapeutic and physical (Belge et al., 2022). These discoveries do not reduce the psyche to its neuronal substrate. Rather, they demonstrate a dynamic interaction between psychological processes and brain structure. This relationship aligns unexpectedly with certain intuitions Freud had about the plastic and dynamic character of mental functioning (Freud, 1926). The convergence suggests that Freud's shift toward psychological explanations was not a rejection of biology but rather a recognition that a different level of analysis was necessary to capture the complexity of mental phenomena.Modern neuroscience has begun to provide empirical validation for certain Freudian concepts. Three areas in particular demonstrate this convergence between psychoanalytic intuition and neuroscientific discovery: mechanisms of dissociation, memory suppression, and the neurobiological basis of conversion disorder.Dissociation refers to a disruption in the usually integrated functions of consciousness, memory, identity, or perception of the environment. Operationally, it manifests along a spectrum from common experiences such as daydreaming to pathological conditions like dissociative identity disorder.Clinically, dissociation can be through that from the as dissociation and dissociation manifestations of psychological 2024). 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