"Looking Down": Neuropsychoanalytic Dialogues Podcast - Episode 3
Oliver Turnbull on the trigeminal nerve, the oral stage, and a downward-looking neuropsychoanalysis
Most of us in neuropsychoanalysis have spent the last twenty-five years working our way upward from the upper brainstem. We start with the reticular activating system and the periaqueductal grey, follow the ascent through the diencephalon and the limbic structures, and end up somewhere in the cortex. The story we tell is a story of elaboration. Affect originates in the depths and is then layered, regulated, represented, remembered, traded off. Oliver Turnbull has been part of that ascent for as long as anyone. In conversation on the Neuropsychoanalytic Dialogues podcast, which I co-host with Curtis Holt-Robinson, he turns the orientation around.
NPSA Dialoges Episode 3 | Oliver Turnbull: Affective Consciousness
The invitation he issues toward the end of the interview is to be a downward-looking neuropsychoanalyst. He has spent recent years teaching cranial nerves at the Bangor medical school, polishing up a body of neuroanatomy he had not used in decades, and what he has found in that descent is, by his own account, considerably more interesting than he had expected. His 2025 paper on the ‘mesencephalic component of the trigeminal nerve’ is the first of what he says will be a series.
The trigeminal nerve is mostly known to clinicians as the sensory supply to the face. Its mesencephalic component is the exception that turns out to be crucially important. This northern extension of the nucleus carries sensation only from the oral cavity, and it lies anatomically directly anterior to the periaquaductal grey, running alongside it. Oliver’s argument is that this proximity is the neurobiological substrate for Freud’s oral stage. He told us he would be prepared to defend the oral stage in court. The communication between the two structures is not the standard synaptic kind. It is volume transmission, the slow diffusion of neurotransmitter into intercellular space, which provides the sort of homeostatic stability that synaptic on-and-off signalling cannot. Two structures next door to each other do not need synapses to talk.
This is a pretty big neuroanatomical claim with extensive implications for theory and clinical applications. The mouth has access to the feeling centre of the brain that no other part of the body has. When patients fall silent before saying something difficult, when the jaw clenches in anger, when the lip catches in restraint, we are watching the trigeminal-PAG relationship in motion. The mouth is a reliable truth-teller, and the anatomy now gives that clinical intuition a structural account. The infant exploring the world by mouth is doing much more than mapping textures. The infant is laying down the first traces of affective experience through the structure that is physically closest to the affective centre. That the proximal digestive tract is among the earliest parts of the nervous system to be myelinated at birth fits the picture rather than complicating it. Survival requires attachment and feeding. The nervous system is built so that those two requirements come online together.
What I find most useful about Oliver’s framing is the way it dignifies the early without sentimentalising it. Bowlby’s work on attachment, Harlow’s monkeys clinging to the cloth ‘mother’, Klein on oral aggression, Bion on beta elements, for which the mouth is the prototype apparatus of metabolism. While none of these are reducible to neuroanatomy, though the neuroanatomical research supports them, and more specifically the recent research on the mesencephalic trigeminal nucleus.
© 2026 Paul Moore
This series of posts on dreams is derived from postgraduate modules, and seminars, I teach for the M.Sc. in Psychoanalytic Psychotherapy, Department of Psychiatry, School of Medicine, and the M.Phil. in Psychoanalytic Studies at the School of Psychology, Trinity College Dublin. The module, “Dreams, Dreaming, and Symbolic Life” (DDSL), is part of the M.Phil. in Psychoanalytic Studies in the School of Psychology. I have developed and delivered the MBQiPA module in various forms, and for several educational institutions, for over 17 years.
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