It’s 3 am. You wake with a parched throat, instinctively reaching for the glass of water on your bedstand. But, your hand never finds it. In fact, your hand never moves at all, because it’s not there. It hasn’t been for months. And yet, you can vividly feel the flexing of tendons, the weight of your hand shifting, the curl of your fingers resting around the cold glass.
This harrowing condition is known as phantom limb syndrome, a phenomenon first observed in the 16th century by French military surgeon Ambroise Pare. Most typically associated with individuals who’ve undergone amputation, phantom limb syndrome refers to the vivid sensation of a missing body part still felt. However, this condition isn’t exclusively tied to trauma. In fact, many individuals born without limbs, a disorder known as congenital aplasia, have reported phantom sensations, despite having no previous physical experience of the limb (Brugger et al., 2000). These reports challenge the notion that phantoms occur solely from loss and instead suggest the possibility of a neurobiological model of the body hardwired into the brain, one that may include representations of body parts physically absent or entirely immaterial.
For decades, only amputees and individuals with congenital aplasia were known to experience such phantoms. However, recent findings have observed this phenomenon in another population: transgender and gender-diverse individuals. A 2023 study by psychotherapist S.J. Langer surveyed over 1400 trans and gender-diverse participants, finding nearly 50% reported “trans phantoms” (Langer et al., 2023). More specifically, the phantoms involved gendered body parts, such as the phallus, breasts, and hips, and were often accompanied by distinct sensory, tactile, and erotic sensations. These findings support earlier clinical findings by neuroscientist V.S. Ramachandran, who spearheaded the first scientific study on phantom limbs in transgender individuals (Ramachandran & McGeoch, 2007). But why and how do these sensations occur?
Perhaps the most popular theory on phantom limbs suggests that such sensations are caused by neuromas: bundles of severed nerves that send faulty signals to the brain after amputation (Collins et al., 2018). Other theories suggest cortical reorganization: the brain’s sensory map reorganizes after amputation, with neighboring areas taking over the region once devoted to the missing limb (Flor 2014). But these theories only extend to amputees; why, then, do phantoms appear in trans individuals or those with congenital aplasia? How can one feel a limb that has never existed?
Langer attributes these phantom sensations to the “free energy principle” and theory of the Bayesian brain (Langer et al., 2023). Simply put, the brain is a predictive organ, continuously generating expectations about sensory input based on prior predictions. These predictions are probabilistic: much like rolling a weighted die, certain outcomes are more likely than others. Over time, the brain constructs distributions of anticipated physiological states. When sensory input aligns with these predictions, the brain achieves equilibrium, conserving energy while maximizing efficiency. However, when a deviation occurs, there is a “prediction error”, which results in “free energy” (Langer et al., 2023). This free energy can be conceptualized as surprise, uncertainty, emotional discomfort, or even dysphoria.
Consider body temperature, for example. The brain expects our temperature to be within a certain range and when it’s not, there is free energy: the brain produces static to tell us something is wrong. In the context of phantoms, a similar mismatch arises when the brain predicts a body part that isn’t there. To minimize free energy and restore equilibrium, the brain attempts to resolve this surprise by generating the missing limb itself. The result? A phantom: the body the brain expects is felt, even if it doesn’t physically exist.
This model may help explain why phantom sensations are reported not only by transgender individuals but also by those with congenital limb deficiency. It further challenges the notion that our sense of body is constructed solely through external feedback, instead suggesting the brain can generate highly specific body representations, even of gendered anatomy physically absent. For trans individuals, this framework may provide a neurobiological basis for the experience of gender dysphoria and phantom sensations.
More broadly, phantom phenomena challenge simplistic definitions of the body as purely physical, forcing us to acknowledge our body as an active construction shaped by the brain’s expectation. Thus, understanding phantom sensations in gender-diverse individuals offers insights into the body schema and how our brains construct the self - not just through what is there, but what the brain expects to be there.
Work Cited
Brugger, P., Kollias, S. S., Müri, R. M., Crelier, G., Hepp-Reymond, M.-C., & Regard, M. (2000). Beyond re-membering: Phantom sensations of congenitally absent limbs. Proceedings of the National Academy of Sciences, 97(11), 6167–6172. https://doi.org/10.1073/pnas.100510697
Collins, K. L., Russell, H. G., Schumacher, P. J., Robinson-Freeman, K. E., O’Conor, E. C., Gibney, K. D., Yambem, O., Dykes, R. W., Waters, R. S., & Tsao, J. W. (2018). A review of current theories and treatments for phantom limb pain. Journal of Clinical Investigation, 128(6), 2168–2176. https://doi.org/10.1172/JCI94003
Flor, H. (2008). Maladaptive plasticity, memory for pain and phantom limb pain: Review and suggestions for new therapies. Expert Review of Neurotherapeutics, 8(5), 809–818. https://doi.org/10.1586/14737175.8.5.809
Friston, K. (2009). The free-energy principle: A rough guide to the brain? Trends in Cognitive Sciences, 13(7), 293–301. https://doi.org/10.1016/j.tics.2009.04.005
Langer, S. J., Caso, T. J., & Gleichman, L. (2023). Examining the prevalence of trans phantoms among transgender, nonbinary and gender diverse individuals: An exploratory study. International Journal of Transgender Health, 24(2), 225–233. https://doi.org/10.1080/26895269.2022.2164101