A groundbreaking study has overturned decades of neuroscientific understanding about brain plasticity following amputation. Researchers at University College London conducted the first longitudinal study examining brain maps before and after limb amputation.

The study followed three individuals scheduled for hand amputation, using functional MRI to map their somatosensory cortex—the brain region containing detailed body maps. Participants were scanned before surgery and repeatedly afterwards (up to five years post-amputation), moving fingers pre-surgery and imagining finger movements post-amputation. The study was highly controlled, with task instructions and timing of measurements remaining consistent each time. Furthermore, the researchers used standardised fMRI procedures across sessions and used consistent tasks pre- and post-amputation.

The established scientific belief was that after amputation, the brain dramatically reorganises its body map—with neighbouring regions (like those controlling the lips) expanding to take over the brain territory previously assigned to the missing limb. However, this study found the opposite: the brain's body map remained virtually unchanged after amputation. The hand representation stayed intact, and neighbouring regions did not expand to ‘take over’ the missing hand's brain territory. This stability was confirmed in additional participants (N=26) who had undergone amputation decades earlier. Previous studies suggesting massive brain reorganisation may have been flawed because they compared amputees to non-amputees rather than tracking the same individuals over time. These studies misinterpreted overlapping brain regions as evidence of reorganisation.

The findings revolutionise phantom limb pain treatment approaches. Rather than trying to restore limb representation in the brain (which never disappeared), treatment should focus on managing damaged nerve endings that send ‘noisy signals’ to the unchanged brain map.

Most significantly, these results offer huge promise for brain-computer interfaces controlling prosthetic limbs. Since the original neural circuits remain stable for years, these technologies can reliably tap into preserved hand representations, potentially restoring sophisticated movement and sensation to amputees.

References: UCL news The brain’s map of the body remains unchanged after amputation https://www.ucl.ac.uk/news/202... (accessed 10.9.25)

ANSWER THE FOLLOWING QUESTIONS!

1. Evaluate the limitations of using only three participants in the main longitudinal study. How might the small sample size affect the validity and generalisability of the findings, and what steps did the researchers take to address this concern?
2. Compare the advantages and disadvantages of the longitudinal approach used in this study versus comparing amputees and non-amputees in the past.
3. How did the researchers ensure standardisation between pre-amputation and post-amputation scanning sessions?
4. Outline one ethical issue which is raised by this study.
5. Suggest one way in which researchers could address the ethical issue you have mentioned in Q4

Challenge:

Research the latest brain-computer interfaces to learn about how they help to restore function.