2-Minute Neuroscience: Phantom Limb

Phantom limb is a condition in which someone who has lost a part of their body (e.g., due to amputation) continues to experience phantom sensations coming from the missing body part. In this video, I discuss some of the hypotheses that have been proposed to explain this strange phenomenon.

For an article (on my website) that discusses phantom limb more in-depth, click this link: https://neuroscientificallychallenged.com/posts/know-your-brain-phantom-limb

TRANSCRIPT:

Phantom limb is a condition in which someone who has lost a part of their body continues to experience phantom sensations coming from that body part. Despite the name, phantom limb doesn’t only occur in limbs, and has also been recorded after the loss of other body parts like breasts, genitals, and even teeth. Phantom sensations are thought to be experienced by almost all amputees, and most suffer from some degree of phantom pain.

Scientists have proposed a number of hypotheses to explain phantom limb, but the phenomenon is still poorly understood. The prevailing explanation is an idea known as cortical reorganization. According to this hypothesis, when a limb is lost, the neurons in the somatosensory cortex that used to respond to signals from that limb begin to respond to signals from other nearby neurons. This can cause sensations felt in other parts of the body to lead to the stimulation of neurons in the somatosensory cortex devoted to the now missing limb, which causes the brain to perceive sensations in the missing limb.

Another hypothesis suggests that your brain maintains an internal representation of your body, which aids in body positioning and movement among other things. But when a limb is lost the body representation can remain intact. This persistent neural representation might lead to the sense that the limb is still there, and could even generate pain when the intention to move the limb is discordant with the lack of sensory feedback from the missing body part.

The peripheral nervous system might also be involved. When a limb is lost, damaged neurons often attempt to repair themselves by growing new extensions. But without a limb to grow into, the new extensions have nowhere to go, and they form a mass of neural tissue called a neuroma. The neuroma can generate erratic signals, which may underlie the sensations and pain associated with phantom limb.

REFERENCES:

Collins KL, Russell HG, Schumacher PJ, Robinson-Freeman KE, O'Conor EC, Gibney KD, Yambem O, Dykes RW, Waters RS, Tsao JW. A review of current theories and treatments for phantom limb pain. J Clin Invest. 2018 Jun 1;128(6):2168-2176. doi: 10.1172/JCI94003. Epub 2018 Jun 1. PMID: 29856366; PMCID: PMC5983333.

Flor H, Nikolajsen L, Staehelin Jensen T. Phantom limb pain: a case of maladaptive CNS plasticity? Nat Rev Neurosci. 2006 Nov;7(11):873-81. doi: 10.1038/nrn1991. PMID: 17053811.

Ramachandran VS, Hirstein W. The perception of phantom limbs. The D. O. Hebb lecture. Brain. 1998 Sep;121 ( Pt 9):1603-30. doi: 10.1093/brain/121.9.1603. PMID: 9762952.

Weeks SR, Anderson-Barnes VC, Tsao JW. Phantom limb pain: theories and therapies. Neurologist. 2010 Sep;16(5):277-86. doi: 10.1097/NRL.0b013e3181edf128. PMID: 20827116.

Видео 2-Minute Neuroscience: Phantom Limb канала Neuroscientifically Challenged