Mirror Touch Synaesthesia (MTS) has slowly sent shockwaves throughout the medical community. MTS was brought to the medical world’s attention in 2005¹. MTS is as weird as it is wonderful because feeling someone else’s pain could be perceived as the best representation of empathy. MTS is defined as a person having a physical reaction or response to something that is happening to someone else². 2% of the population live with MTS³.
Synaesthetes are individuals who have synaesthesia⁴. Those with MTS are referred to as MT Synaesthetes; they can understand and identify facial expressions, and have enhanced social awareness⁵. However, MTS can be severely disruptive. Some synaesthetes become overwhelmed and distressed by their feelings as a result of others’ experiences; this is known as sensory overload⁶,⁷. Sensory overload is defined as receiving excessive input from all your 5 five senses which your brain struggles to cope with⁸. Coping mechanisms, like deep breathing exercises, seem to be effective for MT synaesthetes⁹ ¹⁰. Furthermore, many synaesthetes often assume that everyone is experiencing the sensations they experience¹¹.
Figure 1: A diagram depicting the location of the primary and secondary somatosensory cortexes in the human brain¹⁵.
The neurobiology behind Mirror-Touch Synaesthesia
MTS involves triggering the primary (SI) and secondary (SII) somatosensory cortexes within the synaesthete’s brain (Figure 1)¹². fMRI imaging showed that the same areas of the synaesthete’s brain were activated as that of the individual performing the action¹³. However, the SII in the parietal operculum has more grey matter in the brains of MT synaesthetes¹⁴. fMRI also indicated that the activation of SI and SII was related to increased stimulation of the mirror- touch network¹³. Furthermore, the tactile mirror system, which links MTS and empathy, leads to synaesthetes to physically feel what others are feeling¹³.
Dr Joel Salinas lives with MTS and is a neurologist in the USA¹⁶. He mentions that in MTS, the visual and touch centres of the brain are subconsciously merged and triggered¹⁷. MTS may occur due to mirror neurones in synaesthetes’ brains¹³.
Chicago Med provides necessary neuroscientific knowledge
‘Chicago Med’ is a fictional show which provides an insight into a hospital’s Emergency Department. In Series 2, Episode 12 of Chicago Med, named “Mirror, Mirror”, MTS is represented¹⁸. In the show, two doctors encounter a character named Ariel who exhibits strange symptoms for no apparent reason.
Firstly, a male patient experiences a seizure, which Ariel “imitates.” However, a female doctor finds that Ariel is not exhibiting the signs of a seizure, such as nystagmus or asynchronous muscle movements. Ariel’s mother repeatedly tells Ariel to stop making a scene. Ariel is put into isolation. The male doctor tests a theory that he thinks may apply to Ariel. He has a conversation with Ariel, where he slaps his left cheek. As a result, Ariel feels the pain on her right cheek, a mirrored impact. The doctor diagnoses Ariel with MTS¹⁹.
Showing the reaction of Ariel’s mother is important, because viewers may be able to identify how their reaction to such a situation would be similar. By incorporating MTS and the reactions to it within the storyline, Chicago Med has managed to bring this wonderfully weird condition into the spotlight. Perhaps viewers would feel inspired by the episode go on and learn more about MTS. Increased awareness of this condition could lead to more research interest, allowing research scientists to fully understand MTS through tests and clinical trials.
Reflecting upon mirror neurones
Mirror neurones replicate the sensory experiences, which happens at a heightened level in synaesthetes. These specialised neurones can also help us understand human behaviours and emotions²⁰. Solid evidence of the existence of mirror neurones in humans has been obtained through many imaging techniques, including Functional Magnetic Resonance Imaging²¹. Mirror neurones are in the Broca’s area, inferior parietal cortex and primary motor cortex, as seen in Figure 2 ²⁰ ²².
Mirror neurones are activated when we carry out an action, and when we observe others²⁴. In addition, mirror neurones are motor or visuomotor²¹ ²⁵.
Visuomotor describes the coordination between the visual and motor aspects of the brain, specifically the eyes and the upper and lower limbs²⁶. A visual stimulus would activate visuomotor neurones which results in a motor response such as limb movement²⁷. Mirror neurones are one of two categories of visuomotor neurones²⁷. Mirror neurones are part of an extensive mirroring network. When an individual replicates an action, the mirror neurone fires like it would have fired for the person who carried out the action²⁸. It has also been discovered that mirror neurons play a part in sharing emotions²⁹. Have you ever cringed when someone has fallen? You cringe because the mirror network crosses the threshold between conscious and subconscious thinking, making you think that you had fallen; thus, you respond accordingly. The mirroring experience intensifies and is a more conscious phenomenon³⁰.
Figure 2: A depiction of several regions in the brain such as the Broca's Area and Primary Motor Cortex/Area where mirror neurones are located²³.
Dr Salinas explains that every human has a mirror network in their brains, but synaesthetes tend to have a more extensive network¹⁷. The mirror neurone network is also hyper-activated in MT synaesthetes. Additionally, the threshold between recognising your own body and someone else’s with synaesthetes is extremely blurred, so MT synaesthetes feel sensations in regions where individuals may be experiencing sensations. Additionally, a synaesthete would see their body blend into their surroundings due to the threshold’s blurring³⁰.
Somatic empathy: How it differs in MT synaesthetes
There are many types of empathy³¹ ³²:
Cognitive empathy (putting yourself into someone else’s shoes) Affective empathy (understanding and expressing concern for an individual’s well-being)
Somatic empathy (physical reaction to someone else’s experiences)
Somatic empathy is a response to something that someone else has undergone³². People experience somatic empathy all the time, and this may be in the subtlest ways possible. For example, if someone is embarrassed, you may react physically to this. You might have a feeling of uneasiness like it was you who was embarrassed. Somatic empathy is the most prevalent in MTS. However, in MTS, the patient feels the same sensation, but they feel it on the opposite side to where the impact occurred³³. Intriguing, isn’t it?
Mirror-Touch Synaesthesia is vital in neuroscientific advancement
Usually, synaesthetes have developmental synaesthesia, meaning that they were born with synaesthesia or inherited it genetically⁹ ¹¹. It may be acquired due to limb loss¹⁰. Phantom Limb Pain occurs when an individual loses a limb but still feels a sensation, or unpleasant pain, in the region of the amputated extremity (Figure 3)³⁴ ³⁵. However, the sensations only affect the phantom limb in amputees³⁶. Moreover, the amputees only felt the sensations when humans were touched³⁶.
Figure 3: A visual representation of the sensations experienced by amputees with Phantom Limb Pain³⁷
Those with autism spectrum disorder have a mirror neurone system dysfunction, leading to decreased mirror-neurone activity³⁸ ³⁹. As MTS is caused by elevated mirror neurone activity, researchers have suggested that MTS research may lead to novel autism research that could provide help for individuals with autism⁴⁰. Researchers may discover how to increase mirror neurone activity by studying MT synaesthetes.
MTS occurs more prevalently in people with grapheme-colour synaesthesia⁴¹. Grapheme-colour synaesthesia involves the association of colours to letters or numbers⁴². Thus, MT synaesthetes can have MTS alongside other synaesthetic conditions; however, further research is required to reveal how this is possible⁴¹.
Why is Mirror-Touch so important to the scientific community?
MTS enhances social cohesion⁴³. Social behaviour is heavily impacted by the human ability to understand what others around us are feeling⁵. This can enhance empathy within society.
It would be interesting to discover whether MTS is solely something you are born with, or whether it can be acquired during life. If the latter is found to be true it could be advantageous to healthcare, where a better understanding of patients’ pain may lead to improvements in healthcare standards. Also, it may allow doctors to adapt treatment to suit patients and treat them holistically. Holistic treatment involves the patient’s physical symptoms and emotional trauma to be treated simultaneously. Dr Salinas mentions that MTS helps him be more compassionate towards his patients due to understanding what the patient needs. He, also, uses MTS to strengthen his capability to provide the best care³⁰. Dr Salinas also states that MTS helps him diagnose patients¹⁷. Dr Salinas has also authored “Mirror Touch: Notes from a Doctor Who Can Feel Your Pain”⁴⁴.
Mirror-Touch Synaesthesia – The ultimate superpower
MTS is a physical manifestation of empathy, which could be perceived as a superpower. Understanding one another in more empathetic ways could help us to better take care of one another.
References
1. Blakemore SJ, Bristow D, Bird G, Frith C, Ward J. Somatosensory activations during the observation of touch and a case of vision–touch synaesthesia. Brain. 2005;128(7):1571- 1583. doi:10.1093/brain/awh500
2. Ward J, Banissy MJ. Explaining mirror-touch synesthesia. Cogn Neurosci. 2015;6(2-3):118-133. doi:10.1080/17588928.2015.1042444
3. Medina J, DePasquale C. Influence of the body schema on mirror-touch synesthesia. Cortex. 2017;88:53-65. doi:10.1016/j.cortex.2016.12.013
4. Watson K. What Is Synesthesia? Healthline. Published October 24, 2018. Accessed March 15, 2022. https://www.healthline.com/health/synesthesia
5. Ward J, Schnakenberg P, Banissy MJ. The relationship between mirror-touch synaesthesia and empathy: New evidence and a new screening tool. Cogn Neuropsychol. 2018;35(5-6):314-332. doi:10.1080/02643294.2018.1457017
6. Arnold N. “I literally feel your pain”: what life’s like with mirror-touch synesthesia. BBC Three. Published September 1, 2017. Accessed March 15, 2022.
https://www.bbc.co.uk/bbcthree/article/13a3affc-839d-4743- a5aa-738f9c8a6615
7. Di Maio M. Life and Simulated Death with Mirror Touch Synaesthesia. Affinity Magazine. Published April 9, 2020. Accessed March 15, 2022. http://affinitymagazine.us/2020/04/09/life-and-simulated- death-with-mirror-touch-synaesthesia/
8. Watson K. What Is Sensory Overload? Healthline. Published September 14, 2021. Accessed March 15, 2022. https://www.healthline.com/health/sensory-overload
9. What Is Synesthesia Disorder And How To Cope With It. BetterHelp. Published February 24, 2022. Accessed March 23, 2022. https://www.betterhelp.com
10. What Is Mirror Touch Synesthesia? BetterHelp. Published May 4, 2021. Accessed February 20, 2022. https://www.betterhelp.com
11. Mirror Neurons: Are there people who feel others’ pain? Spotify. Published April 22, 2010. https://open.spotify.com/episode/6Wep53JXcvNuP6RG3Bv4dY
12. Cioffi MC, Moore JW, Banissy MJ. What can mirror-touch synaesthesia tell us about the sense of agency? Front Hum Neurosci. 2014;8. doi:10.3389/fnhum.2014.00256
13. Banissy MJ, Ward J. Mirror-touch synesthesia is linked with empathy. Nat Neurosci. 2007;10(7):815-816. doi:10.1038/nn1926
14. Holle H, Banissy MJ, Ward J. Functional and structural brain differences associated with mirror-touch synaesthesia. NeuroImage. 2013;83:1041-1050.
doi:10.1016/j.neuroimage.2013.07.073
15. Alternative Figure 6.1A: Motor and Somatosensory Cortical Areas – Lateral View. Oxford University Press. https://learninglink.oup.com/access/content/blumenfeld3e- student-resources/blumenfeld3e-alternative-figure-6-1a-motor- and-somatosensory-cortical-areas-lateral-view
16. About JOEL SALINAS. Joel Salinas, M.D. Accessed February 24, 2022. https://joelsalinasmd.com
17. Mirror Touch Synesthesia. Radio Health Journal. Published September 29, 2019. https://radiohealthjournal.org/mirror- touch-synesthesia/
18. Chicago Med S2 E12: Mirror, Mirror. NBC. Published February 2, 2017. https://www.nbc.com/chicago- med/video/mirror-mirror/3459807
19. Mirrored Touch Synaesthesia? | Chicago Med. youtube. Published March 11, 2018. https://www.youtube.com/watch? v=G2NKTDI5OCM
20. Mathon B. Les neurones miroirs: de l’anatomie aux implications physiopathologiques et thérapeutiques. Rev Neurol (Paris). 2013;169(4):285-290. doi:10.1016/j.neurol.2012.10.008
21. Rizzolatti G, Craighero L. THE MIRROR-NEURON SYSTEM. Annu Rev Neurosci. 2004;27(1):169-192. doi:10.1146/annurev.neuro.27.070203.144230
22. Kilner JM, Lemon RN. What We Know Currently about Mirror Neurons. Curr Biol. 2013;23(23):R1057-R1062. doi:10.1016/j.cub.2013.10.051
23. Peate I, Nair M. Fundamentals of Anatomy and Physiology for Student Nurses. John Wiley & Sons, Incorporated; 2011. http://ebookcentral.proquest.com/lib/salford/detail.action? docID=822491
24. Rizzolatti G, Sinigaglia C. The mirror mechanism: a basic principle of brain function. Nat Rev Neurosci. 2016;17(12):757- 765. doi:10.1038/nrn.2016.135
25. Lamm C, Majdandžić J. The role of shared neural activations, mirror neurons, and morality in empathy – A critical comment. Neurosci Res. 2015;90:15-24. doi:10.1016/j.neures.2014.10.008
26. Binder MD, Hirokawa N, Windhorst U, eds. Visuomotor. In: Encyclopedia of Neuroscience. Springer Berlin Heidelberg; 2009:4354-4354. doi:10.1007/978-3-540-29678-2_6383
27. Fadiga L, Fogassi L, Gallese V, Rizzolatti G. Visuomotor neurons: ambiguity of the discharge or ‘motor’ perception? Int J Psychophysiol. 2000;35(2-3):165-177. doi:10.1016/S0167- 8760(99)00051-3
28. Acharya S, Shukla S. Mirror neurons: Enigma of the metaphysical modular brain. J Nat Sci Biol Med. 2012;3(2):118. doi:10.4103/0976-9668.101878
29. Molenberghs P, Cunnington R, Mattingley JB. Brain regions with mirror properties: A meta-analysis of 125 human fMRI studies. Neurosci Biobehav Rev. 2012;36(1):341-349. doi:10.1016/j.neubiorev.2011.07.004
30. Ep. 195 - Mirror Touch with Joel Salinas M.D. Spotify. Published June 13, 2017.
https://open.spotify.com/episode/77muyl3v0QG8C07EnManh3
31. Cherry K. What Is Empathy? Verywell Mind. Published May 2, 2020. Accessed February 24, 2022. https://www.verywellmind.com/what-is-empathy-2795562
32. Clarke J. Cognitive vs. Emotional Empathy. Verywell Mind. Published October 4, 2021. Accessed February 24, 2022. https://www.verywellmind.com/cognitive-and-emotional- empathy-4582389
33. Nall R. Is Mirror Touch Synesthesia a Real Thing? Healthline. Published January 13, 2020. Accessed February 20, 2022. https://www.healthline.com/health/mental-health/mirror-touch- synesthesia
34. Hanyu-Deutmeyer AA, Cascella M, Varacallo M. Phantom Limb Pain. In: StatPearls [Internet]. StatPearls Publishing; 2022. Accessed March 25, 2022. http://www.ncbi.nlm.nih.gov/books/NBK448188/
35. Waldman SD. Phantom Limb Pain. In: Atlas of Common Pain Syndromes. Elsevier; 2019:403-406. doi:10.1016/B978-0-323- 54731-4.00103-1
36. Goller AI, Richards K, Novak S, Ward J. Mirror-touch synaesthesia in the phantom limbs of amputees. Cortex. 2013;49(1):243-251. doi:10.1016/j.cortex.2011.05.002
37. Phantom Limb Pain Management. Purple Prosthetics. Published January 25, 2020.
https://purpleprosthetics.com/phantom-limb-pain-management/
38. Baron-Cohen S, Robson E, Lai MC, Allison C. Mirror-Touch Synaesthesia Is Not Associated with Heightened Empathy, and Can Occur with Autism. Yamasue H, ed. PLOS ONE. 2016;11(8):e0160543. doi:10.1371/journal.pone.0160543
39. Linkovski O, Katzin N, Salti M. Mirror Neurons and Mirror- Touch Synesthesia. The Neuroscientist. 2017;23(2):103-108. doi:10.1177/1073858416652079
40. Stoel Gammon K. Touching Me, Touching You. ABC News. Published June 18, 2007. Accessed March 22, 2022. https://abcnews.go.com/Health/story?id=3284488&page=1
41. Ward J. The Co-occurrence of Mirror-Touch With Other Types of Synaesthesia. Perception. 2019;48(11):1146-1152. doi:10.1177/0301006619875917
42. Ruiz MJ, Dojat M, Hupé J. Multivariate pattern analysis of fMRI data for imaginary and real colours in grapheme–colour synaesthesia. Eur J Neurosci. 2020;52(5):3434-3456. doi:10.1111/ejn.14774
43. Banissy MJ. Mirror-Touch Synaesthesia: The Role of Shared Representations in Social Cognition. Doctoral. UCL (University College London); 2010. https://discovery.ucl.ac.uk/id/eprint/19307/
44. Salinas J. Mirror Touch: Notes from a Doctor Who Can Feel Your Pain.; 2018.