Sixth Sense and Beyond

How many senses do we have? Most of us would say that we have five senses - taste, sight, smell, touch, and hearing. What if I say in addition to the traditional big five, there are sixth, seventh and eighth senses as well. Some of you would have thought of sixth sense when I asked, "How many senses do we have?”. But do you know what sixth sense actually is? No, it’s not the ability to perceive something which isn't actually there or a gut feeling.

A new study suggests that the sixth sense is the awareness of one's body in space or sense that deals with how our brain understands where our body is in space. This sense is called proprioception. It plays an important role in balance, coordination, and movement control. It allows us to move smoothly and precisely, and to make quick adjustments to our movements when necessary!

Confused?

Don’t worry, in the series of blogs, we will try to understand the senses beyond the big five. In the current blog we try to understand the sixth sense.

Now, let’s try to feel our proprioceptive senses.

Close your eyes and touch your left knee with your right hand.

It was easy, right? Most of us would have easily accomplished this small task. Why? Because of proprioception - our sixth sense.

If you actually did this task, you would have noticed that you did not use your sense of sight to locate your knee, your eyes were likely closed. You didn’t smell your knee or hear it, or taste it. You already knew where it was before you touched it. This sense of our own body, its position and its movement is called “proprioception.” The proprioceptive sense seems like a mystery because we are largely unaware of them though we are using it every day.

Simply put, proprioception is the ability to sense the orientation of our body in the environment or our ability to sense exactly where our body is. It works unconsciously in our body and allows us to move quickly and freely without having to consciously think about where we are in an environment.

There are several factors that will weaken our proprioceptive senses. Brain injuries, stroke, and arthritis can lead the proprioception sense to work weakly. Proprioception capabilities can also be impaired when joints are injured, such as with ligament sprains, or a joint injury. Also, ageing has been shown to reduce proprioception sense.

All the above factors can happen to us or at least ageing. So, to keep up with our proprioception sense we can involve ourselves in,

• Balance training: Exercising using foam or Harbinger can help in moving limbs and the whole body.

• Passive movement training: Moving the body passively by an apparatus or machine

• Somatosensory stimulation training: This type of training employs external stimulation upon our body such as electrical and magnetic stimulation, acupuncture, and vibration. These are a few techniques mentioned that will aid us in improving and keeping up with our sixth sense.

Further, by knowing about the sixth sense, proprioception, and ways to improve we should also know that the understanding of senses beyond the big five is still growing. There is some debate about exactly what falls under the definition of proprioception. Some researchers define proprioception narrowly, as the ability to sense the position and movement of the body, while others define it more broadly, to include other types of sensory input that contribute to movement control. There is debate about how to apply findings from proprioception research to real-world contexts, such as rehabilitation or sports training. Overall, these debates highlight the complexity of the concept of proprioception, and the ongoing efforts to better understand how it works and how it can be applied in various settings.

In summary, the sixth sense- proprioception is mysterious and involves a complex signalling process in our body. Without proprioception, we wouldn’t be able to sense our body parts precisely. It affects our daily lives. Although there are ways to improve proprioceptive senses, it is still very limited. Scientific understanding of it is still narrow and much of it is still waiting to be discovered.

References

• “The Role of PIEZO2 in Human Mechanosensation” Journal Article. 201 New England Journal of Medicine Alexander T. Chesler, PhD, Marcin Szczot, PhD, Diana Bharucha-Goebel, M.D 1355-1364, 375 10.1056/NEJMoa1602812 [doi] https://www.nejm.org/doi/full/10.1056/NEJMoa1602812 New England Journal of Medicine October 6, 2016, 375(14):1355

• “Multimodal MR-imaging reveals large-scale structural and functional connectivity changes in profound early blindness”. PLOS One (2017). https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173064(opens in new tab)

• Simon Gandevia and Uwe Proske, “Proprioception: The Sense Within,” TheScientist, Aug 31, 2016, https://www.the-scientist.com/features/proprioception-the-sense-within-32940

• Khanacademy, “Proprioception and kinesthesia”, https://www.khanacademy.org/science/health-andmedicine/nervous-system-and-sensory-infor/somatosensation-topic/v/proprioception-kinesthesia

• Prakash Jha, Irshad Ahamad, Sonal Khurana, Kamran Ali, Shalini Verma and Tarun Kumar, “Proprioception: An Evidence-Based Narrative Review,” Res Inves Sports Med. 1(2). RISM.000506. 2017, p14, https://pdfs.semanticscholar.org/60b0/e483e5b17f2ffec286dedfc38bba79d384bb.pdf?_ ga=2.34305953.1453459681.1588401674-1888949605.1588401674

• Prakash Jha, Irshad Ahamad, Sonal Khurana, Kamran Ali, Shalini Verma and Tarun Kumar, “Proprioception: An Evidence-Based Narrative Review,” Res Inves Sports Med. 1(2). RISM.000506. 2017, p15, https://pdfs.semanticscholar.org/60b0/e483e5b17f2ffec286dedfc38bba79d384bb.pdf?_ ga=2.34305953.1453459681.1588401674-1888949605.1588401674