BANGOR UNIVERSITY

Body and Brain: How is your body represented in your brain?

The School of Psychology at Bangor University offers students an opportunity to gain first-hand experience in world-class research. Students in the third year of their undergraduate degree work alongside research active psychologists to design experiments, test participants, analyse data, and write research reports with the potential for future publication. We would like to introduce you to some of the cutting-edge research currently being undertaken by our students this year. This article will focus on the fascinating world of the body schema to demonstrate how research is exploring the way that the body can be represented (and misrepresented) in the brain.

How does your brain understand your body? Look at your own hand and the hand of someone next to you – how does your brain know that one hand belongs to you and must be protected from harm or damage? Do you have an internal ‘sense’ of your body? And, more interestingly, could you ever make fundamental mistakes about your own body? Dr Fay Short and Dr Robert Ward are working with students at Bangor University to explore how the body is represented in the brain and how the brain can misrepresent the body.

The internal representation of the body in the brain is known as the body schema (Head & Holmes, 1911). Your body schema distinguishes between the parts that belong to your body and the rest of the world. It could be argued that two experiences contribute to this distinction between ‘body’ and ‘not body’: physical sensation from the body and physical control over the body. Early research exploring the cortex of the brain has revealed that the sensory cortex is responsible for creating the experience of physical sensation from the body and the motor cortex is responsible for granting control over the body (Penfield & Rasmussen, 1950). Modern research, however, has found that the body schema is not merely a result of sensation and control. Our body schema is actually a complex concept influenced by a wide range of factors including sensation, control, proprioception, vision, emotion, and memory. In fact, the body schema is so complex that it is vulnerable to many different types of error.

Your brain can misrepresent your body by extending the schema to include things that are not a part of your actual body. Amputee patients will often report an awareness of their missing limb and, perhaps even more astonishingly, some stroke patients have reported an awareness of additional body parts, such as an extra arm (Khaten et al, 2009) or even an extra head (Turnbull et al, in prep)! These phantom limbs and supernumerary phantom limbs demonstrate how the body schema can include body parts that no longer exist or have never existed. Research has also found that the body schema can even include external objects that are not real body parts at all. The rubber hand illusion shows how synchronous stroking of a hidden real hand and a visible rubber hand can result in the weird sensation that the rubber object is the real hand (Botvinick & Cohen, 1998). All of these findings suggest that our body schema is quite flexible and current research at Bangor University is exploring how this flexibility could help people to improve their interactions with external objects. We are using virtual reality techniques to encourage the body schema to incorporate tools and equipment; for example, could we help sportsmen incorporate their equipment into their body schema to improve performance? In terms of the brain, a tennis player could quite literally have a racket that is an extension of the self!

Your brain can also misrepresent your body by modifying the schema to appear physically unattractive or abnormal. Patients diagnosed with body dysmorphic disorder will fixate on specific parts of their body with the belief that the part is abnormal or unattractive. This disorder is currently classed as a mental illness, but it is possible that there may be underlying neurological causes for this misrepresentation of the body. Current research at Bangor University has highlighted the importance of control over the body (Short & Ward, 2009), so perhaps the experience of poor control over the body (particularly during the ‘clumsy’ teenage years of physical development) contributes to these negative feelings. Perhaps the misrepresentation of the body schema can be corrected by giving the patient an opportunity to experience successful and graceful control over his or her own body? We are using virtual reality techniques to investigate reactions to ‘ugly’ hands and explore how we could manipulate feelings towards these limbs by providing the participant with control over their movement. We are hopeful that our research in this area may further our understanding of this devastating illness.

This article has provided a brief overview of the exciting research currently being conducted in the virtual reality lab by Dr Fay Short and Dr Robert Ward at Bangor University. We hope that you have found this article interesting, and please do not hesitate to contact us at f.short@bangor.ac.uk if you would like any further information.