Sensory information and the brain

Professor Ramesh Rajan's research is predicated on the over-riding hypothesis that a huge part of our internal lives and our interactions with the world are guided by our senses, by what we hear, see, touch, smell, taste and our other senses.

Using this overarching theme, he studies sensory processing in the brain to understand how brain disorders affect the way in which we receive and process information about the world, to shape and guide our internal lives and our responses to the world and how the many cognitive, motor, memory and emotional deficits in brain disorders may flow from disordered sensory processing that distorts our world view and our interactions with self and others. 

He studies models of traumatic brain injury and the processing of sensory information, as well as how brain alterations in conditions like Huntington's Disease, Multiple Sclerosis, Autism Spectrum Disorders, and Parkinson's Disease, affect the ability to understand our most powerful communication tool, namely speech, in noisy backgrounds.

'Our world is noisy and crowded and operating in it requires us to extract information of interest from competing, but uninformative or unnecessary, information. For example, when you listen to speech, people are often talking in the background. When you look around a messy room, you're able to identify the book or toy you're interested in. I'm interested in how we pick up what's of interest and discard what's not, from all the information that bombards us. This isn't just a case of what we hear but also a case of how the brain selects what to attend to and what to suppress, and how the brain uses its memory and experience to guide that selection and the perception.'

Ramesh is also trying to understand how traumatic brain injury impacts on our ability to process sensory information.

'In some forms of traumatic brain injury, using CAT scans or MRIs doesn't identify any visible damage and so it's hard to find what's going wrong. Yet these people have cognitive deficits, memory loss, movement disorders, etc. We've found a new set of effects in how they process sensory information, which impacts on producing the appropriate response. When we produce a response, we have to take in the information that's coming, such as catching a ball that's coming towards you. The parts of the brain that control movement and learning produce the wrong responses - not necessarily because there's something wrong with them, but because they're getting the wrong information as to what to do.'