WinSPIRE: Science in the NewsClose your eyes for a second. Even without seeing anything, you can probably still tell whether you’re sitting or standing, feel the temperature of the room, and hear the sounds around you. That’s because your brain doesn’t experience the world through just one sense at a time. Instead, it’s constantly blending sight, sound, touch, smell, and taste into a single reality. Psychologists call this multimodal perception: the idea that our everyday experience is built from all the senses cooperating at once. This teamwork happens so smoothly that we rarely notice it. That is, until something goes wrong.
So, what happens when a disease damages a part of the brain responsible for combining or interpreting sensory information? In some cases, the sensory organs (such as the nose, eyes, or skin) are completely healthy, yet a person still loses their sense of smell, struggles to recognize faces, or feels numbness in their hands. In these cases, your sensory organs aren’t the problem at all. The breakdown stems from the brain’s inability to process what those organs are detecting.
Think of your senses as reporters and your brain as the newsroom. Your eyes, ears, and skin gather the raw footage, but none of those details mean anything until the brain processes and edits them together into a story you can actually use. So when neurological injuries or brain diseases damage the newsroom, the reporters can still be doing their jobs, but the story comes out incomplete or missing. This raises two big questions: first, how do different brain diseases disrupt sensation? And second, if the brain can lose this ability, can it also relearn it?
Depending on which area of the brain is damaged, brain disorders disrupt sensation in different ways. For example, early signs of Alzheimer’s disease and other forms of dementia often include a loss of the sense of smell, which can affect how food tastes. As the disease spreads to areas that process visual information, patients may find it hard to recognize faces or detect moving objects. Since the eyes and the brain are developed relatively close together, researchers are studying whether these early sensory changes could help doctors catch dementia sooner.
Various other brain disorders show this same disconnect between the senses and the brain, just in different ways.
On paper, these conditions look very different, but they are similar in that they all cause breakdowns in how the brain translates sensory information into experience.
Helen Keller is probably the most well-known example of what happens when that translation process is disrupted early and severely. After losing both her sight and hearing from severe illness before she turned two, she learned to communicate fluently through touch, using finger-spelling and sign language with the help of her teacher, Anne Sullivan. Her case is usually brought up as one of the earliest examples of the brain’s flexibility, and it raises a question worth pondering: if the brain can lose access to two senses and still find a way to build a complex understanding of the world, what exactly is happening inside it to make that possible? The phenomenon known to experts as neuroplasticity can help us answer this question.
Neuroplasticity is the nervous system’s ability to reorganize itself both physically and functionally in response to injuries, diseases, or new experiences. It can be compared to “teaching an old dog new tricks,” but this phrase undersells it. It’s actually more like teaching a dog to use an entirely different set of legs.
Picture a city’s traffic system after a major road closure. Cars can’t just stop moving, so the drivers reroute through side streets, and eventually the city adjusts traffic lights and widens the smaller roads to handle the new flow. With enough time, a functional, although slightly different, traffic pattern emerges. The brain works similarly after being damaged. Nearby, healthy regions gradually take over some of the damaged area’s responsibilities, rerouting information through new pathways instead of trying to rebuild the original.
One of the clearest examples of this rerouting is cross-modal plasticity, where people who lose one sense start relying more heavily on their others. In cases of early blindness, brain-imaging studies have found that the visual cortex (the part of the brain that processes sight) gets repurposed to process touch so it can help blind individuals read Braille. Your brain is remarkably adaptable and works hard to optimize its processing abilities no matter the circumstances. Essentially, losing one sense can make the remaining ones sharper, since the brain no longer has to divide its attention between as many streams of information.
However, when it comes to neuroplasticity, timing matters. Losing a sense early in life, especially in childhood, gives the brain more room to remap unused areas for other purposes, which is part of why some people who were blind from birth develop touch or hearing abilities that are sharper than average. Losing a sense later in life tends to work differently: the brain doesn’t usually “upgrade” the remaining senses so much as get better at using what it already has more efficiently, relying more on practice and attention.
Of course, none of this means that recovery is guaranteed, automatic, or the same for everyone. Neuroplasticity depends on the type of damage, its location, a person’s age, and even how much they actively practice using their remaining senses. But the fact that it happens at all makes it worth paying attention to, especially as it could be harnessed to work around and treat neurological issues.
The brain is responsible for translating situations into taste, touch, sound, sight, and smell, and it doesn’t give up easily when that translation fails. Instead, thanks to neuroplasticity, it often looks for other ways to understand the world around it.
Written by: Destiny Blanton and Agasya Mukkapati
Edited by: Katie Holmes, Hazel Milla, and Lauren Griffith