New study shows touch works independently of vision in object identification
A study published by The Journal of Neuroscience challenges the more traditional scientific belief that using touch to recognize objects depends on visual circuitry in the human brain.
The idea is that feeling the shape of an object somehow conjures up visual information about that object but new research by Melvyn Goodale and Jody Culham from Western University’s Brain and Mind Institute and Jacqueline Snow from the University of Nevada, Reno shows instead that there are areas of the brain that allow us recognize objects with the hands alone and that they can operate, surprisingly normally, without engaging those brain areas that normally get input from the eyes.
The research team studied a patient with extensive damage to the lower half of the brain on both sides, which are areas critical for recognizing objects using vision. In the study, the patient was unable to recognize any objects using vision, whether they were displayed as pictures or real objects but the patient was able to recognize objects using only her hands.
When the patient explored different objects using only her hands in the functional magnetic resonance imaging (fMRI) scanner at Western’s Centre for Functional and Metabolic Mapping, her brain responses – in the undamaged areas associated with touch – were virtually indistinguishable from those of healthy people who performed the same task.
“These new findings call into question the common belief that the brain areas supporting object recognition are ‘multisensory,’ underlying the identification of objects using both vision and touch,” explains Snow, the lead author of the paper titled, ‘Preserved Haptic Shape Processing after Bilateral LOC Lesions.’
The study raises important questions about which brain areas are truly multisensory, as well as how our ability to use one sensory system (for example, touch) can be resilient to brain damage that affects other sensory systems (such as vision).