Washington, May 29 (Inditop): Touch alone can activate portions of the brain triggered when people look at objects, a new study has found.
According to researchers, the finding shows that these regions process information about objects using different types of sensory input.
The discovery was made after studying a man, known as HJA , who suffered a stroke that left a large bilateral lesion in part of the brain important for object recognition, specifically in the lateral occipital cortex (LO).
As a result, although the man was not blind, he could not process visual input normally; objects appeared to him as unrecognizable jumbles.
“It’s difficult to imagine. If he looked at a pen, he might see lines, but he couldn’t say which were the pen and which weren’t,” Harriet Allen of the University of Birmingham said.
However, the man could still recognize everyday objects by grasping them, the study showed.
In the study, the researchers had HJA and control participants observe pictures of objects and scrambled images while they were being scanned by functional magnetic resonance imaging. Participants were also scanned while they touched objects with one hand.
Within a subset of the regions found in control participants, HJA showed activity only for tactile objects, suggesting that these regions are specifically involved in successful multi-modal recognition.
The results showed that activation of dorsal LO by tactile input is not secondary to visual recognition. Rather, it can operate directly through the sense of touch.
“Our data indicate, for the first time, that at least some regions in the LO can be activated normally from touch, even when input from ventral LO is lesioned and visual recognition is prevented. This is consistent with estimates of effective connectivity from fMRI that have implied that there are direct connections between somatosensory cortex and LO,” the researchers said.
The study has been published online on May 28th in Current Biology, a Cell Press publication.
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