Sensory stimulation induces tensor fields, which specifically transform brain activity

•Vector fields of brain activity are transformed by sensory input.•Sensory input may be represented as a tensor field that transforms brain activity.•We report significant properties of tensor fields in PET and fMRI data.•Sensory input is reflected by the field that acts upon the field of brain activity. It was recently shown that brain activity can be represented as a stimulation-specific vector field. Since the vector field of brain activity is specifically transformed by sensory input, we suggested that a tensor field that transforms brain activity reflects sensory input. We calculated the tensor fields that transform brain activity between visual baseline and auditory word processing in PET data and between environmental sounds and auditory word processing in fMRI data. In the first comparison, significant clusters formed a distributed network over the brain cortex. In the second comparison, clusters were more localised in the temporo-frontal network of speech processing. Our study therefore demonstrated that tensor fields reflect the sensory input that specifically transforms brain activity.