Prior information improves tactile representation in primary somatosensory cortex

Successful navigation through the world requires the integration of sensory input with prior information about the environment. Although it has been shown that stimuli which match prior expectations can be detected faster and more accurately, little is known about the integration of prior information with incoming tactile stimulation in human somatosensory areas. It is also unknown if prior information can induce somatotopic activity in the primary somatosensory cortex (S1) in the absence of tactile stimuli. Based on a vibrotactile detection paradigm we assess how prior information impacts the behavioral performance of participants and how it concurrently modulates BOLD activity and multivariate representations of tactile stimuli in somatosensory areas within a human neuroimaging study. The supra-voxel somatotopic organization of S1 allows us to dissociate representations of tactile stimuli and the modulation thereof by prior information with the resolution permitted by fMRI. We find that vibrotactile stimuli that match participants’ expectations enhance stimulus perception, and that this behavioral enhancement is associated with higher decoding accuracies of stimulus representations in the S1 and a concurrent decrease in BOLD levels in the area. Additionally, we show that prior cues are capable of inducing somatotopic BOLD activity even prior to the onset of tactile stimulation, that tactile stimuli can be decoded from this preparatory activity and that the precision of the decoding is related to the upcoming behavioral performance of participants.