Sanchez, G. | Search bioRxiv

bioRxiv2018

Prediction-related neural activity during silent periods is sharply tuned

Prior experience shapes sensory perception by enabling the formation of expectations with regards to the occurrence of upcoming sensory events. Especially in the visual modality, an increasing number of studies show that prediction-related neural signals carry feature-specific information about the stimulus. This is less established in the auditory modality, in particular without bottom-up signals driving neural activity. We studied whether auditory predictions are sharply tuned to even carry tonotopic specific information. For this purpose, we conducted a Magnetoencephalography (MEG) experiment in which participants passively listened to sound sequences that varied in their regularity (i.e. entropy). Sound presentations were temporally predictable (3 Hz rate), but were occasionally omitted. Training classifiers on the random (high entropy) sound sequence and applying them to all conditions in a time-generalized manner, allowed us to assess whether and how carrier frequency specific information in the MEG signal is modulated according to the entropy level. We show that especially in an ordered (most predictable) sensory context neural activity during the anticipatory and omission periods contains carrier-frequency specific information. Overall our results illustrate in the human auditory system that prediction-related neural activity can be tuned in a tonotopically specific manner.

neuroscience↗

bioRxiv2017

Decoding across sensory modalities reveals common supramodal signatures of conscious perception

An increasing number of studies highlight common brain regions and processes in mediating conscious sensory experience. While most studies have been performed in the visual modality, it is implicitly assumed that similar processes are involved in other sensory modalities. However, the existence of supramodal neural processes related to conscious perception has not been convincingly shown so far. Here, we aim to directly address this issue by investigating whether neural correlates of conscious perception in one modality can predict conscious perception in a different modality. In two separate experiments, we presented participants with successive blocks of near-threshold tasks involving tactile, visual or auditory stimuli during the same magnetoencephalography (MEG) acquisition. Using decoding analysis in the post-stimulus period between sensory modalities, our first experiment uncovered supramodal spatio-temporal neural activity patterns predicting conscious perception of the feeble stimulation. Strikingly, these supramodal patterns included activity in primary sensory regions not directly relevant to the task (e.g. neural activity in visual cortex predicting conscious perception of auditory near-threshold stimulation). We carefully replicate our results in a control experiment that furthermore show that the relevant patterns are independent of the type of report (i.e. whether conscious perception was reported by pressing or withholding a button-press). Using standard paradigms for probing neural correlates of conscious perception, our findings reveal a common signature of conscious access across sensory modalities and illustrate the temporally late and widespread broadcasting of neural representations, even into task-unrelated primary sensory processing regions.

neuroscience↗