Synchronization Between Temporal and Parietal Cortex During Multimodal Object Processing in Man

TLDR

Synchronous neuronal activity in cat visual cortex is thought to bind different perceptual qualities of an object. The study aimed to identify neural patterns common to pictorial, spoken, and written presentations of objects. EEG was recorded from 19 scalp electrodes in 19 participants while they viewed, heard, or read objects, and coherence between electrodes was analyzed to detect modality‑independent patterns. Human subjects showed increased beta‑1 coherence between temporal and parietal electrodes when processing semantic objects, suggesting that this synchrony underlies multimodal binding.

Abstract

A series of recordings in cat visual cortex suggest that synchronous activity in neuronal cell ensembles serves to bind the different perceptual qualities belonging to one object. We provide evidence that similar mechanisms seem also to be observable in human subjects for the representation of supramodal entities. Electroencephalogram (EEG) was recorded from 19 scalp electrodes (10/20 system) in 19 human subjects and EEG amplitude and coherence were determined during presentation of objects such as house, tree, ball. Objects were presented in three different ways: in a pictorial presentation, as spoken words and as written words. In order to find correlates of modality-independent processing, we searched for patterns of activation common to all three modalities of presentation. The common pattern turned out to be an increase of coherence between temporal and parietal electrodes in the 13–18 Hz beta1 frequency range. This is evidence that population activity of temporal cortex and parietal cortex shows enhanced coherence during presentation of semantic entities. Coherent activity in this low-frequency range might play a role for binding of multimodal ensembles.