9 - McGurk In The Brain

Question 1

What is the classical view of multisensory integration?

Answer 1

Feedforward convergence of unimodal signals as primary mechanism of multisensory integration.
Multisensory expressed by firing rate changes in neural populations receiving convergent inputs from different modalities.

Question 2

Why is the classical view not sufficient to account for all aspects of multisensory processing?

Answer 2

Strong cross-modal interactions and modulation already occur in primary cortices, a result that is difficult to reconcile with the notion of hierarchical convergence.
Convergence scenario does not appear flexible enough to allow for rapid recombination of cross-modal signals into completely novel precepts.
Does not explain how low-level information can remain accessible, because the high-level representation is no compositional and does not explicitly make reference to elementary features.

Question 3

What is the new view?

Answer 3

The temporal correlation hypothesis - coherence of neural signals allows highly specific patterns of functional connectivity to be created, which enables flexible and context-dependent binding, the selection of relevant info and the efficient routing of signals through processing pathways

Question 4

Gamma band activity

Answer 4

Activated with multimodal integration, enhanced in a mismatch

Question 5

Posterior parietal activation was followed by a rise in GBA over occipital cortex. Explain

Answer 5

Top-down driven modulation of earlier visual networks by higher parietal motion processing regions

Question 6

Ventral processing steeam

Answer 6

Involved into not only in representation of purely acoustic pattern changes but also in the representation of illusory phonetic deviance even if it is caused by incongruent visual stimuli.