4 - neural mechanisms of auditory streaming

Question 1

What is auditory scene analysis?

Answer 1

Process by which the auditory system groups and segregates components of acoustic mixtures to construct perpetual representations of sound sources or auditory images.

Question 2

What is the temporal coherence boundary?

Answer 2

The frequency separation above which alternating sequence invariable splits into separate perceptual streams.

Question 3

What is the fission boundary?

Answer 3

The frequency separation below which segregation is impossible, irrespective of presentation rate and alternating sequence is invariably perceived as a connected whole.

Question 4

What is the population separation hypothesis?

Answer 4

Sound elements segregated into separate streams whenever they activated well-separated populations of auditory neurons that are selective to frequency or any other sound attributes that have been shown to support stream segregation

Question 5

What is the object-based attention theory?

Answer 5

Dependent on the listener’s intentions and guided by representations of previously encountered auditory objects that are now stored in memory, attention would simply serve to enhance the perception of a particular stream in the auditory scene, while suppressing others.

Question 6

Why is streaming not a pre-attentive process?

Answer 6

It is unlikely that the brain would waste resources representing large numbers of potential decompositions of auditory scenes into streams prior to attentional selection

Question 7

Attention influences stream formation

Answer 7

• Modulate responses to different features, thus modifying the neural representation, and ultimately, perceptual saliency of these features.
• Attention can influence streaming by modulating the temporal coherence of neural populations