Psych202 - Introduction to cognitive neuroscience
Lecture 9 - Hearing 2: Temporal Binding and Memory
Overview:
1. Temporal Binding and Memory
2. The Auditory Event-Related Potential (ERP)
3. Adaptation and Memory in Auditory Cortex
4. The Mismatch Response
Section 1 - Temporal Binding and Memory
Visual Feature Binding
● Visual cortex has many areas, each representing specific
features (colour, motion, form or combinations)
● For example, the information about a rolling red ball (shape,
colour, motion - speed and direction) is distributed across
several areas - info is distributed
● Information put together to generate an integrated percept of
○ This process of integration is called visual feature
binding.
Binding in hearing?
● Many areas in the auditory cortex, but we don’t know what they are doing.
● The auditory cortex doesn’t represent sound features (pitch, loudness, location) in separate areas. -
mixed up in each field
● It is unclear what the feature-binding analogy in the auditory system might be
● How to piece information together - temporal binding (or temporal integration) - follow speech
and make sense of it
What do you see?
This information -shape, position in space and colours - gained from a
50millisecond snippet - visual system - integrated the information
Unless there's time involved the auditory system is not able to make sense
of the stimulus
What do you see?
Visual information makes no sense without space.
Auditory information makes no sense without time.
Visual grouping through binding
Grouping of visual information across space - dog in the photo
Visual system segregates the information in the picture
, Visual Grouping: Gestalt Principles
Lines close to each are grouped, things that look similar are grouped and a figure and its background
Auditory Grouping is vital - organisation of auditory across time
● Sounds from many sources sum at the eardrum
● Sounds need to be grouped into separate streams for us to make any sense of the auditory
environment - grouped as streams in time
○ auditory scene analysis (ASA; Bregman, 1990).
Auditory Scene Analysis (ASA)
● Components of sounds are segregated and grouped according to
proximity:
○ Frequency
○ Time
○ Sound source location
● Auditory stream segregation
● Auditory stream integration
● Two related but separate processes - separate streams that are segregated and within each stream
we have integration - heard together so belong to the same stream
How do you hear sounds?
● not heard in isolation - heard as members of streams
● Streams are groups of sounds, extended in time
● The way you hear a sound does not depend just on the sound - depends
on the historical context of the sound - what came just before
The Problem of Temporal Binding
● Spectrogram: an image of how the frequency structure of a sound
evolves.
● The brain’s task is to map this time-evolving structure to meaning.
● But the auditory system never ”sees” the spectrogram equivalent, only a
small fraction at a time - past sounds no longer exist
● This is a limitation which can only be overcome with memory
Temporal Binding Needs Memory
● Temporal binding is the combination of information over time.
● Memory is the retention of information over time.
● Thus, hearing is essentially a process of memory (and so is seeing).
● Perception is sensory stimulus and memory.
● To understand temporal binding and perception, we need to start hunting for memory in sensory
systems
Lecture 9 - Hearing 2: Temporal Binding and Memory
Overview:
1. Temporal Binding and Memory
2. The Auditory Event-Related Potential (ERP)
3. Adaptation and Memory in Auditory Cortex
4. The Mismatch Response
Section 1 - Temporal Binding and Memory
Visual Feature Binding
● Visual cortex has many areas, each representing specific
features (colour, motion, form or combinations)
● For example, the information about a rolling red ball (shape,
colour, motion - speed and direction) is distributed across
several areas - info is distributed
● Information put together to generate an integrated percept of
○ This process of integration is called visual feature
binding.
Binding in hearing?
● Many areas in the auditory cortex, but we don’t know what they are doing.
● The auditory cortex doesn’t represent sound features (pitch, loudness, location) in separate areas. -
mixed up in each field
● It is unclear what the feature-binding analogy in the auditory system might be
● How to piece information together - temporal binding (or temporal integration) - follow speech
and make sense of it
What do you see?
This information -shape, position in space and colours - gained from a
50millisecond snippet - visual system - integrated the information
Unless there's time involved the auditory system is not able to make sense
of the stimulus
What do you see?
Visual information makes no sense without space.
Auditory information makes no sense without time.
Visual grouping through binding
Grouping of visual information across space - dog in the photo
Visual system segregates the information in the picture
, Visual Grouping: Gestalt Principles
Lines close to each are grouped, things that look similar are grouped and a figure and its background
Auditory Grouping is vital - organisation of auditory across time
● Sounds from many sources sum at the eardrum
● Sounds need to be grouped into separate streams for us to make any sense of the auditory
environment - grouped as streams in time
○ auditory scene analysis (ASA; Bregman, 1990).
Auditory Scene Analysis (ASA)
● Components of sounds are segregated and grouped according to
proximity:
○ Frequency
○ Time
○ Sound source location
● Auditory stream segregation
● Auditory stream integration
● Two related but separate processes - separate streams that are segregated and within each stream
we have integration - heard together so belong to the same stream
How do you hear sounds?
● not heard in isolation - heard as members of streams
● Streams are groups of sounds, extended in time
● The way you hear a sound does not depend just on the sound - depends
on the historical context of the sound - what came just before
The Problem of Temporal Binding
● Spectrogram: an image of how the frequency structure of a sound
evolves.
● The brain’s task is to map this time-evolving structure to meaning.
● But the auditory system never ”sees” the spectrogram equivalent, only a
small fraction at a time - past sounds no longer exist
● This is a limitation which can only be overcome with memory
Temporal Binding Needs Memory
● Temporal binding is the combination of information over time.
● Memory is the retention of information over time.
● Thus, hearing is essentially a process of memory (and so is seeing).
● Perception is sensory stimulus and memory.
● To understand temporal binding and perception, we need to start hunting for memory in sensory
systems
