Auditory Processing and Sound Localization

Flashcards focusing on the key concepts of auditory processing, sound localization, and related neurological structures.

They refer to the differences in timing (ITD) and intensity (IID) of sound reaching the left and right ears, which help in sound localization.

What are interaural differences (ITD/IID)?

contains neurons that are systematically arranged according to the spatial receptive fields related to sound localization.

What is the significance of the inferior colliculus in sound localization?

Neurons that fire maximally when sound signals arrive simultaneously at both left and right ears.

Define 'coincidence detectors'.

describes a neuron's responsiveness to various ITD/IID values, indicating its spatial receptive field for sound.

What does the term 'tuning curve' describe?

The simultaneous transmission of different types of auditory information through distinct pathways, facilitating efficient processing.

What is 'parallel processing' in auditory information?

provide large, reliable connections that enhance phase-locking mechanisms critical for coding timing differences.

What role do calyx synapses play in auditory processing?

emit ultrasonic pulses and interpret returning echoes to detect prey, measure distance, and assess object features.

How do bats use echo-location?

refers to the change in frequency of the echo relative to the emitted pulse, used to determine relative velocity of targets.

What is 'Doppler shift' and its significance in bats' echo-location?

located in the left hemisphere, is crucial for speech production and is responsible for articulating language.

Describe the key features of Broca's area and its function.

A condition where patients can produce fluent speech but have significant difficulties in understanding language.

What is 'Wernicke’s aphasia'?

refers to the time delay between when a sound reaches one ear versus the other, playing a key role in sound localization.

What is Interaural Time Difference (ITD)?

for humans is approximately 0.6 milliseconds, which occurs when sounds originate from the sides, such as at 90° or 270° azimuth.

What is the maximum ITD for humans?

Refers to the difference in sound intensity between ears, helping to determine the elevation of a sound source.

What is Interaural Intensity Difference (IID)?

respond selectively to sounds from specific locations, contributing to effective sound localization.

What role do space-specific neurons play in barn owls?

explains how ITD is transformed from a timing code to a spatial code using delay lines and coincidence detectors.

What is the Jeffress Model?

tonotopically by frequency, with low frequencies represented anteriorly and high frequencies posteriorly.

What does A1 refer to in auditory cortex organization?

describe how neurons have characteristic frequencies they respond to most strongly, often sharpened by inhibitory inputs.

What are tuning curves in the context of auditory processing?

processes 'what' (the meaning of sounds), while the dorsal pathway processes 'where/how' (the spatial and functional aspects of sounds).

What is the difference between the ventral and dorsal pathways in auditory processing?

emit ultrasonic pulses and analyze returning echoes to detect prey and obstacles, calculating distance and velocity through time delays and Doppler shifts.

How do bats use echolocation?

a specialized region of the cochlea in bats that is tuned to highly sensitive frequencies, allowing for improved echo detection.

What is the acoustic fovea in bats?

a sensitive time ending around 10-12 months, during which infants can learn phonetic contrasts but lose the ability to recognize non-native sounds thereafter.

What is a critical period for language acquisition in humans?

the phenomenon where adults classify speech sounds into discrete categories, resulting in reduced sensitivity to intermediate sounds.

What is categorical perception in speech processing?

enhances an infant's ability to learn speech contrasts compared to passive exposure, indicating the importance of engagement.

How does social interaction affect language learning in infants?

one processes speech meaning ('what'), while the other is involved in speech production and sensorimotor integration ('where/how').

What are the roles of the ventral and dorsal streams in human speech processing?