Review: The Biological Basis of Audition

Recanzone and Sutter

Presented by Joseph Schilz

Outline

Introduction Organization of Audition Auditory Spatial Processing

Interactions with visual stimuli Ventriloquism effect Ventriloquism after-effect

Auditory Temporal ProcessingTemporal integrationForward maskingGap detection

Introduction

Audition and vision major sensory systems Audition does not have the significant history

of research that vision does Differences between audition and vision Tasks in decoding audition:

Where a sound came fromSpectral propertiesTemporal propertiesIdentifying what sound represents

Review's focus: location and temporal properties

Organization of Audition

Fig 1. Recanzone and Sutter

Organization of Audition

Fig 2.Recanzone & Sutter

Organization of Audition

Fig 2. Kalatsky et al.

Tonotopy

Organization of Audition

Fig 2:Bitterman et al.

Tonal Tuning

Organization of Audition

Fig 2.Bizley & King

Tonal/Spatial Tuning

Organization of Audition

Fig 1: DesignAhveninen et al.

“What” and “Where” Paths?

Organization of Audition

Fig 2: ResultsAhveninen et al.

“What” and “Where” Paths?

Auditory Spatial Processing

Cues Interactions with visual stimuli

Ventriloquism effect Ventriloquism after-effect

Auditory Spatial Processing

Fig 3. Recanzone and Sutter

Cues

Auditory Spatial Processing

Fig 1. Yu and Young

Cues

Auditory Spatial ProcessingVentriloquism effect

Definition

Cognitive factors “unity assumption”

Non-cognitive factors Timing Compellingness Spatial discrepancy/agreement

Auditory Spatial ProcessingVentriloquism effect

Early studies assumed that the more precise modality would “capture” the less precise modality.

Later studies showed a near optimal “mixing” of modality reports, respecting the measure-error variance of each modality.

Auditory Spatial ProcessingVentriloquism effect

Fig 2: Design and ResultsKording et al.

Auditory Spatial ProcessingVentriloquism after-effect

If subject is presented with audio/visual stimuli of a consistent spatial disparity, subjects spatial perception of acoustic space shifted after

Long lasting Does not transfer across frequencies Different from other adaption illusions: lasts

tens of minutes, does not transfer across frequencies, in the same direction of adapting stimulus.

Auditory Spatial ProcessingVentriloquism after-effect

Fig 4: Design and ResultsRecanzone

Auditory Spatial ProcessingVentriloquism after-effect

Difficulty of single unit recording in illusions.

Direct projection from auditory to visual (observed in primates)

Direct projection from visual to auditory (observed in ferrets)

Several areas in brain with multisensory response

Ghanzafar study

Auditory Temporal Processing

Definition Temporal integration Forward masking Gap detection

Auditory Temporal ProcessingDefinition

Can mean processing of temporal aspects of stimuli or ability of neurons to encode stimulus by temporal aspects of firing

We refer to former

Temporal processing could be interpreted to include spectral processing

We don't consider spectral processing here

Auditory Temporal ProcessingTemporal integration

Our environments are noisy; audition might wait a bit and let noise average itself out before passing on a percept

On the other hand, some decisions need to be made quickly; audition shouldn't hold onto information for too long

How to assess? At what levels is this occurring?

Auditory Temporal ProcessingTemporal integration

Fig 4. Dallos and Olsen

Auditory Temporal ProcessingTemporal integration

Varies with loudness, frequency, duration

Bloch's Law (Loudness x Duration = k) Leaky integrator model

Mean integration times of 30-40msec in humans

Auditory Temporal Processing

Clock et al. found similar constants of integration in chinchilla cochlear nucleus neurons and chinchilla behavior

Exponential leaky integrator fit model well

But, auditory nerve neurons had time constants much larger

Explanation

Temporal integration

Auditory Temporal ProcessingForward masking

Two sounds presented sequentially, with some gap, sometimes subject will not perceive second sound.

Depends on many factors Generally measured as a

function of first sound's duration.

Fig 4. Recanzone and Sutter

Auditory Temporal ProcessingForward masking

Likely a result of adaptation.

Auditory Temporal ProcessingGap detection

Temporal resolution vs. temporal integration One paradigm for temporal resolution: gap

detection

Humans able to detect gaps in noise as small as 1-2msec

Auditory nerve firing shows gaping pattern Likely some role of cortex in detecting gaps,

as shown by lesion, deactivation studies

Auditory Temporal ProcessingGap detection

Fig 2. Zhang et al.

Additional Works ReferencedAhveninen et al. Task-modulated “what” and “where” pathways in human auditory

cortex PNAS 2006 103 (39) 14608-14613; published ahead of print September 18, 2006, doi:10.1073/pnas.0510480103

Y. Bitterman, R. Mukamel, R. Malach, I. Fried, & I. Nelken Ultra-fine frequency

tuning revealed in single neurons of human auditory cortex Nature 451, 197-201 (10 January 2008)

Jennifer K. Bizley, Andrew J. King, Visual-auditory spatial processing in auditory cortical neurons, Brain Research, Volume 1242, Multisensory Integration, 25 November 2008, Pages 24-36, ISSN 0006-8993, DOI: 10.1016/j.brainres.2008.02.087.

P. Dallos, W. Olsen, Integration of energy at threshold with gradual rise-fall tone pips. Journal of the Acoustical Soc. of America.Vol. 36, pp. 743-751, April 1964

V Kalatsky, D Polley, M Merzenich, C Schreiner, Mstryker, Fine functional organization of auditory cortex revealed by Fourier optical imaging PNAS 2005 102 (37) 13325-13330; published ahead of print September 1, 2005, doi:10.1073/pnas.0505592102

Additional Works Referenced

Kording KP, Beierholm U, Ma WJ, Quartz S, Tenenbaum JB, et al (2007) Causal Inference in Multisensory Perception. PLoS ONE 2(9): e943.

doi:10.1371/journal.pone.0000943

Recanzone G, Rapidly induced auditory plasticity: The ventriloquism aftereffect. Proc. Natl. Acad. Sci. USA Vol. 95, pp. 869–875, February 1998

J Yu, E Young, Linear and nonlinear pathways of spectral information transmission in the cochlear nucleus PNAS 2000 97 (22) 11780-11786

W. Zhang, R.J. Salvi, S.S. Saunders, Neural correlates of gap detection in auditory nerve fibers of the chinchilla, Hearing Research, Volume 46, Issue 3, July 1990, Pages 181-200, ISSN 0378-5955, DOI: 10.1016/0378-5955(90)90001-6.