Skip to main content

Advertisement

A model of the primary auditory cortex response to sequences of pure tones

The neurons in the primary auditory cortex (A1) are unable to sustain responses to sequences of stimuli presented at rates exceeding approximately 20 Hz. The ventral medial geniculate body, which provides the main input to A1, is in contrast able to respond to sequences with rates upward of 200 Hz. This filtering of periodic stimuli has been attributed to thalamocortical synaptic depression [1, 2]. However, there also exists a frequency-selective filtering below 20 Hz known as differential suppression [3, 4]. Such filtering produces a receptive field refinement in A1 neurons, rendering them more selective to the frequency of presented tones as the presentation rate is increased.

This phenomenon is thought to play a fundamental role in auditory grouping (or auditory stream segregation, known as auditory streaming) phenomena, organizing sequential sounds into perceptual streams, reflecting distinct ambient sound sources [5]. Here we propose a simple model of A1 that can account for the differential suppression phenomenon. Our model has constraints compatible with recent physiological findings in A1, such as the approximate balance of inhibition and excitation [6, 7], the presence of thalamocortical synaptic depression [1], and the role of intracortical and thalamocortical synapses in the formation of A1's activity pattern [8].

References

  1. 1.

    Rose HJ, Metherate R: Auditory thalamocortical transmission is reliable and temporally precise. J Neurophysiol. 2005, 94: 2019-2030. 10.1152/jn.00860.2004.

  2. 2.

    Denham SL: Cortical synaptic depression and auditory perception. Computational models of auditory function. Edited by: Greenberg S, Slaney M. 2001, Amsterdam: NATO Science Series: Life Sciences, IOS, 312: 281-296.

  3. 3.

    Fishman YI, Reser DH, Arezzo JC, Steinschneider M: Neural correlates of auditory stream segregation in primary auditory cortex of the awake monkey. Hearing Research. 2001, 151: 167-187. 10.1016/S0378-5955(00)00224-0.

  4. 4.

    Fishman YI, Arezzo JC, Steinschneider M: Auditory stream segregation in monkey auditory cortex: effects of frequency separation, presentation rate and tone duration. J Acoust Soc Am. 2004, 116: 1656-1670. 10.1121/1.1778903.

  5. 5.

    Bregman AS: Auditory Scene Analysis: The perceptual organization of sound. 1990, MIT, Cambridge, MA

  6. 6.

    Wehr M, Zador AM: Balanced inhibition underlies tuning and sharpens spike timing in auditory cortex. Nature. 2003, 426: 442-446. 10.1038/nature02116.

  7. 7.

    Wu GK, Arbuckle R, Liu B, Tao HW, Zhang LI: Lateral sharpening of cortical frequency tuning by approximately balanced inhibition. Neuron. 2008, 58: 132-143. 10.1016/j.neuron.2008.01.035.

  8. 8.

    Liu B, Wu GK, Arbuckle R, Tao HW, Zhang LI: Defining cortical frequency tuning with recurrent excitatory circuitry. Nat Neurosci. 2007, 10: 1594-1600. 10.1038/nn2012.

Download references

Acknowledgements

E.M., J.P.L. and G.D. acknowledge the financial support of the European research project EmCAP (FP6-IST, Contract No. 013123). R.A acknowledges the financial support of the European research project DiM.

Author information

Correspondence to Johan P Larsson.

Rights and permissions

Reprints and Permissions

About this article

Keywords

  • Primary Auditory Cortex
  • Periodic Stimulus
  • Medial Geniculate Body
  • Differential Suppression
  • Stream Segregation