a Model of the Avian Superior Olivary Nucleus

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a Model of the Avian Superior Olivary Nucleus
Computational Sensorimotor Systems Lab
Raúl Rodríguez Esteban Master Thesis
Defense August 1, 2002
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How does the owl hunt in total darkness ?
Raúl Rodríguez Esteban Master Thesis
Defense August 1st, 2002
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Objectives of the model

• Study the role of the Superior Olivary Nucleus
  (SON) in the auditory system of the avians

• In particular, its influence in the coincidence
  detection process

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Auditory circuitry
NA
NM
NL
SON
Section of a chicken brainstem
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Sound localization in avians
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Two pathways for two coordinates
Sullivan and Konishi (1984)
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Nucleus Angularis (NA)
NA
NM
NM
NA

• Features
• Tonotopic organization
• Anatomically, 4 kinds of cells

Raúl Rodríguez Esteban Master Thesis
Defense August 1st, 2002
Soares et al. (2001)
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Nucleus Angularis (NA)
NA
NM
NM
NA
damped
tonic I
tonic III
tonic II
one-spike

• Features
• Physiologically, 5 kinds of cells

Raúl Rodríguez Esteban Master Thesis
Defense August 1st, 2002
Soares et al. (2002)
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Nucleus Magnocellularis (NM)
NA
NM
NM
NA
Raúl Rodríguez Esteban Master Thesis
Defense August 1st, 2002
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The ITD pathway
NM
NM
NL
Parks and Rubel (1975)
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Nucleus Laminaris (NL)
NM
NM
NM
NM
NL

• Features
• Tonotopic organization
• Bilateral dendrites with a length that depends
  on the frequency
• Inputs that follow the Jeffress model

Raúl Rodríguez Esteban Master Thesis
Defense August 1st, 2002
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Nucleus Laminaris (NL)
Problems
NM
NM
NM
NM
NL
Bilateral summation
Raúl Rodríguez Esteban Master Thesis
Defense August 1st, 2002
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Nucleus Laminaris (NL)
Problems
NM
NM
NM
NM
NL
Timing errors
Raúl Rodríguez Esteban Master Thesis
Defense August 1st, 2002
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The Superior Olivary Nucleus (SON)
NA
NM
NL
SON
Yang et al. (1999)
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Model proposal
Yang et al. (1999)
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Electrical behavior of neurons
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Passive behavior
Ball-and-stick model (Rall 1959, 1960)
Data recorded by Katrina Macleod
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Active behavior
Hodgkin and Huxley (1952)
Data recorded by Katrina Macleod
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Model proposal
lden120?m dden4.8?m
dsoma18?m
laxon40?m daxon4.8?m
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The SON model connected
SON
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Results improvement of the coincidence detection
in NL

• Reducing high frequency mistakes due to
  bilateral summation

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Results hypothesis about the heterogeneity of
the SON

• Three studies talk about the anatomical and
• physiological heterogeneity of the SON cells
• (Takahashi and Konishi, 1988 Carr et al., 1989
  Lachica et al., 1994)

• However, the most recent study declares
  homogeneity, although using a small sample (n23)
• (Yang et al., 1999)

• Our model suggests that there is some kind of
  physiological or anatomical adaptation for
  different types of inputs

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Future work

• Assess the relationship between the NA and the
  SON

• Simulate heterogeneity in the SON cells

• Link the NM to the SON

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Acknowledgements

• Jonathan Simon
• Katrina Macleod
• Catherine Carr
• Daphne Soares
• Sridhar Kalluri
• Michael Burger
• Nichola OHara

• Hisham Abdalla
• Matt Cheely
• Timothy Horiuchi
• Rock Shi
• Jonathan Fritz
• Mounya El Hilali
• Nikolaos Kanlis
• And the rest of the NS Lab

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Results the parameters of the model