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a Model of the Avian Superior Olivary Nucleus. C omputational S ensorimotor S ystems L ab. Raúl Rodríguez Esteban Master Thesis Defense August 1, 2002. Comparing the sound cues of its ears. How does the owl hunt in total darkness ?. Raúl Rodríguez Esteban Master Thesis Defense - PowerPoint PPT Presentation
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a Model of the Avian Superior Olivary Nucleus
Raúl Rodríguez EstebanMaster Thesis Defense
August 1, 2002
Computational
Sensorimotor
Systems
Lab
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
How does the owl hunt in total darkness ?
Comparing the sound cues of its earsRaúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Objectives of the model
• In particular, its influence in the coincidence detection process
• Study the role of the Superior Olivary Nucleus (SON) in the auditory system of the avians
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Auditory circuitry
NM NA
Section of a chicken brainstem
SON
NL
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Sound localization in avians
ITD:Azimuth(longitude)
Interaural Time Difference (ITD)
ILD: Elevation (latitude)
Interaural Level Difference (ILD)
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Two pathways for two coordinates
Sullivan and Konishi (1984)
NANA
ILD pathway
NMNM
ITD pathway
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Nucleus Angularis (NA)
NANMNMNA
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002Soares et al. (2001)
Features: - Tonotopic organization- Anatomically, 4 kinds of cells
Features: - Tonotopic organization- Anatomically, 4 kinds of cells
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
NMNM
Features: - Physiologically, 5 kinds of cells
Features: - Physiologically, 5 kinds of cells
Nucleus Angularis (NA)
NANA
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
dampedtonic I tonic III
tonic II
one-spike
Soares et al. (2002)
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Nucleus Magnocellularis (NM)
NANMNMNA
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Features: - Tonotopic organization- Spherical soma with few dendrites
Features: - Tonotopic organization- Spherical soma with few dendrites
Phase locking
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
The ITD pathway
NMNM
NL
Parks and Rubel (1975)
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Features: - Tonotopic organization- Bilateral dendrites with a length that depends on the frequency- Inputs that follow the Jeffress model
Features: - Tonotopic organization- Bilateral dendrites with a length that depends on the frequency- Inputs that follow the Jeffress model
Nucleus Laminaris (NL)
NMNM
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
NMNM
NL
Coincidence Detection
‘AND gate’
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Nucleus Laminaris (NL)
NMNM
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
NMNM
NL
Problems
Bilateral summation
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Nucleus Laminaris (NL)
NMNM
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
NMNM
NL
Problems
Timing errors
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
The Superior Olivary Nucleus (SON)
NM
NL
NA
SON
Yang et al. (1999)
Excitatory
Inhibitory
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Model proposal
Banks and Sachs (1991)Yang et al. (1999)
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Electrical behavior of neurons
Passive(Rall)
Active(Hodgkin & Huxley)
• Every part of the cell can be approximated as a piece of cable (compartment)
• Branched areas can be simplified as much as we need
• The soma and the axon have gates that are opened at certain voltages
• These gates can be described mathematically
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Passive behavior
-0.12
-0.08
-0.04
0
-0.12
-0.08
-0.04
0
Data recorded by Katrina MacleodBall-and-stick model (Rall 1959, 1960)
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Active behavior
-0.08
-0.04
0
0.04
-0.08
-0.04
0
0.04
Hodgkin and Huxley (1952)
Data recorded by Katrina Macleod
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Model proposal
lden=120mdden=4.8m
laxon=40mdaxon=4.8m
dsoma=18m
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
The SON model connected
SONConnections not modeled
NA
Components modeled and unknown
NL
NM
Model by Jonathan Z. Simon
Sound
Simon et al. (2001)
Connections alreadystudied
Funabiki et al. (1998)Yang et al. (1999)
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Results: improvement of the coincidence detection in NL
• Reducing high frequency mistakes due to bilateral summation
• Increasing the discrimination ratio by reducing ‘good’ and mistaken spikes evenly
0
800
0 30 60SON spike rate (Hz)
NL spike rate (Hz)
0
4
8
12
Discrimination
In phase
Out of phase
Discrimination
0
800
0 30 60SON spike rate (Hz)
NL spike rate (Hz)
0
4
8
12
Discrimination
In phase
Out of phase
Discrimination
• These improvements occur only in certain cases
0
400
0 30 60SON spike rate (Hz)
NL spike rate (Hz)
0
2
Discrimination
In phase
Out of phase
In phase, one SON
Out of phase, one SON
Discrimination
0
400
0 30 60SON spike rate (Hz)
NL spike rate (Hz)
0
2
Discrimination
In phase
Out of phase
In phase, one SON
Out of phase, one SON
Discrimination
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
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 (n=23)(Yang et al., 1999)
• Our model suggests that there is some kind of physiological or anatomical
adaptation for different types of inputs
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Future work
• Assess the relationship between the NA and the SON
• Simulate heterogeneity in the SON cells
• Link the NM to the SON
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Acknowledgements
• Jonathan Simon• Katrina Macleod• Catherine Carr• Daphne Soares
• Sridhar Kalluri• Michael Burger• Nichola O’Hara
• Hisham Abdalla• Matt Cheely• Timothy Horiuchi• Rock Shi
• Jonathan Fritz• Mounya El Hilali• Nikolaos KanlisAnd the rest of the NS Lab
Raúl Rodríguez EstebanMaster Thesis Defense
August 1st, 2002
Results: the parameters of the model